摘要:

ANALYST, JANUARY 1987, VOL. 112 SHORT PAPERS Diazotised 4-Nitroaniline as a Chromogenic Determination of Trace Amounts of Pyrrole Ahmad K. Ahmad and Younis 1. Hassan 97 Reagent for the in Aqueous Solution Department of Chemistry, College of Education, Mosul University, Mosul, Iraq and Wadala A. Bashir Department of Chemistry, College of Science, Mosul University, Mosul, Iraq A sensitive spectrophotometric method for the determination of trace amounts of pyrrole in aqueous solution is described, The method is based on the reaction of pyrrole with diazotised 4-nitroaniline to produce, in the presence of sodium acetate, an intense yellow, water-soluble, stable monoazo dye, which shows maximum absorption at 420 nm. A graph of absorbance versus concentration indicates that Beer's law is obeyed over the concentration range 5-100 pg of pyrrole in a final volume of 25 ml, i.e., 0.2-4 p.p.m., with a molar absorptivity of 2.32 x 104 I mol-1 cm-1, a Sandell sensitivity of 0.0029 pg cm-2, a relative error of +0.9 to -1.7% and a relative standard deviation of 0.6-2.0%, depending on the concentration. A study has been made to determine the optimum conditions of the colour reaction.Interferences from foreign organic compounds have been examined and the structure of the monoazo dye is suggested. Keywords: Pyrrole determination; diazotised 4-nitroaniline reagent; spectrophotometry Pyrrole is an important five-membered heterocyclic ring because its nucleus occurs in many natural compounds, e.g., alkaloids, chlorophyll and haematin. Pyrrole also occurs in coal tar and bone oil.1 The presence of the pyrrole group in hydrocarbons is undesirable because it promotes gum forma- tion, sedimentation and discoloration .* Among the various methods available for trace analysis, spectrophotometry continues to be one of the most popular because it is simple and economical .3 The spectrophotometric methods available for the determination of pyrrole are very few and are not completely satisfactory.The method based on the reaction with 4-dimethylamin~benzaldehyde~ to give a red colour seems to be slow unless the reaction mixture is heated to boiling and the reagent is in alcohol. Other methods5.6 based on the reaction with isatin in hydrochloric acid to yield a blue colour are affected by the concentration of acid.Therefore, a new spectrophotometric method for the determination of pyrrole seems desirable. This paper describes a spectro- photometric method for the determination of pyrrole, which relies on the coupling reaction of pyrrole with diazotised 4-nitroaniline reagent to form, in the presence of sodium acetate, an intense yellow azo dye suitable for the quantitative determination of trace amounts of pyrrole in aqueous solu- tion.The intense azo dye is water soluble and does not require prior extraction. Experimental Apparatus Spectral measurements were carried out on a Unicam SP 1800 UV double-beam recording spectrophotometer and absorb- ance readings were made on a Bausch and Lomb Spectronic 710 single-beam digital spectrophotometer using 1-cm silica matched cells.Reagents All chemicals used were of analytical-reagent grade. Stock pyrrole solution, 10 mg ml-1. Dissolve 0.25 g of pyrrole in ethanol and adjust the volume to 25 ml in a calibrated flask with the same solvent. Store in a refrigerator. Working pyrrole solution, 50 pg ml-1. Dilute 0.5 ml of the stock pyrrole solution to 100 ml with distilled water in a calibrated flask. Store this solution in a refrigerator when not in use. Diazotised 4-nitroaniline reagent solution, 2 mM. This solution is prepared in the same manner as described elsewhere7 except that the standing time before the volume is adjusted to 100 ml is 30 min instead of 5 min. This reagent solution is stable for one week when kept in a refrigerator at 0 "C. Sodium acetate solution, 1 M. Dissolve the appropriate amount of sodium acetate trihydrate in and dilute to volume with distilled water.Prepare the 0.08 M solution by dilution. Foreign compound solution, 0.1 mg ml-1. Dissolve the compound in 10% V/V ethanol in a calibrated flask, except for carbazole, for which 65% ethanol should be used. Procedure Transfer increasing volumes of working pyrrole solution, covering the range 5-100 pg, into a series of 25-mi calibrated flasks. Add 10 ml of distilled water, 0.5 ml of 0.08 M sodium acetate solution, 2 ml of 2 mM diazotised reagent and dilute to volume with distilled water. Mix and allow the reaction mixture to stand for 10 min to attain full colour formation. Measure the absorbance against a reagent blank, prepared in the same manner but containing no pyrrole, at 420 nm using 1-cm cells.The colour is stable for at least 1 h. A straight-line calibration graph is obtained, indicating that Beer's law is obeyed over a concentration range of 0.2-4 p.p.m. The apparent molar absorptivity (referred to pyrrole) , calculated by the formula given in reference 8, is found to be 2.32 X 104 1 mol-1 cm-1 and the Sandell sensitivity is 0.0029 pg cm-2. For subsequent experiments, 50 pg of pyrrole were taken and the final volumes were 25 ml. Results and Discussion Absorption Spectra When very dilute aqueous solutions of pyrrole and diazotised 4-nitroaniline reagent solution are mixed in the presence of sodium acetate, an intense yellow monoazo dye forms immediately. The intense azo dye formed shows a maximum absorption at 420-422 nm, in contrast to the reagent blank, which shows a maximum absorption in the ultraviolet region98 ANALYST, JANUARY 1987, VOL.112 ~ ~~ ~ ~~ ~ Table 1. Standard deviation and precision of the proposed method Amount of pyrrole Relative Relative standard takenlyg error, * % deviation,* YO 25 - 1.7 1.7 50 -1.6 0.6 100 +0.9 2.0 O.