ISSN:0003-2654    

DOI:10.1039/AN99621FX021

出版商:RSC    

年代:1996

数据来源: RSC

摘要:

ANALAO 121 (6) 5344R, 697-888, 73N-92N (1 996) JUNE 1996I1111REVIEWS53 RICONFERENCE PAPERSFOREWORD 697PLENARY 69970571 171 573374374975576 1767773779785789793'"An al y stThe analytical journal of The Royal Society of ChemistryCONTENTSSilicones and Their Determination in Biological Matrices-A Review-Biljana A. CaviC-Vlasak, MichaelThompson, Dennis C. SmithSensors and Signals Ill-Malcolrcl R. SmythConducting Polymers and the Bioanalytical Sciences: New Tools for Biomolecular Communications-AReview-S. 6. Adeloju, G. G. WallaceSurface Modification of Thin Film Gold Electrodes for Improved In Vivo Performance-Mark Hyland, JamesA. McLaughlin, Dao-Min Zhou, Eric T. McAdamsMoisture-activated, Electrically Conducting Bioadhesive Interfaces for Biomedical Sensor Applications-A.David WoolfsonReaction/Diffusion With Michaelis-Menten Kinetics in Electroactive Polymer Film. Part 1.The Steady-stateAmperometric Response-Michael E. G. Lyons, James C. Greer, Catherine A. Fitzgerald, ThomasBannon, Philip N. BarlettKinetic Separation of Amperometric Sensor Responses -Robert J. ForsterInterpreting Signals From an Array of Nonspecific Piezoelectric Chemical Sensors-Patricia McAlernon,Jonathan M. Slater, Philip Lowthian, Mark AppletonChemometric Techniques in Multivariate Statistical Modelling of Process Plant-M. Hartnett, G. Lightbody,G. W. IrwinDetermination of 2-Furaldehyde in Transformer Oil Using Flow Injection With Pulsed AmperometricDetection-John W. Dilleen, Chris M. Lawrence, Jonathan M.SlaterCharacterization of Carbon Paste Electrodes In Vitro for Simultaneous Amperometric Measurement ofChanges in Oxygen and Ascorbic Acid Concentrations In Vivo-John P. Lowry, Martyn G. Boutelle, RobertD. O'Neill, Marianne FillenzBispecific Multivalent Antibody Studied by Real-time Interaction Analysis for the Development of anAntigen-inhibition Enzyme-linked lmmunosorbent Assay-Heiko W. Reinartz, John G. Quinn, Kurt Zanker,Richard O'KennedyStrategies for Decreasing Ascorbate Interference at Glucose Oxidase-modifiedPoly(epheny1enediamine)-coated Electrodes-Karl McAteer, Robert D. O'NeillDifferential-pulse Voltammetric Determination of Clenbuterol in Bovine Urine Using a Nafion-modifiedCarbon Paste Electrode-Siobhan Moane, Malcolm R.Smyth, Michael O'KeefeDissolved Oxygen Sensor Based on Fluorescence Quenching of Oxygen-Sensitive Ruthenium ComplexesImmobilized in Sol-Gel-derived Porous Silica Coatings-Aisling K. McEvoy, Colette M. McDonagh, BrianD. MacCraithSensing of Chlorinated Hydrocarbons and Pesticides in Water Using Polymer Coated Mid-infrared OpticalFibres-James E. Walsh, Brian D. MacCraith, Mary Meaney, Johannes G. Vos, Fiona Regan, AntonioLancia, Slava ArtjushenkoPreparation of Polypyrrole Composites and the Effect of Volatile Amines on Their ElectricalProperties-Benjamin P. J. de Lacy Costello, Phillip Evans, Norman M. RatcliffeSAMPLE HANDLING799803807Formation of Thiocyanate During Removal of Sulfide as Lead Sulfide Prior to CyanideDetermination-John C. Wilmot, Ljiljana Solujic, Emil B.Milosavljevic, James L. Hendrix, W. Scott RaderExtraction of Salinomycin From Finished Layers Ration by Microwave Solvent Extraction Followed byLiquid Chromatography-M. Humayoun Akhtar, Louise G. CroteauDithizone-anchored Poly(viny1pyridine) as a Chelating Resin for the Preconcentration and Separation ofGold(iii) From Platinum(iv), Copper(ii) and Mercury(ii)-Rupal Shah, Surekha DeviContinued on inside back cover-THE ROYALCHEMISTRYl~fofTflationServices Cambridge, EnglandTypeset and printed by Black Bear Press Limited,0003-2654C199616:l-81 3 Simple Flow Injection Spectrofluorimetric Method for Speciation of Thallium-Tomas Perez-Ruiz, CarmenMartinez-Lozano, Virginia Tomas, Rocio CasajusATOMIC SPECTROSCOPY/SPECTROMETRY81 7825Anion Mobilization From Aqueous Media by Ion Associate Extraction Into Supercritical Carbon DioxideWith On-line Detection by Flame Atomic Absorption Spectrometry-Jin Wang, William D.MarshallInductively Coupled Plasma Atomic Emission Spectrometric Determination of Gallium, Phosphorus andOther 0x0-anion Forming Elements in Geological Materials-K. Satyanarayana, K. Subramaniam, A. V.Raghunath, G. V. RamanaiahMOLECULARSPECTROSCOPY/SPECTROMETRY831835Enhancement by Cycloalkanes of the Chemiluminescent Oxidation of Sulfite-David A. Paulls, AlanTownshendIn Situ Surface Enhanced Resonance Raman Scattering Analysis of a Reactive Dye Covalently Bound toCotton-P. C. White, C. H. Munro, W. E. SmithCapillary Electrophoretic Separation of Metal Ions in the Presence of Polyethylene Glycols-CostasStathakis, Richard M.CassidyHigh-performance Liquid Chromatography Coupled With Array Inductively Coupled Plasma OpticalEmission Spectrometry for the Separation and Simultaneous Detection of Metal and Non-metal Species inSoybean Flour-Jorg Schoppenthau, Joachim Nolte, Lothar DunemannDiscriminative Analysis of Zooplankton Individuals by Pyrolysis-Gas Chromatography Combined WithOn-line Methylation-Yasuyuki Ishida, Shinichi Isomura, Shin Tsuge, Hajime Ohtani, Tatsuki Sekino,Masami Nakanishi, Takashi KimotoDevelopment of a Fluorescence Polarization lmmunoassay for the RGirtine Detection ofN-Desmethylzopiclone in Urine Samples-Erik Mannaert, Paul DaenensDevelopment and Evaluation of a Dipstick lmmunoassay Format for the Determination of AtrazineResidues On-site-Christine Wittmann, Ursula Bilitewski, Thomas Giersch, Ulrich Kettling, Rolf D.SchmidStabilized Needle Electrode System for In Vivo Glucose Monitoring Based on Open FlowMicroperfusion-Geraldine P. Rigby, Paul W. Crump, Pankaj VadgamaDevelopment of Ultraviolet-polymerizable Enzyme Pastes: Bioprocess Applications of Screen-printedL-Lactate Sensors-Ingrid Rohm, Meike Genrich, Wendy Collier, Ursula BilitewskiImpedance Sensor for Dissolved Nitrogen Oxide Using a Series Piezoelectric Crystal Device-Yuanjin Xu,Changyin Lu, Yan Hu, Lihua Nie, Shouzhuo YaoSEPARATION SCIENCE839845853BIOANALYTICAL857863SENSORS871877883887 CUMULATIVE AUTHOR INDEXN E w S AN D VIEWS 73N78N Conference DiaryBook and Software Reviews83N Courses84N89N Sensing A Better Future91 N Papers in Future Issues92N Technical Abbreviations and AcronymsInterviews with Professor G. Guilbault and Mr R. LundinCover picture: A composite of the significant elements discussed during the 'Sensors and Signals'symposium held in Dublin, showing the sensors (membrane and gas), signal processing andinterpretation of results

ISSN:0003-2654    

DOI:10.1039/AN99621BX023

出版商:RSC    

年代:1996

数据来源: RSC

摘要:

