摘要:

March, 19661 SHORT PAPERS 205 SHORT PAPERS Micro Determination of Inorganic Phosphorus in Plasma BY B. B. BAUMINGER AND G. WALTERS (Chemical Pathology Department, New Cross Hospital, Wolverlzarnpton) SEVERAL methods are available for determining inorganic phosphorus in biological fluids. The macro method described by King and Wootton,l which is used in this laboratory, is satisfactory and has produced good results. The possibility was therefore considered of adapting this method to a micro scale, so reducing the amount of plasma required to one-tenth of that used hitherto, as the amount of blood usually available from an infant for a complete analysis is small. The proposed method has been shown to produce reliable results for phosphorus in plasma of children, and for the last 8 months it has been extended to the routine determination of phos- phorus in plasma and dilute urine of adults.Because of the similarity of the two methods, only a short account is given here to show the results of comparative determinations of phosphorus by the proposed micro method and by the macro method. Table I shows the modification of the amounts of reagents used in the micro method as compared with those used hitherto. The concentration of the blue molybdophosphate was measured at 700 mp in 4-cm micro cuvettes. TABLE I COMPARISON OF AMOUNTS FOR MACRO AND MICRO METHODS Marco method, Micro method, 1111 ml Volume of sample . . .. .. .. 1.0 0.1 1.0 Volume of de-mineralised water . . .. Volume of trichloroacetic acid . . .. 9.0 3.0 Volume of filtrate .. . . .. .. 5.0 2.5 - Volume of perchloric acid . . .. .. 0.4 0.2 Volume of ammonium molybdate .. 0-4 0.2 Volume of reducing agent . . .. .. 0.2 0.1 METHOD APPARATUS- A Unicam SP500 or SP600 spectrophotometer was used for optical-density measurements. REAGENTS- Prepare all solutions from analytical-grade reagents and de-mineralised water. Trichloroacetic acid solution-Make an 11 per cent. w/v aqueous solution. If necessary, filter before use through a Whatman No. 42 filter-papcr. Reducing agent solution-Dissolve 0.2 per cent. of l-amino-2-naphthol-4-sulphonic acid (purified) in an aqueous solution containing 12 per cent. w/v of sodium metabisulphite and 2.4 per cent. w/v of anhydrous sodium sulphite. Transfer the solution into a brown bottle and store it a t 4OC.It is stable for 2 to 3 months. Stock phosphorus standard solution (100 pg of phosphorus per 0.1 mZ)-Dissolve 4394 mg of potassium dihydrogen phosphate in fresh de-mineralised water and dilute to 100 ml. Add several drops of chloroform as preservative. Dilute phosphorus standard solution (a) 4pg and (b) 8 p g of phosphorus per 0.1 ml-Dilute the stock standard solution (a) 1 to 25 and (b) 1 to 12.5. An accurate automatic delivery of some of the reagents was introduced.206 SHORT PAPERS [Analyst, Vol. 91 PROCEDURE- Into glass-stoppered tubes of 5 ml capacity place 1 ml of de-mineralised water, and wash in, by means of a micro pipette, 0.1 ml of unhaemolysed plasma, freshly separated, or 0.1 ml of de-mineralised water for the reagent blank, or 0.1 nil of dilute standard phosphorus solution (a) or (b).Add to each tube 3 ml of trichloracetic acid, stopper the tubes and mix the solutions well. Allow the tubes to stand a t room temperature for 5 to 10 minutes for complete precipitation of the proteins. Filter off the protein on to a dry 7-cm M’hatman No. 42 filter-paper, and collect the filtrate in suitable tubes. Transfer 2-5 ml of the clear filtrate by pipette into small tubes, add 0.2 ml of perchloric acid and mix. Add 0.2 ml of ammonium molybdate and mix; finally, add 0.1 ml of reducing agent and mix well. After 20 minutes measure the optical densities of the sample, A , the reagent blank, A,, and the standard, A,,, against water. Calculate the weight of phosphorus in mg per 100 ml of plasma from the formula: 4 (A - AB)/(AST - A,) or 8 ( A - AB)/(AsT - AB).RESULTS COMPARISON OF RESULTS- method. In order to establish this micro method, it was compared with King and Wootton’s macro The results in Table I1 show that the agreement was generally excellent. TABLE I1 COMPARISON OF MACRO AND PROPOSED MICRO METHODS FOR PHOSPHORUS IN CONTROL SERUM AND HUMAN PLASMA Specimen x €3 c D E F G H I I< L &I N 0 P R J Q Phosphorus in plasma by- Rfacro method, Micro method, nig per 100 ml mg per 100 ml 6.8 6.7 10 0 10.2 7.7 7 . s 4 s 4.7 4.0 4.0 1.6, 1.7 1.7, 1.7 8.1, 8-0 7.9, 9.0 3.5 3-5 3.7 3.8 3.3 3.4 8.6 8.7 5.2 5.2 2.5 2-6 3.0, 3.5 3.8, 3.8 4-2 4.4 6.1 6.1 10.8, 10.8 10.8, 10.7 - L-- 7- 4.2, 4.2, 4.2 4-3, 4.2, 4.2 Differencc - 0-1 + 0.2 + 0.1 - 0.1 +0.1, 0, 0 0 +0*1, 0 -0.2, 0 0 -+ 0.1 + 0.1 + 0.1 0 -0.1 -0.1, 0 + 0.2 0, -0.1 0 PRECISION- The precision of the micro method was evaluated by determining the standard deviation with a freshly prepared control serum. For each set of tests, 10 sera, three standard phosphorus solutions and two reagent blanks were used. The standard deviation calculated on 20 duplicate determinations was +Om05 nig of phosphorus per 100 ml. REFERENCE 1. King, E. J., and Wootton, I. D. P., “Micro-analysis in Medical Biochemistry,” Third Edition, Received July 14t12, 1905 J. & A. Churchill Ltd., London, 1966, p. 77.