* r 350 400 450 500 550 Wavelengthhm Fig. 1. Absorption spectra of: A, 50 pg of pyrrole, treated as described under Procedure and measured against a reagent blank; and B, reagent blank measured against distilled water near 325 nm and almost zero absorption in the visible region (380-550 nm). Fig. 1 shows the spectra of the azo dye and of the reagent blank. A wavelength of 420 nm, characteristic of the azo dye, was therefore used in all subsequent determina- tions.Study of the Optimum Reaction Conditions The effects of various parameters on the absorption intensity of the azo dye were studied and the reaction conditions were optimised. Effect of Diazotised Reagent In order to achieve the optimum spectrophotometric condi- tions,' three diazotised reagents were tested. These reagents were diazotised orthanilic acid, diazotised sulphanilic acid and diazotised 4-nitroaniline. The latter reagent showed the most useful results for the determination of pyrrole and was therfore studied further with respect to the effect of its concentration on colour formation. The azo dye formation reached a maximum with about 1 ml of the 2 mM diazotised 4-nitroaniline reagent solution and remained at this maximum when 2-5 ml of the prescribed reagent concentration were added. A 2-ml volume of 2 mM diazotised reagent solution was therefore adopted in the procedure.Effect of Alkaline Solution The addition of mineral acid to the azo dye solution resulted in a decreased intensity, whereas the addition of alkali caused a bathochromic shift. Sodium acetate, sodium hydrogen car- bonate, sodium carbonate and sodium hydroxide were exam- ined. The experimental investigations revealed that the resultant colour, although less intense, becomes more stable with decreasing base strength, and sodium acetate was chosen for further studies. The use of 0.5 ml of 0.08 M sodium acetate solution gave a reasonable sensitivity and the colour became stable for at least 1 h. Increasing the amount of sodium acetate led to an increased colour intensity but limited stability. Effect of Light and Temperature Light had no appreciable effect on the absorbance of either the sample or blank solution.The same absorbance was obtained whether the reaction was performed in daylight or in the dark. Temperatures in the range 5-15 "C had no effect on * Four determinations. Table 2. Effect of foreign compounds on the determination of 50 bg of pyrrole. The amount of interferent added in each instance was 100 pg Interferent Interference, % 4-Aminopyridine . . . . . . . . . . + 1.2 2-Aminopyrimidine . . . . . . . . +0.2 Carbazole . . . . . . . . . . . . +2.7 4-Diphenylamine-4-sodium sulphonate . . +0.3 Furan-2-carboxylic acid . . . . . . . . -4.0 Histidine . . . . . . . . . . . .-0.3 Indole-3-propionic acid . . . . . . . . +4.9 Nicotinic acid . . . . . . . . . . -4.2 1 ,lo-Phenanthroline.H,O . . . . . . -1.6 Phenol . . . . . . . . . . . . . . +3.9 Pyrazole -3.3 Thiophene-2-carboxylic acid . . . . . . + 2.7 Tryptamine . . . . . . . . . . . . -2.1 Tryptophan . . . . . . . . . . . . -3.7 . . . . . . . . . . . . . . . . . . . . . . . . . . Uracil -1.2 the colour intensity. However, increasing the temperature to 45°C resulted in a 10% loss of intensity. Therefore, it is recommended that the determination is carried out at room temperature (15 "C). Order of Addition of Reagents The order of addition cited in the procedure should be followed. The colour becomes less stable when sodium acetate is added after the diazotised reagent. Effect of Time on Colour Development A study of the effect of time on colour development showed that the reaction mixture should stand for 10 min in order to achieve an absorbance that is stable for at least 1 h.Accuracy and Precision In order to check the accuracy and precision of the method, pyrrole was determined at three different concentrations. The results are shown in Table 1 and indicate that the method is satisfactory. Interferences In order to illustrate the selectivity of the method, the interference effects of various organic compounds were examined by carrying out the determination of 50 pg of pyrrole in the presence of each of the interferents using the recommended procedure, The results obtained are given in Table 2. Nature of the Dye Pyrrole couples with diazonium salts predominantly at the 2-position.9 Job's method of continuous variations showed that the dye has the composition 1 : 1 (pyrrole : diazotised 4-nitroaniline reagent), indicating a monoazo dye.The mechanism of azo dye formation may be written as follows:ANALYST, JANUARY 1987, VOL. 112 99 I H H r H The azo dye is soluble in water, acetone, dioxane, ethanol, ethoxyethanol, methanol, propanol and tetrahydrofuran. The dye is also quantitatively extracted into benzene, carbon tetrachloride, chloroform and diethyl ether. Conclusion A simple and sensitive spectrophotometric method for the determination of trace amounts of pyrrole in aqueous solution has been developed, based on the formation of an azo dye following the coupling of pyrrole with diazotised 4-nitro- aniline reagent in the presence of sodium acetate. 1. 2. 3. 4. 5. 6. 7. 8. 9. References Finar, I. L., “Organic Chemistry,” Fourth Edition, Volume 1, Longman, London, 1963, p. 746. Snell, F. D., and Snell, C. T., “Colorimetric Methods of Analysis,” Third Edition, Volume 4, Van Nostrand, Princeton, 1954, p. 241. Kalyanaraman, S., Sugiyama, A., and Fukasawa, T., Analyst, 1985, 110, 212. Thompson, R. B., Symon, T., and Wankat, C . , Anal. Chem., 1952, 24, 1465. Guest, G. H., andMacFarlane, W. D., Can. J. Res., 1939,17B, 133; Chem. Abstr., 1939, 33,58795. Fromm, F., Mikrochemie, 1935, 17, 141; Chem. Abstr., 1935, 29, 53867. Sulaiman, B., and Bashir, W. A,, Analyst, 1984, 109, 1409. Rahim, S. A., Bashir, W. A., and Ibraheem, B. B., Analyst, 1984, 109, 955. Morrison, R. T., and Boyd, R. N., “Organic Chemistry,” Third Edition, Allyn and Bacon, Boston, 1973, p. 1008. Paper A6165 Received February 27th, 1986 Accepted July 28th, 1986