Analyst, June 1996, Vol. 121 (53R-63R) 53R Silicones and Their Determination in Biological Matrices A Review Biljana A. CaviC-Vlasaka*, Michael Thompsona* and Dennis C. Smithb a Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario M5S 1 A1 , Canada Ontario M5S IA4. Canada Centre for Biomaterials, University of Toronto, I70 College Street, Toronto, Summary of Contents Introduction Properties and Applications of Silicones Biochemistry of Elemental Silicon and Silicones General Approach to the Determination of Trace Amounts of Survey of Methods Used for Non-specific and Silicones in Biological Materials Silicon-specific Microstructural Determination of Silicones in Tissues (Microanalysis) Silicon-specific (Elemental) Techniques for the Detection of Silicones in Biological Materials Survey of Silicone-specific Techniques IR, FTIR and Raman Spectrometry NMR Spectrometry GC and GC-MS Methods Silicone Biotransfonnation Products in Biological Samples Problem of Speciation of Silicon and Identification of Conclusions References Keywords: Silicones; trace analysis; biological samples; biotransformation; review Introduction In recent years, a revolution has taken place in the biological sciences in terms of the transition from relatively macroscopic research to enormous advances in molecular biology.These advances have been driven, in part, by the development of techniques such as multi-dimensional NMR, high-resolution DNA sequencing, routine high throughput of structures by charge-coupled device X-ray crystallography, polymerase chain reaction technology, recombinant DNA methods and an array of other methods.Such advances have led to an expansion in the generation of biologically derived products. These entities have presented tremendously challenging tasks for the analytical chemist in terms of the identification and the determination of species present in complex biological mat- rices. The purity of protein-based drugs (and the necessary regulatory baggage that is associated with these moieties) and analysis of fermentation broths are just two examples in this area. Another aspect of the analytical chemistry of biological matrices which presents almost overwhelmingly difficult prob- lems for the analytical scientist is the examination of specific tissues in relation to the deliberate placement of devices in the human body.In this connection, the use of modern biomaterials spans a large range of structures from artificial teeth, veins and * To whom correspondence should be addressed. knees to heart pacemakers and the like. The number of materials being employed for the fabrication of these devices is also large, from metals such as titanium to polymers such as polyurethane. One species that has been used extensively in vivo in recent times is silicone. For example, this material is utilized in the construction of catheters and mammary and facial implants. Among the most widely used devices have been breast prostheses, which consist of a silicone elastomer envelope containing a silicone gel. The latter is typified as 25% of a high relative molecular mass (300 000400 000 Da) cross-linked polysiloxane matrix containing 75 % of low relative molecular mass (6000-19 000 Da) polydimethylsiloxane fluid.More than 1000000 of these breast implants have been placed in women in the USA and more than 100000 in Canadian women. Experimental and clinical evidence has accumulated to show that silicone elastomers in vivo shed particulate matter that may provoke an inflammatory response. Silicone gel-filled implants may release silicone fluid also by diffusion through the silicone elastomer envelope or by frank rupture of the envelope. Fibrosis and (in the long term) calcification in response to these sequelae have been observed. A variety of other clinical complications have also been attributed to silicone implants, including immune reactions, specifically various types of connective tissue disease. Considerable controversy exists as to the nature and magnitude of these effects.A major problem in the evaluation of clinical effects of inorganic and organic forms of silicon is the lack of information on ‘normal’ ranges of silicon systemically and locally in the body. Further, few mechanistic studies have been carried out on the migration, transfer, biodegradation and excretion of sili- cones. There are many gaps in our knowledge of silicon biochemistry and few reliable studies of, for example, silicon concentrations in blood and serum. Because of the ubiquity of silicon and silicones, trace element analysis for silicon requires a particularly careful approach with stringent precautions. The analysis of tissues for silicones is also problematic because of their potential fugitivity and volatility.The magnitude and importance of the clinical questions related to silicon and silicones demand a definitive approach to the available analytical procedures. In this review, we present a perspective on analysis in biological matrices. Properties and Applications of Silicones The term silicone, first used by Kipping in 1901 ,2 is a generic name for polymers based on organosilicon chemistry and the polysiloxanes, containing the Si-0-Si backbone in general. The most important siloxane polymers are polydimethylsiloxanes (PDMS), [-Si(CH&O-],. PDMS exist as linear polymers with degrees of polymerization varying from 0 (hexamethyldisilox- ane) to more than 1000, and as cyclic chains or rings.A variety54R Analyst, June 1996, Vol. 121 of other silicone polymers are produced by replacing the methyl groups with different organic substituents. Trifunctional molec- ular siloxane species bear potential cross-link sites producing branching within the molecule. Depending on the degree of polymerization and cross-linking pattern, silicone materials could be of fluid, gel, gum (elastomer or rubber) or resin type. PDMS are generally considered to be chemically and physiologically inert materials. Although they are recognized as compounds which are stable to thermal and oxidative degrada- tion, their thermal rearrangements are possible in the presence of both acids and bases. A thermodynamic equilibrium mixture of PDMS contains approximately 88% of linear and 12% of cyclic siloxane components at temperatures up to 200 "C.3 The PDMS backbone is the structural component for one of the most flexible chain molecules, both in the dynamic (ability of molecule to change spatial arrangements by rotations around its skeletal bond) and in the equilibrium sense (ability of a chain to be compact when in the form of a random coil).The most important reasons for this flexibility lie in the remarkable length of the Si-0 bond (compared with the C-C bond) and in the particular openness of the Si-0-Si bond angle (in comparison with the usual tetrahedral bond). High rotational and oscillatory freedom of the methyl side groups and low intermolecular interactions are considered to be the origin of some extraordi- nary properties of PDMS, such as low values for characteristic pressure, bulk viscosity (q), entropies of dilution and excess volumes on mixing PDMS with solvents. In contrast, PDMS possess remarkably high permeability to gases.4 Silicones possess excellent ability to modify surfaces and interfaces.The low liquid surface tension of PDMS (16-21 mN m-1 at room temperature depending on molecular weights) accounts for their tendency to accumulate at air-substrate surfaces. This feature is associated with the flexibility of the siloxane bond, freedom of methyl groups and the high energy and partial ionic nature (41% ionic bond contribution) of the siloxane bond. The partially ionic siloxane backbone is susceptible to hydrolysis by water at extremes of pH.3,5,6 General structures for, and some of the properties of, some linear and cyclic siloxanes are shown in Fig.1 and Table 1. Most of the physical properties of PDMS increase on insertion CH, r 7~~ 1 CH, (4 I I CH3- Si - 0 - Si - 0 - Si - CH, 1 1 1 1 1 - 0 - S i - 0 - r r"' 1 L CH3 Jn Fig. 1 siloxanes. General structure of (a) linear (MDnM) and (b) cyclic (D,) of dimethylsiloxane units. The viscosity of highly polymerized PDMS could be as high as several million centistokes. Whereas hexamethyldisiloxane is considered to be a very volatile compound (Table l), highly polymerized PDMS are distin- guished by their involatility. The best solvents for all PDMS fluids are aromatic and aliphatic hydrocarbons and chlorinated solvents.Highly polymerized PDMS are incompatible with mineral oils and alcohols. Silicones are excellent dielectrics and provide a very high electric impedance. Silicones are recog- nized by excellent mechanical durability but at the same time they are materials of weak tensile strength.9 Although silicon is an important trace element for plants and animals, playing an indispensable role in the biosphere, organosilicon compounds have not been positively identified as naturally occurring. There is no conclusive evidence that organic compounds in which silicon is bound to oxygen or nitrogen occur in nature. Also, naturally occurring organosili- con compounds containing silicon+arbon linkages have not been unequivocally detected in natural systems.3JOJ 1 However, man-made organosilicon compounds, mainly siloxanes, are widely dispersed throughout the environment.Silicones are the hydrolysis and polymerization products of organochlorosilanes, which are prepared from silica. Silica is heated and reduced to silicon, which is treated with methyl chloride in order to produce chlorosilanes. Dimethyldichlorosilane as a major monomer forms dimethylsilanediol when treated with water. This last, unstable compound condenses into siloxanes.2 Since they were first commercially introduced in the USA in 1943,2 the production and application of silicones has grown rapidly so that it was estimated in 1990 that some 700 000 tons of silicones are produced annually.12 The properties of silicones described briefly above yield the basis for their very wide application.Silicone materials are applied in a variety of fields. Some of their most common applications are their uses as adhesives, protective coatings, caulking materials, encapsulation media, high-performance elastomers, membranes, water repellents, surfactants, anti- foaming agents, lubricants, polishes, printing inks, textile finishes, hydraulic, heat-transfer and dielectric fluids, electrical insulators, organic syntheses aids, liquid phases for gas chromatography, silylation agents, release control agents for agricultural chemicals, et~..3,479,~~ Being non-toxic and mainly non-irritating, silicones are also applied in the cosmetic industry during the fabrication of shampoos, hair conditioners, per- spirant formulations, sunscreen formulations and different make-up products (the high refractive index of silicones contributes to the gloss of products).14 Some biologically active siloxanes (e.g., 2,6-cis-diphenyl- hexamethylcylcotetrasiloxane) find practical application as therapeutic agents in medicine and as reference drugs in experimental pharmacology.Silicones are also applied as drug release and delivery compounds.lO Silicones that are distinguished by high-purity grade are called medical-grade silicones and, in this form, can be applied clinically. As biocompatible materials (non-rejection by tissue is claimed)l5 with minimal reactivity with biological systems, Table 1 Properties of some linear and cyclic siloxanes Refractive index, nD25 Compound (ref. 7) Hexamethyldisiloxane (MM) 1.3748 Octamethyltrisiloxane (MDM) 1.3822 Decamethyltetrasiloxane (MD2M) 1.3872 Octamethylcyclotetrasiloxane (D4) 1.3940 Decamethylcyclopentasiloxane (D5) 1.3957 Density (25 "C)/g cm-3 (ref. 7) 0.7619 0.8200 0.8536 0.950 0.9528 Viscosity (25 OC)/cS (ref.7) 0.65 1.04 1.53 2.30 3.87 Vapour pressure BpPC (25 "C)/mmHg (ref. 7) (ref. 8) 100.5 41.73 152.5 - 196.4 - 175.4 0.85 211.0 -Analyst, June 1996, Vol. 121 55R they have been in some way used in almost all surgical fields. Inertness, stability and pliability of silicones make them important devices in cardiovascular surgery as parts of tubing and membrane systems incorporated in cardiovascular devices such as by-passes and pacemakers. The same properties have been the reason for their application as orthopaedic implants (silicone-rubber joints), in facial reconstruction and as mam- mary and penile implants.They are also parts of drainage systems and catheters. Silicone artificial skin and contact lenses take advantage of the high permeability of these materi- The silicone breast implant is the subject of tremendous current controversy. There are estimations that almost 1 million women have used them either for cosmetic or reconstruction purposes over three decades.17.18 The question of the safety of breast implants and their possible adverse effects on health is the subject of numerous discussions. The basic structure of silicone breast implants is a silicone rubber (elastomer) envelope filled with silicone gel or saline. The envelopes are sometimes coated with polyester polyurethane.The reinforce- ment of silicone rubber is performed by the introduction of fine particles of silica. Silicone gel is a mixture of relatively low and high molecular mass PDMS components.19.20 als.9,15.16 Biochemistry of Elemental Silicon and Silicones Silicon is one of the most prevalent elements on our planet. Most living organisms contain at least trace levels of silicon and some primitive organisms even have a silicate skeletal structure. In biological systems, as well as in the whole environment, silicon occurs in its inorganic form mainly as silica, silicic acid and silicates, but it can be specifically associated with naturally occurring organic compounds. So far there is no conclusive evidence for the existence of isolated natural organosilicon compounds.1 However, there is an estimation that approx- imately 1010 tonnes of silica are involved in the biogeochemical cycle." Silicon is one of the major components of natural waters (Table 2) occurring in this medium in the form of monosilicic acid.21 The large-scale production and application of silicone compounds seems to have had little ecological impact, even with regard to their stability and environmental persistence. Model studies show that silicones are not biodegradable but can be subject to chemical degradation in the environment. Under the catalytic activity of soil components and its moisture content, silicones can undergo rearrangements and hydrolysis to lower polymerized linear and cyclic products. Higher volatile components can undergo photolytic oxidation in the atmosphere to give water-soluble silanols.Finally, long-term exposure to soil components and sunlight will lead to their ultimate degradation products: carbon dioxide, water and silicic acid.22 Although silicones have liposoluble structures, they do not bioconcentrate in the aquatic environment.' The molecules are not small enough to pass through cell membranes. In contrast, smaller fractions are assumed to be too volatile to endure in aquatic media. There is a suggestion that in vivo, ingested siloxanes undergo simple chemical reaction rather than enzymatically catalysed hydrolysis to silanols (Fig. 2)." In this form, originally liposoluble silicone compounds could be excreted via the kidneys. Although silicon is recognized as an essential trace element participating in the normal metabolism of higher animals, its biochemical mode of action on the molecular level is not very clear.It has been suggested that silicon serves as a cross-linking agent by forming linkages between individual glycoso- aminoglycan chains and joining them to core proteins to form proteoglycans. Glycosoaminoglycans are evolutionary primi- tive, negatively charged unbranched polysaccharide polymers. Proteoglycans themselves are found in all connective tissues and epithelial cells. In this way, silicon deficiency especially affects bone and cartilage formation.23 Silicon is also apparently a major component of osteogenic cells and is present in especially high concentrations in the metabolically active state of the cell, reaching relatively high levels in the mitochondria of these cells.It has been shown that silicon participates in the biochemistry of the subcellular enzyme-containing structures affecting enzymic activity. Interrelationships between silicon and other elements such as molybdenum and aluminium have been established. Silicon-molybdenum contents in plasma and tissues are inversely affected by their mutual presence. A relationship between silicon and aluminium levels in tissues is considered to have relevance to Alzheimer's disease through the formation of aluminosilicate ~lates.~4 It has been postulated that silicon provides strength and elasticity to the connective tissue and biological structures on the basis of the association of decreased elasticity (of the arterial walls in atherosclerosis) to the decreased silicon content (of the arterial walls) through ageing.25.26 There is an estimation that man assimilates 9-14 mg of silicon daily.27 Important amounts of silicon are incorporated in foods such as vegetables, grain, rice and dairy products and in beverages such as beer.28~29 A high-fibre diet usually results in an increase in the intake of ingested silicon.A large fraction of ingested silicon, absorbed across the intestinal wall, is rapidly excreted in the urine. The absorption mechanism of silicon from food, beverages and drinking water and the proportion of absorbed silicon which is retained in the body are not kn0wn.2~>30 Silicone compounds themselves are present in food through antifoaming agents added to canned fruit and vegetable products.Substantial amounts of silicones can be incorporated in alimentary products by their contact with silicone-containing compounds during storage and packaging. It is probable that silicon compounds ingested and absorbed from different sources are submitted to biotransformation, contributing to the total level of organosilicon species in the human body. Literature reports concerning the metabolism of organosili- cons are disperse and mainly refer to pharmaceutical products. R R R R I I I I I I I I OH7R - Si - 0-Si - R __t R -Si -OH + R-Si -0- R R R R Table 2 Concentrations of silicon in some natural waters2' Water Concentration/ mg 1-1 Soil solution 1-40 Streams 0.8-15 Groundwater 3.5-28 Sea- water: Bulk 1-7 Surface 0.0001-0.2 R R R R I I I H I I H++R- Si - 0- Si - R - R -Si - 0 - Si - R I 1 + 1 R R R R R R R R H20+R- Si - 0 - Si - R - R - Si -OH + RSi - OH +H+ R R R R I H I I I I I I + I Fig.2 Possible metabolic breakdown of silicones.'56R Analyst, June 1996, Vol. 121 Many synthesized pharmacological organosilicon compounds are so lipophilic that the excretion through kidneys is negligible. Their biotransformation into more hydrophilic derivatives is mainly supposed to take place in the liver.10 Silicon is introduced in the pharmaceutical industry by another class of interesting products such as pro-drugs. By the silylation of biologically active molecules of drugs having amino or hydroxyl groups, more lipophilic structures are formed which cross lipophilic membranes readily. In vivo, silylated drugs undergo non-enzymic hydrolysis under mild physiological conditions in the body fluids (owing to their chemical lability) or possible enzymically catalysed hydrolysis, releasing the parent drug.10.11 The metabolism and biotransformation of silicones have not been studied in detail.There are no experimental data on the studies of pathways for possible enzymic degradation of silicones under physiological conditions. The nature of inter- actions of silicone compounds with large biological molecules, such as plasma proteins, is another area where there has been limited theoretical and experimental work published. It has been reported that plasma proteins sequentially adsorb to hydrophobic silicone materials and undergo progressive conformational rearrangements leading to their denaturation.Among proteins which most rapidly adsorb are albumin, fibrinogen and immunoglobulin G.31.32 There is also an important theoretical issue concerning the possible immu- nogenicity of silicones. Silicone compounds possess the potential for creating antigen-antibody binding sites. Silicone surfaces provide a major electronegative static charge and electrostatic forces are known to be important for immuno- chemical binding. Moreover, hydrogen bonding (through side groups of silicones) and hydrophobic interactions will also be important in antigen-antibody binding. It has been proposed that the antigenicity of silicone may be in its adjuvant function by inducing conformational changes in native proteins.33-37 Implanted medical devices such as silicone breast implants represent a major potential source of silicone compounds in the human body.Silicone fluid can diffuse ('bleed') out of the envelope and PDMS possibly could migrate into the body. Because of their high relative molecular mass, the diffusion of higher viscosity silicones is not expected. Lower relative molecular mass siloxanes may be small enough for diffusion, each molecular structure having a different potential for biological mobility and activity. It seems probable that some of those compounds could be solubilized in some lipid-containing fractions of body fluids and tissues, according to the conclu- sions of some studies.3*,39 Possible transformations of PDMS, such as hydrolysis, could lead to the formation of monomeric hydroxylated molecules, following pathways similar to those described in Fig.2. General Approach to the Determination of Trace Amounts of Silicones in Biological Materials Although there is an extensive literature dealing with the determination of silicones and the analytical chemistry of silicones in general, there is only a limited amount of work published regarding the presence of silicones or/and their degradation products in biological samples or related matrices. Two possible reasons lie behind this observation. As can be gleaned from the facts cited above, the biochemistry of silicones, biotransformation pathways and metabolism of organosilicon compounds and silicon in general are still very unclear. Accordingly, the particular analytical targets are ill- defined.Second, the determination of silicones, especially in trace amounts, is subject to numerous operating difficulties, mainly connected with their ubiquitous presence and the instability of some species. The determination of silicones in biological materials can be classified as trace analysis, assum- ing that the species measured are fairly uniformly distributed in a matrix, or as microanalysis when the silicone particles are dispersed in a heterogeneous matrix.40 Accidental contamination by omnipresent silicone com- pounds can occur during all steps of the analytical procedure. Stopcock grease, lubricants in syringes, pump fluids, fluids for glassware treatment, silicone rubber for different tubing, sealing, septa or O-ring elements and self-adhering labels are only some of the potential sources of silicones in laboratories.In gas chromatographic analysis, for example, leakage of silicone chromatographic columns at temperatures above 200 "C takes place. Further, it is essential to avoid contamination during sampling procedures. When collecting biological samples, some commonly used items such as talc-powdered gloves or silicone-lubricated syringes should be absolutely avoided. Silicon-specific analyses such as those performed by all atomic spectrometric techniques are especially subject to contamination originating from silicon-containing dust. This makes de-dusting and vacuum cleaning of laboratory space a mandatory component of the trace elemental analysis proce- dure. It is desirable that at least sample preparation should be done under Class 10 or 100 (clean room) laboratory conditions or in cabinets under laminar air How frustrating elemental contamination of all equipment components in the case of silicon can be is very well illustrated for the case in which the concentrations of 18 different elements in plasma were measured in parallel after storage of plasma samples in washed and unwashed plasticware.It was found that only in the case of silicon detection was the washing of plasticware for trace elemental analysis (inductively coupled plasma atomic emission spectrometry) e~sential.