摘要:

April, 1982 SHORT PAPERS 459 Deter m i nation of M or p h i ne a nd M or p h i ne- 6 - nicotinate by an /n Situ Reaction on Chromatographic Plates with Dansyl Chloride R. Wintersteiger Institut f u r Pharmazeutische Chemie, Universitat Graz, A-8010 Graz, Austria Keywords : Morphine and morphine-6-nicotinate determination ; morphine- 3,6-dinicotinate ; dansylation ; derivatisation by overspotting Nicomorphine (morphine-3,6-dinicotinate) has proved to be a very powerful analgesic, which shows a much more advantageous spectrum of activity than m0rphine.l When stored correct 1 y , morphine-3,6-dinico t inat e, the active substance in various Vilan preparations, remains virtually unhydrolysed. Only as a consequence of improper or too long a storage, or under the influence of heat, do morphine-6-nicotinate and morphine form as decomposition products. In order to achieve a sensitive method of detection of these products, dansyl chloride (1 -dimethylaminonaphthalene-5-sulphonyl chloride) has been used for derivatisation .This reagent has been used for several years for the fluorimetric determination of primary and secondary amines or compounds with a phenolic group.2 The reaction with dansyl chloride is usually carried out in solution. Frei et aL3 have determined carbamates and urea herbi- cides by means of thin-layer chromatography by overspotting the sample spots with dansyl chloride. This paper describes a modified application of this technique, using morphine and morphine-6-nicotinate as examples. It is thus possible to carry out quickly a quantitative determination of phenolic compounds in the presence of other easily decomposable phenolic esters.The reaction time was 60min at room temperature. Experimental Apparatus 44, equipped with a thin-layer chromatographic attachment. fluorescence indicator, from Macherey-Nagel (Duren, West Germany) were used. were washed once with the eluent and activated before use. The fluorimetric measurements were made -with a Perkin-Elmer spectrofluorimeter, MPF Chzromatographic plates. Silica gel G plates, 20 x 20 cm, 0.25-mm layers, without The plates460 SHORT PAPERS Analyst, Vol. 107 Reagents All of the reagents used were of analytical-reagent grade. Reagent for derivatisation. Dansyl chloride (2 mg) obtained from E. Merck, Dannstadt, West Germany was dissolved in 1 ml of acetone.Dipping solution. Triethylamine - 3% V/V solution of hydrogen peroxide - ethanol (30 + 30 + 20). Solvent system. Chloroform - methanol - water (30 + 55 + 10). The hR, (R, x 100) value for morphine was 36 and for morphine-6-nicotinate it was 47. Stock solutions. Morphine (10 mg) and morphine-6-nicotinate (10 mg) were dissolved in 50 ml of methanol - water (1 + 1). From this solution, amounts of between 10 and 1 ml, corresponding to 200-20 ng per 2 p1, were pipetted into 20-ml flasks and diluted to 20 ml with methanol - water. The 20-ml flasks each contain 5 mg of morphine-3,6-dinicotinate to balance the effect that this substance, which is present in the samples, has on the fluores- cence intensity . Procedure Aliquots of 2 pl of the standard and the sample solutions are applied to the thin-layer chromatographic plate with 2 - 4 microcaps.These substance spots are also overspotted with 2 p1 of the dansyl chloride solution. Immediately afterwards, the chromatogram is placed in a drying cupboard at 100 "C. After 8 min the plate is developed in the solvent system in the dark, and is air dried in the dark for about 5 min. The thin-layer chromato- graphic plate is then dipped quickly into the dipping solution and is dried for 30min in a vacuum oven at room temperature. The dansylates are marked under the ultraviolet lamp at 366 nm and measured at an excitation wavelength of 330 nm and at an emission wave- length of 510 nm. Results and Discussion When dansyl chloride reacts with the appropriate substances in solution, the resulting hydrochloric acid can be eliminated by using buffers.Comparative analyses with and without buffers showed that better results could be obtained without any additional applica- tion of the buffer to the thin-layer chromatographic plate. The application of 2 p1 of the reagent in acetone is sufficient for derivatisation, although 2 p l of the sample solution in methanol - water were applied first. In spite of the different polarities of the solvents no difference in the resulting intensities of fluorescence could be found even if 3 or 5 p1 of the reagent solution were used. The drying of the thin-layer chromatographic plate resulted in a strong reduction in the fluorescence of the dansyl derivatives. Through dipping the chromatogram into a mixture of triethylamine, hydrogen peroxide and ethanol, an optimum stabilisation could be achieved as well as a considerable enhancement of fluorescence intensity of the substance spots.The optimum reaction time for the derivatisation of morphine and morphine-6-nicotinate is 8 min at 100 "C (see Table I); 55-60% of the maximum fluorescence intensity is achieved after only 1 min. Nachtmann et aL4 were also able to observe different kinds of fluorescence behaviour of various dansyl derivatives. TABLE I KINETICS OF THE DANSYLATION OF MORPHINE AND MORPHINE-6-NICOTINATE Relative peak area after different reaction times/min Compound '1 3 5 8 10 15 20 30 40 Morphine . . . . .. .. 415 675 750 830 830 831 820 800 760 Morphine-6-nicotinate . . .. 215 275 320 348 350 345 325 300 250 I t is possible that a steric effect is also the cause of the behaviour in this instance, because morphine-6-nicotinate is substituted with nicotinic acid in the 6-position. In order to eliminate any influence of morphine-3,6-dinicotinate on the dansylation, as a result ofApril, 1982 SHORT PAPERS 461 differently distributed proportions in the substance spot, an adequate amount of morphine- 3,6-dinicotinate was added to the standard solutions.A better sensitivity, 800 pg for morphine and 5 ng for morphine-6-nicotinate, was obtained with the Macherey-Nagel material than with the Merck thin-layer chromatographic plates. The determination is linear for between 2 and 200 ng of morphine and for between 5 and 200 ng of morphine-6-nicotinate. The reproducibility of the method was tested with morphine as well as with morphine-6-nicotinate by a series of ten assays, each treated under identical conditions. The relative standard deviations obtained for each 50ng per spot was 1.25% for morphine and 1.84% for morphine-6-nicotinate. References 1 . 2. 3 . 4. Zirm, K. L., and Pongratz, A., Arzneim.-Forsch., 1915, 9, 511. Seiler, N., and Wiechmann, M., Exfierientia, 1965, 21, 203. Frei, R. W., Lawrence, J. F., and LeGay, D. S., Analyst, 1973, 98, 9 . Nachtmann, F., Spitzy, H., and Frei, R. W., Anal. Chim. Acta, 1975, 76, 57. Received August 26th, 1981 Accepted October 26th, 1981