ISSN:0003-2654    

DOI:10.1039/AN9871200097

出版商:RSC    

年代:1987

数据来源: RSC

摘要:

ANALYST, JANUARY 1987, VOL. 112 101 Spectrophotometric Determination of Dobutamine Hydrochloride Using 3-Methyl benzothiazolin-2-one Hydrazone Michael E. El-Kommos Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Assiut University, Assiut, Egypt A spectrophotometric procedure is described for the determination of dobutamine hydrochloride. The proposed method uses 3-methylbenzothiazolin-2-one hydrazone as the chromogenic reagent. A mixture of aqueous solutions of the drug and reagent is treated with cerium(lV) ammonium sulphate in an acidic medium. Dobutamine reacts to give a pink colour with a A,,,. at 510 nm ( E ~ ~ ~ . = 1.5 x lo4 I mol-l cm-l). Beer's law is obeyed in the concentration range 4-20 yg ml-1 of dobutamine in the final assay solution. The procedure described was successfully applied to the determination of the bulk drug and its dosage form (Dobutrex vials).Keywords: Spectrophotometry; dobutamine hydrochloride determination; 3-methylbenzothiazolin-2-one h yd razon e Dobutamine hydrochloride { (+)-4-[2-3-p-hydroxyphenyl-1- methylpropylamino)ethyl]-benzene- 1,2-diol hydrochloride} is a sympathomimetic agent which has direct effects on beta-adrenergic receptors. These effects mean that the drug has a prominent inotropic action on the heart.1 It is widely used in the form of Dobutrex vials in the management of heart failure associated with organic heart disease, myocardial infarction and cardiac surgery. The USP XXI describes a gas chromatographic assay for both the pure drug and the injection after silylation with 1-trimethysilylimidaole, using a flame ionisation detector and n-triacontane as an internal standard.2 Other spectrophoto- metric,3 GLC4 and HPLCS methods have been reported.Although the official USP procedure is very reliable, the instrumentation and effort required for the assay are much greater than those required for a spectrophotometric assay. In this paper the development of a procedure based on the formation of a coloured reaction product with 3-methylbenzo- thiazolin-Zone hydrazone (MBTH) is reported. The colour produced is stable and reproducible and is proportional to the concentration of dobutamine. This highly sensitive procedure is simple, rapid and readily adaptable to both the bulk drug and unit dose determinations. Experimental Apparatus A Pye Unicam SP 1750 spectrophotometer (Pye Unicam, Cambridge, UK) with an AR 55 linear recorder and SP 1805 programme controller was used.Samples Dobutamine hydrochloride, pharmaceutical grade. Obtained as a gift from Eli Lilly (Windlesham, Surrey, UK), and used as a working standard. Dobutamine hydrochloride injection. Dobutrex vials (Eli Lilly) containing dobutamine hydrochloride equivalent to 250 mg of dobutamine were used. Preparation of sample solutions An accurately weighed amount of dobutamine hydrochloride, or the contents of the Dobutrex vials, was dissolved in water and diluted stepwise to obtain a concentration of 30 pg ml-l of dobutamine hydrochloride. Reagents water. 5% H2so4. Assay Procedure A 2.0 ml aliquot of the assay solution was transferred into a stoppered test-tube and 2.0 ml of MBTH solution were added.After 5 min, 2.0 ml of cerium(1V) ammonium sulphate solution were added and the contents were mixed thoroughly. After 30 min, the absorbance of the solution was measured at 510 nm against a blank similarly prepared but using 2.0 ml of distilled water instead of the sample solution. MBTH solution, 0.2% mlV. Freshly prepared in distilled Cerium(IV) ammonium subhate solution, 0.075% mlV in Construction of Calibration Graph About 30 mg of dobutamine hydrochloride were accurately weighed, dissolved in water and diluted to volume in a 100-ml calibrated flask. This solution was diluted stepwise to give a series of concentrations suitable for the construction of the calibration graph in the range 12-60 pg ml-1; 2.0 ml of each solution were used for the colour formation with MBTH as described under Assay Procedure. Results and Discussion Reaction Mechanism Dobutamine hydrochloride forms a pink product (Amax.= 510 nm) with MBTH in the presence of cerium(1V) ammonium sulphate in acidic media. The molar absorptivity of the chromogen was found to be 1.5 x l o 4 1 mol-1 cm-1. Under the reaction conditions, MBTH (I), on oxidation with Ce4+ ions, loses two electrons and one proton forming an electrophilic intermediate (11), which is the active coupling species.610 Two moles of this intermediate undergo electrophilic substitution with the two phenolic moieties of 1 mol of dobutamine to form a coloured product (111) according to the scheme shown overleaf. Optimisation of Variables Eflect of MBTH concentration The optimum concentration of MBTH leading to maximum colour stability was found to be 2 ml of 0.2% reagent per 6 ml of the reaction mixture.Lower reagent concentrations gave102 ANALYST, JANUARY 1987, VOL. 112 r 1 I L II N-N N-N cH3-8 i L s c H 3 - N ( . 3 0 \ N-N A ' 0.6 L m e g 0.4 Q a 0.2 0 350 430 510 590 670 hlnm Fig. 1. Spectra of dobutamine - MBTH prepared with A, 0.05%, B, 0.10%, C, 0.15%, D, 0.20% and E, 0.25% MBTH. solution. Concentration of dobutamine hydrochloride is 7.3 pg ml-l in the final assay solution $ 0.4 C crr 2 0" 0.2 Q 0 350 430 510 590 670 hln m Fig. 2. S ectra of dobutamine - MBTH prepared with A, 0.025%, B, 0.050$, C, 0.075%, D, 0.100% and E, 0.125% cerium(1V) ammonium sulphate solution. Concentration of dobutamine hydro- chloride is 7.3 pg ml-* in the final assay solution N-N CH3-N + Table 1.Effect of H2S04 concentration on colour intensity Absorbance at 510 nm h2504 concentration, YO 4 pg ml-1 8pgml-l 12 pg ml-1 1 .o 0.172 0.283 0.399 2.0 0.190 0.312 0.438 3.0 0.204 0.337 0.473 4.0 0.226 0.372 0.520 5.0 0.225 0.370 0.520 ~ Table 2. Effect of reaction time on colour intensity. The concentration of dobutamine hydrochloride in the final assay solution was 16 pg m1-1 Time/min 5 10 15 20 25 30 35 Aslo 0.607 0.621 0.630 0.638 0.643 0.648 0.648 Time/min 40 45 60 90 120 150 180 A510 0.649 0.649 0.648 0.647 0.631 0.605 0.575 colours of higher intensities (Fig. 1) but these faded very quickly with time, probably owing to the formation of a mixture of monosubstituted dobutamine derivatives.Effect of Ce4+ concentration The optimum concentration of cerium(1V) ammonium sul- phate solution leading to maximum colour stability was found to be 2 ml of 0.075% solution per 6 ml of the reaction mixture. Higher concentrations of the Ce4+ ion gave colours of higherANALYST, JANUARY 1987, VOL. 112 103 Table 3. Assay of dobutamine hydrochloride in bulk drug and Dobutrex vials by the MBTH method. All determinations were in triplicate Amount taken/ Recovery f SD, Amount added Recovery f SD, Sample mg YO mg YO - - Raw material . . . . 30.0 99.7 k 1.20 Rawmaterial . . . . 60.0 99.4 f 0.94 - - Rawmaterial . . . . 90.0 100.1 f 0.86 - - Dobutrexvials . . . . 150.0 99.2 rt 1.03 60.0 100.1 f 0.97 Dobutrexvials . . . . 180.0 99.6 k 0.98 60.0 99.3 f 1.16 intensities (Fig.2) but these faded very rapidly with time, probably owing to the formation of several oxidation products or the oxidation of the chromogen itself. Effect of H2S04 concentration The optimum concentration of H2S04 solution in which cerium(1V) ammonium sulphate was dissolved was found to be 5% (Table 1). Higher concentrations did not affect the colour intensity. Effect of reaction time The maximum colour intensity was obtained after 30 min at 20 It 5 “C. The colour was stable for a further hour (Table 2). Quantification, Adherence to Beer’s Law, Sensitivity, Accu- racy and Precision A linear correlation ( r = 0.9996) was found between the absorbance at 510 nm and the concentration of dobutamine hydrochloride in the range 4-20 pg ml-1 in the final assay solution.The minimum detectable amount was found to be 1.0 pg of dobutamine hydrochloride. The reaction can therefore be used for the identification of the drug in bulk or in dosage forms. The precision of the proposed method was determined by analysing ten replicate samples, each contain- ing 10 pg ml-1 in the final test solution. At this concentration level the standard deviation was 0.80%. Application to Bulk Drug and Dosage Form Analysis The suggested method was applied to the quantitative determination of dobutamine hydrochloride in the raw material and in Dobutrex vials (Table 3). The results obtained indicate that the method is suitable for routine quality control analysis. The proposed method has the added advantages of simplicity and rapidity over the recent USP derivatisation gas chromatographic method.The proposed method has also two advantages over the previously reported spectrophotometric method using thiosemicarbazide.3 Firstly, MBTH is stable in the solid state whereas thiosemicarbazide is hygroscopic. Secondly, in the proposed method, aqueous solutions are used throughout the whole procedure, whereas in the thiosemi- carbazide method acetone , which is volatile and less suitable for spectroscopic measurements, is used as a diluting solvent. The author thanks Miss V. Mason, Lilly Research Centre, Ltd., UK, for the samples supplied. 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. References Reynolds, J. E., and Prasad, A. B., Editors, “Martindale. The Extra Pharmacopoeia,” Twenty-eighth Edition, Pharmaceut- ical Press, London, 1982, p. 8. “United States Pharmacopeia, XXIth Revision, National Formulary XVIth Edition,” United States Pharmacopeial Convention, Rockville, 1985, p. 348. El-Kommos, M. E., Analyst, 1983, 108,380. Murphy, P. J., Williams, T. L., and Kau, D. L., J. Pharmacol. Exp. Ther., 1976, 199, 423. McKennon, D. W., and Kates, R. E., J . Pharm. Sci., 1978,67, 1756. Hunig, S., and Fritsch, K. H., Ann. Chim., 1957, 609, 143. Hunig, S . , Balli, H., Breither, E., Bruhne, F., Geiger, H., Grigart, E., Muller, F., and Quast, H., Angew Chem., 1962, 74, 818. Bartsch, R. A., Hunig, S., and Quast, H., J . Am. Chem. SOC., 1970, 92, 6007. Gasparic, J., Svobodova, D., and Pospisilova, M., Microchim. Acfu, 1977, 241. El-Kommos, M. E., Arch. Pharm. Chem. Sci. Ed., 1982, 10, 146. Paper A61181 Received June 4th, 1986 Accepted August 19th, 1986

