摘要:

326 AHalyst, May, 1968, Vol. 93, $$. 32f3-327 Spectrophotometric Determination of Carbinoxamine Maleate in Tablets containing Caffeine, Sulphamethoxypyridazine and Alginic Acid BY L. MOSCONI (Luborutori GZuxo S.P.A ., Verona, Italy) An ion-exchange chromatographic technique is described for a spectro- photometric determination of carbinoxamine maleate in the presence of caffeine and sulphamethoxypyridazine. A modified procedure is developed for tablets containing alginic acid. IN addition to methods hitherto proposed, which include non-aqueous titration,l a fluorimetric method2 and a colorimetric assay with bromocresol green: the spectrophotometric deter- mination of carbinoxamine described in this paper has proved especially useful for pharma- ceutical tablets containing analytically similar substances such as caffeine and sulphamethoxy- pyridazine. Clearly, a spectrophotometric procedure is applicable only if the carbinoxamine is previously separated from interfering substances.This is achieved by chromatography of an aqueous solution on a weakly acidic ion-exchange cellulose, on which carbinoxamine is retained; interfering compounds are not held and can be completely separated by elution. The carbinoxamine is then eluted as the hydrochloride with 0-5 N hydrochloric acid. If alginic acid, a widely used disintegrating agent, is present, the procedure needs modification as alginic acid absorbs carbinoxamine from aqueous solution. EXPERIMENTAL REAGENTS- Sodium chloride, 0.5 M. Sodium hydroxide, 3 N. Hydrochloric acid, 0-5 N. Chloroform. Carboxymethylcellulose, CM 11 Whatmart.PREPARATION OF THE COLUMN- Make a slurry of 1 g of carboxymethylcellulose with about 10 ml of 0.5 N hydrochloric acid and transfer it quantitatively to a glass column (1 cm i.d. x 25 cm) between two plugs of glass-wool. Wash the column with distilled water until the effluent is neutral. PROCEDURE- (1) Alginic acid absent-Prepare an aqueous solution of the sample, so that the car- binoxamine concentration is about 0404 per cent. w/v (concentrations of caffeine and sulphamethoxypyridazine may be up to twenty times greater). If necessary, filter the solution through a sintered glass filter, then pass 10.0ml of the solution through the column. Discard the effluent, wash the column with 100 ml of distilled water and elute with 0.5 N hydrochloric acid; collect 20 ml of the eluate in a graduated flask.Measure the extinction in a 1-cm cell against 0.5 N hydrochloric acid at 264 mp, and calculate the carbinoxamine content of the sample. The Ei2m value for carbinoxamine is 245 at 264mp. 0 SAC and the author.MOSCONI 327 (2) Alginic acid @resent-Prepare a solution of the sample in 0-5 M sodium chloride, so that the carbinoxamine concentration is about 0.02 per cent. w/v. Filter through a sintered glass filter, then transfer 10-0 ml of the filtrate into a separating funnel. Add 2 ml of 3 N sodium hydroxide and extract five times with 20-ml portions of chloroform. Filter the extracts through a layer of anhydrous sodium sulphate, which is supported on a plug of absorbent cotton-wool, and evaporate the filtrate on a boiling water bath, finally evaporating it to dryness under nitrogen. Dissolve the residue in hot distilled water and transfer it quantitatively into a 50-ml graduated flask; cool and dilute to volume.Proceed as in Procedure (1) from “pass 10.0 ml of the solution through the column. . . .” DISCUSSION The ultraviolet absorption curve of carbinoxamine in 0.5 N hydrochloric acid shows a maximum at about 264mp; the Ei:m value determined experimentally at this maximum is 245. Solutions follow the Lambert -Beer law over a range of concentrations from O W 0 4 to 0.004 per cent. (optical densities from about 0-1 to l o o ) , and the shape of the peak is unaffected by chromatography on carboxymethylcellulose. Table I shows the effects of caffeine and sulphamethoxypyridazine on the determination of carbinoxamine without, and after, chromatography. TABLE I RECOVERY OF CARBINOXAMINE FROM AQUEOUS SOLUTIONS* Purification treatment 7 - 3 Extraction and Other substances added None Chromatography chromatography None .... .. . . 0,490 0.490 0.485 Caffeine .. .. .. .. >3 0.490 f 0.006 - Sulphamethoxypy-ridazine . . >3 0.490 f 0.006 - Alginic acid? . . .. . . 0.120 - 0.120 Alginic acid+ sodium chloride, 0.6 M? . . . . 0.490 - 0-486 hydrochloric acid. * Results expressed as extinction values of a 0*0020 per cent. solution in 0.6~ t Solution centrifuged. The sorption of carbinoxamine by alginic acid in aqueous solution may be prevented by adding sodium chloride, but such a solution is clearly unsuitable for chromatography. Under alkaline conditions, carbinoxamine can be extracted quantitatively with chloroform ; the solution, when evaporated to dryness, yields a residue free from salt and alginate, and is suitable for ion-exchange chromatography. Results in Table I show satisfactory recovery by this method in the presence of alginate. Over-all recovery on formulated products was 99 2 per cent. I thank Mr. W. H. C. Shaw for his helpful advice. REFERENCES 1. 2. 3. Meites, L., Editor, “Handbook of Analytical Chemistry,’’ First Edition, McGraw-Hill Book Co. Inc., New York, Toronto and London, 1963, Section 13, p. 201. Jensen, R. E., and Haurn, R. T., J . Phurm. Sci., 1964, 53, 836. Tanaka, I., Otani, S., Nakayashiki, J., and Fujita, S., Yukuzuiguku [Arch. Pruct. Pharm.], 1964, 24, 303; Chem. Abstr., 1966, 63, 1664a. Received November 8th, 1967

ISSN:0003-2654    

DOI:10.1039/AN9689300326

出版商:RSC    

年代:1968

数据来源: RSC

摘要:

328 Autalyst, May, 1968, Vol. 93, fip. 3.28-329 Determination of Acetylglutamine in Pharmaceutical Preparations BY L. MOSCONI (Laboratori Glaxo S.P.A., Verona, Italy) A colorimetric method for the quantitative determination of acetyl- glutamine, after acid hydrolysis, is proposed. An ion-exchange chromato- graphic procedure is described for the elimination of interfering substances in pharmaceutical preparations. ACETYLGLUTAMINE, like glutamine and glutamic acid, is used for treating metabolic disorders of the central nervous system and has the advantage of being much more stable than glutamine in aqueous so1ution.l There are few references to acetylglutamine in the literature and, as far as is known, no method is given for its determination. The method described here is based on the liberation of ammonia from acetylglutamine by boiling with acid and colorimetric measurement of the ammonia with Nessler’s reagent.In formulated preparations it is necessary first to eliminate degradation products of acetylglutamine that interfere; such products are glutamine and ammonium salts of acetyl- glutamic acid, glutamic acid and 5-pyrrolidone-2-carboxylic acid. This can be achieved by passing a solution of the preparation through a suitable cation-exchange resin. The acetyl- glutamine is not retained and is determined in the eluent after hydrolysis. The Nessler determination is liable to interference from many organic substances and inorganic ions, which give rise to colours or precipitates. It is necessary, therefore, to isolate the ammonium ions before the colorimetric reaction.The Kj eldahl distillation method is not suitable, as volatile interfering substances may be present (e.g., alcohols or aldehydes), and others may liberate ammonia under alkaline conditions. EXPERIMENTAL REAGENTS- Again, the method used is ion-exchange. Hydrochloric acid, 2 N. Sulpphuric acid, 3 N. Gum acacia solution, 1 per cent. w/v, freshly prepared. Nessler’s reagent-Prepare according to the British Pharmacopoeia 1963, p. 961. A nzberlite CG120 (200 mesh). PREPARATION OF EACH COLUMN- Wash 1.0 g of the resin with 2 N hydrochloric acid until clean, and prepare a column (1 cm in diameter) between two plugs of absorbent cotton-wool. Pass ammonia-free water through the column until the effluent is free from chloride ions.Prepare two columns in this manner. PROCEDURE- Prepare an aqueous solution of the sample, so that the concentration of acetylglutamine is about 1 mg per ml. Collect the effluent in a 50-ml graduated flask and pass water through the column until the graduation mark is reached. Mix 10-0 ml of the solution with 0.5 ml of 3 N sulphuric acid and boil under reflux for 5 hours. Cool the solution, neutralise with dilute aqueous sodium hydroxide and adjust to 50 ml with water. Pass 20.0 ml of this solution through the second resin column. Wash with ammonia-free water until the effluent gives no reaction from interfering substances Pass 25 ml of this solution through the resin column. 0 SAC and the authors.MOSCONI 329 with Nessler’s reagent. Elute the column with three 5-ml portions of 2 N hydrochloric acid, neutralise the eluate with aqueous sodium hydroxide and dilute to volume in a 20-ml graduated flask.To 5-00 ml of the neutral eluate add 2 ml of fresh gum acacia solution, swirl it, add 2 ml of Nessler’s reagent and, after 1 minute, read the colour with a blue - green filter against water in l-cm cells. Prepare a calibration graph by similarly treating 5ml of standard aqueous solutions containing 100 and 200 pg of ammonium chloride per 5 ml. Carry out a blank determination on 5ml of ammonia-free water and deduct the extinction value from those of sample and standards. Calculate the acetylglutamine content of the sample (1 pg of ammonium chloride = 3.52 pg of acetylglutamine). DISCUSSION The amount of resin in the first column is adjusted according to the amount of impurities to be removed.Glutamine, ammonium ions, various basic organic compounds, some of which may be coloured, and inorganic cations are retained by this first column. The acetylglutamine and other classes of substances pass through in the effluent. The hydrolysis is carried out in weakly acidic solution, so that after neutralisation a weak solution of cations is obtained. This aids the subsequent chromatography. The ammonium ions produced by the hydrolysis of the acetylglutamine are retained in the second column, while other interfering substances, inorganic anions and organic compounds not held on the first column, are not retained. Recovery of acetylglutamine in the presence of degradation products was shown to be quantitative for each stage of the analysis, and an over-all recovery of 97 1 per cent. was obtained by comparison with the ammonium chloride standards, the optical densities of which follow the Lambert - Beer law. A few classes of substances (e.g., amides and ureides) interfere with the determination, but they can usually be eliminated by solvent extraction before hydrolysis. Sedative sub- stances, such as bromural, carbromal, diethylbromoacetamide or meprobamate, which may be formulated with acetylglutamine, can be extracted from aqueous solutions with diethyl ether or chloroform. The method also gives good results with mixtures containing 60 per cent. of sugar. I thank Mr. W. H. C. Shaw for many useful suggestions. REFERENCE 1. Sekules, G., and Guadagnini, G., Furmuco, Ed. Prut., 1966, 21, 22. Received October 4th, 1967