ISSN:0003-2654    

DOI:10.1039/AN9820700459

出版商:RSC    

年代:1982

数据来源: RSC

摘要:

462 Book Reviews Analyst, April, 1982 ANALYSIS OF NON-METALS IN METALS. PROCEEDINGS OF THE INTERNATIONAL CONFERENCE, BERLIN (WEST), JUNE 10-13, 1980. Edited by GUNTHER KRAFT. Pp. xiv + 546. Walter de Gruyter. 1981. Price DM148. ISBN 3 11 008443 0. The properties of metals can be adversely affected by the presence of non-metals although in certain instances the effects may be beneficial. This applies not only to mechanical and metal- lurgical properties but also to nuclear ones, such as neutron capture cross-section. The effects can be produced by concentrations as low as 0.1 pg g-l, whereas the content may rise to as much as 1 mg g-1 in certain metals. The determination of these levels of oxygen, nitrogen, hydrogen, carbon, sulphur, boron and fluorine imposes considerable strain on conventional chemical methods.In the last decade there have been notable improvements in accuracy and precision resulting from the introduction of more modern techniques such as hot extraction and activation analysis. A four-day symposium to discuss the progress to date was called in June 1980 by the Fach- gruppe Analytische Chemie der Gesellschaft Deutscher Chemiker. Other groups taking part were the Non-Metals in Non-Ferrous Metals team of the Bureau Communautaire des References of the Commission of the European Communities and The Chemists’ Committee of the Gesellschaft Deutscher Metallhutten und Bergleute of the Verein Deutscher Eisenhiittenleute. This volume is a collection of some 36 papers given a t the symposium, many with exhaustive references.In the next section of 15 papers on the determination of non-metals in metal by activation analysis two are in French, three in German and ten in English. In the final section on non-metals in non-ferrous metals two papers are in French, three in English and eight in German. Every paper carries an abstract in English, which in some instances is merely a brief r6sum6 of the contents but in others it is a fairly full summary of the relevant details. All the papers contain much information in graphic or diagrammatic form and in the non- English versions enable one to decide how much translation would be beneficial. A useful list of referents’ names and addresses is given a t the end of the book together with a subject index. An important feature is the rapid publication achieved in a relatively short period of time from the ending of the conference. By this means an authoritative and up-to-date account is available from a group of specialist contributors on a subject that is exercising analysts more and more each year.W. R. NALL The first eight papers on non-metals in iron and steel are in German. CHEMICAL TECHNICIANS’ READY REFERENCE HANDBOOK. Second Edition. By GERSHON J. SHUGAR, RONALD A. SHUGAR, LAWRENCE BAUMAN and ROSE SHUGAR BAUMAN. Pp. xxiv + 867. McGraw-Hill. 1981. Price k27.95. ISBN 0 07 057176 7. The authors’ expressed aim was to produce an “omnibook” to provide anyone from under- graduate to graduate student to trained chemist with a guide to “every single step” when per- forming normal chemical laboratory procedures.This was a very broad remit to undertake and indeed impossible to achieve fully in that one laboratory’s normal practice may by another be regarded as extraordinary or sophisticated. The breadth of material and wealth of detail make i t difficult to summarise the contents briefly. All the basic operations such as heating, cooling, measuring temperature, evaporation of liquids, mechani- cal agitation, filtration, recrystallisation, sublimation, extraction, centrifugation, distillation, weighing, glassblowing and pH measurement are included, as are techniques of measurement of physical properties of materials in general, volumetric analysis and chromatography. Use of gases, ground-joint glassware and plastic laboratory ware is also detailed. Particularly useful are chapters on pressure and vacuum, electricity and laboratory tools and hardware.Chapters that deal with more theoretical material are in parts too compressed and thus considered to be less useful ; these include basic concepts in organic chemistry, determination of elements in organic chemistry, the electromotive series (i.e., electroanalysis) and that on the electromagnetic spectrum, which amazingly explains how to use a Duboscq colorimeter. If what you want is included you will, or should, be pleased and save time in instructing or