ISSN:0003-2654    

DOI:10.1039/AN9871200101

出版商:RSC    

年代:1987

数据来源: RSC

摘要:

ANALYST, JANUARY 1987, VOL. 112 105 SOFTWARE REVIEW From time to time, The Analyst will publish reviews of computer software packages designed for analytical applications. Commercial and other suppliers of such packages are invited to submit analytical software for review; full technical specifications should be included. CLUE A. Thielemans, M. P. Scientific Software, Manual only $41.50; tions: Computer: Language: Operating system: Required peripherals: Minimum memory: Storage medium: Order Ref. No.: Computer: Language : Operating system: Required peri p hera Is: Minimum memory: Storage medium: Order Ref. No.: Derde and D. L. Massart. Elsevier 1985. Price $405; Df1975; €105; Dfl100; f25. Technical specifica- Apple II, I t + , Ile, Ilc Applesoft BASIC (interpreter and com pi led) DOS3.3 140 K 5Y4-in diskette drive 48K RAM (interpreter) 64K (com pi led) 5 l/4- i n d i s ke t t e ISBN 0 444 42335 4 PC-BASIC (interpreter and com piled) 180W360K 5%inch diskette drive 128K RAM 5V4-in diskette ISBN 0 444 42336 2 IBM-PC, -XT, -AT PC-DOS 2 .~ , 3.0 CLUE is a program that performs cluster analysis on a microcomputer. It is based on a hierarchical divisive method and can be used to detect similarities and differences between objects that are characterised by several measurement vari- ables. This pattern recognition technique is useful in many branches of science; in analytical chemistry it is most often applied to investigate whether complex samples have a common or a different origin. The maximum size of the data matrix that the program can handle is 50 objects by 50 variables, so real-world problems of somewhat more than moderate size can be attacked with the program.The documentation describes how the source code can be modified to trade off a number of variables for more objects. If the program is used to its limits the availability of the compiled-Basrc version (64K needed) helps to keep the run-time within practical limits. Much attention has been paid to the user interface of the program, which is menu driven, Together with the excellent documentation this guides the user through the steps neces- sary to perform a complete cluster analysis. Data input to the program can come from the keyboard or from disk. Keyboard data can be stored on disk and edited for later use. A minor nuisance is the strict formatting rules that demand decimal notation in one particular range and scientific notation outside this range.A nice feature is that data can be appended to a data matrix that is already stored on disk. To obtain meaningful results in cluster analysis, trans- formation of the original input data should be performed if the range of values is quite different for different variables. The program offers two options: a logarithmic transformation and the Z-transform. The results of these transformations can also be saved to disk. The clustering can be done on the objects, but also on the variables, using either the Euclidian distance or the correlation as the measure of similarity. In the Euclidian distance option the program can take care of the frequently encountered problem of missing values.If the clustering is to be based on another dissimilarity measure, the required dissimilarity matrix can be entered directly from keyboard or disk on the condition that the values increase with increasing dissimilarity. The actual clustering takes some time, but its progress can be followed on the screen. The end results are presented in a kind of graphical output that needs some polishing to become recognisable as the dendrograms that are normally used for this purpose. The documentation of the program is, as stated before, excellent. The manual consists of a 77-page users’ guide with a completely worked out example and clear instructions for the installation of the program. The scientific background is given in a 25-page section with references to the relevant literature. The availability of the source code on disk and its listing in the manual enable the user to combine (parts) of the program with data acquisition routines. In conclusion, it can be said that CLUE is a well written, well documented and complete package for cluster analysis on data sets of moderate to medium size. Its price does not exactly make it a bargain, but the amount and quality of the code certainly are worth it. M . Bos

ISSN:0003-2654    

DOI:10.1039/AN9871200105

出版商:RSC    

年代:1987

数据来源: RSC

摘要:

106 ANALYST, JANUARY 1987, VOL. 112 ~~ Mass Spectrometry. Volume 8. A Specialist Periodical Report. Senior Reporter M. E. Rose. Pp. xvi + 360. Royal Society of Chemistry. 1985. f70; $126. ISBN 0 85186 328 0. This volume, under the Editorship of a new Senior Reporter, M. E. Rose, maintains the high standards set by his predecessors. In contrast to Volume 7, where an attempt was made to use modern printing methods with some disastrous consequences, this volume has been produced by conven- tional methods, resulting in a high quality product, but at a high price. It is to be hoped that the price of Volume 9 will be more reasonable, as the book is to be produced from camera-ready copy. As with previous volumes, contributions consist of a combination of reviews of the latest developments (1982-84) of key areas in mass spectrometry together with specialist reviews of areas of current topical interest.Chapters that fall into the former category are those by I. Powis on “Ionization Processes and Ion Dynamics”; M. A. Baldwin on “Structures and Reactions of Gas-phase Organic Ions”; T. R. Kemp on “Devlopments and Trends in Instrumentation”; J. H. Bowie on “Reactions of Organic Negative Ions in the Gas Phase”; M. E. Rose on “Gas ChromatographyMass Spectrometry and High-performance Liquid Chromatography/Mass Spec- trometry”; D. J. Harvey on “Drug Metabolism, Pharmaco- kinetics and Toxicity”; and J. Charalambous on “Metal- containing and Inorganic Compounds Investigated by Mass Spectrometry.” J. R. Chapman contributes on “Applications of Computers and Microprocessors in Mass Spectrometry ,” an area not covered in Volume 7, but present in previous volumes.In all instances the authors have done a thorough job, delineating recent developments in these areas and the current status of these topics. The remaining chapters are of a topical nature with J. Dannacher and J.-P. Stadelmann providing an excellent review of the fundamentals of photo- electron + photoion coincidence spectroscopy and its impact on our understanding of ionic decomposition phenomena. N. M. M. Nibbering in his chapter on “Fourier-transform Ion Cyclotron Resonance” provides a useful description of the basics of the technique and its utility in furthering our understanding of gas-phase ion chemistry. Unfortunately, some of the most important developments in this area, from the point of view of the analytical mass spectrometrist, i.e., improvements in sample introduction methodology and high mass applications, have been too recent for inclusion in this chapter.Fast atom bombardment mass spectrometry has revolutionised the ability of mass spectrometrists to provide useful structural information from mass spectrometrically difficult molecules. Much has been written about the qualita- tive aspects of this technique. R. M. Caprioli provides an insight into the ability of the technique to provide quantitative data and a systematic review of the various factors involved in the production of useful spectra. The volume is recommended to all practising mass spec- trometrists, as it provides a readily accessible overview of recent developments in the area and is of particular value as a source for developments in areas which they do not specialise.It will also be of considerble value to scientists interested in applying mass spectral techniques to the solution of problems in their discipline, because an insight can be rapidly gained into the utility of mass spectral techniques in a wide range of areas. The only reservation I have about the volume is cost, as &70 represents a major investment for the individual pur- chaser. D. E. Games BASIC Molecular Spectroscopy P. A. Gorry. Pp. x + 144. Butterworths. 1985. Price f8.95. ISBN 0 408 01553 5. This book, according to the author, has the aim of providing an introduction to molecular spectroscopy for first- and second-year undergraduates in chemistry and physics and covers the physical chemistry theory of the interaction of the electric field component of light with molecular or electronic motions.Following introductory chapters on BASIC and the quantum treatment of molecules, the main topics dealt with are rotational, vibrational, Raman and electronic spectra. Each chapter consists of two parts, essentially theory and three or four programs written in BASIC (hence the title of the book) to provide practical examples and illustrations of the topics under consideration. There are suggestions for further reading and some problems (but no solutions). Despite the modest aims claimed by the author, only a first-class graduate planning a PhD in physical chemistry will be able to read this book.At best it could provide a summary of the topic to be used in conjunction with a lecture course. The average undergraduate chemistry student could not cope with the maths, and the brevity of the book takes all the fascination out of the subject. The result is boring. Only rarely does the author permit a qualitative view or model of the processes in question. The rest is equations. It is not clear for whom the computer programs are provided. I cannot see the average student eagerly modifying the programs so that they run on the particular micro that is accessible and then tapping them in, far less modifying them to suit his or her own particular needs as the author suggests. The lecturers running the spectroscopy course might be more interested.It is really at these persons that the book is aimed (and jolly useful they will find it). No practical aspects of any kind are mentioned, so there is not even the merest hint that most of the spectroscopies mentioned are actually used by practising chemists to provide analytical information. J . F. Tyson Handbook of Polycyclic Aromatic Hydrocarbons. Volume 2. Emission Sources and Recent Progress in Analytical Chemistry. Edited by Alf Bjarseth and Thomas Ramdahl. Pp. x + 416. Marcel Dekker. 1985. Price $95 (USA and Canada); $1 14 (all other countries). ISBN 0. 8247 7442 6. Widespread interest and the rapidity of recent developments in the whole field of polycyclic aromatic hydrocarbons (PAHs) and related compounds (PACs) have encouraged the Editors to assemble a second volume to update and add new information to their original Handbook published in 1983.The book is organised into 11 chapters contributed by 13 well known experts in the field. As before, the contents are nicely balanced between emission sources, recent progress in analy- tical chemistry and exposure, uptake, metabolism and detec- tion of PAHs in the human body. The scale of the problem is put into perspective in Chapter 1, where the reader learns that it is estimated that 6000 metricANALYST, JANUARY 1987, VOL. 112 107 tons of PAHs per year are emitted in the USA alone. The next three chapters discuss specific emissions from coal-fired plants, combustion of biomass and automobiles, respectively. The two main analytical chapters are updates on HPLC and GC.The continued growing importance of HPLC in this field is reflected by the fact that it is the longest chapter in the book and that most of the 104 references cited (1980-84) were not in the original Handbook. Nitrogen-containing PACs have generated particular interest over the past few years and the second longest chapter in the book reviews the nomenclature, chemical, physical and biological properties and the analytical chemistry of these compounds. Finally, of particular analytical concern, is an account of the work of the Joint Research Centre of the Commission of the European Communities to produce certified reference compounds for calibration of analytical methods and apparatus. This is an excellent book. A wealth of data is clearly presented in the form of tables, figures and chromatograms.Moreover, the text is readable and the book should therefore appeal to all who have more than a cursory interest in the control of these hazardous and ubiquitous pollutants of the human environment. R. Amos Cell Components Edited by H. F. Linskens and J. F. Jackson. Modern Methods of Plant Analysis. New Series, Volume 1. Pp. xx + 399. Springer-Verlag. 1986. DM238. ISBN 3 540 15822 7; 0 387 15822 7. This new series on methods of plant analysis begins with a volume on cell components and organelles. It is designed to replace the original series, under the same title and by the same publishers, which was published in seven volumes between 1956 and 1964. That series is now no longer modern and, in view of the ever expanding literature in this area, the use of “modern” in any title must be treated with some caution.However, a scan of the references in each chapter gives numerous papers of 1983-84 vintage as well as the occasional 1985 contribution. It is, therefore, as up-to-date as one could expect. The Editors of the new series are H. F. Linskens and J. F. Jackson, who will attempt to amalgamate the styles and views of each contributor into a coherent unit. The Editors state that they have not tried to interfere too much but in the reviewer’s opinion this has led to some chapters not attaining the high quality set by most. This volume contains chapters on cell wall isolation, cell wall chemistry, protoplasts, the marker concept in cell fractionation, plasma membranes, vacuoles, protein bodies, lipid bodies, chloroplasts as a whole, chloroplast envelope membranes, chloroplast thylakoid membranes, ribulose- biphosphate carboxylase, non-green plastids, mitochondria, endoplasmic reticulum, polyribosomes, the nucleus and microtubules.The normal format is an introduction followed by detailed methodology for the particular component, which not only gwes the different methods for isolating the different components but also gives details of purity procedures. Many of the chapters give useful information on places where extra care is required. This is to be recommended for the inex- perienced worker. The chapters all contain a wide range of photographs and figures which should help the novice to see what he is looking for and assist in setting him off in the right direction.Inevitably in such a volume, all chapters are not of the same standard. The chapter on cell wall chemistry, structure and components is neither sufficiently up-to-date nor does it consider many of the essential modern methods of analysis. The authors and Editors, in addition, should pay more attention to their proof-reading. There are too many irritating spelling mistakes in some chapters. Nevertheless, this book is a most welcome addition to any library that supports laboratories concerned with plant stud- ies. It will be well used by young and old alike. It is a pity that the cost of the whole series will limit the purchase to libraries; a set in the laboratory or the office would be ideal. The reviewer looks forward to seeing the future volumes in the series.Ian M. Morrison Developments in Polymer Characterisation, Volume 5 Edited by J. V. Dawkins. Developments Series. Pp. x + 343. Elsevier Applied Science. 