ISSN:0003-2654    

DOI:10.1039/AN9689300328

出版商:RSC    

年代:1968

数据来源: RSC

摘要:

330 Analyst, May, 1968, Vol. 93, $p. 330-336 The Thermometric Determination of Grignard Reagent Concentration BY R. D. PARKER AND T. VLISMAS (Analytical Research Section, Midland Silicones Limited, Barry, Glamorgan) Two simple thermometric procedures have been applied to the quanti- tative analysis of Grignard reagents. In the first method the Grignard reagent was titrated with a standard solution of isopropyl alcohol and the end-point located by monitoring the temperature change. In the other method a single measurement of temperature was made after reacting the Grignard reagent with an excess of isopropyl alcohol. The maximum tem- perature reading was then referred to a temperature scale directly calibrated in concentration units. THE heat change accompanying a chemical reaction provides a basis for the quantitative analysis of a participating reactant.If a titrimetric procedure is used the end-point, in favourable circumstances, is distinguishable by a discontinuity in the plot of temperature reading versus volume of titrant. Alternatively, as the magnitude of the heat change in a chemical reaction is directly proportional t o the amount of an individual reactant consumed, it is possible to calibrate a temperature scale in terms of concentration units, thus providing a direct-reading quanti- tative method of analysis. The application and potential usefulness of such a direct-reading thermometric method has been demonstrated, on the basis of much improved instrumentation, by Wasilewski, Pei and Jordan.1 The thermometric technique has been applied to the analysis of several types of organo- metallic corn pound^,^^^^^ and it appeared to be a promising approach for the analysis of Grignard reagents.There was good reason to expect that reagents could be found that would be selective for the active Grignard reagent in the presence of its oxidation and hydrolysis products, a factor that has to be taken into account in other analytical approaches.5 A titrimetric and a direct-reading thermometric method have been developed for the determination of Grignard reagents, and a comparison made with an acidimetric double- titration procedure already developed and reported6 by the authors of the present paper. EXPERIMENTAL I The initial part of the investigation was primarily concerned with the selection of a suitable titrant for Grignard reagents, and an account of this investigation is given later in this paper.It was finally concluded that isopropyl alcohol was the most suitable of those examined, and was the titrant adopted for the method described below. REAGENTS- molecular sieve, type GA, &inch pellets, for at least 2 days. with molecular sieve, type 4A, &inch pellets, for at least 2 days. APPARATUS- Titration and reaction ceZL-This is a spherical Dewar flask of about 80-ml capacity, fitted with three B14 necks, one of which accommodates a thermistor temperature probe, type F15. Electronic services-See Fig. 1. 0 SAC and the authors. Toluene-Dry analytical-reagent grade toluene by allowing it to stand over B.D.H. Isopro$~yl alcohod-Dry analytical-reagent grade isopropyl alcohol in a similar mannerPARKER AND VLISMAS 331 D A = Thermistor element fitted with 814 Teflon B = Vacuum jacket with silvered inner surface C = 814 necks D = No.30 suba seal caps fitted to the inlets for the introduction of titrant and sample E = Magnetic stirrer cone joint Fig. 1. Titration and reaction cell Lifiear +otediometric recorder-Flat-bed type made by Beckman Instruments, Model 93602, and used at a sensitivity of 100-mV full-scale deflection. Electrical circuit-See Fig. 2. This is basically a Wheatstone bridge arrangement in which the thermistor probe forms one arm of the bridge. The out-of-balance output from the bridge, resulting from variation in the resistance of the thermistor with temperature, is fed to the recorder.Battery t---+- R, = Thermistor, type F15, electronic services (I 00 ki2 at20OC) R, = 8.8-m resistor Battery = +volt dry cell R, = 40-kLI resistor L R, = 50-kC2 resistor R, = 100-k!2 variable resistor Fig. 2. Details of bridge circuit332 PARKER AND VLISMAS : THERMOMETRIC DETERMINATION [Analyst, Vol. 93 Microsyringe @umP-Model No. 234-3, manufactured by Sage Instruments Inc. Fit to the pump a 10-ml syringe to which a No. 6 hypodermic needle is attached. Adjust the flow-rate to about 0-5 ml per minute. Syringes-Two millilitre, all-glass, fitted with No. 6 hypodermic needles. THERMOMETRIC TITRATION PROCEDURE- Conditioning of apfiaratus-Fit the thermistor element into the titration flask containing a polythene-covered stirrer magnet. Add sufficient dry toluene to cover the thermistor element and seal the remaining necks with serum caps.Insert a No. 6 hypodermic needle through one of the serum caps to release excess of pressure during titration. Place the flask on the magnetic stirrer unit, then switch on the recorder and the resistance bridge, and adjust the variable resistance R, of the resistance bridge until the recorder pen is on a satisfactory base-line. -Time Fig. 3. A typical recorder plot for the titrimetric method in which A is the reaction of Grignard reagent with water and oxygen in the reaction flask; B, the titration of excess of Grignard reagent; C, sample titration; D,, excess of titrant; and D,, titration time Inject, by means of a syringe, about 2 ml of Grignard sample through the serum cap into the titration flask.This should cause a rapid increase in temperature as the Grignard reagent reacts with the water and oxygen in the cell (see A, Fig. 3). If necessary, adjust R, to keep the recorder pen on the chart. When the temperature of the reaction flask begins to fall, adjust R, to bring the recorder pen to the original base-line position. Fill the microsyringe pump with the molar solution of isopropyl alcohol in toluene, then insert the hypodermic needIe attached to the microsyringe pump through one of the serum caps sealing the titration cell, and switch on the syringe pump to titrate the excess of Grignard reagent. This titration is accompanied by a rise in temperature. At the end-point of the titration the temperature ceases to rise and the normal cooling curve is recorded (see B, Fig.3). Continue the titration for about half a minute after the end-point has been reached, then switch off simultaneously the syringe pump and chart recorder, and mark the time on the chart when the syringe pump was stopped. Extend the linear sections of the heating and cooling curves, in the proximity of the temperature maximum, until they intersect. Measure on the time axis the interval between this point of intersection and the point at which the pump was switched off (D1 cm). This distance represents the excess of titrant in the reaction flask, and this has to be taken into account in the subsequent calculation. Sample titratiort-Inject about 2 ml of Grignard sample into the reaction vessel, switch on the chart recorder, adjust R, to bring the pen on the base-line, then switch on the syringe pump and note the time on the chart before starting the titration. If necessary, adjust R, again; continue the titration for about half a minute beyond the temperature maximum, then switch off the syringe pump and the chart recorder.May, 19681 OF GRIGNARD REAGENT CONCENTRATION 333 Extend the linear sections of the heating and cooling curves, in the proximity of the temperature maximum, until they intersect.Measure on the time axis the interval between this point of intersection and the point at which the pump was switched on (D, cm). Titration time interval = - + D2 minutes L where L cm per second is the chart speed. SELECTION OF TITRANT AND RESULTS- Several compounds were found to give an appreciably exothermic reaction with Grignard reagents, but there were, however, certain disadvantages found in the behaviour of some of the compounds examined that limited their application as titrants in a quantitative analytical procedure.Table I shows the results obtained by titrating a solution of phenylmagnesium bromide with various compounds by the method described above. The results obtained with methanol, isopropyl alcohol and butanol are in good agreement with the value obtained by the acidimetric double-titration rneth~d.~ 8-Hydroxyquinoline and carbon tetrachloride proved unsatisfactory, as the Grignard reagents reacted with more than one functional group per molecule, giving results that were lower than the acidimetric double-titration method.A poor end-point was obtained with benzophenone, although the result showed moderate agreement with the acidimetric double-titration method. TABLE I THERMOMETRIC TITRATION OF PHENYLMAGNESIUM BROMIDE Phen ylmagnesium bromide, per cent. Titrant (0-5 M solution in toluene) W/W* Nature of end-point Methanol .. .. .. .. 29.9 Sharp Isopropyl alcohol . . .. .. 29.5 sharp 8-E y drox yquinoline . . . . 25.6 Sharp Butanol . . .. .. .. 30-0 Sharp Benzophenone . . .. .. 31.2 Poor Carbon tetrachloride . . .. 19.6 Poor * A vahe of 29.1 per cent. w/w for phenylmagnesium bromide was obtained by the acidimetric double-titration method5 for this solution. TABLE I1 THERMOMETRIC TITRATION OF PHENYLMAGNESIUM CHLORIDE Phenylmagnesium chloride, per cent. Methanol .. .. .. .. 16-0 Poor end-point.Solid deposited Butanol . . .. .. .. 16.4 } on thermistor element Isopropyl alcohol .. .. 15.8 Sharp Titrant (M solution in toluene) w/w* Nature of end-point * A value of 15.4 per cent. w/w for phenylmagnesium chloride was obtained by the acidimetric double-titration methods for this solution. Table I1 shows the results obtained by the thermometric titration of a solution of phenyl- magnesium chloride with various alcohols. Close agreement is shown with the acidimetric double-titration method. Isopropyl alcohol proved to be the best of the alcohols examined and was used as a M solution in toluene. The titrimetric procedure, finally developed with isopropyl alcohol as titrant, was used to analyse a variety of Grignard reagents, and in Table 111 the results are compared with those obtained by the acidimetric double-titration method. In a statistical appraisal of the precision of the method carried out with a solution of phenylmagnesium chloride, a coefficient of variation of 0.59 was obtained for nineteen results.334 PARKER AND VLISMAS : THERMOMETRIC DETERMINATION [Autalyst, Vol.93 EXPERIMENTAL I1 In the alternative analytical approach developed, isopropyl alcohol was again used as the thermometric reagent. In this method, however, it was used in the form of a 2 M solution in diethyl ether. It is important that the same solvent is used for both the thermometric reagent and Grignard reagent in order to eliminate any effect from the heat of mixing. TABLE I11 THERMOMETRIC TITRATION OF VARIOUS GRIGNARD REAGENTS Grignard reagent, per cent.w/w Thermometric double-titration -metric Grignard reagent titration method Methylmagnesium bromide . . .. 23.8 23.0 Ethylmagnesium iodide . . .. 41.4 41-4 Phenylmagnesium bromide . . .. 19.1 18.2 Phenylmagnesium bromide . . .. 33-8 34.0 Methylmagnesium iodide . . .. 10.1 9.9 DIRECT-READING THERMOMETRIC PROCEDURE- The apparatus is the same as that used for the titrimetric method, except that the syringe pump is omitted. Preparation of caZibration graPh-A separate calibration graph must be prepared for each Grignard reagent. Prepare a series of solutions of the Grignard reagent such that the concentration range of interest is satisfactorily covered, and determine the concentrations of these solutions by the former titrimetric method.Carry out the following procedure for each of the calibration samples. Add 50.0 ml of 2 M solution of isopropyl alcohol to the reaction cell, switch on the chart recorder and adjust to a suitable base-line. Weigh accurately 0.8 ml of the Grignard sample, introduce it into the reaction cell and measure the temperature rise in the manner illustrated in Fig. 4. The small peak that extends above the corrected temperature reading is assumed to be caused by localised heating in the vicinity of the themistor element as a result of partial mixing of the reactants. Fig. 4. Typical recorder trace for direct-reading method Draw a calibration graph by plotting the temperature-rise reading against the corre- sponding weight of Grignard reagent. Sample analysis-Carry out exactly the same procedure as that for the calibration samples, noting the temperature rise.Read from the calibration graph the weight of Grignard reagent corresponding to the temperature rise observed and calculate the concentration of the solution.May, 19681 OF GRIGNARD REAGENT CONCENTRATION 335 RESULTS The satisfactory calibration graphs prepared for methylmagnesium iodide and phenyl- magnesium chloride were found to be straight lines passing through the origin. The results for phenylmagnesium chloride are given in Table IV. The method is quick (each determination requiring about 5 minutes) and is, therefore, useful for routine repetitive analysis of the same Grignard reagent, but is, however, limited because of the necessity for calibration by a second method. TABLE IV CALIBRATION FOR PHENYLMAGNESIUM CHLORIDE Phenylmagnesium chloride in 0.8-ml aliquot, g 0~0100 0.0270 0.0439 0-0585 0.0734 0.0876 0.0991 0.1022 0.1 107 0.1160 Peak height, cm* 1.8 4.7 7.9 10.7 13.2 15.3 17.4 17.8 19.2 20.6 * 1-cm recorder deflection = 0.080° C. The authors thank the Directors of Midland Silicones Ltd. for their permission to publish this paper, and also the Chief Analyst, Mr. J. F. Lees, for his support and advice. REFERENCES 1. 2. 3. 4. 5. Wasilewski, J. C., Pei, P. T., and Jordan, J., Analyt. Chem., 1964, 36, 2131. Everson, W. L., Ibid., 1964, 36, 854. Everson, W. L., and Ramirez, E. M., Ibid., 1965, 37, 806. -,- , Ibid., 1965, 37, 812. Vlismas, T., and Parker, R. D., J . Organomet. Cham., 1967, 10, 193. Received October 16th, 1967