ISSN:0003-2654    

DOI:10.1039/AN9669100205

出版商:RSC    

年代:1966

数据来源: RSC

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March, 19661 SHORT PAPERS 207 An Improved Iodine Determination Flask for Whole-bottle Titrations BY E. J. GREEN* AND D. E. CARRITT (Department of Geology and Geophysics, Massachusetts Institute of Technology, Cambridge, Massachusetts) IT has long been recognised that volatilisation losses of iodine may result in significant analytical errors in iodimetry. Matsuyamal has pointed out that the volatilisation of iodine may be reduced by coniplexing with iodide to form the tri-iodide ion. This laboratory has been engaged in a studyZ of the Winltler titration and we have found that significant errors may result from volatilisation, even with tri-iodide complexing, when iodine aliquots are transferred from glass-stoppered bottles before titration with thiosulphate. Fig. 1 . Iodine volatilisation losses dur- ing sample transfers.Apparent oxygen concentration of identically equilibrated samples. Four replicate Winkler titrations performed on each group; means and ex- tremes indicated. A, whole flask titrated; B, gently poured into the Erlenmeyer flask; C, gently poured into Erlenmeyer flask and D, 100 ml aliquot was transferred, with a then back into the flask; pipette, in an Erlenmeyer flask Fig. 1 shows the variability of the apparent dissolved oxygen concentration (assumed to be proportional to the iodine concentration in the Winkler titration) of identically equilibrated samples of distilled water. Each point represents the mean of a set of four replicate determinations. It is seen that the iodine concentration found decreases with each transfer step.In the case where aliquots were removed from the sample bottle by using a pipette, it was found that the result was highly variable, possibly a consequence of the variable partial vacuum over the solution during the pipetting step. This conclusion is of some consequence to oceanographic analysts as, in thc currcnt Winltler procedure most widcly used aboard ship, iodine aliquots are transferred by pipette prior to titration. liecently C a r ~ e n t e r , ~ in discussing the IVinkler titration, has recommended whole-bottle titrations in which volatilisation losscs are reduced by elimination of the transfer step. His method requires that concentrated thiosulphate reagent be delivered by micro burette so that only 1 ml of titrant is added and titrations may be performed in the glass-stoppered sample bottle.An alternative method is herein suggested which has been used successfully in this laboratory. It consists in using easily constructed sample bottles (Fig. 2) in which the stoppers displace enough volume such that, when the stoppers are removed, titrations of the entire contents of the flask may be performed without transfer. CONSTRUCTION The sample bottle consists, in part, of the ordinary 250-ml Erlenmeyer-shape iodine deter- mination flask available commercially (Corning No. 5400) with a standard taper 22 solid glass * Present address : Department of Chemistry, Carnegic Institute of Technology, Pittsburgh, Pennsylvania, U. S. A.208 SHORT PAPERS n [Analyst, J’ol. 91 Corning part Corning part no.5400 no. 6710 Fig. 2. An improvcd iodine determina- tion flask for wholc-bottle titrations. stopper. The solid glass stoppers are discarded, and substituted with long nipples blown from standard taper 24/40 full length inner joints with sealed tube (Corning No. 6710). The closed, sealed tube which projects into the flask to within 3 cni from the bottom displaces a volume of about 10 C.C. Bottles and stoppers are cngraved with numbers to avoid mismatching when the flasks are calibrated “to contain” by weighing. Repeated fillings and weighings give a precision of better than 0.01 per cent. No attempt was made to make the flask volumes identical. Made as described, the 16 stoppered flasks made in this laboratory contained, on the average, 242 ml with a range of *4.4 nil. The variation in flask volume removes any unconscious bias on the part of the operator to try to get the same result on replication. This work was supported by the National Science Foundation under contract GP-4S6. REFERENCES 1. 2. Matsuyama, G., in Kolthoff, F. Rf., and Belcher, R., Editors, “Volumetric Analysis,” Volume 111, “Titration Methods,” Interscience Publishcrs, Sew York, 1957, Ch. \-I, p. 203. Green, E. J., “ A Redetermination of the Solubility of Oxygen in Sea \Yater and Some Thermo- dynamic Implications of the Solubility Relations,” Ph.1). Thesis, Department of Geology and Geophysics, Massachussetts Institute of Technology, 1965. 3. Carpenter, J. H., Limtzol. Uceaizogt., 1965, 10, 141. Received J i o I e Sth, 1965

ISSN:0003-2654    

DOI:10.1039/AN9669100207

出版商:RSC    

年代:1966

数据来源: RSC

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208 SHORT PAPERS [Analyst, J'ol. 91 An Automatic Determination of Thoria in Thoria - Urania Mixtures BY W. A. STUART (U.K. Atomic Etzergy Research Establislznzent, Harwell, Didcot, Bevks.) DURING the course of studies into the mixing of solids for nuclear fuel elements, it was necessary to analyse a large number of samples of thoria - urania for their thoria content. The method used should be quick and accurate enough not to contribute significantly to the apparent mixing errors. The chosen method is based on a modification of the manual method of Clinch1 using thoron [ l-(o-arsono-phenyl-azo)-2-naphthol-3,6-disulphonic acid sodium salt]. The apparatus used is the Teclinicon AutoAnalyzer which has been fully described elsewhere.293 Samples are dissolved in nitric acid with the addition of a small amount of ammonium fluoride to attack the thoria. The solution is made up to a standard volume with distilled water, and an aliquot is placed on the sampler of the AutoAnalyzer.Since fluoride interferes with the colour formation it is necessary to add aluminium to complex it. Also, uranium gives a small, positive interference, which is allowed for by making up standards for the two mixing ratios of urania to thoria used, namely 10 to 1 and 100 to 1.March, 19661 SHORT PAPERS 209 Mixing coil Colorimeter 540 mu 15 mm --I flow-ce‘l + Recorder Waste f Sampler1 wash 0.045 .I t I 0 I1 Fig. 1. Flow diagram of the Xuto-Xnalyzcr as uscd in the automatic *All pump tubing is Tygon, and internal method for dctcrmining thorium. diameters arc quoted EXPERIMENTAL The flow scheme is shown in Fig.1. The thoron reagent is highly colourcd and, in the absence of a diluting effect due to the sample volume, gives an optical density of about 0.3 with respect to the blank reading obtained with water as diluent. For this reason it is necessary to use air and samples lines of the same size, and to use a “double crook” sample device such that, when the sample line is out of the sample, then the air line is in water. Also, if there is a time when air only enters both lines, an extraneous peak, “an air blip” will be recorded, so the sample and air lines are made the same length from the junction ,4 to their inlet ends (Fig. 1). The sampler rate is 40 per hour, but half the positions are occupied by water to give additional washing between samples.r<EAnAcS X1-s- Thovon reagent-Mix 600 ml of 0.1 per cent. w/v aqueous solution of thoron with 200 nil cf 10 per cent. w/v aqueous solution of hydroxylammoniuni chloride, add 80 ml of concentrated hydrochloric acid and make up to 2 litres with distilled water. Aluminium nitrnte solution-Dissolve 100 g oi aluminium nitrate, Al(IJO,),.BH,O, in distilled water and make up to 1 litre. A nznzonium fluovide solzttion-Dissolve 0-4 g of ammonium fluoride in distilled water and make up to 0.5 litrc. PROCZDGRE- Dissolve samples weighing up to 100 nig by adding 0.25 nil of ammonium fluoride solution and 2.5 ml of concentratcd nitric acid. Heat on a hot-plate until all thc thoria has dissolved and no more brown fumes are evolved. ,4fter cooling, dilute the solutions in calibrated flasks with distilled water to give a thoria content in the range of 15 to 40pg ml-l.Make standard solutions by taking accurately weighed aliquots of thoria and urania in the correct ratio and treating as samples. Prepare a calibration curve and check it a t five points evcry 25 samples. This frequency of checking is not necessary, but it gave a convenient proof of the reliability of the method a t all times. In fact, the same calibration curves were obtained over a period of about 6 months. DISCUSSION The reproducibility of the AutoAnalyzer method for one solution was found by feeding 10 aliquots through the system. Table I shows some results.2 10 SHORT PAPERS [Analyst, Vol. 91 TABLE I Mean concentration Coefficient of variation, Method Ratio of urania t o thoria of thoria, per cent. p g ml-l AutoAnalyzer . . 10: 1 9.75 0.70 100: 1 16.39 0.52 Manual .. .. 100: 1 660 0.29 These coefficients of variation are acceptable, as the best mixes at present show a coefficient The automatic method is capable of producing 20 analyses per hour, and even with a large of variation greater than 2 per cent. for ten samples. number of standards is much quicker than the manual method. REFERENCES 1. 2. 3. Clinch, J., Analytica Chim. Acta, 1956, 14, 162. “Conference on Automatic Chemical Analysis, New York, November 12th t o 14th, 1959,” Ann. Skeggs, L. T., jun., Amer. J. Clin. Path., 1957, 28, 311. 1V.Y. Acad. Sci., 19G0, 87, 609-951. Received September 30th, 1965