1986. Price f45. ISBN 0 85334 401 9. In a brief Preface, Dr. Dawkins summarises the contributions and also their relationship (if any) to papers in the earlier collections. Most of the authors are members of universities, in Canada, Denmark, England, Scotland, Sweden, USA and Wales. There may be one (or perhaps two) contributors who are employed with major US manufacturers of polymers and products in this field (and for which the development of new and improved materials would be expected to be a primary concern). The nine authors provide us with six chapters. The first topic is small-angle neutron scattering (SANS) with particular reference to the conformation of polymer chains and the determination of dimensions of molecules.The new material is stated to include recent results for amorphous and semi- crystalline polymers, together with examples for deformed networks, block copolymers, blends of polymers and poly- mers in solution. Theoretical aspects are discussed and it is fair to comment that the subject itself is no longer new and that (as it employs neutron beams) it is very costly in practice. Other topics are: the examination of polymer solutions using photon correlation spectroscopy; the measurement (on-line) of relative molecular mass and long-chain branching by means of size exclusion chromatography with scattering of low-angle laser light; gel permeation chromatography in the analysis of hydrophilic polymers and polyelectrolytes; dynamic mechanical thermal analysis of polymers; and the application of fluorescence techniques.Theoretical considerations play a prominent part through- out the text and this militates against its usefulness from the point of view of the working analyst. In a review for The Analyst (and bearing in mind also the current cost of volumes of this nature), one can only place emphasis on the aspects that are likely to be of value to the majority of readers. The most practical chapter (and the one which perhaps makes the most interesting reading) is on the application of gel permeation chromatography to hydrophilic polymers and polyelectrolytes. It contains a good deal of useful information about, for example, the use of standard polymers in calibrat- ing many types of column packings and their properties in relation to this use.The volume includes a total of about 1000 references, and has a good index. It is thought likely to appeal to the theoretician and the research worker, and that it would be purchased by specialised libraries. D. Simpson108 ANALYST, JANUARY 1987, VOL. 112 Applications of NMR Spectroscopy to Problems in Stereochemistry and Conformational Analysis Edited by Yoshito Takeuchi and Alan R. Marchand. Methods in Stereochemical Analysis, Volume 6 . Pp. x + 221. VCH. 1986. Price DM135. ISBN 0 89573 118 5 (VCH Publishers); 3 527 26145 1 (VCH Verlagsgesellschaft). NMR spectroscopy has evolved over 40 years from a phenomenon of interest only to physicists into a technique that embraces just about all the physical, chemical, biochemical, analytical and medical sciences.The title of this volume suggests that a fairly narrow part of this field is being reviewed. In practice, however, a very wide and diverse field is covered, perhaps too wide to be of total interest to any one reader. The first chapter, by I. 0. Sutherland, provides a com- prehensive survey of the complexes formed by crown ethers and related compounds. The rate processes and energy profiles of this unique guest - host chemistry are discussed in depth, providing some very interesting data. Unfortunately, this chapter appears to have been completed well before the others in the book, as it is fully referenced only up to the end of 1981.The application of liquid crystal NMR to the determina- tion of the geometry of oriented molecules is reviewed by P. Diehl and J. Jokisaari. Although the complexity of the spectra limit the method to molecules of similar size to p-chlorotolu- ene, the accuracy of the geometry obtained is phenomenal, stated to be at least 100 times better than electron diffraction or IR spectroscopy. In Chapter 3, R. Kitamaru provides a very substantial survey of 13C relaxation theory applied to the conformation and dynamics of macromolecules. For analytical chemists, Chapter 4 by Terao and Imashiro may be of more interest as it deals with solid-state NMR at high resolution using 13C cross-polarisation and magic angle spinning (CPMAS) , providing sharp spectra devoid of the dipolar coupling effects normally observed with solids.The 13C spectra obtained are similar to those obtained in solution, although sometimes perturbed slightly by crystal packing and other environmental effects. Thus a new and valuable technique for sampling solids is available with further applica- tions, for instance, in studying polymorphism, intermolecular interactions, molecular motion in solids and chemical shift anisotropy effects. Considering the importance of 2D NMR in structure determination, Chapter 5 , by Nagayama, is a rather brief review of the subject, which has been reviewed better elsewhere in my opinion. However, it is complemented by Chapter 6, where Kessler and Bermel provide a thorough and authoritative review of 2D NMR applied to peptide conforma- tion in solution.For all laboratories where NMR spectroscopy research is carried out, this volume, like others before it, will be received with interest, although the organic chemist in the field of stereochemistry and conformational analysis may be disap- pointed, in that only ca. one third of the book is devoted to what he understands from the title. The amount of informa- tion packed into this volume suggests overall that it is probably good value for money, despite the relatively high price. W. A. Thomas Modern Techniques of Surface Science D. P. Woodruff and T. A. Delchar. Pp. x + 453. Cambridge University Press. 1986. ISBN 0 521 30602 7. That the classical divisions of science into chemistry, physics, etc., have broken down is nowhere more clearly demonstrated than in the vitally important study of surfaces.A would-be researcher in this field must be analyst, electrician, vacuum specialist and mathematician as well as both physicist and chemist. Whatever his or her background, today’s surface scientist has great need of a comprehensive introduction to the many and various techniques that are now used both separately and in bizarre and bewildering combinations. Each method, each combination of methods has its own acronym. He who does not know a RHEED from a LEED, who cannot tell a SEXAFS from an EXAFS, who thinks that IRAS is something to do with taxation or that HREELS maybe a dance, has grave and urgent need of this excellent introduction to modern techniques of surface science, where all is revealed.The rapid development of surface science, especially over the last two decades, has by now generated enough experience and data for a critical review to be made of the many techniques that are now available. Such a review is given in this book. A chapter is devoted to each of the important methods for the study of surfaces: electron diffraction, beam scattering, ion bombardment, desorption, work function measurements as well as infrared, photoelectron and Auger spectroscopy. For each subject the basic physics is outlined, the experimental method described and examples of the results are discussed. In this way, the potential of each technique and its advantages and disadvantages can readily be understood and appreciated. A further important aspect of modern surface studies that is emphasised is the complemen- tary nature of much of the data produced by these individual techniques, nicely reflecting the experimental reality that most equipment is designed to permit a single sample to be investigated in many different ways.There is also a particul- arly valuable introductory chapter in which the differences to be expected, especially in diffraction, between two-dimen- sional (as in surfaces) and three-dimensional (as in solids) arrays of atoms, are carefully examined. This book reveals, in a most dramatic way, just what “analysis,” at least for a surface, means today. To analyse a surface is not only to identify the elements present but also to determine their juxtaposition, their order or their lack of it, their state of chemical combination, to identify any chemical reactions that they may or may not have indulged in whilst on the surface, to find out whether the adsorbate atoms have formed a monolayer, or have congregated into islands or are hopping around all over the place, etc. Such are the challenges of surface analysis. This book clearly shows how these challenges are to be met. The book is well produced, up-to-date and introduces the reader, through its wide choice of examples and numerous references, to all major aspects of the current literature. This invaluable introduction to the techniques of modern surface science will, because of the breadth of topics covered, be equally indispensable to the novice and experienced researcher alike. D. S . Urch