~* Some cleaning procedures for the preparation of ' silicone-decontaminated' laboratory plasticware have been described.29 Although generally perfor- med with sound analytical chemical procedures, it is essential in the case of silicone determinations to perform in parallel as many control analyses as possible and also recovery studies simulating the same conditions as for actual samples.The purity of available reagents, solvents and standards is another major concern in silicone determinations. It is necessary to check if the purity grade of all applied chemicals is satisfactory before any actual measurements are performed. Some silicone compounds are unstable, so working solutions should be prepared on a daily basis and stored properly, sealed and kept in a dry place. Another problem is the availability of standard reference materials for biological matrices. In most instances, specific silicone compounds are determined using laboratory standards.Finally, the detection limit is defined as twice the standard deviation of the analytical blank.29.40 Although many of the sources of both contamination and losses of analysed species are observed generally in trace analysis, there are a number of problems specifically associated with analyses for silicones. Silicones are considered to be very stable materials, but their trace amounts are subject to losses of different origin. Molecules such as silanols are especially sensitive and unstable, undergoing condensation even under mild conditions, so that their determination becomes a partic- ularly difficult analytical task. The low heat of vaporization and subsequent rapid evaporation of low molecular mass siloxanes contribute to their losses or sometimes even to cross-contamina- tion between analysed samples.Silicones have a strong affinity for adsorption on glass and all siliceous materials. They also absorb atmospheric m~isture.~O The possibility that a detected species can, in reality, be a rearrangement or reaction product resulting from thermal or catalytic rearrangements of silicones rather than original compounds should always be assumed. Rearrangements of silicones to lower molecular mass species take place in the presence of strong acids or bases.40 If a sample contains traceAnalyst, June 1996, Vol. 121 57R amounts of components having (CH&Si moieties, a hydrolytic cleavage of the Si-CH3 bond can occur, especially in the presence of certain metals (e.g., Fe, A1 and Ca).43 In biological materials, silicones or/and their biotransforma- tion products are usually present in very small (trace) amounts and together with various amounts of other components of physiological origin.Extraction or matrix removal and pre- concentration steps are, therefore, a mandatory component of analytical procedures, which at the same time should preserve the identity and integrity of the original compound. Conse- quently, analytical methods applied to the detection and quantification of species, and ultimately the identification of their specific molecular structures, should be based on a reliable separation procedure and a highly selective and sensitive detection device (analytical instrumentation). This review will discuss some of the basic analytical techniques that have been employed in the area.Survey of Methods Used for Non-specific and Silicon-specific Microstructural Determination of Silicones in Tissues (Microanalysis) Silicone prosthetic devices have widespread application. Al- though often characterized by their supposed biological inert- ness, side reactions and pathological conditions provoked by the presence of silicone take place. This makes experimental techniques for the demonstration of their possible dispersion in the tissue surrounding a particular prosthesis indispensable. The most frequent problem related to the application of gel- filled silicone implants is the potential rupture of the silicone shell elastomer. Several techniques are applied in medical diagnostics for the evaluation and detection of implant ruptures.Deterioration of breast implant capsules is most commonly revealed by film-screen X-ray techniques such as mammo- graphy and ~eromamrnography.~~6 Computed tomography has been reported as a more specific and sensitive technique for the detection of implant ruptures, but patients are also exposed to ionizing radiation.47 Of all techniques used for the evaluation of silicone prosthesis in vivo, magnetic resonance (MR) imaging constitutes the most recent technique and, together with sonography, represents the only non-invasive imaging m0daiity.~5.~8.49 It was reported that MR imaging involving a silicone-selective pulse sequence is highly effective for detect- ing the leakage of silicones from implants.48 Microscopic methods are most frequently used in medical research laboratories for the positive identification of silicone in tissue surrounding the implant and in tissue more distant from the device.Light microscopic examination of tissues is usually applied for the recognition of silicone fragments of optically detectable size range in histological and cytological specimens. There are difficulties in visualizing silicone in tissues using conventional light microscopy because generally silicone is refractile, non-polarizable and non-stainable. Alternative light microscopic techniques such as phase-contrast and dark-field microscopy have been proposed to improve silicone detec- tion.50 More detailed studies usually use light microscopy only as a screening device for the determination of silicone-containing tissue areas. Conclusive identification of silicon components is subsequently performed by electron microscopy coupled with X-ray analysis.In electron-probe X-ray spectrometry (EPXRS), analytical microcharacterization of a tissue sample is obtained by focusing an electron beam of moderate energy on to the microscopic area of the sample at the location where elemental composition is to be determined. The atoms in a very small volume of the sample are excited by the incident electrons and, on returning to the ground state, emit X-rays characteristic of the excited elements. In SEM, the sample image is obtained by either backscattered or transmitted electrons. The X-rays produced in SEM are usually detected and measured by applying energy-dispersive X-ray analysis (EDXA) for quanti- tative elemental analysis.Electron probe microanalysis has been applied (to cite only some of the numerous studies) to identify and demonstrate the extent of silicon-containing material within tissue blocks.51-57 Identification of the silicon spectral peak in an X-ray energy spectrum in these studies was correct, but information regarding the chemical form of the silicon-containing compounds could not be provided. Elec- tronic transitions which are obtained from X-ray frequencies applied during X-ray analysis are independent of the type of bonding of silicon with other atoms and therefore cannot be used to elucidate the chemical structure of compounds. Silicon-specific (Elemental) Techniques for the Detection of Silicones in Biological Materials Atomic spectrometric techniques are by far the most frequently applied methods for the determination of total silicon in a variety of biological materials.Unfortunately, the information obtained from these methods is limited because they are incapable of revealing the structure of original silicon-contain- ing compound. Electrothermal atomization (sometimes known as graphite furnace) atomic absorption spectrometry (ETAAS), is generally the most frequently used technique in laboratories for the determination of traces of silicon in biological samples. Compared with flame atomic absorption spectrometry (FAAS), its detection limits are 10-100 times better, and analyses are performed with microlitre levels of solubilized sample.58 Inductively coupled plasma atomic emission spectrometry (ICP AES) is also a very sensitive technique providing high temperatures and an inert atmosphere of the discharge.Together with direct current plasma atomic emission spectroscopy (DC AES), it presents a technique which is also widely applied in trace elemental analysis laboratories. When ETAAS is applied, a necessary step during the preparation of samples is the addition of chemical modifiers that retain the analytes at higher temperatures in the furnace and aIlow volatilization of interfering matrix compounds. It is frequently the case that lower relative molecular mass silicones are inclined to volatili- zation and disappearance from the system before atomization and actual measurement. Addition of calcium compounds is based on an enhancing effect of calcium on the absorbance of silicon.29.59 Introduction of a graphite furnace oxidation step to eliminate organic interferences is also rec0rnmended.~9 It is important to mention that earlier studies involving spectrophotometric methods were based on the formation of silicomolybdate (Si02.12M003) for the determination of sili- con in biological fluids and tissues.51.6662 The major analytical concern in all these studies is the elimination of phosphorus, which is usually present in large amounts in biological samples and interferes with the spectrophotometric determination of silicon.A number of atomic spectrometric methods have been developed for the measurement of the total silicon content in blood and other body fluids such as urine.59,63-68 Many studies involved measurements in the body fluids of patients with renal failure. The results indicate a decrease of silicon excretion through urine and an increase (accumulation) in other body fluids, mainly blood, compared with levels considered to be ‘nomal’.28769-80 Higher silicon contents were also measured in tissues of patients with renal failure.81 A study also reported traces of silicon in tissues of patients submitted to haemodi- alysis, where the origin of the silicone was attributed to tubing incorporated in the dialysis apparatus.82 Somewhat elevated concentrations of elemental silicon were measured in the blood5 8R Analyst, June 1996, Vol.121 of patients with silicone breast implants.29.83.84 ETAAS con- firmed the presence of silicon in tissues of patients with silicone breast prosthesess5 via an already developed method for measuring silicon in heptane extracts.86 Higher silicon levels were also measured in tissues of cadaveric patients with silicone implants, when nitric acid digestion and subsequent DC AES measurement were employed.87 It is important to take into consideration that methods involving extraction of silicon-containing compounds with organic solvents and subsequent elemental analysis for total silicon content of extracts give only partial and very vague information with respect to silicon speciation.Organic solvents can extract liposoluble silicone compounds but also possibly some inorganic silicon species in colloidal form. Also, there is great uncertainty regarding the possible nature of association with proteins and the subsequent solubility of these species in organic solvents.From the analytical point of view, it is very interesting to compare different results for 'normal' silicon levels in blood and its components obtained in different studies (Table 3). The methods applying FAAS obviously lack sensitivity. Some extremely high measured levels indicate severe contamination, which are inevitable if all the previously discussed precautions are not considered as part of the analytical procedure. Possible accidental contamination is also frequent and can be traced in most of the cited studies by high silicon concentrations in some controls in comparison with lower levels in patients where higher concentrations are actually expected. These variations can also be caused by silicon ingestion and the level becomes elevated through sources such as a high-fibre diet or higher silicon levels in drinking water.28 Generally, the values in Table 3 indicate that silicon-containing species are likely to be found in plasma.A good statistical analysis is necessary for accurate and reliable presentation of results in these types of study. Some studies involving the determination of elemental silicon in foods are potentailly interesting in relation to biological matrices. Silicone (PDMS) defoamers were extracted from fruit juices and beer with chloroform and measured by FAAS.88 A collaborative study reported good results with PDMS extraction with 4-methylpentan-2-one from pineapple juice and measurements with FAAS.89 By acidifying fruit juice samples with hydrochloric acid before extraction, better phase separation was obtained.g0 Silicones, added to edible fats and oils as defoamers and antioxidants, could be measured directly by ETAAS after dilution with isooctane, applying furnace air oxidation for reduction of matrix interferences.91 Survey of Silicone-specific Techniques IR, FTIR and Raman Spectrometry Silicones can be very easily identified by their IR spectra because of the high specificity of the spectral patterns of organic groups attached to silicon, although differences in relative molecular mass or relative molecular mass distribution could be overlooked.In contrast, UV spectrometry is not a very good tool for identifying silicones because of their lack of absorption of UV radiation, except for aromatic substituents.IR spectrometry is especially useful for the identification of silicone molecular structures and for quantitative analysis when well characterized reference standards are available. The strong absorption of the siloxane part of a silicone molecule makes it a very distinctive feature in an IR spectrum. As expected, IR spectrometry is not sensitive enough for trace analysis. Better sensitivity for trace analysis can be obtained by preconcentration with solvent extractions or applying prior gas or liquid chromatographic separation. In trace analysis, the most characteristic band is that originating from the symmetrical methyl deformation [(CH3)2Si] at 1262 cm-1 (wavenumber). This is used as an isolated band for quantification with minimum interferences from the matrix.92.93 Raman spectrometry is a very attractive technique for the characterization of biological materials because it can be performed on neat samples.The same applies to attenuated total reflectance (ATR) IR spectrometry of biological samples. This technique permits the study of the surface of a sample when it is too thick for transmission methods. The penetration depth of the IR beam into the sample is a function of wavelength, angle of incidence of the IR beam and the relative refractive index and is usually expected to be several micrometres. For the analysis of solid microsamples, FTIR spectrometry is a preferred technique because of its energy throughput advantage over dispersive IR techniques.92 An early study reported the use of IR spectrometry for the determination of trace amounts of silicones in foods and biological samples such as lung tissue, blood and animal organs.94 Silicones could be extracted from a matrix with benzene or chloroform if direct extraction in carbon disulfide is not possible.It was reported that the final concentration of silicone in the solvent should be at least 50 ppm (0.05 mg ml-1) for measurements in a microcell. Basically the same method was applied for the detection of silicone defoamers in beer and yeast samples, but low recoveries were obtained and also the spectra exhibited many peaks due to interfering species. This Table 3 Normal total silicon levels in human blood measured in some studies Ref. King et a1.60 Lo and Christian63 Mauras et al.69 Dobbie and Smithw Berlyne and Carus065 Matusiewicz and Barnes66 Roberts and Williams7' Gitelman and Alderman79 Hosokawa and Y o ~ h i d a ~ ~ Marco-Franco et al.76 Bercowy et a1.68 Malata et al.83 Peters et al.29 Teuber et al.84 Year Technique 1955 Spectrophotometry 1978 ETAAS 1980 1982 1983 1984 1990 1990 1990 1991 1994 ICPAES FAAS ETAAS ICPAES DCPAES ETAAS ETAAS ICPAES DCPAES 1994 ETAAS 1995 ETAAS 1995 ICPAES Blood component Serum Whole blood Serum Whole blood Serum Serum Serum Plasma Plasma Serum Serum Whole blood Plasma Serum Whole blood Whole blood Serum Concentration/ vg 1-' (ppb) 1400 1490 770 110 600 f 125 309.6 f 82.1 140 f 14 170 f 100 220 f 80 10-250 < 300-5000 < 400-4000 < 200-4000 42-366 130 k 70 2600 24.23-26.66Analyst, June 1996, Vol.121 59R was supposed to be overcome by the application of acetone- benzene as extraction solvents and NaOH for the removal of interfering components. The recoveries were improved but the introduction of the base probably contributed to the partial cleavage of siloxane b0nds.