ISSN:0003-2654    

DOI:10.1039/AN9689300330

出版商:RSC    

年代:1968

数据来源: RSC

摘要:

336 Analyst, May, 1968, Vol. 93, pp. 336-338 The Gas-chromatographic Examination of Certain Antistatic Additives in Polyethylene BY J. T. DAVIES AND B. H. DENHAM" (The Metal Box Company Limited, Research and Development Department, Kendal Avenue, Westjields Road, Acton, London, W.3) This paper describes the gas-chromatographic examination of two classes of compounds used as antistatic agents in polyethylene, the alkyl diethanolamides and the alkyl diethanolamines. Two methods are given for the extraction and determination of alkyl diethanolamides in polyethylene. THIS paper describes the gas-chromatographic examination of two classes of polymer additives, the alkyl diethanolamides and diethanolamines, as their trimethylsilyl ethers. These two classes of compounds are frequently added to polyethylene to improve its antistatic properties.Two methods were used for the quantitative extraction of alkyl diethanolamides from polyethylene and their subsequent determination by using an internal standard. Current methods of analysis include infrared spectroscopy and thin-layer chromato- graphy. Both of these methods have inherent disadvantages; infrared spectroscopy is not always sensitive enough and may suffer from interference from other organic materials, and, with thin-layer chromatography, although sensitive and specific, it is difficult to obtain quantitative results. 2H40H C2H40H R'-CON / R-N 'C,H40H Alkyl diethanolamine R and R' are n-alkyl chains. 'c2H4oH Alkyl diethanolamide EXPERIMENTAL GAS CHROMATOGRAPHY OF ALKYL DIETHANOLAMIDES AND DIETHANOLAMINES- Long-chain amines or amides have been chromatographed directly, but diethanol deriva- tives have the additional factor of two hydroxyl groups in the molecule; polyols are not chromatographed readily because of the polarity of the hydroxyl groups.Recently, it has been shown by Sweeley, Bentley, Makita and Wells1 that the reaction of polyols with hexa- methyldisilazane, which occurs at room temperature, produces trimethylsilyl ether derivatives that can be chromatographed. Commercial samples of long-chain diethanolamines and diethanolamides were reacted with hexamethyldisilazane by dissolving about 10 mg of the sample in 0.7 ml of anhydrous pyridine and then adding 0.2 ml of hexamethyldisilazane, followed by 0.1 ml of trimethyl- chlorosilane to catalyse the reaction; 1.0 pl of the resulting solution was then injected on to the column.Suitable column conditions were obtained with a 5 foot x &inch glass column, packed with 5 per cent. of silicone gum rubber SE30 or E301 on 80 to 100-mesh Chromosorb W. The chromatograph used was a Pye 104, with twin columns and flame-ionisation detectors. The oven was operated isothermally at 235" or 250" C. The carrier gas used was nitrogen, which was dried with the standard Pye drier before reaching the chromatograph. Fig. 1 indicates that the chromatographic conditions described will readily distinguish between the diethanolamides with different n-alkyl chain lengths, and similarly between the diethanolamines. * Present address : J. J.'s (Chromatography) Limited, King's Lynn, Norfolk. 0 SAC and the authors.DAVIES AND DENHAM 337 6 li I 0 lo Time, minutes Key to Peaks I.Pyridine and silating agents 4. Lauric diethanolamide 2. Caprylic diethanolamide 5. Myristic diethanolamide 3. Capric diethanolamide 6. Pal mit ic d iethanolamide Fig. 1. Chromatogram of 10 pg of a commercial diethanolamide a t 250" C Several commercial antistatic agents (diethanolamides and diethanolamines) have been examined by gas chromatography, and it is often possible to distinguish between them because of the variation in n-alkyl chain composition. When a mixture of two antistatic agents (a diethanolamine and a diethanolamide) was chromatographed, as described above, the peaks obtained did not overlap. Thus either may be examined in the presence of the other.DETERMINATION OF ALKYL DIETHANOLAMIDES EXTRACTED FROM POLYETHYLENE- An internal standard was used for all of the quantitative work. Stearic diethanolamide was chosen because it could be introduced at the beginning of an extraction and would be silated with the extracted antistatic agent. It was present in small amounts in certain of the commercial diethanolamides analysed, but this did not preclude its use as an internal standard. Several grams of stearic diethanolamide were prepared in the laboratory by using the method of Trowbridge, Falk and Krems2 In low and medium density polyethylene the concentration of diethanolamides is about 0.10 per cent. Two types of extraction were investigated. Dissolution - precipitation method-A known amount of internal standard was added to 400ml of nonyl acetate in a 500-ml beaker.Ten grams of the polyethylene sample were added, and the beaker was then placed on a hot-plate and its contents were stirred until the polyethylene dissolved. The beaker was allowed to cool and the re-precipitated poly- ethylene removed by filtration. The nonyl acetate was evaporated off in a rotary evaporator. The residue was dissolved in methanol and the resulting solution carefully evaporated to dryness in a small sample flask. Soxhlet-extraction method-A known amount of internal standard was added to 200 ml of chloroform, and this solution was then used to extract 10 g of polyethylene sample for 16 hours in a Soxhlet flask. The solution was allowed to cool, any precipitated polyethylene removed,338 DAVIES AND DENHAM and the chloroform then evaporated off in a rotary evaporator.The residue was dissolved in methanol and the solution carefully evaporated to dryness in a small sample flask. Calibration standards were prepared, each containing a known amount of the com- mercial alkyl diethanolamide being determined and the same amount of internal standard as was added to each sample. All of the samples were silated and chromatographed. With both types of extraction the relative areas of the peaks for the extracted alkyl diethanolamide were found to be similar to the relative areas of the peaks in the original diethanolamide samples. The response of the flame-ionisation detector was shown to be linear to varying amounts of the silyl ether derivatives of the alkyl diethanolamides, in the range 2 to 12 mg per ml.The amount of diethanolamide in each of the extracts was calculated by comparing the peak- area ratios of the lauric diethanolamide to internal standard of the calibration standard and the extracts. RESULTS In a series of recovery experiments, known amounts of alkyl diethanolamides and internal standards were added to a solution of polyethylene in nonyl acetate, and to pure chloroform. After removal of the solvents and silation, the recoveries of alkyl diethanolamides were in the range 90 to 110 per cent., measured with respect to the internal standard. The difficulty with work that involves the analysis of additives in polymers is the preparation of polymers containing known amounts of additives.Polyethylene samples containing nominal amounts of alkyl diethanolamide were prepared by a polymer supplier, and the samples were analysed by both the dissolution - precipitation (nonyl acetate) and extraction (chloroform) methods. The results are given below. Nominal concentration, Nonyl acetate method, Chloroform method, per cent. per cent. per cent. 0.10 0.08 0.07 0.15 0.10 0.11 0.20 0.13 0.14 While losses may occur in the nonyl acetate method, they will not affect the ratio of alkyl diethanolamide to internal standard, and it thus provides a working method. The fact that the chloroform-extraction technique, with which losses of internal standard do not occur, gives similar results indicates that the Soxhlet extraction gives a good recovery of the alkyl diethanolamides.The reason for the difference between the measured and nominal figures is most probably the re-arrangement of alkyl diethanolamides a t the elevated temperatures of polymer pro- cessing, with the resultant loss of alkyl diethanolamide. This has been described by Kroll and Nadeau3 and Schick: who say that the first by-product is an amide ester. This compound has been identified in heated alkyl diethanolamides and in processed polymers containing alkyl diethanolamides by the authors, by using thin-layer chromatography and infrared spectroscopy. DISCUSSION Of the two extraction techniques described, the Soxhlet method of extraction with chloroform is easier to operate on a routine basis, although the nonyl acetate method is more amenable to recovery experiments. The extraction techniques outlined, followed by gas chromatography, should be applicable to the determination of alkyl diethanolamines in polyethylene. The thermal re-arrangements described above for alkyl diethanolamides will not occur with alkyl diethanolamines. The authors acknowledge the helpful discussions with Dr. F. J. Smith, Monsanto Chemicals Limited, Hythe, Southampton. REFERENCES 1. 2. 3. 4. Sweeley, C. C., Bentley, R., Makita, M., and Wells, W. W., J . Amer. Chem. SOC., 1963, 85, 2497. Trowbridge, J. R., Falk, R. A., and Krems. I. J., J . Org. Chem., 1966, 20, 990. Kroll, H., and Nadeau, H., J . Amer. Oil Chem. SOL, 1967, 34, 323. Schick, M. J., “Non-Ionic Surfactants,” Edward Arnold (Publishers) Ltd., London, 1967, p. 217. Received November 16th. 1967