re-instructing yourself or whoever is to do the task. The instructions are written in clear, simple, The book starts with and emphasises throughout responsibility and safety practices,BOOK REVIEWS 463 numbered statements, the equipment required is detailed and what it looks like is indicated (drawing or photograph).How the pieces are used in a procedure, the sequential steps in per- forming the task or acquiring the data, the precautions to be observed and finally how to do the calculations needed to be able to utilise the data are clearly explained. Should you need to remove a stuck glass stopper, safely empty a 50-gallon drum of diethyl ether, explain how a pressure regulator valve works or detect the colloidal state, there are no problems as all is explained. Potential readers should not be put off by the title; for the British market, where the US use of the term technician may be misunderstood, a better title would have been simply “Chemical Laboratory Handbook.” This excellent book, together with The Royal Society of Chemistry book “Hazards in the Chemical Laboratory,” should be regarded as mandatory reading for all new graduates before they reach industry, where experiments are not always rigged to work even in expert hands, the boss is often busy and not inclined to be amused by failure, nor these days can afford to ignore hazardous practices.More experienced chemists will find the volume an excellent aide nzemoire. D. THORBURN BURNS APPLICATIONS OF GLASS CAPILLARY GAS CHROMATOGRAPHY. Edited by WALTER G. JENNINGS. Chromatographic Science Series, Volunze 15. Pp. viii + 629. Marcel Dekker. 1981. Price SwFr186. ISBN 0 8247 1223 4. This is a book of 15 chapters by 20 contributors. It has an introduction on the evolution of open tubular columns followed by system requirements. The remaining chapters deal with appli- cations in xenobiotic research, air and air pollutants, water and water pollutants, pesticides, clinical medicine, beer, hops, grapes, wines, brandies, food and flavours, essential oils, fatty acids, bile acids, amino acids and steroid hormones.There is a large number of references (around 1 800 in total) and a fairly good index (this latter is a good point of the volume as books of this nature often dispense with an index). The book is printed in a clear typescript that is relatively easy to read, and all the diagrams are clear, although in some instances rather small for the detail they possess. One hesitates to single out any individual contributor for praise or criticism.Suffice to say that in some instances rather more practical detail could be given and some of the chapters, together with their numerous references, may be regarded as short reviews rather than more practical applications. In general this is a useful book for the experienced chromatographer dealing with a wide field of applications and would be recommended to libraries. D. SIMPSON TRACE ELEMENT ANALYTICAL CHEMISTRY IN MEDICINE AND BIOLOGY. PROCEEDINGS OF THE FIRST INTERNATIONAL WORKSHOP, NEUHERBERG, FEDERAL REPUBLIC OF GERMANY, APRIL 1980. Edited by PETER BRATTER and PETER SCHRAMEL. Pp. xviii + 851. Walter de Gruyter. 1980. Price DM180. ISBN 3 11 008357 4. Most of us regard expensive books that are the record of a meeting held some time ago as a poor buy for our libraries, as they are often overtaken by developments in a rapidly changing subject.This book is a collection of papers based upon material presented at a Workshop on trace-element analysis in medicine and biology held in West Germany in April 1980. So the organisers have produced the book fairly rapidly and the contents are an up-to-date account of developments in this fashionable topic. Haste is evident in parts of the book, however; for example, the Panel Discussion that closed the meeting is badly in need of editing (the verbatim record of what the translators thought was said makes curious reading). This is a minor blemish in an otherwise well produced book. The opening contribution from Professor Feinendegen is a review of the medical aspects of trace-element research and sets the scene for later, more specialised lectures. This scholarly account should also alert the more complacent amongst British and American workers that by no means all first-class research is published in English language journals.Inevitably, the quality of the contributed papers is more uneven and there is some repetition. A few contributors are more intent on justifying their own favourite analytical