~5 Some early analytical studies performed on human tissues reported the application of the IR technique for the positive determination of silicone structures. Silicones were detected in brain and kidney tissues of patients submitted to heart-lung machines, where silicone defoamers are added to the bubble oxygenator.96 After extraction with benzene and purification of extracts on alumina columns, silicones dissolved in dichlo- romethane were confirmed by IR spectrometry. In another study silicone particles, located by light microscopy in capsular tissues of silicone breast implants patients, were confirmed by means of the same te~hnique.9~ A laser Raman microprobe was used to detect silicones in the lymph node of a patient with a silicone elastomer finger-joint prosthesis.98 Small sections (2-20 pm) of the specimens were mounted on sapphire sample supports and irradiated with 5 14.5 nm green radiation from an argon-krypton laser for the collection of the Raman scattered radiation.The main limitation of the method is in its sensitivity, which mainly depends on the Raman scattering efficiency of the analyte compound in a given matrix, and the distribution of the Raman scatter (analyte) by the matrix. Studies were performed using FTIR-ATR analysis to evaluate in vivo adsorption of blood components (fibrin, cellular elements) on silicone rubber99 or on silicone elastomer membranes by exposure to flowing blood.100 The same technique was applied to evaluate protein adsorption on silanized surfaces of polymethacrylic soft contact lenses.101 A method was developed for the detection of silicones (2-12 mg per gram of tissue) in a rabbit muscle tissue adjacent to silicone implants, based on FTIR-ATR analysis of methylene chloride extracts.Some recent studies extensively used FTIR microspec- trometry for the detection of silicone structures in breast tissues of silicone implant patients.103-105 Usually, a removed implant is applied as a control 'fingerprint' for spectral confirmation. In some instances the FTIR spectra of tissue samples revealed the presence only of an Si-0 stretch without an Si-C stretch which is present in original silicone gel.'W This suggests a possible hydrolytic cleavage of the silicon-carbon bond of silicone.Near-IR Raman spectrometry with laser excitation at 782 nm (reduced fluorescence interference compared with excitation at 5 14.5 nm98) was also used for the detection of silicone in lymph nodes of breast implant patients.106 It was suggested that the method could be extended to the in vivo analysis of living tissues. NMR Spectrometry Silicones are mainly composed of atomic nuclei which resonate in a magnetic field, which makes them responsive to the NMR technique. Most of the functional groups attached to silicon have distinctive proton resonances so that lH NMR is generally used for qualitative and quantitative analyses of silicones.However, 29Si NMR has become widespread in recent times and is the technique of choice for structural differentiation, because of its ability to distinguish between different silicone species and the specificity of its response.107 Quantitative NMR spectra are usually applied for the determination of structure and the analysis of mixtures. NMR is generally not used in trace analysis because of its lower sensitivity compared with other techniques. However, the information obtained by Garrido and co-workers108-112 on the migration and biodegradation of silicone compounds in differ- ent tissues and blood samples of model animals and silicone implant patients, by means of NMR, seems to exceed the results of all other studies performed so far. In the course of the cited studies, 1H NMR spectrometry was used for the examination of the degradation of silicones in vivo and 2% NMR spectrometry, with a broad-band magic angle spinning (MAS) probe (to eliminate broadening from dipole- dipole coupling and chemical shift anisotropy), was employed for the analysis of tissue and blood samples in vitru.Migration and biodegradation of silicones in breast implant patients were reported.ll1 The presence of unchanged silicone (peak at -22 ppm), hydrolysed silicone where methyl groups are substituted by hydroxyl groups (peaks at -30 to -80 ppm), silica (peaks at -90 to - 1 15 pprn), pentacoordinated silicon complexes (peaks at -120 to -150 ppm) and alkyl- and hydroxyl-terminated silicone (peaks at 0 to -15 ppm) were detected. The concentrations of silicone in examined blood samples, accord- ing to this study, exceed by 1000-10000 times the average concentrations of elemental silicon obtained in similar studies where AAS was used.29,83,84,113 The application of lH NMR spectrometry in a localized manner for the detection of silicones in the liver of breast implant patients in vivo resulted in a sensitivity to ppm levels of silicon.112 Gas Chromatography and Gas Chromatography-Mass Spectrometry Methods Gas chromatography and GC-MS are appropriate for the molecular identification and structure determination of sili- cones and for the sensitive determination of trace amounts of these species in biological materials. Separation (using high- resolution capillary columns) together with identification on the basis of retention times and quantification of silicones by GC, usually with flame ionization detection (FID), is a common procedure.In contrast, LC is rarely used in analyses for silicones because of their non-polar nature, which makes them unsuitable for LC separation. The qualitative capability of the MS detector improves the performance of GC, making the GC- MS method the most sensitive and selective technique for the quantification of specific silicone species. The nature of silicone compounds and their fragmentation patterns impose many restrictions on their determination by GC-MS. The high boiling point of high molecular mass PDMS renders them unsuitable for GC separation. Some unstable silicone species such as silanols must be derivatized before introduction into the GC column in order to protect them from condensation.The unambiguous identification of both larger linear (> MDSM) and cyclic ( > D6) siloxanes through their electron impact (EI) mass spectra is generally not possible, because of the predominance of identical rearrangement ions regardless of the original structure. It is recommended that the best clue for the characterization of silicones is through a combination of the structural information given by EI fragmen- tation patterns and the molecular mass information provided by the chemical ionization method.' l 4 One of the important problems in GC-MS analysis is that GC-MS systems are major sources of background silicone through PDMS stationary phases which are generally applied for GC separation and also through components such as septa and seals made of silicone rubber or silicone diffusion pump fluids.Among the numerous studies dealing with both the GC and MS or GC-MS of silicones, only a small number were concerned with the presence of silicones in biological materials or related matrices. 2,6-cis-Diphenylhexamethylcyclo- tetrasiloxane (Fig. 3), a drug proposed for the treatment of prostate carcinoma, was determined in human serum with a reported sensitivity of 0.1 ng ml-1 by means of mass fragmentography after extraction with heptane.115 The60R Analyst, June 1996, Vol. 121 hydroxylated products of the same drug [(a) dimethylsilanediol, (b) methylphenylsilanediol, (c) trimethylphenylsiloxanediol and (4 phenol (Fig.3)] obtained by biodegradation were determined in urinary samples at ppm levels by means of GC- MS. l6 The derivatization of hydroxylated metabolites ex- tracted with diethyl ether-ethanol was performed using hexam- ethyldisilazane (HMDS) in an acidified medium. HMDS, in the presence of catalytic amounts of acetic acid, as a mild reagent does not promote the formation of new siloxane bonds. It was reported that the silyl derivatives obtained have suitable GC properties with respect to their stability and volatility. Although satisfactory results were obtained after the evaporation of samples and extracts containing hydroxylated silicones, it is possible that both the evaporation and derivatization processes can result in partial or even total loss of the species under study due to their degradability, reactivity and volatility and also their expected low concentrations.Gas chromatography and GC-MS methods for the determi- nation of water-borne organosilanols and water-insoluble organosilicons have been developed with the possibility of detection of ppm to ppb levels of silic0nes.~3 The derivatization of silanols with hexamethyldisiloxane (HMDSO) was per- formed after digestion with hydrochloric acid. Further, HMDSO is employed as a selective, in situ, trimethylsilylation and extraction agent. On the basis of the previous method, a procedure was developed in which PDMS oligomers were determined in connective tissue around mammary prostheses at a detection limit of 6 pg g-1.117 Unlike other methods, where laboratory standards of chemical species under investigation were used for quantification, the GC quantification was performed using octamethyltrisiloxane and the silicone levels were expressed as dimethylsiloxane equivalents. The same method was applied for the evaluation of silicone levels in human milk.118 The application of the method demands extreme caution in order to eliminate possible losses of unstable silicone compounds.Also, the demand for silica-free and acid-resistant equipment, such as tightly sealed high-quality PTFE plastic- ware, makes this procedure extremely expensive for routine analysis involving numerous samples. The method is not suitable for phenyl-substituted silicones because of possible acid-catalysed hydrolytic cleavage of phenyl-silicon bonds.It was reported in an early study that silicones could be extracted from the blood of breast implant patients and determined by MS, but no details on the analytical procedure applied were given. 119 Experiments involving measurements of linear (MM- MD13M) and cyclic (D3-D9) silicones in fish tissues at a detection limit of 0.3 pg g-1 using GC and GC-MS, after the Ph Me I I .Si - 0 -Si I Me I Me I :H3 Ph I Ph 743 HO- Si - OH HO- Si - OH HO- Si - 0 - Si - OH D O H I I I I CH3 CH3 CH3 CH, ( 4 ( b) (4 (4 Fig. 3 Structure of 2,6-cis-diphenylhexamethylcyclotetrasiloxane and its biodegradation products: (a) dimethylsilanediol, (h) methylphenyl- silanediol, (c) trimethylphenylsiloxanediol and (6) phenol.* addition of silicones to the food, showed that only small amounts of these compounds were retained by the fish after 6 weeks of feeding, in contrast to much higher absorption of PCBs. l*O Silicones were extracted from tissues with hexane. GC-MS was used for the confirmation of particular silicone structures and capillary GC with FID was applied for determi- nation of trace levels of silicone. Evaporation of lower relative molecular mass species took place during the preparation of samples. Some other studies involving GC-MS methods for the determination of silicones in the environment could potentially be extremely valuable for the detection of trace amounts of silicones in biological matrices. A sensitivity of 0.2 ng ml-1 was achieved by the purge-and-trap GC-MS method described for the determination of octamethylcyclotetrasiloxane (D4) in water.I21 Since the method is extremely sensitive it could suffer from background contamination coming from other volatile materials present in the laboratory environment, such as solvents.PDMS associated with airborne particles were collected with Teflon filters and extracted with 1,2,2-trifluoro- 1,l72-trichloro- ethane (Freon 113) or dichloromethane.122 It was reported that silicone fluid at a detection limit of 0.1 ng was determined by pyrolysis GC-MS, by applying a correlation between major identified pyrolysis products (cyclic siloxanes) and the starting silicone material. One of the major problems related to the application of the cited methods to real biological samples (the described work was performed mostly on synthetic samples) is connected with analytical standards.Uncertainty regarding the presence of actual compounds in the samples under investigation and the unavailability of actual silicone compounds render the quantita- tive detection of silicone biodegradation products a difficult problem with an extremely questionable outcome. The demand for structurally close compounds as internal standards some- times conflicts with features of other steps in the applied procedure, making the choice of a suitable internal standard another problem for the analytical chemist (e.g., ions of different m/z values must be produced for mass spectra). Although GC-MS seems to be an ideal technique for the identification of silicones and their biodegradation products in biological samples, the difficulties described above substan- tially reduce the number of reported and successful relevant studies. Problem of Speciation of Silicon and Identification of Silicone Biotransformation Products in Biological Samples One of the most important considerations in the many analytical studies discussed above is the identification of small molecules or biomolecules incorporating biological silicon or silicone biodegradation products, Some of the cited ~tudies,1~~109-~ 1 where positive identification of biochemically modified sili- cone species was reported, are not persuasive in terms of the methodological approach and, accordingly, the positive con- firmation of the conclusions derived from experimental results cannot be accepted.Under physiological conditions, the possible existence of biodegradation products associated with siloxane bond cleavage leading to hydroxylated silicone compounds116 seems a more probable mechanism for bio- transformation of silicone compounds than the cleavage of silicon-carbon bonds with the same O U ~ C O ~ ~ . ~ ~ ~ , ~ ~ ~ Inter- actions of silicones with proteins is another issue with more theoretical assumptions than experimental confirmation. If the existence of silanol degradation products is assumed, then their association with proteins via hydrogen bonding is very likely. The formation of associations where components of protein functional groups are pentacoordinately bonded to the silicon atom could be another alternati~e.*~3 It was suggested that61R Analyst, June 1996, Vol.121 Table 4 Techniques for the analysis of silicones in biological matrices Technique Application X-ray methods Atomic spectrometric methods Elemental microcharacterization of tissue samples Elemental determination of silicon in biological materials FAAS ETAAS, ICPAES and DCPAES IR spectrometry FTIR and Raman spectrometry NMR spectrometry GC and GC-MS Determination of silicones in extracts from biological materials Determination of silicones in solid biological microsamples Determination of silicones in biological samples in vivo and Determination of silicones in extracts from biological materials in vitro Level of sensitivity mg g-' mg 1-' 1-' mg 1-l mg g-' Pg 1-' mg 1-' silicon is only unspecifically adsorbed to serum proteins.lz4 In this study, HPLC was applied for separation and ETAAS for the detection of silicon-containing fractions.Gel electrophoresis is another separation technique that could be applied to give information on particular protein binding. Some other techniques which are still under development, such as matrix-assisted laser desorption/ionization (MALDI) MS and electrospray MS, which permit the measurement of intact molecular ions of high molecular mass biopolymers, could yield valuable information on silicone and silicon binding to proteins in future work. Conclusions Table 4 summarizes analytical techniques used for the determi- nation of silicones in biological samples and described in this review. Although most of them are distinguished by relatively high reported sensitivities and capabilities to examine different kinds of biological samples, only the methods based on atomic spectrometric techniques have been widely used for the determination of silicone levels in biological samples.It is evident that although an important interest in the determination of silicones in biological matrices exists, the identification of silicone biodegradation products is the most significant problem which has not been solved so far. 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M., and Pickles, D., Analyst, 1955, 80, 441. Jankowiak, M. E., and Le Vier, R. R., Anal. Biochem., 1971, 44, 462. Austin, J. H., Rinehart, R. W., and Ball, E., Microchem.J . , 1972, 17, 670. Lo, D. B., and Christian, G. D., Microchem. J., 1978, 23,481. Dobbie, J. W., and Smith, M. J. B., Scot. Med. J., 1982, 27, 17. Berlyne, G. M., and Caruso, C., Clin. Chim. Acta, 1983, 129, 239. Matusiewicz, H., and Barnes, R. M., Spectrochim. Acta, Part B, 1984, 39, 891. Tanakd, T., and Hayashi, Y., Clin. Chim. Acta, 1986, 156, 109. Bercowy, G. M., Vo, H., and Rieders, F., J . Anal. Toxicol., 1994,18, 46. Mauras, Y., Riberi, P., Cartier, F., and Allain, P., Biomedicine, 1980, 33, 228. Berlyne, G., Dudek, E., Adler, A. J., Rubin, J. E., and Seidman, M., Kidney Int., 1985, 28, Suppl. 18, S-175. Roberts, N. B., and Williams, P., Clin. Chem. (Winston-Salem, N.C.), 1990,36, 1460. 255-268. 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 1 06 107 108 109 Gitelman, H.J., Alderman, F. R., and Perry, S. J., Am. J . Kidney Dis., 1992, 19, 140. Hosokawa, S., and Yoshida, O., Int. Urol. Nephrol., 1990, 22, 373. Hosokawa, S., Oyamaguchi, A., and Yoshida, O., Nephron, 1990,55, 375. Hosokawa, S., and Yoshida, O., Int. Urol. Nephrol., 1991,23, 281. Marco-Franco, J. E., Torres, V. E., Nixon, D. E., Wilson, D. M., James, E. M., Bergralh, E. J., and McCarthy, J. T., Clin. Nephrol., 1991, 35, 52. Netter, P., Steinmetz, J., Gillet, P., Kessler, M., Bardin, T., Fener, P., Bumel, D., Gaucher, A., Pourel, J., and Bannwarth, B., Lancet, 1991, 337, 554. Wrobel, K., Blanco Gonzalez, E., and Sanz-Medel, A., J . Anal. At. Spectrom., 1993,8, 915. Bellia, J.P., Newton, K., Davenport, A., Birchall, J. D., and Roberts, N. B., Eur. J . Clin. Invest., 1994, 24, 703. Wrobel, K., Blanco Gonzdez, E., and Sanz-Medel, A., J . Anal. At. Spectrom., 1994, 9, 28 1. Indraprasit, S., Alexander, G. V., and Gonick, H. C., J. Chron. Dis., 1974, 27, 135. Leong, A. S. Y., Path, M. R. C., Disney, A. P. S., and Gove, D. W., N. Engl. J . Med., 1982, 306, 135. Malata, C. M., Varma, S., Scott, M., Liston, J. C., and Sharpe, D. T., Med. Progress Technol., 1994, 20, 251. Teuber, S. S., Saunders, R. L., Halpem, G. M., Brucker, R. F., Conte, V., Goldman, B. D., Winger, E. E., Wood, W. G., and Gershwin, M. E., Biol. Trace Elem. Res., 1995,48, 121. Thomsen, J. L., Christensen, L., Nielsen, M., Brandt, B., Breiting, V. B., Felby, S., and Nielsen, E., Plast.Reconstr. Surg., 1990, 85, 38. Felby, S., Forensic Sci. Int., 1986, 32, 61. Evans, G. R. D., Slezak, S., Rieters, M., and Berkowy, G. M., Plast. Reconstr. Surg., 1994, 93, 1 1 17. Kacprzak, J. L., J. Assoc. Off. Anal. Chem., 1982,65, 148. Parker, R. D., J . Assoc. Off. Anal. Chem., 1990, 73, 721. Gooch, E. G., J . AOAC Int., 1993, 76, 581. McCamey, D. A., Iannelli, D. P., Bryson, L. J., and Thorpe, T. M., Anal. Chim. Acra, 1986, 188, 119. Lipp, E. D., and Smith, A. L., in Analytical Chemistry of Silicones, ed. Smith, A. L., Wiley, New York, 1991, pp. 305-345. Crompton, T. R., in The Chemistry of Organic Silicon Compounds, ed. Patai, S., and Rappoport, Z., Wiley, Chichester, 1989, pp. 39". Homer, H. J., Weiler, J. E., and Angelotti, N. C., Anal.Chem., 1960, 32, 858. Sinclair, A., and Hallam, T. R., Analyst, 1971, 96, 149. Ruediger, F., and Baudisch, H., Beitr. Pathol., 1973, 149, 39; Chem. Abstr., 1973, 79, 134082t. Smahel, J., and Sell, J., Mater. Technol., 1978, 6, 51; Chem. Abstr., 1978,89, 53104f. Abraham, J. L., and Etz, E. S., Science (Washington, D.C., 1883-), 1979,206,716. Seifert, L. M., and Greer, R. T., J . Biomed. Muter. Res., 1985, 19, 1043. Kennedy, J. H., Ishida, H., Staikoff, L. S., and Lewis, C. W., Biomater. Med. Dev. Art. Org., 1978, 6, 215. Deng, X. M., Castillo, E. J., and Anderson, J. M., Biomaterials, 1986, 7, 247. Habal, M. B., Quigg, J. M., Peck, L. S., Lin, T. L., Martin, P., Hatton, H., Ohmstede, D., Famworth, S., and Goldberg, E. P., in Presented at The 19th Annual Meeting of the Society for Biomaterials, April 28-May 2, 1993, Birmingham, AL, 1993, p. 230. Centeno, J. A., and Johnson, F. B., Appl. Spectrosc., 1993,47, 341. Hardt, N. S., Yu, L. T., La Tone, G., and Steinbach, B., Mod. Pathol., 1994, 7, 669. Emery, J. A., Spanier, S. S., Kasnic, G., and Hardt, N. S., Mod. Pathol., 1994, 7, 728. Frank, C. J., McCreery, R. L., Redd, D. C. B., and Gander, T. S., Appl. Spectrosc., 1993, 47, 387. Taylor, R. B., Parbhoo, B., and Fillmore, D. M., in Analytical Chemistry of Silicones, ed. Smith, A. L., Wiley, New York, 1991, pp. 347419. Pfleiderer, B., Moore, J., Ackerman, J. L., and Ganido, L., Polym. Prepr., 1992, 33, 767. Garrido, L., Pfleiderer, B., Papisov, M., and Ackerman, J. L., Magn. Reson. Med., 1993, 29, 839.Analyst, June 1996, Vol. 121 63R ~~~ 110 111 112 113 114 115 116 117 118 Pfleiderer, B., Ackerman, J. L., and Garrido, L., Magn. Res. Med., 1993, 30, 534. Garrido, L., Pfleiderer, B., Jenkins, B. G., Hulka, C. A., and Kopans, D. B., Magn. Res. Med., 1994, 31, 328. Pfleiderer, B., and Garrido, L., Magn. Res. Med., 1995, 33, 8. Macdonald, P., Plavac, N., Peters, W., Lugowski, S., and Smith, D., Anal. Chem., 1995, 67, 3799. Moore, J. A., in Analytical Chemistry of Silicones, ed. Smith, A. L., Wiley, New York, 1991, pp. 421-470. Hammar, C. G., Freij, G., Stromberg, S., and Vessman, J., Acta Pharmacol. Toxicol., 1975, 36, Suppl. 111, 33. Vessman, J., Hammar, C. G., Lindeke, B., Stromberg, S., Le Vier, R., Robinson, R., Spielvogel, D., and Hanneman, L., in Biochemistry of Silicon and Related Problems, ed. Bendz, G., and Lindqvist, I., Plenum Press, New York, 1978, pp. 535-558. Baker, J. L., Le Vier, R. R., and Spielvogel, D. E., Plast. Reconstr. Surg., 1982, 69, 57. Bejarano, M. A., and Zimmer, M. A., Determination of Low Levels of Silicones in Human Breast Milk by the Aqueous Silanol Functionality 119 120 121 122 123 124 Test, Dow Coming, Midland, MI, 1991, Report No. 1991-10000- 36332. Uretsky, B. F., O’Brien, J. J., Courtiss, E. H., and Becker, M. D., Ann. Plast. Surg., 1979, 3, 445. Bruggeman, W. A., Weber-Fung, D., Opperhuizen, A., Van der Steen, J., Wijbenga, A., and Hutzinger, O., Toxicol. Environ. Chem., 1983, 7, 287. Moore, J. A., and Bujanowski, V. J., in Analytical Chemistry of Silicones, ed. Smith, A. L., Wiley, New York, USA, 1991, pp. Weschler, C. J., Sci. Total Environ., 1988, 73, 53. West, J. K., and Hench, L. L., J . Biomed. Muter. Res., 1994, 28, 625. Wrobel, K., Blanco GonzBlez, E., Wrobel, K., and Sanz-Medel, A., Analyst, 1995, 120, 809. Paper 5106641 G Received October 9,1995 Accepted December 14,1995 82-84.