ISSN:0003-2654    

DOI:10.1039/AN9689300336

出版商:RSC    

年代:1968

数据来源: RSC

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Analyst, May, 1968, Vol. 93, p p . 339-341 339 The Determination of Total Sulphur in Grasses by Indirect Polarography of the Sulphate Ion BY M. I. E. LONG (Animal Health Research Centre, P.O. Box 24, Entebbe, Uganda) A method is described for the determination of total sulphur in grasses, based on the polarographic determination of lead following the precipitation of sulphate, resulting from nitric acid - magnesium nitrate digestion, as lead sulphate. SULPHUR is an essential element for plant growth, and has been shown to enter into the copper - molybdenum metabolism of ruminants.1 The minimal dietary level of sulphur required to satisfy the requirements of a lactating cow has been reported as 0.1 per cent.2 During investigations into the mineral status of pastures available to dairy cattle in the “fertile crescent” around the northern shores of Lake Victoria, it was deemed advisable to examine the sulphur content of these pastures, in view of the probable low soil-sulphur content of the area.3 Methods for the determination of sulphur in soils and plants have been described, following various digestion procedures, with oxidising agents such as perchloric acid, mag- nesium nitrate - nitric acid,3 nitric acid - hydrochloric acid,4 potassium chlorate5 and potassium nitrate - nitric acid.6 All of these are claimed to give satisfactory results, and various methods for the determination of the sulphate resulting from the above procedures have been published.Most of them have been based on the measurement of the turbidity of the barium sulphate cloud, following addition of barium chloride under strictly defined conditions. Several worker^^^^^^^* have specified the use of solid barium chloride added to acidic sulphate solutions.Crystal size and batch of barium chloride used, time of standing, type of acid and its concentration and weight of crystals added, all influence the optical density of the resulting barium sulphate cloud.3 Steinbergs4 found that the use of a concentrated barium chloride solution provides satisfactory reproducibility if the barium chloride contains sufficient heavy metal impurities, such as lead, and traces of sulphate to provide an adequate concentration of nuclei for the formation of uniform barium sulphate crystals. An indirect polarographic method for the determination of sulphate has been devised by Baranowski and Gregorowie~.~ This involves the polarography of the lead ion, after precipitation as lead sulphate and subsequent dissolution of the latter in saturated ammonium chloride solution.This procedure, following the destruction of organic matter and oxidation of sulphur to sulphate with magnesium nitrate - nitric acid,3 forms the basis of the proposed method. METHOD APPARATUS- Cambridge DE electronic recorder. REAGENTS- Polnrograph-A Cambridge general-purpose instrument was used in conjunction with a All reagents should be of analytical-reagent grade. Nitric acid, fuming, sp.gr. 1.52. Nitric acid, s$.gr. 1-41. Nitric acid, 2 N. 0 SAC and the author.340 LONG: DETERMINATION OF TOTAL SULPHUR IN GRASSES [Analyst, Vol.93 Magnesium nitrate solutiort3-Prepare from 5 g of Specpure magnesium (obtainable from Johnson, Matthey Co. Ltd., London) by dissolving it in 90 ml of nitric acid, sp.gr. 1.41, the resulting solution being made up to 100 ml with distilled water. Ammolaiu solu~ion, 1 + l-Prepare from ammonia solution, sp.gr. 0.91. Lead nitrate, 0.2 M. Dioxan. Acetone wash liquid-Mix equal volumes of acetone and distilled water. Base solution-Saturated ammonium chloride solution. Standard lead solutiort-Dissolve 0.3997 g of lead nitrate in 1 litre of distilled water. Standard sulpkate sohtion-Dissolve 0.2812 g of potassium sulphate in 1 litre of distilled 1 ml of solution = 0.25 mg of lead. water. PROCEDURE- Weigh 0-5 g of the grass sample into a 25-ml beaker. Add 3 ml of fuming nitric acid and allow it to stand overnight.Place on a hot-plate and slowly raise the temperature until occasional bubbles appear. When almost dry, add 2 ml of magnesium nitrate and evaporate to dryness on a water-bath. Complete the ashing in a muffle furnace at 350" C overnight. Dissolve the residue in a minimum of concentrated nitric acid. After evaporation to dryness on a water-bath, add water to dissolve the soluble residue and add ammonia solution 2 to 3 ml in excess. Filter off the resulting precipitate, and remove ammonia from the filtrate by heating on a water-bath. Transfer the remaining solution to a 25-ml calibrated flask, make just acid with dilute nitric acid and make up to the mark with distilled water. Transfer a 5-ml aliquot to a 10-ml conical centrifuge tube.Add 5 ml of dioxan and 1 ml of 0.2 M lead nitrate solution. Mix thoroughly and leave in a refrigerator at 5" C for 2 hours. Centrifuge the lead sulphate precipitate, and wash twice with acetone wash mixture. After drying at 60" C, dissolve the precipitate in 5 ml of base solution. Transfer the solution to a polaro- graphic cell and de-oxygenate with nitrogen for 2 minutes. Record the polarograrn from -0.2 to -0.8 volt against the mercury pool E+ = -0.45. A suitable sensitivity is 1/20. CALIBRATION- A series of suitable aliquots of the standard lead solution is used to prepare the calibration graph. Evaporate these to dryness on a water-bath and dissolve the residues in 5ml of base solution. Polarograph the resulting solutions after de-oxygenation, as above.With the levels of total sulphur found in Uganda grasses, a suitable range is up to 2 mg of lead per 5 ml of base solution. Results obtained are given in Tables I and 11. TABLE I RECOVERY OF SULPHUR FROM ALIQUOTS OF A STANDARD SULPHATE SOLUTION Aliquot, Sulphur, Sulphur found, Recovery, ml mg mg per cent. 1 0-052 0.053 101.9 2 0.104 0.101 97.1 3 0-155 0.152 98-1 TABLE I1 RECOVERY OF SULPHUR ADDED TO A 0.5-g GRASS SAMPLE Sulphur found, Recovery, m g per cent. .. .. .. 0.067 - Grass alone . . .. .. .. Grass + 0.100 m g of sulphur as potassium sulphate . . 0.161 104.0 Grass + 0.169 mg of sulphur as methionine . . .. 0.224 98.6 Each result is the average of triplicates. DISCUSSION The method described provides a means of determining the sulphur content of grasses with a degree of accuracy more than sufficient for the purpose required.The success of earlier turbidimetric techniques is entirely dependent on the formation of reproducibleMay, 19681 BY INDIRECT POLAROGRAPHY OF THE SULPHATE ION 341 turbidities, which in turn is highly susceptible to operator influences. It is suggested that the method described does not involve such sensitive techniques. Once the initial digestion is completed the procedure is comparatively rapid and precipitation of lead chloride by chloride ion is prevented by conducting the precipitation in water - dioxan mixture.’ The levels of lead normally present in forages are too low to cause any significant error. Significant levels of lead would lead to precipitation of sulphate early in the procedure. Grateful acknowledgment is made to the Permanent Secretary, Ministry of Animal Industry, Game and Fisheries, for permission to publish this paper. 1. 2. 3. 4. 5. 6. 7. 8. 9. REFERENCES Dick, A. T., Int. Grassld Congr., 1956, 7, 368. Whitehead, I). C., “Nutrient Minerals in Grassland IEer;bage,” Commonwealth Agricultural Butters, B., and Chenery, E. M., Analyst, 1959, 84, 239. Steinbergs, A., Ibid., 1953, 78, 47. Saalbach, E., Kessen, G., and Judel, G. K., Zalcdter. Forsck., 1962, 15, 6. Chaudry, I. A., and Cornfield, A. H., Analyst, 1966, 91, 628. Holeton, B. E., and Linch, A. J., A d y t . Chew., 1950, 22, 819. Sheen, R. T., Kahler, €3. L., Ross, E. M., Betz, N. H., and Betz, L. D., INd. Engmg Chenz. Analyt. Baranowski, R., and Gregorowiez, Z., Chemia Analit., 1965, 9, 125. Received June 5th, 1967 Bureaux, Hurley, Berks., 1966, p. 2. Edn, 1935, 7, 262.