ISSN:0003-2654    

DOI:10.1039/AN9669100208

出版商:RSC    

年代:1966

数据来源: RSC

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2 10 SHORT PAPERS [Analyst, Vol. 91 A Rapid Method for Determining the Moisture Content of Gelatin and Animal Glue BY R. T. JONES ( T h e Gelatine and Glue Research Association, Warwick Street, Birmingham 12) THE British Standard methods1r2 for determining the moisture contents of gelatins or animal glues require a drying time of 18 & 1 hours. The reproducibility of the methods, and also the relation to shorter drying times have been e~amined.~ I t is not possible to determine the absolute moisture content, but the British Standard methods define a set of conditions that gives sufficiently meaningful and reproducible results for most purposes. For many research and commercial applications, however, the time required is too long. This paper describes the investigation of a rapid infrared-heating method of moisture determination.The temperature and time of drying were varied for several gelatins and glues to determine a suitable set of conditions. The latter were then kept fixed, and moisture determinations for several additional gelatins were carried out to test for reproducibility, and also the effect of gelatin and glue-grist size. APPARATUS- This consists of an Ediswan 250 watt, 200 to 250-volt infrared lamp, clamped vertically above the centre of a metal pot, 9 inches in diameter, 0.1 inch thick and 5.5 inches high. (These are the dimensions of the vessel that we used but they are not expected to be critical.) The pot has a hole bored in the side a t such a height as to enable a thermometer (with its bulb blackened with carbon black), which passes through a rubber bung fitted in the hole, to rest just above the surface of an inverted moisture dish a t the centre of the base of the pot.The lamp is connected in series with a Variac transformer (reading to 260 volt) to the mains. This arrangement makes it possible for the temperature above the surface of the inverted dish to be varied by adjusting the l'ariac without having to alter the position of the lamp. (In the absence of the Variac, calibration of the apparatus can be performed by adjusting the position of the lamp.) In thc arrangement used, the lamp remains fixed with its lowest surface at a distance of 8.5 inches above the surface of the inverted moisture dish. METHOD PROCEDURE- Prepare samples for the moisture determination in exactly the same way as in the British Standard method except for dissolving the gelatin or glue prior to drying.Weigh about 1 g of the sample into a tared stainless-steel dish fitted with an aluminium cover. Introduce 10 ml of distilled water and allow the sample to soak. Switch on the lamp and allow about 1 hour for the system to warm up. To test that reproducible conditions have been achieved, move the thermometer until the bulb rests just above the centre of the inverted dish, and read the tem- perature after allowing several minutes for equilibrium to be attained. (The temperature normallyMarch, 19661 SHORT PAPERS 21 1 varies by f l " C.) Note the Variac reading and then withdraw the thermometer and place the moisture dish containing the sample in position.Adjust the position of the thermometer so that it is just not touching the outside of the dish. Initially, the temperature is lower than indicated in Table I, but when most of the moisture has been removed (after about 45 minutes) the tempera- ture reading remains constant to approximately f 1" C. The relationship between the temperature at the centre of the dish and outside the dish is shown in Table I. (Each time the temperature difference is 8OC.) ESTABLISHMENT AND EXAMINATION OF FIXED CONDITIONS- Determinations of moisture values for gelatins A and B, and glue C were carried out at different temperatures and for different testing periods to decide upon a set of conditions that would give the best correlation, in a short time, with values obtained by the British Standard method. Results are shown in Table I.The recommended procedural conditions adopted were- Temperature outside the dish = 110°C Temperature a t the middle of the dish = 118' C Variac reading = 232 volts Time - - 2 hours With the recommended procedure, moisture determinations for samples A, B and C and also for gelatins D and E (very fine grist size) and for gelatin F (very large grist size) were carried out. The results were compared with those obtained by the British Standard method and are shown in Table 11. EFFECT ON MOISTURE Temperature reading, "C Gelatin Outside or glue the dish A 105 110 B C 115 105 110 105 110 115 Middle of the dish 113 118 123 113 118 113 118 123 * Recommended procedure. RESULTS TABLE I VALUES OF VARYING Variac reading, volts 215 232 240 215 232 215 232 240 Time, hours 2 2.6 3 3.5 4 *2 2.5 3 3.5 1.5 2 2.5 3 3.5 1.5 *2 3 2 2 2 *2 2 2 2 2 2 2 2 0 Y TEMPERATURE AND TIME Moisture values r - k i z G z z Infrared method method: 14.1 14.4 14.3 14.4 14.6 14.5 t 14.3 14.7 14.7 14.7 14.6 14.6 14.9 13-07 13.5 13.2 13-4 13.4 13-9J !:;%} 134 t 13.9 14.4 14.3 ,I 13.5 14.0 t Determinations carried out on different occasions.Mean of five determinations. (The reproducibility of this British Standard method is recorded el~ewhere.~)212 SHORT PAPERS TABLE I1 [Analyst, VOl. 91 Gelatin! or glue A €3 C D E F * Mean MOISTURE VALUES DETERMINED WITH RECOMMENDED PROCEDURE Moisture values w 3 British Standard Infrared method method* 14.3 14.4 14.4 14.6 13-6 13.7 13.5 14.0 13.9 14.0 13.8 t13-9 13.3 13.9 13.7 13.5 11.2 11.3 11.5 11.8 t13.3 1 3 4 13.9 13.5 13.5 713.7 13.5 t l l .6 of five determinations. (The reproducibility Mean infrared value British Standard value x 100 per cent. 100 100.7 99.3 100.7 101.8 9G.4 of this British Standard method is recorded else\~here.~) t L)eterminations carried out on different occasions. DISCUSSION Similar moisture values obtained for the same gelatin or glue on the same, and on different occasions, show the new infrared method to be reproducible and capable of giving values com- parable to those obtained by the British Standard procedure. Agreement with the British Standard method was not quite as good with one samplc of very large grist size, a slightly low value being obtained. This discrepancy is probably due to omission, for the sake of speed, of the dissolving-up stage in which a water-bath is used before drying. I t is still sufficiently accurate for most purposes where a rnoisturc valuc is urgently required. REFERENCES 1. 2. 3. “Methods for the Sampling and Testing of Gelatines,” British Standard 757 : 1959. “Methods for the Sampling and Testing of Animal Glues,” British Standard 647 : 1959. Eastoe, J. E., and Williams, A. P., &f?ifg Chenz., 1959, 374. Received A p r i l &A, l!f66