ISSN:0003-2654    

DOI:10.1039/AN996210053R

出版商:RSC    

年代:1996

数据来源: RSC

摘要:

Analyst, June 1996, Val. 121 73N Book and Software Reviews ICP Softbook By Cognitive Solutions Ltd. Revised and Updated January 1995. Price f295.00 (plus VAT); US$529.00. The value of computer assisted learning is a matter of great debate in the educational world and it is not clear what the real advantages and disadvantages of this mode of study are. Views vary from dread to total commitment and so to give this particular product a fair chance, it was put to the consumers to evaluate and this review is a summary of the feedback from a group of some 25 undergraduate and M.Sc. Analytical Science students who had all attended traditional lectures on atomic spectroscopy. There was unanimous agreement that the soft- ware was easy to use if a little patronizing in places. However, one disadvantage of being user friendly was that students became bored or unchallenged after a short period of time- apologies to the authors, you can’t win this one.On a practical level, the lack of an index or the option to jump into the book at will rather than having to page through it was considered to be a drawback, once the user got the hang of software. There are also one or two notable scientific errors in the text which can lead to confusion. On a positive note the level of material is good for undergraduate and M.Sc. level teaching and well suited to private remedial study and revision. The most striking aspect of the softbook is the ability to have dynamic graphics and the visual diagrammatic features were very popular with students. ‘graphics are a significant advantage of this mode of learning’ As an addition to traditional texts, the softbook is user friendly and requires approximately 1-2 hours to comfortably work through.It is not ideal for browsing, but the graphics are a significant advantage of this mode of learning. The softbook is rather expensive and possibly an important factor when considering the real practical and educational value of computer based learning. Potential users are advised to consider carefully the real advantages of using this type of material before purchase and should certainly obtain a preview copy. S . J . Huswell 5i90075A University of Hull GC Softbook By Cognitive Solutions Ltd. Revised and Updated, January 1995. Price f295.00 (plus VAT); US$529.00. When I was asked to examine and review a computer based learning package called GC Softbook provided by Cognitive Solutions Ltd.I must admit to being less than 100% enthu- siastic. Frankly I don’t like computer based learning packages because I have found them to be too basic, too simple and never as ‘user friendly’ as the advanced publicity claims. In short they may be a good method for the efficient conveyance of information but they are a poor substitute for good face-to-face communication. I did not immediately rush to my computer to try the package. The following weeks witnessed a war of attrition between myself and my wife. She constantly saying that I should ‘sit down and do something about it’, and I producing a range of avoidance excuses culminating in the coining of the immortal phrase ‘not tonight dear-my hard disc is full’.Eventually events overtook me and, whilst I was away working, my wife loaded the package on the computer and began to work her way through it. Her initial response was so positive that I sat down to have a look myself. Not long afterwards I realised that here, at last, was a software package produced for teachers by people who knew what they were doing. Firstly, there is a lot of detail present and the subject is really comprehensively covered. Secondly the structure of the package is well presented and logical-rather like a good book in fact. To a large extent browsing is possible so a student can switch between sections to clarify their own thoughts and make comparisons. Thirdly the diagrams are clear yet detailed and, occasionally, animated.I found this particularly attractive in the injection techniques section because students seldom think about what happens in an injection port and those that do have difficulty in envisioning what happens when the sample is introduced. Not everything is perfect however. The first section of the chapter on injection techniques deals with split injections, yet appears to have no heading, unlike subsequent sections which are clearly defined so the student is forced to think about the differences. Also the section on split injections should be re- written in a way which presents split injection as a process which is variable not fixed. As it stands the student receives the impression that a 1OO:l split ratio is mandatory-it is not! Another well presented, and hence enjoyable, chapter was that dealing with detectors and I was especially pleased to see the atomic emission detector (AED) receiving the attention it is due.I will hazard a guess that in ten years time the AED will have consigned several of the selective detectors to the Science Museum. ‘Give this one a try.’ To summarize therefore I may not (yet) be a convert to computer based learning packages but the GC Softbook preaches a powerful sermon. I actually enjoyed using it, and its potential use in teaching support is clear. It will not replace the truly interactive teaching that is represented by an experienced and enthusiastic lecturer, but it will provide excellent tutorial support and distance learning material. Perhaps the highest accolade however came from my wife who wished that she had had access to this package when trying to explain gas chromatography to first year undergraduates recently.In such circumstances a good support package is invaluable. Give this one a try. M . Cooke 51900726 Sheffield Hallarn University General Principles of Good Sampling Practice By Neil T. Crosby and lndu Patel. Pp. x + 68. The Royal Society of Chemistry. 1995. Price €17.50. ISBN 0-85404-41 2-4. This slim, but useful, volume was prepared under the auspices of the UK Department of Trade and Industry Valid Analytical Measurement Initiative by two members of staff from the Laboratory of the Government Chemist. It can be especially recommended to analytical chemistry students as an introduc- tion to sampling, and to those who have lead sheltered lives, perhaps in academic institutions, who suddenly need to analyse real-world environmental (in the broadest sense) or industrial samples.It might also benefit some supposedly more experi- enced practitioners of analysis. The book is a readable and concise account of how to deal safely with samples that are74N Analyst, June 2996, Vol. 122 hazardous, bulky, or dynamic, and covers all stages from planning a sampling strategy, through to sampling devices and their safe use, to preservation, preparation and subsampling. The contents should be readily understandable even by those with a very limited background in chemistry. ‘a readable and concise account of how to deal safely with samples that are hazardous, bulky, or dynamic’ The presentation is generally attractively clear.However, samplers are notoriously difficult to represent in simple line diagrams, and one or two of the sketches rather stretched my imagination. A useful 83-reference bibliography is included for those needing supplementary reading, but there is no index, presumably because the authors thought this unnecessary in such a short text. While the coverage is generally adequate, there are con- spicuous gaps. Biological materials, or at least biological materials prior to their becoming animal feeds or human food, are almost totally ignored. So if you’re about to head for a forest or moorland site to sample, this is not the book for you! But apart from the gaps, this is a useful and welcome addition to the literature.Malcolm Cresser 5190088C University of Aberdeen Protozoan Parasites and Water Edited by W. B. Betts, D. Casemore, C. Fricker, H. Smith and J. Watkins. Pp. x + 260. Royal Society of Chemistry. 1995. Price €49.50. ISBN 0-85404-755-7. Since the late 1980’s, general awareness of waterborne protozoan parasites has increased dramatically and as a consequence of this, a definite need for an extensive and in depth look at this diverse topic and how such parasites affect public health, locally, nationally and internationally has devel- oped. The contributions in this book were made by delegates attending an international conference entitled ‘Protozoan para- sites and water’ held at York University in September 1994. The influence that protozoan parasites have had and continue to have on the development of drinking water technology, public perception and awareness of drinking water supplies and basic public health protection strategies has been immense and this text provides a comprehensive overview of the subject.It incorporates an easy balance of papers covering a range of topic areas, from an historical perspective of the protozoa to ‘state of the art’ reporting of technological developments in drinking water treatment . The book is divided into related subject parts, each containing a broad range of topic areas, making it relatively straightforward to pin point the information required but at the same time enabling a complete overview to be presented. However, being a collection of independent papers, cross referencing of data between parts is neither prompted or straight forward, unless the reader is familar with the topics.Each part is composed of a range of technical, experimental and theoretical papers, which ultimately provides a balanced view of the subject area from different perspectives. Each chapter is divided into clear sections which makes for easy reading, and with most papers being backed up by a reasonably up-to-date and comprehensive bibliography, there is always further information to be explored. Overall, the figures and tables are clear and usually self explanatory. Because of the quality of technical data presented, e.g., optimization of recovery, analysis and visualization of Cryptosporidium oocysts, this text may be easily used as a methodological laboratory guide.The focus of the book is very much on Cryptosporidium and Giardia, and, despite the fact that other protozoan parasites are mentioned, it seems almost in passing, with only 5 out of 54 papers dealing with subjects other than Cryptosporidium or Giardia. Consequently, the overall emphasis of the book, in relation to the title, seems a little misleading. This lack of balance however is obviously a reflection of the quantity and focus of the work being carried out in the experimental scenario. ‘an interesting and explanatory text on the overall subject but also a detailed practical guide on specific issues. No research labo- ratory or reference library should be without a copy.’ In summary, as an overall text on the subject of protozoan parasites and water, these proceedings provide a substantial amount of information contained within a comprehensive text in which leading experts in the field cover each topic area.This volume could provide not only an interesting and explanatory text on the overall subject but also a detailed practical guide on specific issues. No research laboratory or reference library should be without a copy. P. Towlson 51900820 Department of Health, London Airborne Particulate Matter Edited by T. Kouimtzis and C. Samara. The Handbook of Environmental Chemistry. Volume 4. Part 0. Pp. x + 340. Springer-Verlag. 1995. Price DM198.00; f86.00; oS1544.40; sFr187.00. ISBN 3-540-58932-5. The publication of this latest volume in The Handbook of Environmental Chemistry is particularly timely.Recent epi- demiological research on the health effects of exposure to airborne particles has shown consistent subtle effects which have already led the UK government to adopt a strict air quality standard for the particle fraction known as PMlo, and the USEPA is currently considering setting a standard for PM2.5. Much remains to be done in health effects research on airborne particles as the current links with morbidity and mortality are purely statistical, and there is at present no proven biological mechanism of effect. Equally, there are major gaps in knowledge of the physics and chemistry of airborne particulate matter, but this book makes a useful contribution in reviewing some of the currently available knowledge in this area. The editors have assembled some 1 1 chapters dealing with different aspects of airborne particulate matter, from sources, through ‘an excellent overview of many aspects of the physics and chemistry of atmospheric par- ticles ’ sampling and chemical analysis, to emissions control technolo- gies.Individual chapters deal with, particle emissions, in situ particle formation and reactions, sources, size distributions and transport, physical, chemical and optical properties, chemical mass balance, sampling, inorganic analysis, measurement of acidic particles and gases, organic analysis, particle counting and size analysis and emission control. The chapters are of variable length and hence depth of detail. In most cases, the chapters are authored by well known figures in the field whoAnalyst, June 1996, Vol.121 75N write authoritatively over their particular subject area. There has been no obvious attempt to edit the material to remove the many overlaps within it, although overall, these are not a major detraction from the quality of the book, and could be argued as a positive feature as each chapter is a fairly self-contained account which can be read without reference to the others. The level of treatment is generally quite advanced and this is a book clearly aimed at the research community, and generally accessible only to readers with a fairly strong background in the field. The assembled information gives an excellent overview of many aspects of the physics and chemistry of atmospheric particles, and will prove an excellent reference book for workers in this field.There are omissions; for example, whilst there is a chapter upon Chemical Mass Balance, there is no detailed discussion of the other receptor modelling techniques which have been widely applied in aerosol source apportionment. Nonetheless, this is a thoroughly useful book which will find its way into many libraries in research institutions. Roy M . Harrison 5i90083B University of Birmingham Handbook of Size Exclusion Chromatography Edited by Chi-san Wu. Chromatographic Science Series. Volume 69. Pp. viii + 454. Marcel Dekker. 1995. Price $175.00. ISBN 0-8247-9288-2. In spite of the emergence of a number of new methods in separation science, size exclusion chromatography (SEC), often referred to as gel-permeation chromatography, remains the method of choice for the determination of the molecular weight distribution of polymers.This collection of reviews sets out recent advances in a number of SEC areas, with particular emphasis on applications. ‘This collection of reviews sets out recent advances in a number of SEC areas, with particular emphasis on applications.’ The book comprises 17 chapters, with a total of 28 authors, all but 5 from the USA. E. G. Malawer contributes an introductory chapter, which is followed by two chapters on recent develop- ments in column packings by E. Meehan (semi-rigid polymer gels), and R. Eksteen and K. J. Pardue (silica-based materials); C. Jackson and H. G. Barth then summarize the use of molecular weight sensitive (viscometric and light-scattering) detectors in SEC.The remaining 17 chapters describe a wide variety of applications of SEC to different polymer types, with an approximately equal division between reviews concerned with natural and synthetic polymers. Included in the former are cellulose and cellulose derivatives, natural rubber, lignin derivatives, starch, proteins, nucleic acids, and unusually (although SEC analysis here presents formidable problems) asphalts. Examples of SEC of synthetic polymers for which progress has recently rapidly advanced are polyamides, pol yes- ten, fluoropolymers, polyacrylamides (PAM), synthetic rub- bers, polyvinylalcohol (PVA), polyvinylacetate, and vinylpyr- rolidone polymers. There is special emphasis on the SEC of co-polymers, with a whole chapter by A. Rudin devoted to this topic; aqueous SEC of synthetic polymers, e.g., PAM and PVA and of natural polymers is given deserved emphasis.Careful editing has ensured a pleasing uniformity of style and presentation, and there is an adequate index. This well-written and informative book belongs on the shelves of all practitioners of SEC. Keith D. Bartle 5190012C University of Leeds Chemometrics: Experimental Design By Ed Morgan. Analytical Chemistry by Open Learning. Pp. xviii + 276. John Wiley and Sons Ltd. 1995. Price f 19.50. ISBN 0-471-95832-8. This book is one in the Analytical Chemistry by Open Learning (ACOL) series of texts and so it is somewhat different from standard textbooks. The scope of the book is ‘Experimental Design’ and it is split into 5 main sections. The first is an overview of basic statistics, covering errors and significance testing and ANOVA, all of which are important in experimental design.The second section introduces the basics of design, especially randomization, replication and blocking as well as some simple experimental designs. Part three covers factorial designs while the fourth section covers briefly fractional factorials and the final section covers response surface method- ology and central composite designs. The scope of the book is very good. The reader will get a full grounding in experimental design; it is well written and easy to read with many useful examples. In the areas of maths and chemistry working through ‘The reader will get a full grounding in experimental design; it is well written and easy to read with many useful examples.’ problems and theory is very important and ample good examples are provided.The statistics section is very clear and will serve well as a referesher. The randomization and blocking section (which includes ANOVA) is well balanced and clear. The final section of the book also includes a brief refresher of matrix maths which is very welcome in this text. Sections three and four cover factorial and fractional designs, a topic which students do find challenging, especially the calculation of effects and interactions. This is dealt with thoroughly, showing both commonly used methods for calculation and for displaying graphically the design responses. Section five is the most complex part of the book, with a great deal of detail on the mechanics of response surface methodology (RSM) and central composite design (CCD). The level of detail is useful to give a good understanding of RSM and CCD, but I think that students might find this a somewhat difficult chapter to get to grips with; it is easy to lose sight of the aims because of the maths.On balance this is a good text for the undergraduate or masters student studying analytical chemistry; it is reasonably priced and well produced. A. D. Walmsley 5190059 J University of Hull ~ ~~~~ Capillary Electrophoresis Guidebook. Principles, Opera- tion, and Applications Edited by Kevin D. Altria. Methods in Molecular Biology. Volume 52. Pp. ix + 350. Humana Press. 1995, Price $74.50; f49.00. ISBN 0-89603-31 5-5. ~ ~~~~ Volume 52 in the Methods in Molecular Biology Series, as the title suggests, is not a standard text on a relatively new analytical technique.It comprises two separate sections. Part I is indeed a guidebook in which the editor and principal author has recorded his obvious expertise in the practical use of capillary electrophoresis (CE). In Part I1 he has used his knowledge of this rapidly developing field to compile a collection of contributions from other international scientists who are expert in specific areas of the general field of CE. Part I is a very practically oriented account of basic operating procedures to obtain separation and quantitation using modem76N Analyst, June 1996, Vol. 121 electrophoretic techniques. It consists of 1 1 fairly short chapters by the editor. These cover basic theory of CE, commercial equipment design and aspects of separation and quantitation.The chapters on optimisation of precision and sensitivity will be of particular interest to chromatographers dealing as they do with the perceived limitations of CE compared with LC. AIso of interest is the chapter on method validation which outlines validation procedures for several types of drug assay. Part I concludes with chapters on fraction collection, trouble shooting and a very quick guide to good instrument practice. All of the topics in this first section of the text are designed to help the reader to get practical results. Many of the chapters are generously illustrated with flow charts which allow the application of basic theory in a practical context. Quantitation methods are explained in detail and, while many are those encountered and employed generally in drug analysis, it is useful to have these discussed for CE where the factors affecting peak area differ from those in LC.Part I1 is more conventional in that it consists of individual chapters dealing with particular techniques or applications involving CE. Micellar electrochemical chromatography, capil- lary gel electrophoresis and chiral separations all receive individual chapters. There is a chapter devoted to capillary electrochromatography which, although brief, reviews some of the theoretical aspects and also assesses the practical problems associated with this embryonic technique. The chapter on sample stacking deals with the concentration sensitivity limits of CE and explains the principles and consequences of on- column sample concentration by transient isotachophoresis and field amplification.There are application chapters on bases including nucleosides and oligonucleotides, the separation of peptides and protein digests and a separate chapter on pharmaceutical analysis in which impurity determinations, main component assays and chiral analysis are reviewed. This section concludes with a general chapter on applications in various diverse fields which illustrates the breadth of applica- tion of CE as a separation method. This text is very well referenced and will provide a valuable source of literature information channelled into specific areas. The book is modern and several chapters contain notes added in proof which add to the topicality and thus usefulness of the material.It will be helpful to separation scientists who are convinced of the merits of LC and who wish to assess CE for themselves. It will also be an invaluable aid for students who wish to obtain an overview of, as the editor describes it, ‘the wonderful world of CE’. R . B . Taylor 5190097B Robert Gordon University, Aberdeen Chemometrics in Environmental Chemistry. Applica- tions Edited by J. Einax. The Handbook of Environmental Chemistry. Volume 2. Part H. Pp. vii + 346. Springer- Verlag. 1995. Price DM 198.00; f86.00. ISBN 3-540-58943-0. If you are an environmental scientist who deals with multi- variate data sets then this book is worth reading. Despite the disparate nature of the subject covered in each chapter the common theme of chemometrics ties the whole volume into a coherent text book.This book forms a sub-volume of Volume 2 of what appears to be a continually evolving handbook of three volumes on environmental chemistry. Volume 2 is broadly based on reactions and processes in the environment. This sub-volume (2H-Applications) along with a sister sub-volume (2G- Statistical Methods, not reviewed here) are concerned with the use of chemometrics in environmental applications. The stated aims of the editor of the volume are to describe basic principles of modem chemometric methods applied to representative problems of environmental chemistry and, in doing so, to arouse the interest of the environmental scientist not yet concerned with applying statistical and mathematical methods to his own field of work.These objectives appear to have been achieved. ‘If you are an environmental scientist who deals with multivariate data sets then this book is worth reading.’ The book is divided into nine chapters each written by an expert author. Chapters 1 and 2 look at applications for organising and extracting data from large data sets, namely library search methods for spectral data of organic compounds and pattern recognition for classification and identification of organic compounds from mass spectra. The following three chapters give specific examples of how chemometric methods can be adapted to the solution of specific problems of resolving mixtures and identifying sources in airborne particulate analy- sis; finding solutions to important geochemical problems in petroleum geochemistry; modelling quantitative structure activ- ity and structure property relationships as the basis for the assessment of potential damage to the ecosphere and/or human beings.The problems of validating analytical methods, the evaluation of performance of laboratories involved in environ- mental analysis, the management of data related to statistical processing and quality control and the use of laboratory management information systems are addressed in the next three chapters. Finally, the last chapter gives an overview of automated analysis for the monitoring of water quality. Considering the wide range of the contributions to this volume, the editor has managed to put together a sensible and logical structure, apart from the last chapter which is related to water quality monitoring.This seems to have rather tenuous links to chemometrics and seems out of place compared to the other contributions. Each of the chapters is a very detailed account of its subject with a very comprehensive list of references. The level of detail is such that it could not be read from cover-to-cover and the reader needs to have some basic knowledge of chemometric methods to make the most of the information. However, as a book to dip into in order to look at a specific technique, the detail and background make it an excellent reference volume. Although the areas covered are quite diverse the examples are explained in enough detail to allow the reader to see how the solution to the problems described can relate to their own applications.Mark Cave 5190080H British Geological Survey, Keyworth, Nottingham ~ Advances in Electrochemical Science and Engineering. Volume 4 Edited by Heinz Gerischer and Charles W. Tobias. Pp. v i + 430. VCH. 1995. Price DM248.00. ISBN 3-527-29205-5. This volume contains six chapters which address challenging problems in a variety of areas in both fundamental and applied electrochemistry. The first three chapters are mainly concerned with the study of electrochemical reactions occurring at surfaces. The first of these deals with scanning tunnelling microscopy (STM) of semiconductor electrodes. STM is now a powerful tool in surface science, and when operated in the form77N Analyst, June 1996, Vol. 121 ~~ ‘this volume is a good addition to this rela- tively new series on electrochemical science and engineering9 of scanning electrochemical microscopy (SECM), can provide important information on fast heterogeneous and homogeneous reactions and processes occurring at electrode surfaces.The second chapter then deals with the specific subject of the surface chemistry of silicon in fluoride electrolytes. This has important applications in the areas of microelectronics, sensors and photocatalysis, but is again a subject which has benefitted greatly from spectroscopic and microscopic techniques which can probe surfaces on an atomistic scale. This theme is again taken up in chapter three which shows how FTIR spectroscopy can be used in situ to characterize the metal-electrolyte interface at a molecular level, using examples such as the adsorption of carbon monoxide, alcohols, pseudohalide ions and oxyanions at a variety of electrode surfaces. The next two chapters then deal with electrochemical reactions in non-aqueous and mixed solvents and at phase boundaries. Although these are written from a fundamental electrochemistry viewpoint, the informa- tion provided would have some relevance for electroanalytical chemists interested in areas such as organic-phase enzyme electrodes and sensors. The final chapter then discusses electrolytic processes for pollution treatment and pollution prevention. All the chapters have been written by well renowned scientists in their respective fields. Because of the range of topics covered, however, I can only really recommend the book for purchase by libraries of institutions where a good deal of fundamental or applied electrochemistry is being carried out. For the practising analytical (electro)chemist, the book is probably too specialized. Nevertheless, this volume is a good addition to this relatively new series on electrochemical science and engineering, and a worthy tribute to one of its editors in particular, Prof. Heinz Gerischer, who passed away shortly after completing his editorial work on it. Malcolm R. Smyth 51900 78F Dublin City University

ISSN:0003-2654    

DOI:10.1039/AN996210073N

出版商:RSC    

年代:1996

数据来源: RSC

摘要:

78N Analyst, June 1996, Vol. I21 Conference Diary Date 1996 July 1-3 3-4 5-1 1 8-12 14-18 15-17 15-19 17-19 21-26 22-23 22-25 23-26 28-1/8 Conference Location 9th International Symposium on Polymer Analysis and Characterization (ISPAC-9) UK Oxford, Atmospheric Chemistry of Sulfur in Relation to Aerosols, Clouds and Climate London, UK 14th Analytical Chemistry Division Adelaide, Conference Australia XVI International Congress of Clinical Chemistry UK London, International Symposium on Environmental Sydney, Chemistry and Toxicology Australia 4th European Conference on Thermal Plasma Athens, Processes Greece 9th International Conference on Quantitative Surface Analysis UK Surrey, 8th Biennial National Atomic Spectroscopy Symposium (BNASS) UK Norwich, 38th Annual Rocky Mountain Conference on Analytical Chemistry USA Denver, CO, 33rd R & D Topics Meeting Nottingham, UK Sixth International Meeting on Chemical Sensors USA Gaithersburg, 12th Annual Waste Testing and Quality Assurance Symposium USA Washington, DC, AACC 48th Meeting and Clinical Laboratory Exposition USA Chicago, IL, Contact Professor John Dawkins, Department of Chemistry, Loughborough University of Technology, Loughborough, Leicestershire, UK LE 1 1 3TU Fax: +44 (0)1509 233163 The Royal Society, 6 Carlton House Terrace, London SWlY 5AG, UK Tel: +44 (0)171 839 5561.Paul Lindon, Royal Australian Chemical Institute, Analytical Chemistry Group (SA) Tel: +61 8 226 6414. Fax: +61 8 226 6316. E-mail: pwl@hcl.health.sa.gov.au Mrs. Pat Nielsen, XVIth International Congress of Clinical Chemistry, P.O.Box 227, Buckingham, UK MK 18 5PN Fax: +44 (0) 1280 6487 InterSECT '96, P.O. Box 787, Potts Point, NSW 201 1, Australia Tel: +61 2 357 2600. Fax: +61 2 357 2950 Dimitrios Rapakoulias, Chemical Engineering Department, University of Patras, P.O. Box 1470, Rio Patras, Greece Tel: +30 61 993361. E-mail: http://armodios.chemeng.upatras,gr. Professor J. E. Castle, University of Surrey, Department of Materials Science and Engineering, Guildford, Surrey UK GU2 5XH Tel: +44 (0)1483 259150. Fax: +44 (0)1483 259508. E-mail: j .castle@surrey:ac.uk Ms. Brenda Holliday, BNASS Secretariat, Royal Society of Chemistry, Thomas Graham House, Science Park, Milton Road, Cambridge, UK CB4 4WF Tel: +44 (0)1223 420066. Fax: +44 (0)1223 423623 Glenda E. Brown, USGS NWQL, 5293 Ward Road, Arvada, CO 80002, USA Tel: +1 303 467 8122.Fax: +1 303 431 8331 The Secretary, Analytical Division, Royal Society of Chemistry, Burlington House, Piccadilly, London WlV OBN, UK Tel: +44 (0)171 437 8656. Fax: +44 (0)171 437 8883 Howard H. Weetall, National Institute of Standards and Technology, 222/A353, Gaithersburg, Maryland, 20899, USA Tel: +1 301 975 2628. Fax: +1 301 330 3447. E-mail: weetall@micf.nist.gov Department of Meetings, Attn. ACS/EPA Symposium, American Chemicl Society, 1155 16th St. NW, Washington, DC 20036, USA Tel: +1 202 872 6286. Fax: +1 202 872 6128. E-mail miscmtgs@ acs.org 1996 AACC Annual Meeting, American Association for Clinical Chemistry, 2101 L Street NW, Suite 202, Washington, DC 20037- 1526, USA Fax: +1 202 833 4576Analyst, June 1996, Vol.121 79N ~- Date Conference August Location 10-13 11-15 11-16 11-16 20-23 2 1-23 25-29 25-30 42nd International Conference on Analytical London, Science and Spectroscopy Canada Microscopy and Microanalysis '96 Minneapolis, MN, USA Gordon Research Conference on Plasma New Hampton, USA Processing Science NH, ICORS '96: XV International Conference on Raman Spectroscopy USA 7th International Symposium on Osaka, Pharmaceutical and Biomedical Analysis Japan (PBAT '96) Pittsburgh, Fourth International Symposium on Capillary York, . - Electrophoresis 212th American Chemical Society National Meeting XXIII EUCMOS September 1-7 1 -7 4-6 8-1 1 8-12 8-1 3 Cellular and Molecular Biology 2nd World Congress Euroanalysis IX Traceability and Comparability of 'Amount of Substance' Measurements 22nd Annual Meeting of the British Mass Spectrometry Society 4th International Conference on Nanometer Scale Science and Technology CLEO '96: European Conferences on Lasers and Electro-Optics UK Orlando, FL, USA Balatonfured, Hungary Ottawa, Canada Bologna, Italy Noordwijkerhout, The Netherlands Swansea, UK Beijing, China Ham burg, Germany Contact Martin Stillman, University of Estern Ontario, Department of Chemistry, London, ON N6A 5B7, Canada Tel: +1 519 661 3821.Fax: +1 519 661 3022. E-mail: stillman@uwo.ca Microscopy and Microanalysis '96,4 Barlow Landing Road, Suite 8, Pocasset, MA 02559, USA Tel: +1 508 563 1155. Fax: +l 508 563 121 I . E-mail: businessoffice@msa.microscopy.com; WWW: http://www.msa.microscopy.com S.L. Girschick, University of Minnesota, Department of Mechanical Engineering, 11 1 Church St. S., Minneapolis, MN 55455, USA Tel: +1 612 625 5315. Fax: +1 612 624 1398. E-mail: sig.@maroon.tc.umn.edu Professor S. Asher, Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, USA Professor Susumu Honda, Faculty of Pharmaceutical Sciences, Kinki University, Kowakae 3-4-1, Higashi Osaka 577, Japan Fax: +81 6 721 2353 Dr. T. L. Threlfall, Industrial Liaison Executive, Department of Chemistry, University of York, York, UK YO1 5DD Tel: +44 (0)1904 432576. Fax: +44 (0)1904 4325 16 E-mail: js20@york.ac.uk Department of Meetings, American Chemical Society, 1155-15th NW, Washington, DC 20036, USA Tel: +1 202 872 4396. Fax: +I 202 872 6128. E-mail: natlmtgs@acs.org Professor Dr.J. Mink, Department of Analytical Chemistry, University of VeszprCm, P.O. Box 158, H-8201 VeszprCm, Hungary Congress Secretariat, Suite 353, 2660 Southvale Crescent, Ottawa, Ontario, Canada K1B 4W5 Tel: +1 613 247 1344. Fax: +I 613 247 2187/9317. E-mail: mhamelin@ottawa.net Professor Luigia Sabbatini, Euroanalysis IX, Dipartimento di Chimica, Universith di Bari, Via Orabona, 4, 70126 Bari, Italy Tel: +39 80 544 2020. Fax: +39 80 544 2026 Linda Catterson, Workshop Secretary, Laboratory of the Government Chemist, Queens Road, Teddington, Middlesex, TW 1 1 OLY, UK Tel: +44 (0)181 943 7423. Fax: +44 (0)181 943 2767. E-mail: lc@lgc.co.uk Dr. Fred Mellon, Institute of Food Research, Norwich Laboratory, Norwich Research Park, Colney, Norwich, UK NR4 7UA Tel: +44 (0)1603 255299.Fax: +44 (0)1603 452578 E-mail: fred.mellon@ bbsrc.ac.uk Shijin Pang, Beijing Laboratory of Vacuum Physics, Chinese Academy of Sciences, P.O. Box 2724, Beijing 100080, People's Republic of China Tel: +86 10 256 8306. Fax: +86 10 255 6598. E-mail: pang@ image.blem.ac .cn CLEO/Europe '96, Institute of Physics, Meetings and Conferences Department, 47 Belgrave Square, London, UK SWlX 8QX80N Analyst, June 1996, Vol. 121 Date Conference Location Contact 9-1 1 Sixth International Symposium on Field Flow Ferrara, F. Dondi, Department of Chemistry, University of Tel: +39 532 291154. Fax: +39 532 240709 Dr. Vladimir Spirko, Academy of Sciences of the Czech Republic, The J. Heyrovsky Institute of Fractionation Italy Ferrara, Via L.Borsari, 46, 1-44100 Ferrara, Italy 9-1 3 PRAHA96: 14th International Conference on Prague, High Resolution Molecular Spectroscopy Czech Republic 10-14 International Symposium and Exhibition on Graz, Biomedical Optics IV Austria 1 1-1 3 International Symposium on Biological Espoo, Monitoring in Occupational and Finland Environmental Health 15-17 Third European Congress of Pharmaceutical Edinbrugh, Sciences Scotland 15-20 21st International Symposium on Stuttgart, Chromatography Germany 15-20 1996 European Workshop in Chemometrics Bristol, UK 15-20 XV National Reunion of Spectroscopists Oviedo, Spain 16-18 The Third International Conference on Nantes, Applications of Magnetic Resonance in Food France Science 16-19 International Ion Chromatography Reading, Symposium UK 16-20 5th International Conference on Plasma Durham, Source Mass Spectrometry UK 23 12th ICP-MS Applications Meeting Julich, Germany 24-26 Mass Spectrometry Processes for the Julich, Determination of Trace Elements Germany 26-27 4th International Symposium on Bucharest, Biotechnology Now & Tomorrow Romania Physical Chemistry, Dolejskova 3, CZ- 18223 Praha 8, Czech Republic Fax: +42 2 858 2307.E-mail: praha96@ jh-inst.cas .cz. or praha96@ wcpj .chemie. uni-wuppertal.de Francoise Chavel, Executive Secretary, European Optical Society, B.P. 147-9 1403 Orsay Cedex, France Tel: +33 1 69 85 35 92. Fax: +33 1 69 85 35 65. E-mail: francoise.chavel@iota.u-psud.fr Kristiina Kulha, Finish Institute of Occupational Health, Topeliukenkatu 41 a A, FIN-00250 Helsinki, Finland Tel: +358 4747 551.Fax: +358 4747 548. E-mail: kku@occuphealth.fi; WWW: http://www.occuphealth.fi 3rd EUFEPS Congress, Marshwood House, 52 Gresham Road, Staines, Middlesex, TW18 2AN, UK Tel: +44 (0)1784 464106. Fax: +44 (0)1784 455078 GDCh-Geschaftsstelle, Abt. Tagungen, Varrentrappestr. 40-42, Postfach 90 04 40, D-6000 Frankfurt am Main 90, Germany Tel: +49 69 791 7358. Fax: +49 69 791 7475 Caroline Hutcheon, School of Chemistry, University of Bristol, Cantock’s Close, Bristol B58 ITS, UK Tel: +44 (0)117 928 9000 or +44 (0)117 928 7658. Fax: +44 (0) 1 17 925 7295 Conference Secretariat,, XV Reuni6n Nacional de Espectroscopia, Grupo EspaAol de Espectroscopia, C/Serrano 12 1, 28006 Madrid, Spain Fax: +34 (9)1645557 G. J. Martin or V. Foucault, FacultC des Sciences, Laboratoire de Resonance MagnCtique NuclCaire et RCactivitiC Chimique, U.R.A.- CNRS 472, 2 rue de la Houssini?re, 44072 Nantes Cedex 03, France Tel: +33 4037 3169. Fax: +33 4074 9806 Century International, P.O. Box 493, Medfield, MA 02052, USA. Tel: +1 508 359 8777; Fax: +I 508 359 8778 or Phil Jones, Department of Environmental Sciences, University of Plymouth, Drake Circus, Plymouth, Devon, PL4 8AA, UK Tel: +44 (0)1752 233000. Fax: +44 (0)1752 233035 Dr. Grenville Holland, Department of Geological Sciences, Science Laboratories, South Road, Durham City, UK DHl 3LE Fax: +44 (0)191 374 2510 Dr. J. S. Becker, Forschungszentrum fur Chemische Analysen, D-52425 Julich, Germany Tel: +49 2461 612698. Fax: +49 2461 612560 Dr. J. S. Becker, Forschungszentrum fur Chemische Analysen, D-52425 Julich, Germany Tel: +49 2461 612698.Fax: +49 2461 612560 Ioana Spirescu, Romania Biotehnos S.A., Str. Dumbrava Roslo, nr. 18, Bucuresti 70254, Romania Tel: +40 1 210 20 15. Fax: +40 1 210 97 05. E-mail: dcornel@ cbb.bth.ro 29-04 23rd Annual Conference of the Federation of Kansas City, FACSS, 201B Broadway Street, Frederick, MD Tel: +I 301 846 4797. Analytical Chemistry and Spectroscopy USA 21701-6501 USA Societies (FACSS)Analyst, June 1996, Vol. 121 8 IN ~- Date Conference October Location 2-4 3-4 14-18 20-25 22-25 22-25 28-29 29-30 30-3 1 Second Australian Conference on Vibrational Brisbane, Spectroscopy Australia Validation in Capillary Electrophoresis Y ork, UK 7th International Beijing Conference and Shanghai, Exhibition on Instrumental Analysis (BCEIA) China Expoquimia Equiplast Eurosurfas Barcelona, Spain Pollutec 96 Lyon, France 8th Conference and Exhibition on Analytical Instrumentation Spain Barcelona, Monitor '96 Manchester, UK Third European Symposium on Near Infrared (NIR) Spectroscopy.On-Line Use Kolding, Denmark International Workshop on Metallothioneins Geel, Belgium November 4-8 International Symposium on the Industrial Johannesburg, Application of the Mossbauer Effect South Africa 12-1 5 International Exhibition and Conference for Basel, Chemical Technology, Analytical Technology Switzerland and Biotechnology 13 Capillary Electrophoresis Meeting Hertfordshire, UK 13-15 13th Montreux Symposium on Liquid Mon treux, Chromatography-Mass Spectrometry Switzerland 17-22 1996 Eastern Analytical Symposium Somerset, NJ, USA 21 Spectroscopic Detection in Process Analysis Hull, (11) UK Contact Peter Fredericks, School of Chemistry, Queensland University of Technology, P.O.Box 2434, Brisbane, Queensland 400 1, Australia Tel: +61 7 3864 2341. Fax: +61 7 3864 1804. E-mail: p. fredericks .@ qut. edu. au Dr. T. L. Threlfall, Industrial Liaison Executive, Department of Chemistry, University of York, York, UK YO1 5DD Tel: +44 (0)1904 432576. Fax: +44 (0)1904 4325 16 E-mail: js20@york.ac.uk BCEIA '97 General Service Office, Room 585, Chinese Academy of Sciences Building, P.O. Box 2143, Beijing 100045, China Tel: +86 10 6851 1814. E-mail: bceia@aphyOl .iphy.ac.cn Expoquimia Equiplas Eurosurfas, Fira de Barcelona, Avda. Reina Ma Cristina, E-08004, Barcelona, Spain Michele Jackson or Vinod Mahtani, Promosalons (UK) Ltd., 82 Bishops Bridge Road, London W2 6BB, UK Tel: +44 (0)171 221 3660.Fax: +44 (0)171 792 3525 8as Jornadas de Analisis Instrumental (JAI) Expoquimia, Av. Reina Ma Christina-Palacio No. 1, 08004 Barcelona, Spain Tel: +93 233 20 00. Fax: +93 233 23 11, +93 423 63 48 Spring Innovations, 185A Moss Lane, Bramhall, Stockport, Cheshire, UK SK7 1BA Tel: +44 (0)161 440 0082. Fax: +44 (0)161 440 9127 Biotechnological Institute, Holbergsvej 10, P.O. Box 8 18, DK-6000 Kolding, Denmark, Attn: Lone Vejgaard (Chairman) Tel: +45 75 52 04 33. Fax: +45 75 52 99 89 Dr Guy Bordin, European Commission-Joint Research Centre-IRMM, Retieseweg, B-2440 Geel, Belgium Fax: +32 14 584 273. E-mail: bordin@irmm.jrc.be Herman Pollak, Mossbauer Laboratory, University of the Witwatersrand, Private Bag 3, WITS 2050, Johannesburg, South Africa Tel: +27 11 716 4053/2526.Fax: +27 11 339 8262. E-mail: isiame@physnet.phys.wits.ac.za L. E. Loew, ilmac96, Messe Bassel, CH-4021 Basel, Switzerland Tel: +41 61 686 2707. Fax: +41 61 686 2188 Mrs Gill Caminow, The Chromatographic Society, Suite 4, Clarendon Chambers, 32 Clarendon Street, Nottingham NG1 5JD, UK Tel: +44 (0)115 950 0596. Fax: +44 (0)115 950 0614 M. Frei-Hausler, Postfach 46, CH-4123 Allschwil 2, Switzerland Tel: +41 61 481 2789. Fax: +41 61 482 0805 EAS, P.O. Box 633, Montchanin, DE 19710-0633, USA Tel: +1 302 738 6218. Fax: +1 302 738 5275 Dr. J. S. Lancaster, BP Chemicals, Hull Research Centre, Saltend, Hull, UK HU12 8DS Tel: +44 (0)1482 894803.Fax: +44 (0)1482 89217182N Analyst, June 1996, Vol. 121 Date Conference Location Contact 24-30 4th Rio Symposium on Atomic Spectrometry 1997 January 4-9 The Fourth International Symposium On: Giza, New Trends in Chemistry The Role of Egypt Analytical Chemistry in National Development Buenos Aires, Argentina Osvaldo E. Troccoli, Quimica Analitica, Facultad de Ciencias Exactasy Naturales, Ciudad Universitaria, (1428) Buenos Aires, Argentina Tel: +54 1 783 3025. Fax: +54 1 782 0441. E-mail: troccoli@ trazas.uba.org or batiston@cena.edu.ar 12-16 International Conference on Flow Injection Orlando, Analysis-ICFIA 97 USA 12-17 1997 European Winter Conference on Plasma Gent, Spectrochemistry Belgium 20-24 First Asia-Pacific EPR/ESR Symposium 26-30 9th International Symposium on High Performance Capillary Electrophoresis and Related Microscale Techniques March 9-14 CANAS '97 Colloquium Analytische Atomspektroskopie 16-21 48th Pittsburgh Conference on Analytical Chemistry and Applied Spectroscopy April 13-17 213th American Chemical Society National Meeting 14-19 Genes and Gene Families in Medical, Agricultural and Biological Research: 9th International Congress on Isozymcs May 12-16 European Symposium on Photonics in Manufacturing I11 Professor Dr.M. M. Khater, Chemistry Department, Faculty of Science, Cairo University, Giza, Egypt ICFIA 97, Sue Christian, P.O. Box 26, Medina, WA Fax: +1 206 454 9361. E-mail: sue@flowinjection.com L. Moens, Secretariat, 1997 European Winter Conference, Laboratory of Analytical Chemistry, University of Gent, Proeftuinstraat 86, B-9000, Gent, Belgium Tel: +32 9 264 66 00.Fax: +32 9 264 66 99 E-mail: plasma97@rug.ac.be Professor C. Rudowicz, Chairman, LOC & IOC, City University of Hong Kong, Department of Physics and Materials Science, 83 Tat Chee Avenue, Kowloon, Hong Kong Tel: +852 2788 7787. Fax: +852 2788 7830. E-mail: apsepr@cityu.edu.& Shirley Schlessinger, Symposium Manager, HPCE '97, 400 East Randolph Street, Suite 1015, Chicago, IL 60601, USA Tel: +1 312 527 2011. 98039-0026, USA Hong Kong Anaheim, USA Freiberg/Sachsen, Germany G. Werner, Universitat Leipzig, Institut fur Analytische Chemie, Linnestrasse 3, D-04103 Leipzig, Germany Tel: +49 0341 973 6101. Fax: +49 0341 973 6115 Linda Briggs, The Pittsburgh Conference, 300 Penn Center Blvd., Suite 332, Pittsburgh, PA 15235-5503, USA Tel: +I 412 825 3220, +1 800 825 3221. Fax: +1 412 825 3224 Atlanta, GA, USA San Francisco, CA, Department of Meetings, American Chemical USA Society, 115516th St. NW, Washington, DC 20036, USA Tel: +I 202 872 4396. Fax: +I 202 872 6128. E-mail: natlmtgs@acs.org Mrs. Janet Cunningham, Barr Enterprises, 10120 Kelly Road, P.O. Box 279, Walkersville, MD 21793, USA Tel: +1 301 898 3772. Fax: +1 301 898 5596 Texas, USA Paris, France Francoise Chavel, Executive Secretary, European Optical Society, B.P. 147-91403 Orsay Cedex, France Tel: +33 1 69 85 35 92. Fax: +33 1 69 85 35 65. E-mail: francoise.chavel@iota.u-psud.fr

ISSN:0003-2654    

DOI:10.1039/AN996210078N

出版商:RSC    

年代:1996

数据来源: RSC

摘要:

Analyst, June 1996, Vol. 121 83N Courses Date 1996 July 1-2 1-5 9 10-1 1 23-25 Conference Fourier-Transform Infrared Spectroscopy Summer School in Spectroscopic Interpretation Preparing Samples for ICP Analysis Inductively Coupled Plasma Mass Spectrometry Problem Solving for Analytical Leaders August 18-2 1 Capillary Electrophoresis Course 19-2 1 Aerosol and Particle Measurement 22-23 Air and Gas Filtration September 3-5 HPLC Beginners Training Course 3-6 Clinical Nutrition Location Manches ter, UK Manchester, UK Siwood Park, UK Silwood Park, UK York, UK York, UK Minneapolis, USA Minneapolis, USA Macclesfield, UK Leeds, UK Contact Dr. N. H. P. Smith, Chemistry Department, UMIST, P.O. Box 88, Sackville Street, Manchester, UK M60 Tel: +44 (0)161 200 4491. Fax: +44 (0)161 236 7677 Dr.N. H. P. Smith, Chemistry Department, UMIST, P.O. Box 88, Sackville Street, Manchester, UK M60 1QD Tel: +44 (0)161 200 4491. Fax: +44 (0)161 236 7677 Sally Verkaik, Continuing Education Centre, Imperial College, Room 558, Sherfield Building, Exhibition Road, South Kensington, London, SW7 2AZ, UK Tel: +44 (0)171 594 6882. Fax: +44 (0)171 594 6883. E-mail: cpd@ic.ac.uk Sally Verkaik, Continuing Education Centre, Imperial College, Room 558, Sherfield Building, Exhibition Road, South Kensington, London, SW7 2AZ, UK Tel: +44 (0)171 594 6882. Fax: +44 (0)171 594 6883. E-mail: cpd@ic.ac.uk Dr. T. L. Threlfall, Industrial Liaison Executive, Department of Chemistry, University of York, York, UK YO1 5DD Tel: +44 (0)1904 432576. Fax: +44 (0)1904 432516 E-mail: js20@york.ac.uk 1QD Dr.T. L. Threlfall, Industrial Liaison Executive, Department of Chemistry, University of York, York, UK YO1 5DD Tel: +44 (0)1904 432576. Fax: +44 (0)1904 432516 E-mail: js20@york.ac.uk Registrar, Professional Development and Conference Services, University of Minnesota, 235 Nolte Center, 315 Pillsbury Drive S.E., Minneapolis, MN Fax: +1 612 626 1632 Registrar, Professional Development and Conference Services, University of Minnesota, 235 Nolte Center, 315 Pillsbury Drive S.E., Minneapolis, MN Fax: +1 612 626 1632 55455-01 39 55455-0139 Nikki Rathbone, HPLC Technology Ltd, Macclesfield, Cheshire, UK SKI 1 6PJ Tel: 01625 613848. Fax: 01625 616916 Mrs. Hilary L. Thackray, Department of Continuing Professional Education, Continuing Education Building, Springfield Mount, Leeds, UK LS2 9NG Tel: +44 (0)113 233 3233. Fax: +44 (0)113 233 3240 Entries in the above listing are included at the discretion of the Editor and are free of charge. If you wish to publicize a forthcoming meeting please send full details to: The Analyst Editorial Office, Thomas Graham House, Science Park, Milton Road, Cambridge, UK CB4 4WF. Tel: +44 (0)1223 420066. Fax: +44 (0)1223 420247. E-mail:Analyst@RSC.ORG.

ISSN:0003-2654    

DOI:10.1039/AN996210083N

出版商:RSC    

年代:1996

数据来源: RSC

摘要:

84N Analyst, June 1996, Vol. I21 Interviews With Professor G. Guilbault and Mr. R. Lundin At Sensors and Signals 111, held in Malahide, Co. Dublin, on 26-27 October 1995, the Managing Editor of The Analyst Harp Minhas (HM) and one of the organizers, Professor Malcolm Smyth (MS) took the opportunity to speak to two of the leading participants: Professor Georges Guilbault (GG) of University College Cork, Cork, Ireland and Mr. Rune Lundin (RL) of EDT Instruments Ltd., Dover, Kent, UK. Professor Georges Guilbault HM: GG: HM: GG: HM: GG: MS: GG: Can you give us a brief autobiography, telling how you came to be where you are today? After graduating from Princeton in 1961 I took a short stint with Proctor and Gamble, trying to develop a fluoride electrode. Then I was called into the Military because of the Berlin Wall crisis in 1961 and was assigned to Edgeward Arsenal, MD, where I was given a position as head of detection research for the US Army.The Commanding General gave me my first task, which was to build an alarm for NATO that was completely specific, very sensitive and had to respond within five seconds because that was the limit of the reversibility of the nerve agents that soldiers might be exposed to. The only way I could think of achieving this was with immobilized enzymes. I built the first enzyme alarm back in 1962; a prototype was used by all the NATO countries until about 1990. In 1964 I built the second alarm system, based on ion-mobility, with the help of a physicist, using time of flight of a mass at atmospheric pressure, and that is the current NATO alarm system used today.In the time at Edgeward we did several things, one of which was to develop a fluorescent staining system for enzyme location in histochemistry, which is still very widely used today and isoenzyme separation methods. I built a system for Dade that is used today in the Pheonix Instrument Astra, which is based on measurement with immobilized alkaline phosphatase on a paper strip for thyroxine or digoxin and other similar substances. In New Orleans I accepted a Professorship in 1966 and spent almost 30 years there until this current year when I accepted a Professorship at University College Cork in Ireland, and that is where I am right now. I have always been interested in gadgets and building new systems and I started with Universal Sensors in 1981 and we did about $5000 of business.This last year we did about $800 000 of business and I am in the process of opening the company in Ireland, with a couple of new products I have in mind, which are different from what we did before. Can you tell us more about your research projects? Here in Ireland or before? Well, I assume that you are continuing some of them? The main interests I have now are in immunosensing with immobilized antibodies in different modes and various transducer systems. In optics now we are trying to develop the first prototype for aflatoxins in grain based on the direct binding of the aflatoxin to an antibody on an optode and measuring the fluorescence of the aflatoxin. In a piezoelectric device we have just developed through the company, which we hope to market in Europe for the first time, Universal Sensors Ireland has a new pz tools computer program to drive the piezo instrument to make it operate exactly like the BIACORE, that is so we can monitor antigen-antibody drug receptors or any type of interaction directly on a crystal continuously in a flow system, read the response on the computer, calculate all the binding constants for the reaction and output the results on computer tape.The other products we are trying to develop now are on-line biosensors for the food industry, particularly in bacteria, Listeria, E . Coli and Salmonella, developing a method that can be used directly on-line to measure the contamination of food in production and to measure the concentration of lactoseflactate fermentation in the cheese industry, or to measure alcohol in Jamesons, for example, or several other products.We are working with pharmaceutical companies in Cork on developing this piezo immunosensor to look at drug receptor interactions directly. Also in the clinical field I have contact with a company in Ireland to build a sensor being sponsored by the Forbrit to the Irish Science Foundation, isoenzyme electrodes that could be used directly as probes to measure for LDH 1 and 5, alkaline phosphatase esterophosphatase prostate-specific antigen and other similar new clinical tests. Can I ask you, now that you are an academic, and all academics are now forced to work in applied areas and get involved with company research, how do you, as you have bridged the gap and set up your own company, see the relationship between academia and industry? Well, I view every project as having to have a specific aim to benefit mankind; some specific thing that will be of benefit to somebody and not just do basic research like maybe physical electrochemists do.It’s more applied. All my research has been applied and I think it works very well.in Ireland, because all the research appears to have been goal oriented. Now, ForbritAnalyst, June 1996, Vol. 121 85N HM: GG: MS: GG: MS: GG: HM: GG: MS: GG: HM: GG: HM: GG: HM: GG: HM: GG: is looking directly for final product oriented research and they don’t support basic research anymore. So I think the analytical chemists have the key. How does that compare with the situation in the United States? It’s the opposite.They are more basic research oriented and if something comes about then that’s fine. The only applied research we can get in America is through the, so called, small business grants which are funded by the Federal Government; we have several of those in the company with the Agriculture Department (USDA), where we built the food analysis electrochemical system that we offer through Universal Sensors for direct monitoring of substances in food. We also built a sulfide optical sensor for the USDA to measure sulfide as a preservative in food, and under Department of Defense (DOD) grants the piezoelectric system for nerve agents and for toxins in the air, brevotoxin, saxitoxin and ricin; we built piezo and electrochemical systems for all of those. You have mentioned your work with NATO and DOD; are the armed forces still very interested in sensor technology? I think definitely, not particularly in Europe but in America.In Europe it is primarily collaborative grants between different countries, but in America the DOD has the most money still and, with Congress on a cutting spree, the last area that hasn’t disappeared yet in basic research funding is military research. The larger corporations in America, I hear, are thinking of getting out of pure research and basically funding pure research in the Universities? Well, they are going more into applied research: I think, everyone is really. The days in America of basic research are just about finished now that the Republicans are in power.The next ten years is supposed to be the sensor revolution. How do you see sensors in ten years time; you have already been through 30 years with them? That’s a very good question; it took many years for the electrode to finally come about. I guess the first amperometric electrode was by Clark in 1962 and only recently with Medisense and other companies really marketing these have we seen a boom in biosensors. I think the problem was the medical doctor, who was very opposed to getting into this area. Once that was solved I think the biosensors have taken over. Medisense did a lot for the electrode world with the glucose electrode, even though it still needs some development: I was at the diabetes centre a few weeks ago and they didn’t recommend the Medisense because they said it had too high a degree of variability in response compared with the colorimetric procedures, but I think its an inroad.What I am trying to do is really build electrodes to measure substances like bacteria directly with a ‘pen’ electrode; toxins or isoenzymes for just about anything built the size of a pen. The other area of research is the optrode, and the optrode has been touted as a very good idea because it eliminates the selectivity problems that exist in electrodes, particularly in the brain and blood, where you have many different electroactive compounds, but no one has ever built a small optrode. That is a problem, and even people like Wolfbeis, who pioneered this area, have already given up hope of ever building a tiny optrode the size of an electrode.Whether they will ever come, I don’t know, but I think we can build one maybe twice the size of a pen that works very well. Maybe that is sufficient, I don’t know, but it does have a lot of promise in different areas to the electrode. This conference has tried to bring together people with sensors experience and those with chemometrics; how do you view the whole area of signal processing? Signal processing is a wonderful area, in fact I have a colleague back at the University in New Orleans who is a physical chemist who says it’s ridiculous to talk about 2 : 1 signal-to-noise: he would like to talk about 1 : 15. He claims he can resolve any signal by a suitable chemometrics program in the midst of a hundred other things and there are still limits to what you can do, so I think obviously chemometrics has a strong place in the future.What do you think the future holds in this field? In biosensors? Yes. I think single self-contained probes for assays in the environmental and clinical fields, and in food chemistry is very important. I view immunosensors as being ultimately very important and other areas coming to the fore recently are non-invasive sensors. We built an electrode for glucose 10 years ago using the transbuccal mucosa, and the only problem was the physiology of the patient; not that we could not build the electrode. Today, the Japanese have a wrist watch that athletes can wear to monitor their lactate in sweat while they are exercising, so I think these non-invasive sensors will be very important in the future too.Saliva testing is also important. Do you see any major obstacles in this field, in the field of sensors generally? The only obstacle I can see is really the electronics and how small you can build them and how reliable. I think the basic biochemistry can be solved by designing new antibodies for almost anything now. Professor Guilbault, thank you very much for your time and for imparting your experiences to us. Thank you, the pleasure was mine.86N Analyst, June 1996, Vol. I21 Mr. Rune Lundin HM: RL: MS: RL: MS: RL: MS: RL: HM: RL: MS: RL: MS: RL: Can you tell us a little bit about yourself, your academic background and how you came to be where you are today? I am a chemical engineer by education. In 1969 I joined a company called Bifok AB.Amongst other things I became involved in both the development and selling of ion-selective electrodes. This being a new technique at the time, my colleagues and I would give lectures on the theory and use of ISEs and it was at this time that I first met Jaromir Ruzicka. Some years later Ruzicka presented the first lecture on flow injection analysis, at Lund University. I immediately became interested in the technique of FIA and the possibility of commercializing it. What company were you working for at this time? By this time I was the sole owner of Bifok AB. I was happy to have working for me my old friends Torbjorn Anfalt and Bo Karlberg. As a result of the early demonstrations and lectures that we gave on FIA, many larger organizations showed an interest in forming a partnership with my comapny.Eventually I teamed up with Perstorp AB. With the backing of Perstorp we were really able to develop the FIA system. After two years I sold my company to Perstorp and joined Pernovo AB, the New Business Development arm of Perstorp. At that time, Pernovo’s main business areas were in Plastic Additives and Noise Abatement. The only company in the group on the analytical side was Tecator AB. The aim of Pernovo was to highlight small enterprises such as university research projects, small start-up companies and so on and then to support them with mangement skills and money to help them to grow to a position where they could be absorbed into one of the Perstorp business areas. Tecator had been, in fact, one of the small start-up comanies taken on by Pernovo.At that stage it had consisted five people in a small flat, using their bathroom as a chemical laboratory! When I left Pernovo about five years ago, there were around 30 companies in the analytical/biotec group, which today has a turnover of around 2100 million. Why did you leave? Well, because I did a management buyout of one of the companies in the analytical group, EDT Instruments Ltd. EDT had been one of the companies acquired by Pernovo. We thought it would provide us with a good platform in the UK and improve our links with British universities. EDT were producing low cost products whereas the other analytical companies in the group were producing capital items. This meant that it wasn’t easy to fit EDT products into the sales structure used by Perstorp Analytical.It was difficult to use the same sales person to sell a &20,000 instrument one day and one for &300 the next. For this reason Perstorp decided to sell EDT and so I bought it. Actually my connection with EDT has started as far back as 1978. Bifok had developed and patented a nitrate electrode. EDT bought the membrane under license from us and also became our UK agents for the FIA analysers. I have now been running EDT for 5 years working solely with the electrochemistry products. In fact I threw out all the other product lines. You threw out the spectroscopy? Yes. Whilst areas such as optoacoustic spectroscopy are fascinating, I personally do not have either the background or competence in such techniques.People such as Gordon Kirkbright were no longer with EDT when I bought it, so I felt that there was no champion or driving force for this type of product within EDT. When you were with Pernovo you worked with start-up companies for about I0 years in Science Parks and Universities. What is your view of Science Parks? I think it is a very good idea. You know that a lot of the prospects or ventures coming up will not survive, for a variety of reasons, but there are plenty that not only survive but grow. One of the most difficult aspects is to get someone interested in a project that was developed in a university. People are generally scared to get involved with these products. Do you mean the industrialists? Oh yes. It is difficult when it happens that way round.Of course it is much easier, from an industrialist’s point of view, if they initiate the project or are involved with it from the beginning. What are you, as an industrialist, looking for from an academic? How should that relationship really develop. What are the characteristics of that relationship? It is really a difficult question and I’m afraid there is no straight answer. Sometimes, a company comes to a scientist and asks them to develop something. The scientist does it because it fits a ‘gap’ or ‘niche’ in the industry itself. Or it can happen the other way around too. If we talk of a company operating in the food market sector. Suppose someone was to develop a newAnalyst, June 1996, Vol. 121 87N fat extraction techniqiie. It might well be the case that it would suit this company to take on and develop the new technique, hopefully improving ur perhaps expanding their existing product range.On the other hand, if you are working on a new idea that has no obvious market niche, then it is very, very difficult. In fact, it was identifying this type of project that formed the basis of our work at Pernovo. We would support such projects and either find a suitable place to slot them into within our group or even help the inventors to create a new company. There are few organizations that work in this way. Some of the venture capitalists do of course, but others are more concerned with the financial aspects. How to make capital gains. That is why 1 believe that Science Parks fulfil a useful function.It means that the scientists have to involve themselves in the business side of things. The Science Park environment helps them understand how to begin to commercialize their projects and, even though this may still be a difficult task, it allows the whole process to start on a small scale. There’s less risk involved. HM: RL: HM: RL: MS: RL: MS: RL: MS: RL: MS: RL: Do you personally favour that sort of contact, i.e. with the Science Park, rather than a laboratoryluniversity contact. Yes, I would say that this is probably the only way to be successful to sell an idea. Who can ‘see’ when they come out of a laboratory? Academics are often sure that their special project will have a big market and earn big money. It is often very difficult to convince someone from this background that there is no market for a particular project or that it will not be financially viable.Stanford University has a good system. They have a license department whose sole duty is to commercialize products and/ or create a lot of contacts. This means they can search widely for the right partner for a particular project. They have been quite successful, but even so I believe there are a lot of start-up companies set up by the individuals involved in the projects. How do you actually see academics? Do you, for example, think, that i f I , as an industrialist, have aproblem, they can provide me with the chemistry and I can take over production and commercialization? Or do you see them as partners involved in the project from start to finish? It would depend on my position at any one time.Certainly, if I have a particular development project ongoing in the company, which needs specialized knowledge from time to time, then I wouldn’t hesitate in using my academic contacts as consultants. On the other hand if, through discussion at this type of academic meeting, I come across an idea that I believe in strongly from both a technological and commercial viewpoint then I would be more likely to view this as a potential joint venture. However, as I said earlier, what a scientist may see as commercially viable I may not. Take the chap who spoke earlier about gas sensors; that was a typical example. It seemed to me that there was a great emphasis put on the need to firstly develop such a sensor and secondly develop one that would sell for $5.00.But why develop this type of sensor and why for this price? Is there really a market for this type of product? To sell a sensor for this price would mean the market would have to be enormous to make it commercially viable. Academics do not often ask themselves these questions and when they do they sometimes come up with the wrong answers. Do you mean it’s all too academic? No it’s not too academic. I believe the science is extremely important. Take a sensor as common as a pH electrode. People often describe the pH electrode as an accessory to the meter. I always say that the meter is an accessory to the pH electrode. The knowledge of chemistry and the ability to solve application problems is crucial. It’s not just about making the cheapest, smartest meter.What I mean is, no matter how clever the chemistry behind a potential product and no matter how cheaply it can be made, it must be sold at a price that provides a big enough market to make a profit. In terms of EDT, ion-selective electrodes are very important? Oh yes. In terms of the new technologies and where ion-selective electrodes are going, do you have any comments, and a feel for where the new technology will lead? I think that if you look to ion-selective electrodes, very little has happened over the last 10 years or so. There have been small add-on features, but I haven’t seen a lot happening. We now have the major research in ISFETS, but it is just the beginning and has no real advantage over the electrodes around today. There are new ligands as well as new materials but again, it’s back to finding the niche where they can be used.The development I see as coming from adaptation of electrodes to create new systems or analysers. I work a lot with flow systems to see what can be done in this area. For example, how does changing the environment around the electrode affect performance? What about the area of development of sensor arrays? That is the next thing that will come, and then, of course, the sensors will not be as important as the signal processing. Having said that, when you put these things together you have in effect got a new multi-sensor. I don’t think that you should isolate the sensor as a small element. Take the glassy carbon electrode, i.e., a universal sensor that can be used in so many different ways.It is not an enormous scientific development itself it is the combination of the sensor, the instrument and the chemistry that allows you to achieve something. Then of course you have to set the right price to get the money back. You always have to combine a number of factors when you are trying to put together a system.88N Analyst, June 1996, Vol. 121 MS: RL: MR: RL: HM: This conference has been about Sensors and Signals, so how important with the sensor arrays is the signal processing and processing information you can get? I think that the processing is the most important aspect. It allows you to use an array of sensors which are not particularly specific and develop an analytical system which is. If the sensors themselves cost between $5 to $20 you can see the added value of selling such a system for $20,000! They say that this is the decade of sensor technology. Do you, as an industrialist, feel that it’s going to be such a decade, and that there is a lot of opportunity out there for companies like yourself to exploit this and create wealth and jobs? The next ten years will, I believe, see a move of much of the analytical technology from the laboratory to on-line situations. The chemists will also find themselves working outside laboratory environments. This being the case, I think there will be a need to develop reliable on-line sensors and that this will be true regardless of whether you talk about the paper and pulp industry or life sciences or whatever. The need for more sophisticated results will, I believe, lead to a great demand for all sorts of sensors outside the traditional on-line ones for temperature, pressure, flow and so on. I see this trend as growing very quickly. Thank you very much, Rune, for your time and agreeing to be interviewed.