ISSN:0003-2654    

DOI:10.1039/AN9689300339

出版商:RSC    

年代:1968

数据来源: RSC

摘要:

342 Artalyst, May, 1968, Vol. 93, $$. 342-343 A Titrimetric Method for the Determination of Tetralalkylthiuram Disulphides by Oxidation with C hloramine-T BY KANDALLA RAVINDRANATH AND C. C. PATEL (Department of Inmganic and Physical Chemistry, Indian Institute of Science, Bangalore 12, India) An analytical method for the determination of tetra-alkylthiuram di- sulphides has been developed, based on the quantitative oxidation of carbon disulphide produced by acidified chloramine-T to sulphuric and formic acids. Twentyeight equivalents of chloramine-T are required per mole of a thiuram disulphide. DURING our studies on the reaction of aqueous dithiocarbamates with oxygen, the thiuram disulphides formed in the medium had to be determined. A survey of the literature showed that a thiuram disulphide was determined indirectly by decomposing it with a mineral acid and determining the amount of carbon disulphide, or the corresponding amine, produced.The former was determined either photometrically1 or iodimetrically after converting it into a xanthate2; and the latter was determined either chromatographically3 or photometrically after converting it into a dithi~carbamate.~ In the method described here the thiuram disulphide is determined directly by using acidified chloramine-T as an oxidising agent. Thiuram disulphide decomposes in acidic solution to form a dithiocarbamic acid which, being unstable, decomposes further to form an amine and carbon disulphide: R,NC--S--S--C--NR2 + 2H+ 2R2NC HS .. . . (1). I1 I1 \SH s s Chloramine-T oxidises carbon disulphide to sulphuric and formic acids,6 as shown, but it does not react with the amine, which in acidic solutions forms salts.2CS2 + 140 + 6H20 __+ 4H2S04 + 2HCOOH . . .. . . (3). METHOD REAGENTS- Chloramine-T, 0.2 N-Standardised iodimetrically.6 Sodium thiosuZphate, 0.1 N-Standardised against dichromate. Potassium iodide solution-A 10 per cent. w/v solution in de-oxygenated distilled water. Thiuram disuZphides-Tet rae t h yl- ,7 t e t rapropyl-8 and t e trabut ylt hiuram7 disulphides were prepared and purified by known methods. Solutions of 0.1 to 0.3 per cent. in absolute ethanol were prepared for analysis. PROCEDURE- Transfer, by pipette, l O * O m l of thiuram disulphide solution into an Erlenmeyer flask and add 25.0 ml of standard (0-2 N) chloramine-T solution, together with 12 ml of 2 N hydro- chloric acid.Shake well for about 1 minute, then leave for 45 minutes to complete the reaction. 0 SAC and the authors.RAVINDRANATH AND PATEL 343 Add 10 ml of the potassium iodide solution and leave it in the dark for about 5 minutes to liberate the iodine. Titrate the liberated iodine against standard thiosulphate, with starch as indicator. One mole of thiuram disulphide is equivalent to 14 moles of chloramine-T. The results, which are found to be reproducible, are given in Table I. TABLE I DETERMINATION OF THIURAM DISULPHIDES WITH CHLORAMINE-T Thiuram disulphide Tetraethyl . . .. Tetrapropyl . . .. Tetrabutyl . . . . Amount taken, g . . 0.0210 0.0281 0-0320 0.0336 0.0356 0.0382 . . 0.0078 0.0168 0.0298 0.0339 .. 0.0248 0-0266 0.0366 Amount found, g 0.0210 0.0282 0.0319 0.0337 0.0366 0-0381 0.00783 0.0168 0.0297 0.0339 0.0249 0.0266 0.0366 Difference, g 0~0000 0~0001 -0~0001 0*0001 - 0~0001 -0~0001 0 * 0 0 0 0 3 o*oooo -0~0001 0~0000 0*0001 0~0000 0~0000 Error, per cent. 0.00 0.30 - 0.30 0.30 - 0.28 - 0.28 0.40 0.00 - 0.30 0.00 0.40 0.00 0.00 DISCUSSTOK An attempt was made to determine the nature of the reaction products formed when a thiuram disulphide reacted with acidified chloramine-T, under the experimental conditions used. Infrared spectroscopic examination of the reaction products indicated the presence of the diamine sulphate (R2NH,),S04 rather than the amine hydrogen sulphate, R,NH,.HSO,. During the studies on the determination of dixanthogens with acidified chloramine-TI Rao9 found that different dixanthogens required different equivalents of the oxidant. In the present method, all of the thiuram disulphides tried required twenty-eight equivalents of chloramine-T, thus making the method a more general one. We thank Messrs. Robinson Brothers, West Bromwich, England, for kindly supplying sodium dibutyldithiocarbamate. 1. 2. 3. 4. 6. 6. 7. 8. 9. REFERENCES Clarke, D. G., Baum, H., Stanley, E. L., and Hester, W. F., Analyt. Chem., 1951, 23, 1842. Maurice, M. J., and Mulder, J. L., Mikrochim. Acta, 1967, 661. Brock, M. J., and Louth, G. D., Analyt. Chem., 1955, 142, 414. Heuermann, R. F., J . Ass. Off. Agric. Chem., 1957, 40, 266. Rao, V. R. S., and Murtliy, A. R. V., Talanta, 1960, 4, 206. Bishop, E., and Jennings, V. T., Ibid., 1957, 1, 197. Von Braun, J., Bey. dt. chem. Ges., 1902, 35, 817. Rothestein, R., and Binovic, K., Red. Trav. Chim. Pays-Bas Belg., 1954, 73, 661. Rao, S. R., Talanta, 1961, 8, 746. Received October loth, 1967

ISSN:0003-2654    

DOI:10.1039/AN9689300342

出版商:RSC    

年代:1968

数据来源: RSC

摘要:

344 Analyst, May, 1968, Vol. 93, p. 344 Quantitative Separation of Calcium, Strontium and Phosphate BY N. S. CHICKERUR AND T. S. B. NARASARAJU A QUANTITATIVE separation of calcium and strontium in the presence of phosphate was required in the course of physico-chemical investigations on synthetic solid solutions of calcium and strontium hydroxylapatites ; earlier methods1 s2 s3v4 appeared to fail in the presence of phosphate. In the absence of strontium, calcium and phosphate could be determined to a fairly high degree of accuracy by Washburn and Shear's m e t h ~ d . ~ This method is not applicable in the presence of strontium because of the identical behaviour of these alkaline earths towards the formation of the respective oxalates. The presence of phosphate com- plicates the separation of the alkaline earths ; therefore, in the following experimental pro- cedure, the phosphate was separated first.To a solution containing known amounts of calcium, strontium and phosphate (see Table I) 5 to 6 ml of nitric acid (sp.gr. 1.42) and 10 to 12 ml of 8 per cent. ammonium nitrate solution were added. Phosphate was precipitated at 50" C as ammonium molybdophosphate by adding a 3 per cent. solution of ammonium molybdate until no further formation of yellow precipitate from the supernatant liquid was perceptible. The precipitate was filtered through a 1G4 crucible and washed several times with a solution containing equal volumes of 1 per cent. solution of ammonium nitrate and 20 per cent. nitric acid (spgr. 1-42>. The filtrate was preserved for the determination of calcium and strontium.The precipitate was dissolved in the minimum volume of 0-1 M solution of sodium hydroxide and the phosphate determined by following the previously mentioned m e t h ~ d . ~ The filtrate was made ammoniacal and excess of 1 per cent. ammonium carbonate solution was added to precipitate the calcium and strontium as carbonates. On evaporation to dryness of the solution of the carbonates in 20 per cent. nitric acid a mixture of solid nitrates of calcium and strontium was obtained. The nitrate mixture was allowed to remain in contact with excess of dry acetone6 overnight, after intermittent stirring at convenient intervals for about 6 hours. Calcium nitrate was completely soluble while insoluble strontium nitrate was separated by filtration through a 1G4 crucible, dried at 110" C and weighed.The acetone present in the aqueous solution was evaporated off on a water-bath and the calcium determined by the previously stated r n e t h ~ d . ~ The results of three experiments on mixtures of solutions containing the three elements are shown in Table I. (Department of Chemistry, Banaras Hindu University, Varanasi, India) TABLE I DETERMINATION OF CALCIUM, STRONTIUM AND PHOSPHORUS IN SYNTHETIC APATITES Calcium Strontium Phosphorus r r & Theory, Expt., Theory, Expt. , Theory, Expt. , g g g g g g Synthetic mixture 1 0.1539 0.1545 0.1954 0.1972 0.0264 0.0271 Synthetic mixture 2 0.1578 0.1561 0.1651 0.1687 0-0092 0.0094 Synthetic mixture 3 0.1563 0,1545 0.1998 0.2021 0-0264 0.0271 When the method was applied to 004160g of a solid solution of mixed calcium and strontium hydroxylapatites [(Ca,,(PO,),(OH), + srlo(P04)6(OH)2] the weights found were: calcium, 0-0204 g ; strontium, 0-2167 g ; and phosphorus, 0.0543 g; which gave a gram-atomic ratio per mole of (Ca + Sr)/P = 1-70 (theoretical value, 1.67). We thank Professor G. B. Singh for encouragement and provision of the facilities. REFERENCES 1. 2. 3. 4. 5. 6. 0 SAC and the authors. Kallmann, S., AnaZyt. Chem., 1948, 20, 449. Lerner, M., and Reiman, W., Ibid., 1954, 26, 610. Wilkinson, P. R., Gibson, J. A., and Headlee, A. J. W., Ibid., 1954, 26, 767. Assarsson, G. O., and Balder, A., Ibid., 1952, 24, 1679. Washburn, M. L., and Shear, M. J., J . BZoZ. Chem., 1932-33, 99, 21. Shreve, A. N., Watkins, C. H., and Browning, J. C., Ind. Engng Chem. Analyt. Edn, 1939, 11, 216. Received Septembev Eith, 1967

ISSN:0003-2654    

DOI:10.1039/AN9689300344

出版商:RSC    

年代:1968

数据来源: RSC

摘要:

Analyst, May, 1968, Vol. 93, fq5. 345-352 345 Book Reviews KIRK-OTHMER ENCYCLOPEDIA OF CHEMICAL TECHNOLOGY. Second Edition. Volume 12. IRON Edited by HERMAN F. MARK, JOHN J. MCKETTA, jun., DONALD F. New York, London and Sydney: Price k18 15s. ; price In writing previous reviews of this work (see Analyst, 1963, 88, 899, et seq.), it has been felt that readers of The Analyst would be served most usefully by a review that deals with the mono- graphs under three main headings, namely, those of special analytical interest; those of special chemical interest to analysts; and the rest. This scheme is therefore followed, as far as possible, in the present review. The following, therefore, are the monographs that are likely to prove of special interest to analysts, not necessarily because of the methods given (indeed it is not the policy of this publication to describe analytical methods in detail, but because a knowledge of the properties of the com- pounds concerned is helpful to the analyst, and because the compounds themselves have analytical implications.Lactic acid, for example, is an important fermentation product, the manufacture of which is described with special emphasis on purification, particularly for pharmacopoeia1 pur- poses. Specifications are dealt with, and methods of analysis refer to theknownestablishedmethods. There is also a section on lactic acid derivatives. The monograph on Lecithin is also in this category and, naturally, special reference is made to commercial lecithin, which is usually derived from soya bean.It seems, however, that there is also a prospect of obtaining this substance from coffee, as it is obtained as a by-product in de-caffeinisation. In general, analytical methods follow official standards (in American laboratories at least), but more rapid results axe obtained by ashing the sample, converting the phosphorus into monophosphate and titrating with standard uranyl nitrate solution. Thin-layer chromatography can be used for the quantitative analysis of phospho- lipid fatty acids. Specialised analytical methods are also referred to in the monographs on Malic Acid and Malonic Acid, namely, in the latter instance, titration in non-aqueous solvents with tetramethylammonium hydroxide. Paper chromatography is used to separate malonic acid from other similar acids.Further references to specialised analytical methods occur in the monographs dealing with specific industrial subjects such as Leather, Malts and Laundering (here with special reference to detergents). This volume contains monographs on several important metals, such as Iron and its Compounds (44 pages), Lead, its Utilization and its Compounds (59 pages), Lithium, Magnesium and Man- ganese. For all, the general sequence of treatment is similar, viz., history, properties, occurrence, statistics, manufacture and uses. Such monographs form useful summaries of up-to-date knowledge of the elements to which they refer, and although treatment is adequate it is, naturally, not pursued in any great depth or detail. However, there are ample bibliographies for each.Subjects of more technological interest include Laminated and Reinforced Plastics, Lime and Limestone, Lubrication and Lubricants, and Luminescent Materials. Liquified Petroleum Gas, which is obtained from natural gas or derived from the refining of crude oil, is used as a fuel or as a feedstock for chemical production. It is available principally as propane and butane, or as their mixtures. This is obviously an important and topical subject, although one would not normally look for it under L. Specifications are summarised and, obviously, some interesting analytical problems arise, although they are not dealt with. In addition to these, there are some unexpected monograph headings, for example, Liquid Level Measurement, Macrolide Antibiotics, and four monographs under the prefix Magnetic, namely Materials, Properties, Separation and Tape.Of particular interest is the monograph entitled Literature of Chemistry and Chemical Technology (29 pages), and this is obviously of great importance to users of the Encyclopedia. It is, therefore, rather disappointing that it lists many periodicals without an indication of their origin or where they can be obtained. The periodicals are classified roughly by subject, and although the list does not claim to be exhaustive, it omits a number of non-American journals of importance. The only abstracting services thought to be worthy of mention are Chemical Abstracts and Chemisches Zentvalblatt; the heading Government Documents refers only to the U.S.A.; and the periodical literature of chemical analysis receives no mention whatsoever, not even The Analyst ! Part of this same monograph deals with documentation and the mechanisation TO MANGANESE.OTHMER and ANTHONY STANDEN. Interscience Publishers, a division of John Wiley & Sons Inc. per volume to subscribers to the complete set of 18 volumes fJ15. Pp. xiv + 905. 1967.346 BOOK REVIEWS [Afialyst, VOl. 93 of literature searching, based chiefly on the punched-card system. There are also, however, interesting sections on computer-prepared indexes and on abstracting and indexing, which point to the direction of future trends. As in former volumes, it is perhaps in the monographs dealing with rather specialised subjects, knowledge of which is usually limited, that this Encyclopedia is at its best.Monographs on subjects such as the common metals cannot hope to be fully comprehensive, whereas the specialised types of monographs are written by experts who obviously know their subject extremely well. An example of this in the present volume is the one dealing with Lignin, which is a model of its kind. Luminescent Materials, which includes phosphorescence but not fluorescence, is another. The monograph on Lime and Limestone is also self-contained, and the descriptions of the modern kilns are particularly satisfying. There is a brief reference to the use of lime in the recovery of alkaline paper pulp liquors; however, it is incorrect to say that it is the black liquor that is recovered, because in practice this liquor is evaporated and burned before the causticising stage is applied.In a similar connection, the monograph on linen (flax) refers solely to its use as a source of textiles; there is no mention of its important application as a paper-making fibre. JULIUS GRANT TEXT BOOK OF PHARMACOGNOSY. By T. E. WALLIS, D.Sc., F.R.I.C., F.P.S., F.I.Biol., F.L.S. This well known book was written primarily for pharmaceutical students, and the fact that five editions have appeared within 21 years is eloquent testimony to its value and success. It is also recommended as a reference book for the analytical chemist, and reviews of previous editions have endorsed this view. The analyst must have many skills and, although proficiency with the microscope is less highly rated than formerly, the ability to recognise the characteristics of vegetable tissues is a useful asset whose value is not restricted to the field of food and drugs.The analyst, therefore, requires a reference book to help him in the identification of structures, and in this he will look especially for accuracy of description, clarity of drawings and general guidance. All are to be found in this book. Dr. Wallis is noted for the excellence of his diagrams, and he writes with the authority derived from lifelong study in this field. In addition to the descriptions of the morphology of crude drugs, there is a wealth of informa- tion on their sources, constituents, uses and on likely adulterants. In this fifth edition, the main revisions have been made in these latter sections; the list of references has also been extended and a summary of numerical values for certain diagnostic features has been included as an addendum.The older generation of chemists will recognise a worthy successor to the books of Professor Greenish; many analysts will have reason to be grateful to Dr. Wallis for his continuing efforts in the production of this book. Pp. xii + 652. London: J. & A. Churchill Ltd. 1967. Price 65s. J. F. HERRINGSHAW MOLECULAR COMPLEXES. By J. Rose. Pp. x + 177. Oxford, London, Edinburgh, New York, The complexes formed between metal ions and a host of ligands are well understood, and find wide applications in all aspects of chemistry, particularly in analysis. Molecular or addition complexes, however, are far less well known and to many chemists remain a mystery. The present book does not solve the mystery, but it does summarise the properties of these interesting com- pounds and the theories that have been proposed to explain their properties.Some of the difficul- ties arise from the wide range of compounds that can be considered as molecular complexes. They include the strong ammonia - boron trifluoride complex, the iodine - benzene and transition metal - olefin species and the weak self-complex of p-nitroaniline. The bonding in the complexes is discussed, and also their stability, composition and properties. The effect of structural changes on complex formation is also described, and a separate chapter is devoted to the complexes of the Group I11 elements [e.g., (CH,),As.In(CH,),]. The book concludes with an outline of the few applications that molecular complexes appear to have.The analytical chemist has made little use of molecular complexes. S i x unimportant applica- tions are recorded in 21 lines of text. Yet, as many of the complexes are quite stable and are intensely coloured, it should be a fruitful field for the development of new analytical methods, especially for organic compounds. Toronto, Sydney, Paris, and Braunschweig : Pergamon Press. 1967. Price 50s. ; $8.00.May, 19681 BOOK REVIEWS 347 Although the book contains numerous examples of molecular complexes and their properties, it is not easy to digest and does not give the reader a completely clear picture of the subject. Part of the confusion arises from typographical errors and some peculiar or obscure sections. These include a description of ethanol as an aromatic solvent (p.2), change-transfer! (p. 8), isobiestic instead of isosbestic (p. 35) and nun-metallic umines (p. 86). How does one visualise a “. . . chlorine atom . . . above the middle of the (benzene) ring and outside it” (p. 9) or a *‘. . . npx orbital perpendicular to the place containing the three a-bonds” (p. 19). The stability constants (p. 41) and the velocity constants (p. 55) have no units, and Table 3.1 (p. 65) shows the change in velocity constants, not in reaction rate. The paragraph under this Table is quite obscure. The collection of several references under one reference number should have been avoided, as it leads to awkward and irritating insertions when just one of these papers has to be identiiied later in the chapter.For example, on p. 23, . . . Mulliken (ref. 25, p. 845) indicates which one of six papers in four journals is referred to; a little later, a reference to . . . Slifkin (luc. cit.), after much detective work, probably means ref. 84. The index is brief and casual. It is almost impossible to retrieve information on specific complexes without thumbing through the text. For instance, when an attempt was made to discover whether the Karl Fischer reagent (which includes pyridine - iodine and pyridine - sulphur dioxide molecular complexes, but is not mentioned in the section on analytical applications) was discussed, it was found that pyridine and sulphur dioxide are not indexed, although pyridine complexes appear frequently in the text; the references to iodine led to a mention of the self-complex of iodine (p.18; other self-complexes in the same line of text are not indexed) and to a discussion of complexes of Group IIIB acceptors (pp. 155-156), in which iodine is not even mentioned! Nevertheless, the book contains interesting information on the properties of molecular complexes that should be useful to anyone who wishes to have information about them collected together in this way. A. TOWNSHEND METHODS OF BIOCHEMICAL ANALYSIS. Volume XV. Edited by DAVID GLICK. Pp. x + 531. New York, London and Sydney: Interscience Publishers, a division of John Wiley & Sons Inc. 1967. Price 120s. The micro determination of vitamin A and carotenoids in blood and tissue is reviewed by D. S. McLaren and his collaborators a t the American University of Beirut, Lebanon.The use of trifluoroacetic acid instead of antimony trichloride is recommended for a colour test (J. B. Neeld, jun. and W. N. Pearson, J . Nutr., 1963, 79, 454), and vitamin A in serum is also determined on the unsaponifiable fraction by measuring absorption a t 328 mp in a kerosene - xylene mixture before and after ultraviolet irradiation. D. S. Jackson of Manchester and E. G. Cleary of Portland, Oregon, offer a critical study of the determination of collagen and elastin, fibrous proteins that occur variably in most tissues. Collagen is insoluble but is readily converted into gelatin ; it is determined by measuring protein- bound hydroxyproline by using an appropriate conversion factor depending on the species.The authors discuss purification of collagen and its hydrolysis, and the oxidation of hydroxyproline to pyrrole, prior to forming a coloured derivative with p-dimethylaminobenzaldehyde. The merits of various procedures are discussed and, although final answers have not been possible, substantial guidance is offered. Elastin from different tissues and different mammalian species seems to be a single protein or group of proteins with a characteristic amino-acid composition. There is, however, no quantitative marker, such as hydroxyproline for collagens, so that the amino-acid analysis constitutes the standard of purity. Most methods of purification depend upon the inertness of elastin to protein solvents and its relative resistance to hydrolysis, e.g., collagen is gelatinised and removed with hot water, and the residue is heated in weak alkali to remove protein con- taminants from the elastin.The product is rich in non-polar residues such as glycine, alanine, valine and proline. This survey is penetrating and perhaps a bit gloomy; great emphasis is laid on rigorous control of the purity of the elastin preparation. W. H. Fishman of Boston, Massachusetts, writes on the determination of /i?-glucuronidases. The plural is used because a new enzyme, endo-/3-D-ghcuronidaseJ has been discovered, which is very different in properties and substrate specificity from the familiar 19-glucuronidase. Important relevant work is being camed out on the release of enzymes from lysosomes and microsomes. Sub- strate specificity is reviewed and the most suitable substrate for biochemical work is found to be phenolphthalein mono-B-D-glucosiduronk acid, with fi-dinitrophenyl-/i?