ISSN:0003-2654    

DOI:10.1039/AN9669100210

出版商:RSC    

年代:1966

数据来源: RSC

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212 SHORT PAPERS [Analyst, VOl. 91 A Simplified Method for Determining Copper Compounds Present on Leaf Surfaces BY R. B. SHARP* (Instrumentation Departnient, National Imtitute of Agvicultuval Engineering, Wrest Park, Silsoe, Bedfordshire) AN accurate, yet relatively simple, technique for determining 0 to 1OOOpg of copper on foliage was required for use by unskilled personnel in the field. The colorimetric method based on the use of bis-cyclohexanone oxalyldihydrazone, described by Martin,l is ideal, providing that the final pH of the solution is controlled within the range required for full colour development.2 The method described was found to be more reliable than the modification used by Martin3 and, in obviating the dropwise adjustment of pH, it was more satisfactory for unskilled usage.Wetting agent, Lissapol NDB, was added to the acid extracting * Present address : Harvesting and Handling Department of the National Institute of Agricultural Engineering, \%‘rest Park, Silsoe, Bedfordshire.March, 19661 SHORT PAPERS 213 solution and automatic pipettes were used to dispense all reagents to aid determinations in the field. METHOD All reagent solutions were prepared in the laboratory with de-ionjsed water. REAGENTS- Acid extracting solution, approximately N sulphuric acid-Dilute 14 ml of concentrated sulphuric acid to 500 ml; 0.125 per cent. by volume. Add wetting agent to the solution. AmmoniacaE ammonium citrate-Dissolve 5 g of ammonium citrate and 60 ml of 0.880 ammonia in 500 ml of water. Adjust the strength so that 5 ml of this solution will neutralise 10 ml of the acid extracting solution, with neutral red as indicator.Borate buffer solution-Dissolve 12.4 g of boric acid in 400 ml of water. Add to this a solution of 1.2 g sodium hydroxide in 60 ml of water. Bis-cyclohexanone oxalyldihydrazone reagent-Make a 0.1 per cent. solution by dissolving the solid in a 50 + 50 ethanol and water mixture and warming. Store in a dark bottle and renew fortnightly. PROCEDURE- Fov 0 lo 50-pg anzoztnts of coppev-To the leaf sample add 10 ml of acid extracting solution. Allow the solution to stand for 15 minutes, swirling it every 5 minutes. Add to the solution 5 ml of ammoniacal ammonium citrate, 5 In1 of borate buffer and 10 ml of bis-cyclohexanone reagent. Again allow the solution to stand for 15 minutes, swirling it every 5 minutes.Measure the optical density at 59.5 mp. l3. For amounts of copper greater than 50 pg-Add 10 in1 of acid extracting solution to the leaf sample, leave for 15 minutes as before. Take 1 ml of this liquid, add to it 10 ml of acid extracting solution and 5, 5 and 10 ml of othcr reagents as detailed before. Complete the determination as described above. Multiply the copper value by 10 to obtain the total copper in the original sample. Solutions that arc just beyond the calibrated range of the instrument may be diluted with 25 nil of copper-free water and 5 nil of borate buffer solution. RIultiply the copper value by 2 or 20, as appropriate, to obtain the total copper in the original sample. Over one hundred determinations of copper, made with standard copper solutions during the developincnt and testing of this procedure, gave completely reproducible colours. Inexperienced operators found no difficulty in using this method ; satisfactory readings were obtained with standard copper solutions in the laboratory and field, and deterniination of copper fungicide on foliage were completed in the field. REFERENCES Dilute the reagent (1 + 1-5) with water for use. 1. Martin, J. T., Rep. Agric. Hort. Kes. Stn IJniv. Bristol, 19.55, 98-102. 2. Somers, E., and Garraway, J. L., Chern. 67 Ind., 1957, No. 13, 395. 3. Martin, J. T., Rep. . 4 g ~ i c . Hovt. Res. Stia Univ. Bristol, 1956, 125-6. Received December 7th, 1964

ISSN:0003-2654    

DOI:10.1039/AN9669100212

出版商:RSC    

年代:1966

数据来源: RSC

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214 ANALYTICAL METHODS COMMITTEE [Analyst, VOl. 91 Analytical Methods Committee REPORT PREPARED BY THE ESSENTIAL OILS SUB-COMMITTEE Spectral Characteristics of Eugenol THE Analytical Methods Committee has received the following Report from its Essential Oils Sub-committee of an investigation carried out on the Demetrius and Sinsheimer method.1 The Report has been approved by the Analytical Methods Committee and its publication has been authorised by the Council. REPORT The constitution of the Essential Oils Sub-committee responsible for the preparation of this Report was: Dr. G. W. Ferguson (Chairman), Mr. A. J. M. Bailey, Mr. H. E. Brookes, Dr. K. Field, hlr. D. Holness, Mr. H. T. Islip, Dr. T. L. Parkinson, Miss H. M. Perry, Dr. G. B. Pickering, Mr. J. H. Seager, Mr. S.G. E. Stevens and Dr. B. D. Sully. INTRODUCTION- The determination of phenols in essential oils has, for many years, been carried out by a method based on the solubility of the phenols in an excess of aqueous alkali2 A process of this nature must, however, be somewhat inaccurate, since it makes no allowance for non-phenolic materials that may be soluble in the alkali, nor does it take into account the effect of the possible alkaline hydrolysis of esters producing other alkali-soluble fractions. Demetrius and Sinsheimerl have published a more specific method for the determination of eugenol, based on the difference between the extinction coefficients, at a specified wavelength, of eugenol in alkaline and in acid solution. The method has been studied by the Sub- committee and the results of collaborative tests are given in this Report.During the investigation it was found that polythene containers were unsuitable for the storage of solutions for use in spectroscopy owing to the extraction of light absorbing substances from the polythene. EXPERIMENTAL- A sample of pure eugenol was examined in seven laboratories by the method of Demetrius and Sinsheimer. The measurements of the wavelength of maximum absorption (A,,,ax.) and the differences between the extinction coefficients in alkaline and acid solution are shown in Table I. There was general agreement that the wavelength of maximum absorption was 297 mp (Demetrius and Sinsheimer gave 296 mp), but the variations in the differential absorption coefficients were unexpected.I t was found, however, that these were due to variations between the instruments and could be largely eliminated by calibration with potassium chromate solution3 as a standard, and adopting the procedure of cell interchange. Members reported that the differences between “matched cells” were negligible. TABLE I EXPERIMENTAL VALI‘ES FOR TIIE WAVELENGTH OF MAXIMUM ABSORPTION AND THE 1)IFFEREIVTIAL EXTINCTIOK COEFFICIENT Laboratory. . . . A B c D E G H Mean Amax. m p .. .. 297 297-5 297 296.5 297 297 297 297 297 297.2 297 297 297.5 297 297 A€ (uncorrected) . . 4065 - 4095 3840 4013 - 3030 4025 4080 3970 3996 3996 Redetermination of the differential extinction coefficient after calibration in this way gave the results shown in Table 11, derived from a second sample of eugenol shown to be pure by gas-chromatographic and electrometric-titration methods.I t was observed that for a single operator using a single spectrophotometer the reproducibility was particularly good (less than 1 per cent. variation), and Table I1 therefore includes only the average values for each series of determinations.March, 19661 SPECTRAL CHARACTERISTICS OF EUGENOL TABLE I DETERMINATION OF THE DIFFERENTIAL MOLAR ABSORPTIVITY OF EUGENOL AT 297mp Laboratory . . . . B D E F G H* Mean A€ (corrected) . . 3946 3996 4020 3970 3938 3990 3979 399 1 3978 3988 3957 3994 * The six individual figures represent the average values for different instruments. 215 The mean value for the corrected differential molar absorptivity as determined in six laboratories with a total of eleven different spectrophotometers of the manual and recording types was 3979 with a variation from the mean of -I 1 per cent. RECOMMENDATION- and a differential molar absorptivity at the maximum of 3886. amended to include the following: Demetrius and Sinsheimer reported that eugenol had a maximum absorption at 296 mp In the opinion of the Sub-committee the physical characteristics of eugenol should be “Eugenol, when examined by the Demetrius and Sinsheimer method, shows a maximum absorption at 297 mp, and at that wavelength has a differential molar absorptivity in 0-1 N acid and 0-1 N alkali of 3979.” REFERENCES 1. 2. 3. Demetrius, J. C., and Sinsheimer, J . E., J . Amer. Pharm. Ass., 1960, 49, 522. Analytical Methods Committee, Analyst, 1928, 53, 215. Haupt, G. W., J . Res. S a t . Bur. Stand., 1952, 48, 414.