ISSN:0003-2654    

DOI:10.1039/AN9871200106

出版商:RSC    

年代:1987

数据来源: RSC

摘要:

ANALYST, JANUARY 1987, VOL. 112 109 INSTRUCTIONS TO AUTHORS The Analyst publishes papers on all aspects of the theory and practice of analytical chemistry, fundamental and applied, inorganic and organic, including chemical, physical, biochem- ical, clinical, pharmaceutical, biological, automatic and com- puter-based methods. Papers on new approaches to existing methods, new techniques and instrumentation, detectors and sensors, and new areas of application with due attention to overcoming limitations and to underlying principles are all equally welcome. Papers may be submitted for publication by members of The Royal Society of Chemistry or by non-members. There is no page charge for papers published in The Analyst. The following types of papers will be considered. Full papers, describing original work.Short papers: the criteria regarding originality are the same as for full papers, but short papers generally report less extensive investigations or are of limited breadth of subject matter. Communications, which must be on an urgent matter and be of obvious scientific importance. Rapidity of publication is enhanced if diagrams are omitted, but tables and formulae can be included. Communications receive priority and are usually published within 5-8 weeks of receipt. They are intended for brief descriptions of work that has progressed to a stage at which it is likely to be valuable to workers faced with similar problems. A fuller paper may be offered subsequently, if justified by later work. Communications will normally be examined by one referee.Reviews, which must be a critical evaluation of the existing state of knowledge on a particular facet of analytical chem- istry. Every paper (except Communications) will be submitted to at least two referees, by whose advice the Editorial Board of The Analyst will be guided as to its acceptance or rejection. Papers that are accepted must not be published elsewhere except by permission. Submission of a manuscript will be regarded as an undertaking that the same material is not being considered for publication by another journal. Copyright. The whole of the literary matter (including tables, figures, diagrams and photographs) in The Analyst is copyright and may not be reproduced without permission from the Society or such other owner of the copyright as may be indicated.Regional Advisory Editors. For the benefit of potential contributors outside the United Kingdom, a Panel of Regional Advisory Editors exists. Requests for help or advice on any matter related to the preparation of papers and their submission for publication in The Analyst can be sent to the nearest member of the Panel. Currently serving Regional Advisory Editors are listed in each issue of The Analyst. Manuscripts. Papers should be typewritten in double spacing on one side only of the paper. Three copies of text and illustrations should be sent to the Editor, The Analyst, The Royal Society of Chemistry, Burlington House, Piccadilly, London W1V OBN, and a further copy retained by the author. Proofs. The address to which proofs are to be sent should accompany the paper.Proofs should be carefully checked and returned immediately (by Air Mail from outside Europe). Reprints. Fifty reprints of each paper are supplied free on request. Additional reprints can be purchased if ordered at the time of publication. Details are sent to authors with the proofs. Notes on the Writing of Papers for The Analyst Manuscripts should be in accordance with the style and usage shown in recent copies of The Analyst. Conciseness of expression should be aimed at: clarity is increased by adopting a logical order of presentation, with suitable paragraph or section headings. To facilitate abstracting and indexing by Chemical Abstracts Service, and other abstracting organisations, it would be helpful if at least one forename could be included with each author's family name.Descriptions of new methods should be supported by ex- perimental results showing accuracy, precision and selectivity. The recommended order of presentation is as indicated below: (a) Title. This should be as brief as is consistent with an adequate indication of the original features of the work. The analytical method used in the work should be mentioned in the title. ( b ) Synopsis. A synopsis of about 100 words, giving the salient features and drawing attention to the novel aspects, should be provided for all papers. (c) Keywords. Up to 5 keywords or key phrases, indicating the topics of importance in the work described, should be included after the synopsis. ( d ) Aim of investigation. An introductory statement of the object of the investigation with any essential historical background, followed, if necessary, by a brief account of preliminary experimental work.(e) Description of the experimental procedures. Working details must be gwen concisely. Analytical procedures should preferably be given in the form of instructions; well known operations should not be described in detail. u> Results. These are best presented in tabular form, followed by any statistical evaluation, which should be in accordance with accepted practice. ( g ) Discussion of results. This section will comment on the scope of the method and its validity, followed by a statement of any conclusions drawn from the work. Nomenclature. Current internationally recognised (IUPAC) chemical nomenclature should be used.Common trivial names may be used, but should first be defined in terms of IUPAC nomenclature. SI units. The SI system of units should be used. These units are summarised in the Appendix. The effect on current style of papers for The Analyst includes the following: dimensions should preferably be given in metres (m) or in millimetres (mm); temperatures should be expressed in K or "C (not O F ) ; wavelengths should be expressed in nanometres (nm) frequency should be expressed in Hz (or kHz, etc.), not in c/s or c.P.s.; rotational frequency can be denoted by use of s-1; in mass spectrometry, signal intensity should be expressed in counts s-1 and not in Hz; (not mp);110 (e) radionuclide activity will be expressed in (Bq) or curies (Ci); 1 Ci = 3.7 X 1010 Bq; u> the micron (p) will not be used; 10-6 m wil Abbreviations.SI units should be used. Molaritv becquerels be 1 pm. s generally expressed as a decimal fraction (e.g., 0.375 M). Abbreviational full stops are omitted after the common contractions of metric units (e.g., ml, g, pg, mm) and other units represented by symbols. Abbreviations other than those of recognised units should be avoided in the text. Percentage concentrations of solutions should be stated