technique than selecting an appropriate method for the problem they are considering. For some of us there is an undue emphasis on neutron activation tech- niques, which, however successful in the past, would not be a realistic first choice nowadays. The quality of the Plenary lectures is high.464 BOOK REVIEWS Analyst, Vol. 107 There are several papers giving an account of atomic-spectrophotometric methods, including atomic fluorescence and carbon-furnace emission, also descriptions of electroanalytical and even catalytic rate reaction procedures.A whole section is devoted to X-ray emission (PIXE) and X-ray fluorescence techniques. A review chapter by Hislop surveys the wide choice of methods available to the analyst. A most important section deals with the validity of results obtained by the sensitive techniques. Versieck and Cornelis remorselessly catalogue the extraordinary differences in values for metals found a t parts per billion levels in healthy human serum. Referees should surely note this work and question any submission where the quoted controls are not in reasonable agreement with the lowest consensus mean values for human serum.Practical advice on reducing sample contami- nation is given in a chapter by Behne and other workers describe problems of sample dissolution prior t o analysis. A section of the book is devoted to the growing range of biological reference materials, which, when properly used, should improve quality assurance programmes. Although expensive for the individual reader, the book should be purchased for the libraries of all institutions with any interest in trace-element biology. G. S. FELL METHODS FOR THE EXAMINATION OF WATERS AND ASSOCIATED MATERIALS. By THE STANDING COMMITTEE of ANALYSTS (to REVIEW STANDARD METHODS FOR QUALTTY CONTROL OF THE WATER CYCLE) ; DEPARTMENT OF THE ENVIRONMENT, NATIONAL WATER COUNCIL. HM Stationery Office.A Survey of Multielement and Related Methods of Analysis f o r Waters, Sediments and Other Materials of Interest to the Water Industry, 1980. Pp. 46. 1981. Price f13.20. ISBN 0 11 751529 9. Dissolved Potassium in R a w and Potable Waters, Tentative Methods (1980 Version). 1981. Price f12.40. Z i n c in Potable Waters by Atomic Absorption Spectrophotonzetry, 1980. Pp. 10. 1981. Price k1.70. Dissolved Sodium in R a w and Potable Waters, Tentative Methods (1980 Version). 1981. Price k2.40. Chloro- and Bromo- Trihalogenated Methanes in Water, 1980. Pp. 16. 1981. Price k2.40. ISBN 0 11 751544 2. Bromide in Waters, High Level Titrimetric Method, 1981 (Tentative). Pp. 8. 1981. Price k1.40. Pp. 17. ISBN 0 11 751545 0. ISBN 0 11 751541 8. Pp. 17. ISBN 0 11 751546 9.ISBN 0 11 751543 4. These six booklets are part of the series that provides recommended methods for the deter- mination of water quality, and which supersede the Department of the Environment volume on “Analysis of Raw, Potable and Waste Waters.” The Standing Committee of Analysts is now providing a very useful set of up-to-date methods that can be readily applied by water labora- tories in the UK and elsewhere. It is very encouraging to see the introduction of standard methods based on modern instrumental techniques and the above publications, which have just been released, contribute effectively to this process. Thus the method for halogenated methanes involves gas chromatography after solvent extraction, and the booklets on potassium and sodium both include two alternative methods using flame photometry and flame atomic-absorption spectrometry. The latter technique is also used for zinc determinations but in this instance following pre-concentration of the sample by evaporation in the presence of nitric acid. The method for bromide involves oxidation to bromate with sodium hypochlorite and determination of the bromate iodimetrically and has a limit of detection of 0.09 mg kg-l. The information given about each method is extremely valuable and includes precision, range and speed, as well as accuracy data. The impression given is that the methods have been subjected to detailed evaluation and can therefore be used with confidence. The booklet on multielement methods is a brief summary/review and would be a useful document to give to new employees in a water laboratory. More detailed reading, using the references cited, would however be required to appreciate the theory and methodology of the methods described. J . M. OTTAWAY

ISSN:0003-2654    

DOI:10.1039/AN9820700462

出版商:RSC    

年代:1982

数据来源: RSC