ISSN:0003-2654    

DOI:10.1039/AN9669100214

出版商:RSC    

年代:1966

数据来源: RSC

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216 COMMUNICATIONS [AnaZyst, Vol. 91 Communications Material for publication as a Communication must be on an urgent matter and be of obvious scientific importance. Manuscripts must not exceed 300 words; rapidity of publication precludes the use of diagrams, but tables or formulae may be included if the length of text is reduced appropriately. Communications should not be simple claims for priority. This facility for rapid publication is intended for brief descriptions of work that has made some progress and is likely to be valuable to workers faced with similar problems. A fuller original paper may be offered subsequently, if justified by later work. Manuscripts are not subjected to the usual examination by referees. In- clusion of a Communication is at the Editor’s discretion; a manuscript not accepted as a Communication may, if the author wishes, be submitted to the Editorial Committee as a possible Short Paper and subjected to the usual scrutiny by referees.THE DETERMINATION OF FLUORINE BY NEUTRON ACTIVATION WHEN rapid, repetitive analyses are required, physical methods are usually adopted, as these are readily available for a large number of elements, including most of the metals and many of the non-metals in the periodic table of elements. One notable exception is fluorine. For this we now suggest neutron activation as a means of easily and rapidly examining large numbers of mill products containing fluorite. TABLE I NEUTRON-INDUCED REACTIONS OF FLUORINE Product P Reaction Half-life Ey, MeV lgF (n,y) 20F 10 seconds 1-63 18F (n,2n) l*F* 112 minutes (0.51) l9F (n,p) lgO 29.4 seconds 0.2 and 1.37 18F (n,a) lSN 7.2 seconds 5 to 7 * Positron emitter.Four separate neutron-induced reactions (Table I) can be used to determine fluorine. The (n,y) reaction occurs with neutrons of thermal energies, for which ready access to a nuclear reactor is a t present required. The (n,2n) reaction produces fluorine-18, a positron emitter which, although it has been used to determine fluorine, may be subject to interference from other positron emitters. The long half-life is also a disadvantage. The (n,p) reaction, giving oxygen-19, is clearly a better choice where a fast-neutron generator is available. An expensive high-resolution multi-channel y-spectrometer is required to isolate the 0.2 or 1-37 MeV activity.The (n,a) reaction gives nitrogen-16, which can conveniently be measured with a single- channel spectrometer. Oxygen interferes by giving nitrogen-16 in a (n,p) reaction when a 14-MeV neutron generator is used for the irradiation. However, the threshold value of neutron energy for this latter reaction to occur is about 10 MeV, whilst that for the laF (n,a) 16N reaction is only about 2 MeV. The interference from oxygen can therefore be avoided by using neutrons of intermediate energy. To demonstrate this we have used an available thorium - beryllium radio- isotope source of 1.5 curies, giving approximately 2.8 x lo7 neutrons (of 3 to 5 MeV) per second. Other isotope sources, such as americium - beryllium, of even higher neutron output, would be preferred.Samples (75 g) of fluorite ores and concentrates were weighed into specially designed polythene containers, irradiated for 35 seconds and counted for 30 seconds. The analysing system comprised a thallium-activated sodium iodide crystal, photomultiplier and single-channel y-spectrometer set with a discriminator bias to count only the high-energy activity from nitrogen-16. The fluorine contents were calculated by using a sample of pure crystalline fluorite, ground to pass through This is not practical for industrial use.March, 19661 BOOK REVIEWS 217 a 70-mesh sieve, as the reference material. The results are shown in Table I1 in comparison with results obtained with a pyrohydrolysis technique. TABLE I1 SOME FLUORINE RESULTS Fluorine found Sample material by neutron activation, by pyrohydrolysis; O/ 0) i 0 Fluorite concentrate 1 . . . . 44-5 Fluorite concentrate 2 . . .. 46.2 Fluorite head ore . . .. 19.5 Fluorite flotation product 1 . . 15.8 Fluorite flotation product 2 . . 10.0 Fluorite tailing . . . . . . 5.2 /O 44.7 44.3 19.6 15.7 10.0 5-2 Further work on this system will include the examination of products from a commercial fluorite mill and a short field trial in a fluorite-producing area. Warren Spring Laboratory, Gunnel’s Wood Road, Stevenage, Herts. J. M. BAKES P. G. JEFFERY Received February 2nd, 1966

ISSN:0003-2654    

DOI:10.1039/AN9669100216

出版商:RSC    

年代:1966

数据来源: RSC

摘要:

March, 19661 BOOK REVIEWS 217 Book Reviews STATIONARY PHASE IN PAPER AND THIN-LAYER CHROMATOGRAPHY. Proceedings of the Second Symposiuni held at Liblice, June 10th-12th, 1964. Edited by K. MACEK and I. M. HAIS. Pp. 358. Amsterdam, London and New York: Elsevier Publishing Company. 1965. Price 85s. This volume, edited by two internationally prominent chromatographic workers, records the proceedings of the Second International Symposium on Chromatography held in Czechoslovakia. This symposium dealt exclusively with Paper Chromatography and Thin-layer Chromatography. The book follows the pattern of the proceedings in being divided into 5 major sections, each of which comprises a review paper that summarises the present state of knowledge of a particular field, and a series of original papers and their related discussions.Approximately half of the 50 or so papers are in German, the rest are in English. As is usual at such symposia, the introductory papers do not generally do more than collect and collate work that has been previously published. These papers are of such quality, that both the new research worker starting on a problem, or an established research worker needing background information relevant to his own problem, will find an excellent source of information. I t would be invidious to separate any one paper or section as being superior to the rest, as each part is a well presented contribution to chromatography. The photographs and line drawings of actual separations are very useful in showing the separation obtained, RF values alone do not always enable a worker to obtain a fair comparison of his results with those published by the original author.It is often helpful to be able to relate work done on paper to that done on the newer substrates, and it is possible to obtain much information of this type from a perusal of the book and the excellent indexes provided. The wealth of results obtained with substrates and solvent systems other than cellulose and the more common solvents, is a good indication of the potentialities of thin-layer techniques. When reviewing the corresponding volume dealing with the First International Symposium it was stated that this volume should surely occupy a place on the bookshelves of all chemists working on chromatographic research and development.This remark applies equally to the present volume, which is a worthy successor, and the editors are again to be congratulated on their work. L. s. BARK218 BOOK REVIEWS [Analyst, Vol. 91 PROGRESS IN CHEMICAL TOXICOLOGY. Volume 2. Edited by ABRAHAM STOLMAN. Pp. x + 416. This volume is the second of a series concerned primarily with the analytical aspects of forensic toxicology, but which will also be of interest to those working in allied fields. Nearly one-half of this volume is devoted to recent studies of the absorption, metabolism and excretion of chemicals by the body, and covers the period since the last edition of Professor R. T. Williams’ “Detoxication Mechanisms.” Although most of the results quoted have been obtained with animals and not with man, this chapter merits the careful attention of the forensic toxicologist, who in the past appears to have limited his attentions to a search for the substance suspected to have been administered.While such a procedure may be appropriate in the analysis of the contents of the gastro-intestinal tract, in the examination of the tissues and excreta it may be more profitable to select a method capable of revealing a major metabolite. It is to be hoped that a later volume in this series will include a scheme for analysing biological specimens for these metabolites, which frequently are conjugated to yield water-soluble derivatives, not readily extractable by the usual procedures. The analysis of expired air is now a well-known means of determining blood-alcohol concentra- tion, and a chapter on the application of infrared spectrometry to air analysis suggests that this technique may be extended to a wide range of volatile liquids and gases.However, with only ;t few substances has an attempt been made to establish the relation between the concentration in breath and the likelihood of intoxication, and usually such measurements are limited to a qualitative demonstration of absorption. The section of this chaptcr dealing with the determination of volatile substances in tissues, makes no refcrence to those procedures that take advantage of the volatility, as in the determination of blood alcohol by equilibrating the sample with air, which is then analysed by gas chromatography or other means. The need for rapid diagnostic methods in cases of suspected poisoning is the basis of 2 chapters; one presents a scheme for the determination of basic drugs in biological specimens, though it is limited to those substances that are readily extractable, by ether, from alkaline solution, and which can be steam distilled.-4nother chapter describes reversed-phase chromatography at elevated temperatures, on paper impregnated with triglycerides, and chromatography and electrophoresis on ion-exchange paper. A review of sample preparation before spectrographic analysis provides a useful summary of methods for the destruction of organic matter, and for the purification and concentration of the extract prior to trace-metal analysis, but such refined procedures can rarely be necessary in cases of suspected metal poisoning; they seem to be more appropriate for the determination of normal levels in tissues.The value of the final chapter on the application of thin-layer chromatography in toxicology is not in the brief outline of the technique, which could surely be omitted in a volume of this nature, but in the tables listing RF values of groups of substances of toxicological interest, obtained under defined conditions. New York and London: Academic Press. 1965. Price 100s. J. C. GAGE SPECTROSCOPY IN EDUCATION. Volume 2. SPECTROSCOPIC TECHNIQUES IN ORGANICHEMISTRY. Pp. v + 87 leaves. London: Heyden This spiral-bound book is Vohime 2 of a “Spectroscopy in Education” series, of which the titles of the first four volumes have been announced. The present work deals with infrared spectroscopy (pages 1 to 3 5 ) , nuclear magnetic resonance spcctroscopy (pages 35 to Eil), mass spectrometry (pages 52 to 62) and ultraviolet spectroscopy (pages 63 to 85).The stated intention is to provide concise introductions to the basic theory, experimental methods and interpretative procedures for these three branches of molecular spcctroscopy proper and for mass spectrometry. The principal application is directed towards the determination of the structure of organic com- pounds. The book is designed for use in practical classes by organic chemists, to enable them to interpret results obtained on compounds of unknown structure. The interpretative sections are accompanied by examples of their application to actual spectra. Only for the section on infrared spectroscopy has this ambitious intention been realised to any extent.The 1-page introduction is too brief to be of any value, but the following 12 experi- ments cover many useful matters of practice, including a simple 3-component analysis and an experiment on hydrogen-bonding. The correlation charts for a few important group frequencies clearly show the changes produced by progressive substitution in a way that emphasises the structural implications. By A. J. BAKER, B.Sc., Ph.D., and T. CAIRNS, B.Sc. & Son Ltd. 1965. Price 21s.; $3.50.March, 19661 BOOK REVIEWS 219 Apart from the inadequate “Introduction,” the chapter on ultraviolet spectroscopy deals with diene, polyene, poly-yne, en-yne, carbonyl, enone and c( p-unsaturated carboxyl systems in some detail, with emphasis on the calculation of A,,,,.for various types of substitution by use of the Woodward and similar rules. The discussion of aromatic and heterocyclic chromophores is too brief to be of much value, and the 6 spectra discussed in detail are mainly concerned with ene-one and poly-yne structures. In the chapter on nuclear resonance spectroscopy, the short theoretical introduction is not always clear and the tables of r values are not used directly in the discussion of the 8 rather complex n.m.r. spectra selected for comment. Both the T and 6 conventions for chemical shift are used in this section. The chapter on mass spectrometry leans heavily on Biemann’s summary of fragmentation processes, and the 6 spectra discussed in detail illustrate the occurrence of these processes.The authors’ aims have been achieved with some degree of success in the chapter on infrared spectra and, to a lesser extent, in that on ultraviolet spectra, but the book as a whole, in its present form, is not a satisfactory introductory manual for the student of organic chemistry. G. H. BEAVEN RESEARCH IN MOLECULAR SPECTROSCOPY. Edited by Academician D. V. SKOBEL’TSYN. Pp. viii Authorised translation f r o m the Russian; originally published as Volume 27 of Proceedings of the P.N. Lebedev Physics Institute. This book is a critical review of the instrumental and the more general experimental aspects of vibrational spectroscopy. The first, by G. G. Petrash, is concerned with instrumental errors and their correction in infrared spectroscopy, covering the problems of resolving power and absolute absorption intensities, and the use of computers for error reduction.The second, by A. I. Sokolovksya, reports on experimental methods of studying the effect of temperature on the polarisation, intensity and shape of Raman bands of vapours and liquids. In the third section, A. V. Rahov reviews the effects of molecular rotation on the parameters characterising infrared and Kaman bands, and instrumental methods of investigating these effects. The fourth section, by G . 