in internationally recognised terms. Thus the symbols “m” for mass and “V” for volume are to be used instead of “w” for weight and “v” for volume. The following show the manner of expressing these percentages together with an acceptable alternative given in parentheses: YO m/m (g per 100 g); YO m/V (g per 100 ml); YO V/V.Further implications of the use of the term “mass” are that “relative atomic mass” of an element (A,) replaces atomic weight, and “relative molecular mass” of a substance (M,) replaces molecular weight. Concentrations of solutions of the common acids are often conveniently given as dilutions of the concentrated acids, such as “dilute hydrochloric acid (1 + 4) ,” which signifies 1 volume of the concentrated acid mixed with 4 volumes of water. This avoids the ambiguity of 1 : 4, which might represent either 1 + 4 or 1 + 3. Dilutions of other solutions can be expressed in a similar manner. Tables and diagrams. The number of tables should be kept to a minimum. Column headings should be brief. Tables consisting of only two columns can often be arranged horizontally.Tables must be supplied with titles and be so set out as to be understandable without reference to the text. Either tables or graphs may be used but not both for the same set of results, unless important additional information is given by so doing. The information given by a straight-line calibration graph can usually be conveyed adequately as an equation or statement in the text. The style used in headings to tables and in labels on the axes of graphs, where the numbers represent numerical values, is, for example: Volume/ml. The diagonal line (solidus) will not be used to represent “per”. In accordance with the SI system, units such as grams per millilitre are already expressed in the form g ml-1. For a table (or graph), this would appear as: Concentration of solution/g ml-1.It should be noted that the “combined” unit, g ml-1, must not have any “intrusive” numbers. To express concentration in grams per 100 milli- litres, the word “per” will still be required: Concentrationlg per 100 ml. It may be preferable for an author to express ANALYST, JANUARY 1987, VOL. 112 concentrations in grams per litre (g 1-1) rather than grams per 100 ml. Most diagrams will be retraced and lettered in order to achieve uniform line thicknesses and lettering size and style, so it is not essential to prepare specially traced drawings. However, all diagrams should be carefully and clearly drawn on good quality paper and should be clearly lettered. If possible, complicated flow charts, circuit diagrams, etc. , should be supplied as artwork for direct reproduction in order to avoid time-consuming and expensive redrawing.Three sets of illustrations should be provided, two sets of which may be made by any convenient copying process for transmission to the referees. All diagrams should be accompanied by a separately typed set of captions. Wherever possible, extensive identifying lettering should be placed in the caption rather than on lines on graphs, etc. Photographs. Photographs should be submitted only if they convey essential information that cannot be shown in any other way. They should be submitted as glossy or matt prints made to give the maximum detail. Colour photographs will be accepted only when a black-and-white photograph fails to show some vital feature and can be supplied either as prints or transparencies.References. References should be numbered serially in the text by means of superscript figures, e.g., Foote and Delves,l Burns et al.2 or Hirozawa,3 and collected in numerical order under “References” at the end of the paper. They should be listed, with the authors’ initials, in the following form (double-spaced typing) : 1. 2. 3. Foote, J. W., and Delves, H. T., Analyst, 1983, 108, 492. Burns, D. T., Glockling, F., and Harriott, M., J . Chromatogr., 1980, 200, 305. Hirozawa, S. T., in Kolthoff, I. M., and Elving, P. J., Editors, “Treatise on Analytical Chemistry, Part 11,” Volume 14, Wiley, New York, 1971, p. 23. Journal titles should be abbreviated according to the Chemical Abstracts Service Source Index (CASSZ). For books, the edition (if not the first), the publisher and the place and date of publication should be given, followed by the page number.Authors must, in their own interest, check their lists of references against the original papers; second-hand references are a frequent source of error. The number of references must be kept to a minimum. Appendix The SI System of Units In the SI system there are seven base units- Physical quantity length mass time electric current thermodynamic temperature amount of substance luminous intensity Name of unit metre kilogram second ampere kelvin mole candela Symbol for unit m kg S A K mol cdANALYST, JANUARY 1987, VOL. 112 111 There are two supplementary dimensionless units for plane angle (radian, rad) and solid angle (steradian, sr).Some derived SI units that have special names are as follows- Physical quantity energy force power electric charge electric potential difference electric resistance electric capacitance frequency magnetic flux density radionuclide activity (magnetic induction) Examples of other derived SI units are- Physical quantity Name of unit joule newton watt coulomb volt ohm farad hertz Symbol for unit J N W C V sz F HZ Definition of unit kg m2 s - 2 kgms-2= Jm-1 As kgm2s-3 = Js-1 kgm2s-'A-I = JA-Is-' kg m2 s-3 A-2 = V A-1 A2s4 kg-l m-2 = A s V-1 S-1 tesla T kg s-2 A-1 = V s m-2 becquerel Bq S - 1 SI unit area square metre volume cubic metre density kilogram per cubic metre velocity metre per second angular velocity radian per second acceleration metre per second squared magnetic field strength ampere per metre Certain units will be allowed in conjunction with the SI system, e.g.- Physical Name Symbol quantity of unit for unit volume litre 1 magnetic flux density (magnetic induction) gauss G temperature, t degree Celsius "C radionuclide activity curie Ci energy electronvolt eV Symbol for unit m2 m3 kg m-3 m s-1 rad s-1 m s-2 A m-1 Definition of unit 10-31113 = dm3 10-4 T tl"C = T/K - 273.16 3.7 X 1010Bq 1.6021 x 10-195 The common units of time (e.g., minute, hour, day) and the angular degree (") will continue to be used in appropriate contexts. Decimal multiples and submultiples have the following names and symbols (for use as prefixes)- 10-3 milli m 10-9 nano n 10-6 micro v 10-12 pic0 P Compound prefixes (e.g., mpm) should not be used; 10-9 m = 1 nm. 103 kilo k 106 mega M 109 gigs G 10'2 tera T 1015 peta P 1018 exa E The Royal Society of Chemistry, Burlington House, Piccadilly, London WIV OBN. UK

ISSN:0003-2654    

DOI:10.1039/AN9871200109

出版商:RSC    

年代:1987

数据来源: RSC