ISSN:0003-2654    

DOI:10.1039/AN996210084N

出版商:RSC    

年代:1996

数据来源: RSC

摘要:

Analyst, June 1996, VoE. 121 89N Sensing a Better Future Advances in chemical and physical sensor technology will hold a key to a better future particularly in meeting the needs and demands of the population in health, environmental and related areas. In 1955, and with the support of the International Fund for Ireland, sensor research groups from across Ireland joined together to establish the Biomedical and Environmental Sensor Technology (BEST) Centre. The BEST Centre seeks to promote the growth of a strong biomedical and environmental sensor industry within Ireland and further afield through close collaboration between the participating research groups and industry. The worldwide market for sensors is significant and growing rapidly though it is highly diverse and fragmented. It encom- passes so called ‘smart’ sensors, biosensors, temperature sensors, chemical sensors to name but a few.There is a wide range of underlying technologies involved in the production of sensors, be -they for industrial, environmental or biomedical applications. These include: thick-film (foils, laminates, dipped, screen printed, etc.), thin-film (vacuum deposited, sol-gel, etc.), optoelectronic sensing, solid-state, ceramic (bulk), chemical, biochemical and other synthesized material technologies. The development of these and other technologies and collaboration between them is enabling major advances to be made in a wide range of sensor applications. Concerns over environmental protection issues, and the increasing number of pollution control regulations are stimu- lating sensor developments particularly in the energy manage- ment and pollution control sectors.It is also a growing market for biomedical sensors fuelled by, among other things, the demands of a more affluent and health conscious population. For example, for clinical applications the biosensor market is expected to grow at over 20% per annum. These and other dramatic changes in the sensor industry present a dynamic business opportunity for forward-thinking product manufact- urers. The BEST Centre is a multidisciplinary distributed research centre which brings together established research groups from four universities across Ireland. The Centre represents a partnership between: the Medical Electrodes and Thin-Film Devices groups at the Northern Ireland Bioengineering Centre, University of Ulster; the Biosensors, Chemical and Optical Fibre Sensors groups at the Sensors Technology Centre, Dublin City University; the Pharmaceutical Devices Group at the School of Pharmacy, Queen’s University; and the Thin-Film Devices and Chemical Sensors Group at the Advanced Sensors Research Unit, University of Limerick.The various research groups have already pioneered ad- vances in many areas. These include: World leading disposable ECG electrodes Novel electrically conducting bioadhesive film for sensor adhesion in wet environments Cardiac electrophysiological mapping and monitoring har- nesses for emergency, hospital and home use Solid-state planar technology gas sensors for domestic monitoring and emission control Optical sensors for gas and liquid monitoring systems Electrochemical sensors for nitrate, nitrite and NO, gases Biosensors based on ‘recognition’ molecules such as enzy- mes and novel antibody based technologies Since the establishment of the Centre many new research programmes and projects have been started and bpportunities to develop new families of sensor devices and new exploitable sensing technologies are being created by the diverse and complementary range of physical, biological and chemical science, engineering and medical skills now available.Recent advances include: 0 The further development of specialist gels which, unlike conventional systems, can adhere in wet conditions. These are currently used to painlessly connect monitoring elec- trodes to a baby’s head during birth in order to ensure the early detection of any distress.0 Enhancements to vital signs and biosignal monitoring systems through the addition of blood pressure, body temperature, oxymetry and other features to existing ECG monitors. 0 Bioadhesive ion-selective sensors for rapid diagnostic appli- cations, e.g., in diseases such as cystic fibrosis. A variety of optical, electrochemical and solid-state sensors for water and air quality monitoring in pollution related, personal safety and comfort applications. For further information please contact: Dr. William Montgomery, BEST Centre, University of Ulster; Tel: +44 1232 368922; Fax: +44 1232 366863; Email: W.J.Montgomery@ulst.ac.ukAnalyst, June 1996, VoE. 121 89N Sensing a Better Future Advances in chemical and physical sensor technology will hold a key to a better future particularly in meeting the needs and demands of the population in health, environmental and related areas.In 1955, and with the support of the International Fund for Ireland, sensor research groups from across Ireland joined together to establish the Biomedical and Environmental Sensor Technology (BEST) Centre. The BEST Centre seeks to promote the growth of a strong biomedical and environmental sensor industry within Ireland and further afield through close collaboration between the participating research groups and industry. The worldwide market for sensors is significant and growing rapidly though it is highly diverse and fragmented. It encom- passes so called ‘smart’ sensors, biosensors, temperature sensors, chemical sensors to name but a few.There is a wide range of underlying technologies involved in the production of sensors, be -they for industrial, environmental or biomedical applications. These include: thick-film (foils, laminates, dipped, screen printed, etc.), thin-film (vacuum deposited, sol-gel, etc.), optoelectronic sensing, solid-state, ceramic (bulk), chemical, biochemical and other synthesized material technologies. The development of these and other technologies and collaboration between them is enabling major advances to be made in a wide range of sensor applications. Concerns over environmental protection issues, and the increasing number of pollution control regulations are stimu- lating sensor developments particularly in the energy manage- ment and pollution control sectors.It is also a growing market for biomedical sensors fuelled by, among other things, the demands of a more affluent and health conscious population. For example, for clinical applications the biosensor market is expected to grow at over 20% per annum. These and other dramatic changes in the sensor industry present a dynamic business opportunity for forward-thinking product manufact- urers. The BEST Centre is a multidisciplinary distributed research centre which brings together established research groups from four universities across Ireland. The Centre represents a partnership between: the Medical Electrodes and Thin-Film Devices groups at the Northern Ireland Bioengineering Centre, University of Ulster; the Biosensors, Chemical and Optical Fibre Sensors groups at the Sensors Technology Centre, Dublin City University; the Pharmaceutical Devices Group at the School of Pharmacy, Queen’s University; and the Thin-Film Devices and Chemical Sensors Group at the Advanced Sensors Research Unit, University of Limerick.The various research groups have already pioneered ad- vances in many areas. These include: World leading disposable ECG electrodes Novel electrically conducting bioadhesive film for sensor adhesion in wet environments Cardiac electrophysiological mapping and monitoring har- nesses for emergency, hospital and home use Solid-state planar technology gas sensors for domestic monitoring and emission control Optical sensors for gas and liquid monitoring systems Electrochemical sensors for nitrate, nitrite and NO, gases Biosensors based on ‘recognition’ molecules such as enzy- mes and novel antibody based technologies Since the establishment of the Centre many new research programmes and projects have been started and bpportunities to develop new families of sensor devices and new exploitable sensing technologies are being created by the diverse and complementary range of physical, biological and chemical science, engineering and medical skills now available.Recent advances include: 0 The further development of specialist gels which, unlike conventional systems, can adhere in wet conditions. These are currently used to painlessly connect monitoring elec- trodes to a baby’s head during birth in order to ensure the early detection of any distress. 0 Enhancements to vital signs and biosignal monitoring systems through the addition of blood pressure, body temperature, oxymetry and other features to existing ECG monitors. 0 Bioadhesive ion-selective sensors for rapid diagnostic appli- cations, e.g., in diseases such as cystic fibrosis. A variety of optical, electrochemical and solid-state sensors for water and air quality monitoring in pollution related, personal safety and comfort applications. For further information please contact: Dr. William Montgomery, BEST Centre, University of Ulster; Tel: +44 1232 368922; Fax: +44 1232 366863; Email: W.J.Montgomery@ulst.ac.uk

ISSN:0003-2654    

DOI:10.1039/AN996210089N

出版商:RSC    

年代:1996

数据来源: RSC

摘要:

Analyst, June 1996, Vol. 121 91N Future Issues Will Include Chemometric Analysis of Ageing and Typification of the Vintage Ports-M. Cruz Ortiz, Luis A. Sarabia, Charles Symington, Fernando Santamaria, Montserrat Iniguez New Robust Multivariate Calibration Algorithm Based on Least Median Squares and Sequential Number Theoretical Optimiza- tion Method-Yi-zeng Liang, Kai-tai Fang Observation of Albumin Resonances in Proton Nuclear Mag- netic Resonance Spectra of Human Blood Plasma: N-terminal Assignments Aided by Use of Modified Recombinant Albu- min-Peter J. Sadler, Roy Harris, Sunil Patel, John H. Viles Spline Wavelet Multiresolution Analysis for High Noise Digital Signal Processing in Ultraviolet-Visible Spectrum-Mo Jing- yuan, Lu Xiao-quan High-performance Liquid Chromatographic Determination of Phenols Using a Tyrosinase-based Amperometric Biosensor Detection System-Malcolm R.Smyth, Olubunmi Adeyoju, Emmanuel I. Iwuoha, Dona1 Leech Traceability of Measurement in Chemistry-Yu. I. Alexandrov Entry Efficiency of the CIP- 10 Instrument Annular Aspiration Slot-Peter Gorner, Olivier Witschger, Jean-Francois Fabries Summary of the NIOSH Guidelines for Air Sampling and Analytical Method Development and Evaluation-E. R. Kennedy, Thomas J. Fischbach, Ruiguang Song, Peter M. Eller, Stanley A. Shulman Adsorption of Dissolved Trace Metals From Seawater Onto Solid Surfaces-Vlado Cuculic, Marko Branica Separation and Detection of Condensed Phosphates in Waste- waters by Ion Chromatography-Flow Injection-Ian D. McElvie, David J. Halliwell, Barry T.Hart, Roger H. Dunhill Uranyl Photophysics on Colloidal Silica: an Alternative Luminescence Enhancing Medium for Uranyl Assay-Martin Lopez, D. J. S. Birch Determination of Cyclic Organic Acid Anhydrides in Air Using Gas Chromatography. Part 1. A Review-B. A. G. Jonsson, C. H. Lindh, C. Gustavsson, H. Welinder, Pirkko PfaMi Enzyme-linked Immunosorbent Assay for Detecting Some Benzodiazepines in Urine-Frederick J. Rowell, David Laurie, A. J. Mason, Nigel H. Piggott, John Seviour, D. Strachan, J. D. Tyson Direct Determination of Some Phenothiazine Sedatives in Greyhound Urine by Fluoroimmunoassay-Frederick J. Rowell, A. Mounsey, D. Strachan, V. Rowell, J. D. Tyson New Acetylcholinesterase Amperometric Sensor Based on Tetraphenylporphyrin-Cobalt(I1) Modified Electrode- Shaojun Dong, Qing Deng End-point Determination On-line and Reaction Co-ordinate Modelling of Homogeneous and Heterogeneous Reactions in Principal Component Space Using Periodic Near-infrared Monitoring-Timothy Norris, Paul K.Aldridge Determination of Gasoline Oxygenates in Air Using a Diffusive Sampler-Martin Harper, Christina O'Lear, Amy A. Fiore Shipboard Determination of Dissolved Cobalt in Sea-water Using Flow Injection with Catalytic Spectrophotometric Detec- tion-Liliya K. Shpigun, Irina Ya. Kolotyrkina, Alexander Malahoff Nitrogen Factors for Sheepmeat. Part 2. Lamb Meat- Analytical Methods Committee Determination of Cyclic Organic Acid Anhydrides in Air Using Gas Chromatography. Part 2. Sampling and Analysis of Hexahydrophthalic Anhydride Methylhexahydrophthalic An- hydride, Tetrahydrophthalic Anhydride, and Octenylsuccinic Anhydride-B. A. G. Jonsson, C. H. Lindh, C. Gustavsson, H. Welinder, Pirkko PfaMi COPIES OF CITED ARTICLES The Royal Society of Chemistry Library can usually supply copies of cited articles. For further details contact: The Library, Royal Society of Chemistry, Burlington House, Piccadilly, London WlV OBN, UK. Tel: +44 (0)171-437 8656. Fax: +44 (0)17 1-287 9798. Telecom Gold 84: BUR210. Electronic Mailbox (Internet) LIBRARY@RSC.ORG. If the material is not available from the Society's Library, the staff will be pleased to advise on its availability from other sources. Please note that copies are not available from the RSC at Thomas Graham House, Cambridge.

ISSN:0003-2654    

DOI:10.1039/AN996210091N

出版商:RSC    

年代:1996

数据来源: RSC

摘要:

92N Analyst, June 1996, Vol. 121 Technical Abbreviations and Acronyms The presence of an abbreviation or acronym in this list should NOT be read as a recommendation for its use. However, those defined here need not be defined in the text of your manuscript. AAS ac A D ADC ANOVA AOAC ASTM bP BSA BSI CEN CPm CMOS c.m.c. CRM CVAAS cw CZE dc DRIFT DELFIA DNA EDTA ELISA emf ETAAS EXAFS EPA FAAS FAB dPm FAO-WHO FIR FT FPLC FPD GC GLC HGAAS HPLC ICP id INAA IR ISFET iv im IGFET ISE LC LED LOD LOQ atomic absorption spectrometry alternating current analogue-to-digital analogue-to-digital converter analysis of variance Association of Official Analytical Chemists American Society for Testing and Materials boiling point bovine serum albumin British Standards Institution European Committee for Standardization counts per minute complementary metal oxide silicon critical micellization concentration certified reference material cold vapour atomic absorption spectrometry continuous wave capillary zone electrophoresis direct current disintegrations per minute diffuse reflectance infrared Fourier transform spectroscopy dissociation enhanced lanthanide fluorescence immunoassay deoxyribonucleic acid ethylenediaminetetraacetic acid enzyme linked immunosorbent assay electromotive force electrothermal atomic absorption spectrometry extended X-ray absorption fine structure spectroscopy Environmental Protection Agency flame atomic absorption spectrometry fast atom bombardment Food and Agriculture Organization, far-infrared Fourier transform fast protein liquid chromatography flame photometric detector gas chromatography gas-liquid chromatography hydride generation atomic absorption high-performance liquid inductively coupled plasma internal diameter instrumental neutron activation infrared ion-selective effect transistor intravenous intramuscular insulated gate field effect transistor ion-selective electrode liquid chromatography light emitting diode limit determination limit of quantification World Health Organization spectroscopy chromatography analysis mP MRL mRNA MS NIR NMR NIST od OES PBS PCB PAH PGE PIXE PPt PPb PPm PTFE PVC PDVB QC QA REE rf RIMS rmS rpm RNA SCE SE SEM SIMS SIMCA S/N SRM STM STP TIMS TLC TOF TGA TMS tris TRIS uv UViVIS VDU XRD XRF YAG Commonly Used Symbols M Mr r S U melting point maximum residue limit messenger ribonucleic acid mass spectrometry near-infrared nuclear magnetic resonance National Institute of Standards and Technology outer diameter optical emission spectrometry phosphate buffered saline polychlorinated biphenyl polycyclic aromatic hydrocarbon platinum group element particle/proton-induced X-ray parts per trillion (1012; pg g-1) parts per billion (109; ng g-' parts per million (106; pg g-1) poly(tetrafluoroethy1ene) poly(viny1 chloride) poly(diviny1 benzene) quality control quality assurance rare earth element radio frequency resonance ionization mass spectrometry root mean square revolutions per minute ribonucleic acid saturated calomel (reference) electrode standard error scanning/surface (reflection) electron microscopy secondary-ion mass spectrometry soft independent modelling of class signal-to-noise ratio Standard Reference Material scanning tunnelling (electron) standard temperature and pressure thermal ionization mass spectrometry thin-layer chromatography time-of-flight thermogravimetric analysis trimethylsilane 2-amino-Z-(hydroxymethyl)- propane- 1,3-diol (ligand) 2-amino-2-( hydroxymethy1)- propane- 1,3-diol (reagent) ultraviolet ultraviolet-visible visual display unit X-ray diffraction X-ray fluorescence yttrium aluminium garnet emission analogy microscopy molecular mass relative molecular mass correlation coefficient standard deviation atomic mass

ISSN:0003-2654    

DOI:10.1039/AN996210092N

出版商:RSC    

年代:1996

数据来源: RSC