1‘. Mikhailov, gives an account of the effect of pressure on the structure and the width of the rotational and vibrational Raman spectra of gases, and of the apparatus used in studies of the effects. The book is well-documented, and it contains a bibliography of papers on spectroscopy by members of the Lebedev Institute from 1934 to 1962.Research workers in the field of vibrational spectroscopy should find this volume useful, particularly those concerned with instrumentation or with environmental effects on infrared and Raman spectra. S. F. MASON + 205. New York: Consultants Bureau. 1965. There are 4 sections to the work. GAS CHROMATOGRAPHY OF METAL CHELATES. By ROSS mr. MOSHIER and ROBERT E. SIEVERS Pp. viii + 163. Press. 1965. Price 35s. Oxford, London, Edinburgh, New York, Paris and Frankfurt: Pergamon The determination of metals based on the formation of metal chelates and their subsequent examination hy gas chromatography is probably the most significant advance in inorganic chemistry over the past decade.Gas chromatography is usually regarded as being the province of the organic chemist, because it is essentially a process for separating and analysing volatile mixtures, and until comparatively recently the technique had not made any significant incursions into the field of inorganic analysis. It might have been postulated that some classes of inorganic compounds would be amenable to separation by gas chromatography, e.g., the chlorides of metals such as antimony, niobium, tantalum, tin and titanium are relatively volatile, and a restricted range of certain classes of organo-metallic compounds received early attention in an extension of gas chromatography to inorganic analysis. In general, however, determinations based on the use of these compounds have serious limitations, because they are usually difficult to prepare, and many are prone to hydrolysis.To apply gas chromatography more successfully to the analysis of inorganic constituents, it is desirable that a wide range of elements should react readily and quantitatively with a single reagent, and in this respcct the metal chelates have outstanding advantages. Gas-chromatographic analysis, following chelate formation, is of special interest to the analyst with problems in the inorganic field, and the authors have made a detailed appraisal of the use220 BOOK REVIEWS [Analyst, Vol. 91 of the most useful chelating agents for this purpose. Comment on the use of other volatile inorganic compounds is also adequately covered, with the object of providing a complete realistic assessment of the value of gas chromatography in inorganic analysis and the study of co-ordination compounds.Sensitivity, speed and ease of separating complex mixtures are features of gas chromatography that make it particularly attractive, and its potential in the determination of trace constituents in the inorganic field is impressive. Conditions for the successful elution, separation and the obtaining of sharp symmetrical gas-chromatographic peaks are described. Many illustrations are given, and factors affecting the volatility of metal chelates, and methods for the preparation of metal acetylacetonates and their fluorinated derivatives are also discussed. Qualitative and quantitative analysis, purification, separation of isomers and the study of kinetics and equilibria of co-ordination compounds receive special attention.The general editors of this series are to be complimented for selecting this timely topic for inclusion in their “International Series of Monographs,” and the authors equally praised for making a readable, comprehensive account of the subject available a t a reasonable price. This book is strongly recommended to practical analysts, graduate students and teachers, and, indeed, to all who seek to improve their knowledge of the subject or wish to assess the potentialities of what is unquestionably a useful adjunct to the analyst’s working tools. W. T. ELWELL LECTURES ON GAS CHROMATOGRAPHY, 1964 : AGRICULTURAL AND BIOLOGICAL APPLICATIONS. New York: Plenum Based o n papers Presented at the 1964 Cornell University Pesticide Workshop and the 1964 The modern practice of publishing, in book form, the papers presented at symposia and conferences has been criticised strongly by the majority of reviewers in these columns.The present book does nothing but strengthen the hand of the critics, despite the attempts of the editors to widen its appeal by selecting “the most significant lectures” from two conferences and supple- menting them by several papers “solicited specifically for the purpose of rounding out the presenta- tion.” The two conferences were the Sixth Annual Gas Chromatography Institute held a t Canisius College, Buffalo, New York, from March 30th to April 3rd, 1964, and the Pesticide Residue Analysis Workshop presented by the New York State Agricultural Experiment Station, Cornell University, Geneva, New York, from April 20th to 23rd, 1964.Of these, 6 are presented by representatives of instrument manufacturers and in general, while they would be interesting enough to the analyst who is new to the field, they contain the type of information that is dispensed, free of charge, in the brochures and house magazines of the instrument companies. Two more papers by H. R. Felton, who is the only industrial representative, deal with preparative-scale gas chromatography and chromato- gram trouble shooting without attempting to include the special problems of the field covered by the sub-title of the book and therefore giving the impression that they have been shoved in as make-weights. A further 6 papers emanate from the Southwest Research Institute, San Antonio, Texas (with various permutations of 6 authors) ; 3 of these deal in a general way with instruments, detector systems and so on, and the other 3 with more specific applications, pesticides in water, collection of fruit volatiles and chlorproniazine, its metabolites and related compounds.These latter 3 papers, together with the paper by Lisk and Mattick on the determination of insensitive pesticide residues by the formation of derivatives, are probably the most useful and valuable from the point of view of the practising analyst. The sixteenth paper by Albers and Fahri is an excellent short review of the analysis of blood gases by gas chromatography. Much of the information it contains is already well known or easily accessible and, of the rest, it seems that publication in a recog- iiised journal would have offered a better means of reaching the right audience.Edited by L. R. MATTICK and H. A. SZYMANSKI. Press. 1965. Price $12.50. Pp. viii + 256. Cnnisius College Gas Chromatography Institute. The book contains 16 papers. The purpose of publishing a book like this escapes me. G. E. PENKETH SEMIMICRO QUALITATIVE ORGANIC ANALYSIS : THE SYSTEMATIC IDENTIFICATION OF ORGANIC COMPOUNDS. By NICHOLAS D. CHERONIS, JOHN B. ENTRIKIN and ERNEST M. HODNETT. Third Edition. Pp. xii + 1060. New York, London and Sydney: Interscience Publishers, a division of John Wiley & Sons Inc. This is the third edition of a text-book that was first published in 1947; since that time it has established itself as one of the most comprehensive texts available on qualitative organic analysis.1965. Price i l l .March, 19661 BOOK REVIEWS 22 1 This edition contains considerably more material than earlier ones. The section on laboratory techniques has been expanded and includes descriptions of newer equipment ; there is now a detailed account of thin-layer chromatography, and the chapter dealing with the determination of physical constants has been enlarged. In the last edition the physical constants of some 4100 organic compounds and their derivatives were tabulated ; in the new edition this number has been extended to 7100. The authors are rather cautious in their recommendation of the oxygen-flask method for decomposition of compounds before testing for the elements, and they prefer the older methods.They admit that this method does have possibilities, but do not appear to have given it any serious examination. More work has been published in this field since this book went to press, and it is to be hoped that in a future edition the authors will be more enthusiastic about this much simpler technique. The new edition is a worthy successor to the earlier volumes; there is no similar text known to the reviewer that reaches the same standard in coverage and quality within a single volume. Considerably more space has been devoted to theory. R. BELCHER METHODS IN ZONE ELECTROPHORESIS. By JOHN R. SARGENT, BSc., Ph.D. Pp. iv + 107. Poole, This slim, paper-bound and moderately priced volume is good value, considering the wide area it is meant to cover.The author has wisely chosen to present the subject matter in the form of a laboratory manual, with a relatively small chapter on the theoretical background and the rest of the book devoted to methodology, equipment and well tried procedures. The style is reminiscent of that used by I. Smith (“Chromatographic and Electrophoretic Techniques, Volume 2, Zone Electrophoresis,” Heinemann, London, 1960). In the chapters dealing with electrophoresis in which cellulose acetate, starch gel, agar and polyacrylamide are used as stabilising media for the analysis of a variety of proteins in biological fluids, the methods recommended and the practical hints given seem to be based on the author’s own experience and sound knowledge in choosing experimental conditions most suitable for specific applications.There are, in addition, excellent, though necessarily brief, chapters on immuno-electrophoresis in agar and on preparative block techniques in which starch, PVC, foam rubber, glass powder and Sephadex are used as media. By contrast, the treatment given to such important groups of low molecular-weight compounds as the amino-acids and carbohydrates shows certain weaknesses. Several statements, e.g., that the amino group in zwitterions is dissociated a t high pH values (p. 3) and that lysine moves towards the anode and aspartic acid towards the cathode a t high pH values (p. 23) are rather incongruous and incorrect. The applicability of paper electrophoresis to carbohydrates is dismissed in a few lines, based mainly on the early paper by Consden and Stanier (p.27) and their technique, applying 10 v cm-l is inconsistently called a high-voltage technique. There have been great advances in this field since 1952, reported in books and com- prehensive reviews. Chapter 3, dealing with the technique of high-voltage paper electrophoresis, so important for really satisfactory separations of amino-acids and peptides, would have materially benefited from being based on more recent original literature instead of manufacturers’ booklets of instruc- tions. Dorset: The British Drug Houses Ltd. 1965. Price 8s. 6d. The references following each chapter are well selected and up-to-date. The quoted pressure of 6 p.s.i. (p. 32) is excessive and serves no useful purpose.The book will be welcomed by many, particularly beginners, in the field of proteins. D. GROSS DISTILLATION. Edited by E. S. PERRY and A. WEISSBERGER. Second Edition. Pp. xx + 83s. New York, London and Sydney: Interscience Publishers, a division of John Wiley & Sons Inc. 1965. Price 180s. This comprehensive account of distillation on the laboratory and pilot-plant scale is a com- pletely revised and considerably augmented version of the first edition, published in 1951. During the intervening 16 years, distillation, as a technique for analysing mixtures of volatile substances such as light hydrocarbon fractions from petroleum, has been almost wholly supplanted by gas - liquid chromatography. As a consequence, the 73-page chapter on distillation of liquefied gases and low-boiling liquids in the first edition of this book has been reduced to a single page in the second edition.On the other hand, the second edition contains five chapters on subjects222 BOOK REVIEWS [Analyst, VOl. 91 that were not treated separately in the first edition. The inclusion of two chapters on pilot-scale distillation indicates that the editors have agreed to a widening of the terms of reference of the Weissberger series, which were originally the “comprehensive presentation of the techniques which are used in the organic laboratory.” The book begins with a chapter (239 pages!) on the theory of distillation, including an account of the use of analogue and digital computers in distillation calculations. Chapter 11, on vapour - liquid equilibria, contains a useful account of the methods developed at Shell Development Co.for the correlation of activity coefficients in series of related binary mixtures, and the prediction of activity coefficients where no experimental results exist. In other respects this chapter is disappointing : there are numerous minor errors (three distinguished names are mis-spelt), the theoretical section is unsatisfactory, and the section on experimental determination of equilibria is sketchy. The real meat of the book is to be found in Chapters 111, IV, V and VI, on ordinary fractional distillation, extractive and azeotropic distillation, distillation under moderate vacuum and distillation under high vacuum, respectively. Together these four chapters provide a detailed account of modern distillation practice on the laboratory scale ; it is perhaps noteworthy that, whereas there are several mentions of analytical gas chromatography as an adjunct to distillation, there is no mention of the fact that preparative-scale gas chromatography is increasingly being used, instead of distillation.In Chapter VII, the theoretical and practical aspects of the production of high vacua in connection with distillation are described ; the commercially available equipment, to which reference is made, is wholly American. Chapter VIII contains a somewhat laboured description of the use of sublimation for purifying volatile solids, and Chapter IX contains aplea for the more widespread adoption of continuous distillation as a laboratory-scale technique.The book concludes with chapters on pilot-plant distillation and automation in distillation ; the editors’ objective in including these chapters is stated to be an improvement in communication between the laboratory and the pilot plant, with a feedback to the laboratory of an understanding of the techniques developed for the larger scale. Workers in those laboratories in which fractional distillation is a major preoccupation will probably feel impelled to buy the book. Those, however, in laboratories in which it is a minor activity, may well think that 180s. is too much to pay when several excellent monographs on laboratory distillation techniques are available at modest cost. J. D. Cox MECHANISING LABORATORIES. By E. A. SMITH, B.Sc., M.B.I.M. Pp. x + 205. London: Iliffe In some respects this book is rather stimulating, in others it is disappointing. It is, however, well written and is the kind of book that the executive, in charge of a laboratory, could assimilate in the course of a week-end’s study. He will, of course, have to be willing to look into certain questions such as does his laboratory answer enquiries with maximum speed and efficiency, and is he making the maximum and best use of machines rather than human hands? Perhaps the most important question will be, i s he using the best methods of handling and assessing the results that his laboratory provides? Does he, and this might be true of many analytical chemists, shrink at the idea of using computers? If he is a chemist, even an analytical chemist with an open mind on these matters, then it is likely that a reading of this book, which really only scratches the surface of things, may prove to be rewarding. On the face of it the price of this volume is high, but in particular cases it might prove to be cheap if the right inferences are drawn. Books Ltd. 1965. Price 63s. J. HASLAM

ISSN:0003-2654    

DOI:10.1039/AN9669100217

出版商:RSC    

年代:1966

数据来源: RSC

摘要:

222 BOOK REVIEWS [Analyst, VOl. 91 Erratum JANUARY (1966) ISSUE, p. 17. Replace the right hand side of equation 1 by- Emax. - [K (El - E,) + E21 FEBRUARY (1966) ISSUE, p. 104, 7th line under Table 1. For “0.2 per cent. gelatin solutions” IBID, p. 108, 6th line under Table VIII. For “manganese(r1) ions” read “magnesium(1r) read “0.1 per cent. gelatin solution”. ions”.

ISSN:0003-2654    

DOI:10.1039/AN9669100222

出版商:RSC    

年代:1966

数据来源: RSC