-D-glucosiduronic acid as a second choice.The measurement of low enzyme activity in serum, urine, spinal fluid, etc., is This is a useful review.348 BOOK REVIEWS [Analyst, VOl. 93 discussed in terms of pH and incubation time. Naphthol AS-BI-fl-D-glucosiduronic acid is useful in histochemistry. The Fishman - Green method for glucuronic acid and glucosiduronic acid mixtures with naphthoresorcinol is fully described. There is an interesting treatment of enzyme inhibitors, with saccharo- 1,Clactone as a competitive inhibitor of #%glucuronidase as the focus ; the implications of its metabolic origin are explored. Leech endo-/3-glucuronidase required hyal- uronic acid as substrate. The present state of interpretation of the r8les of glucuronidases, old and new, is surveyed authoritatively.C. A. Anderson from Applied Research Laboratories, Goleta, California, submits a lengthy introduction to the electron-probe microanalyser and its application to biochemistry. This instrument allows an approach to complete analysis to be carried out in sit% on thin sections pre- pared by histological methods. Elements of the periodic system above beryllium can be detected in a few cubic microns. The technique requires an electron optical system, an X-ray detection system, an electron-beam scanning system, a light optical system and a mechanical sample stage. There are also recording and display systems.The instrument can be used as a scanning electron microscope to survey a selected area and not only can the different elements be detected, their chemical bonding can also be studied. The major part of the article (82 pages) is concerned with matters of technique. The section on biochemical applications (32 pages) covers cytochemical and histochemical problems, studies in chemical pathology and dental biochemistry and some interesting issues concerning zinc in tissues. This is a comprehensive survey with a full biblio- N. G. Anderson of Oak Ridge, Tennessee, has an article on preparative zonal centrifugation, which surveys work carried out in the U.S.A. as part of a programme jointly sponsored by the Atomic Energy Commission, the National Cancer Institute and the National Institute of Allergy and Infectious .Diseases.With such backing the contribution should be good! It is, in fact, concise (38 pages), readable, well documented and obviously the work of an expert. Many laboratories all over the world will eventually benefit from this research. C. H. Wang of Corvallis, Oregon, has “radiorespirometry” as his subject. The well known Warburg manometric technique has limitations that are partly overcome by radiorespirometry. This is a type of experiment in which the rate and extent of evolution of respiratory 14CO, is determined in a biological system metabolising uniformly 14C-labelled or specifically 14C-labelled substrates. An alternative designation “14COa pattern analysis” has been used (Tolbert and Cozzeto). The scope of application of the method is surveyed, and there are interesting discussions of the identification and estimation of metabolic pathways as well as the alteration of pathways.The article is important mainly for its technical expertise. Three American authors (J. D. Winefordner, W. J. McCarthy and P. A. St. John) join forces to describe how the measurement of phosphorescence can serve as an analytical approach in biochemistry. After discussing the theoretical background, instrumentation, optimal experi- mental conditions, procedures and methodology (84 pages), the authors come to applications. They claim great versatility for phosphorimetry, especially in conjunction with a prior separation by thin-layer chromatography. The examples are mostly of pharmacological interest with some analyses for amino-acids and nucleic acid constituents. This is an interesting article that can be recommended to all those who have found fluorescence analysis able to meet a special need; phosphorescence analysis may sometimes present a convenient way to tackle a particular task for which there is, so far, no really good method.A series such as this must, today, be influenced by the increasing complexity of scientific instruments, the so-called sophistication effect. Much of the research that goes into improving instrumentation is expensive and indeed might never be profitable on ordinary standards of accounting. Some of it may be a by-product of apparently unrelated studies, but it is good to have the results made generally available.On the other hand, new developments are still possible around central biochemical themes, where the need is for insight rather than novel or elaborate instruments. In this volume Dr. Glick has preserved a reasonable balance between different aspects of biochemical analysis. graphy- R. A. MORTON NIEUWE ONDERZOEKINGEN IN VERBAND MET DE BEPALING VAN SPORENT PLATINA-METALEN. By RENAAT GIJBELS. Pp. 127. Brussels: Paleis der Academien. 1967. Price 270F. (Belgian). In this book, a down-to-earth experimental exposition of neutron-activation analysis is put forward for the determination of trace impurities in noble metals down to the p.p.m. range. ThisMay, 19681 BOOK REVIEWS methodical application of an analytical technique to closely related systems, followed through to its conclusion, will necessarily yield more meaningful results of the systems and the technique used.Neutron-activation analysis is usually accompanied by radiochemical studies of the analytical chemical separations used to isolate the desired activities. The type of spectrometer used to detect the induced activity will depend on the type of radiation emitted by the activated nuclide. The activity recorded may then be related to the mass of the trace element. Separation procedures are described for ruthenium - iridium, osmium - iridium, osmium - gold, osmium plus ruthenium - platinum plus gold plus iridium (by distillation) and gold - iridium, gold - platinum plus iridium and platinum - iridium (by solvent extraction). Special attention has been given to the separation of osmium - ruthenium for a wide range of ratios.The separations could be carried out quantitatively without the use of carriers. Neutron-activation analysis was applied to the determination of traces of osmium and iridium in ruthenium ; ruthenium in rhodium ; ruthenium, iridium and gold in osmium; and osmium, ruthenium, iridium and gold in platinum, by using the above separations. The “addition method” used in the activation analysis is worthy of mention, as this is the corner stone for the absolute evaluation of the amount of trace element in the samples analysed in this book. Numerous reasons validating this are given, as well as a detailed statistical inter- pretation. Meticulous thought has been given in the text to the irradiation aspects in this analysis with neutrons, especially pitfalls that may lead to erroneous results.The second-order effect [inter- ference reaction (n,y)] was theoretically calculated and experimentally determined for the activation of iridium in osmium. As the energies of the most intense y-rays emitted during the decay of the activated nuclides were low, discrimination for the elimination of weaker, high energy 7-rays and their Compton distributions was accomplished by using a very thin sodium iodide crystal. This book may serve as a usefuI guide for a comparison of the sensitivity of neutron-activation analysis with various other analytical techniques, such as spectrographic, X-ray fluorescence, polarographic and colorimetric methods. A lucid introduction is given for each trace element investigated, explaining the logic of the analysis executed.This is followed by the experimental procedure for the radiometric studies of the separations, the neutron irradiation itself and the counting procedures. Experimental data are not hidden but brought to the fore and subjected to statistical analysis that eliminates the often tedious task of the reader to re-calculate when too little information about the method for data reduction is given. Experimental detail is painstakingly explained, without over-stressing trivialities. The book would be an asset to those who seriously consider activation analysis with neutrons and would also be of much use in a university laboratory. Analysis of the resultant spectra was made with a sodium iodide crystal.H. F. ROHM IMMUNOLOGICAL AND BLOOD PRODUCTS. By MARY DAWSON and G. R. MILNE. Pp. x + 193. London: William Heinemann Medical Books Ltd. 1967. Price 30s. PharmaceuiicaE Monogvaphs This monograph sets out to provide a basis for teaching the subject to pharmaceutical under- graduates and “. . . extend naturally to the boundaries of knowledge in all major aspects. . . .” The section on Immunological Products must be judged to have failed to meet these criteria. The important aspect of undergraduate teaching must be to inculcate an understanding of the fundamental principles of the science, rather than familiarity with processes. The latter approach has been a failing of many pharmacy courses in the past. Although detailed information is necessary if the book is to act as a work of reference, the balance between basic science and details of applications should reflect a strong bias towards the former.This weakness is emphasised by the divorce of, e.g., the discussion of Allergy from the introduction, and the use of a discursive style, rather than a tight scientific one. It would also be hoped that any discussion of Immunology should view the subject as a whole and include those aspects of the science that the author mentions briefly in the conclusion, and indeed, those aspects dealt with under “Blood Products.” Apart from these criticisms of the basic approach, certain specific points may be singled out. There is a general lack of diagrams that would aid understanding, e.g., the difference between active and passive immunity and the effect of booster doses of vaccines may be illustrated readily.350 BOOK REVIEWS [Analyst, VOl.93 Fig. 1 implies that acquired immunity cannot be “natural” and that active immunity may be inherited, presumably as a result of genetic factors. The author surely did not intend this, but there is no discussion of the figure and thus no clarification of these points. In Chapter 2 the nature of toxoid, the relationship between toxicity and invasiveness in infection and the problem of serum sickness are dealt with cursorily. It would have been useful to have referred to the methods of separating gamma-globulin given in Part 11. There is doubtful value in giving the statistical data (Chapter 6) without some epidemiological discussion and the sections on new viruses, neorickettsiae and mycoplasmas would seem to belong to volume I of this series of monographs.These shortcomings are highlighted by the excellent bibliography and by contrast with the clear and authoritative treatment of Part I1 on Blood Products. The degree of specialisation in this field makes it unlikely that analysts would wish to undertake immunological examinations of material, but the monograph will presumably furnish interesting background information on an important topic. N. D. HARRIS OPTICAL ROTATORY DISPERSION AND CIRCULAR DICHROISM IN ORGANIC CHEMISTRY. Edited by G. SNATZKE. Pp. xii + 416. London: Heyden & Son Ltd. 1967. Price 96s.; $13.50. The techniques of optical rotatory dispersion and circular dichroism, both manifestations of the effect on polarised light of a chromophore in an optically active molecule, are increasingly used by organic stereochemists and others.Indeed, on page 16 of this book, a progress curve of the number of publications on rotatory dispersion of organic interest is given (about 5 in 1954; about 180 in 1961!). The book contains the lectures given at a Summer School held in Bonn, under the auspices of NATO, in the autumn of 1965. The discussions are not included, nor are several shorter communications, which were highly interesting (one remembers particularly Dr. Carroll’s very helpful comments on instrumental errors, and Professor Mislow on the vexed history of the possible existence of asymmetric organic molecules in meteorites). The tone of the book, then, is primarily instructional (as is implicit in a charming introduction by Ourisson). Although specific analytical applications are not described, any chemist interested in applying measurements of the Cotton effect to organic systems will find this book useful.One or two of the lectures are outstanding, and all are at least highly competent. Sufficient detailed information for specific types of molecule is given that a person completely new to the subject could decide, by using this book alone, whether circular dichroism or optical rotatory dispersion should be considered as a suitable investigatory or analytical method in a particular problem. A most worthwhile chapter is the one by Levisalles, in which the occasional drawbacks in Cotton effect studies are pointed out, and optical activity is compared with other recent physical methods.One rather distressing feature is that there are several chapters reprinted directly from journals (such articles comprise about a third of the book). It is probably valuable to have the information collected in one place, but these chapters (including all of the discussion of polypeptides and proteins) are, in some cases, reprints of articles published in 1964 (k, submitted in 1963) and apparently not brought up to date. In conclusion, the volume seems likely to be useful to a wide variety of chemists. The printing is clear and there are very few misprints. The price appears reasonable for such a lavishly and well illustrated book. R. D. GILLARD TECHNICAL BULLETIN No. 14. Proceedings of a conference organised by the Soil Chemists of the National Agricultural Advisory Service, October 17th-l8th, 1963.Pp. viii + 195. London: H.M. Stationery Office. 1967. Price 40s. The value of publishing proceedings of small conferences can be questioned. The papers are relatively inaccessible to the general reader, and participants may hesitate to report fundamental advances as their subsequent publication in a scientific journal may thereby be restricted by editorial regulations. These disadvantages are emphasised when publication is as delayed as has been the case here. Possibly one should also deprecate the growing habit of giving such proceedings a general title that provides no clue to the nature of the contents, in this instance eighteen papers on various specialised aspects of potassium and magnesium fertiliser problems, rather than the general treatment thereof that one might expect in a technical bulletin.SOIL POTASSIUM AND MAGNESIUM. By the MINISTRY OF AGRICULTURE, FISHERIES AND FOOD.May, 19681 BOOK REVIEWS 351 The papers themselves vary from theoretical considerations of the mechanism of plant uptake and of movement and mobilisation in the soil to statistical evaluation of the correlation between soil analyses, plant uptake and yield. To the soil analyst, the greatest interest will probably lie in the comparisons of the different methods of soil extraction, which are scattered through a number of the papers. As far as potassium is concerned the interpretation problem derives from the fact that plant requirement may not be fully met by exchangeable or dissolved ions in the immediate root zone, and two additional factors are involved, the mobilisation of less-available potassium and the rate of transfer of available potassium into the depleted zones.On the other hand, assessment of any analytical technique for estimating magnesium status in soils should take account both of basic plant requirement and, in herbage plants, of the necessity to meet the requirements of grazing animals, which generally lie at a higher magnesium level. Depression of magnesium uptake by other nutrients, notably potassium and calcium, complicates the interpretation problem. Reports of experimental findings from Ireland and Scotland are included, in addition to those from various parts of the N.A.A.S.area. The papers, therefore, present a reasonably comprehensive survey of the research standpoint regarding potassium and magnesium fertiliser practice in Britain, and explain the reasons for the measures recommended by advisory officers. From this aspect this bulletin can be commended as an introduction to the investigation of soil availability problems, complementing the earlier Technical Bulletin No. 13 on phosphate and those on nitrogen and soil organic matter and on trace elements that await publication. ADVANCES IN X - ~ Y ANALYSIS. VOLUME 10. PROCEEDINGS OF THE FIFTEENTH ANNUAL CONFERENCE ON APPLICATIONS OF X-RAY ANALYSIS HELD AUGUST 10-12, 1966. Edited by JOHN B. NEWKIRK and GAVIN R. MALLETT. Pp. x + 658. New York: Plenum Press. 1967. Price $22.50.It will be assumed that the reader is familiar with the long established form of this series. The present volume reports the proceedings of the 15th Denver Conference, at which the special topics were X-ray diffraction topography and dynamical X-ray phenomena. Of these, nine are on various aspects of X-ray topography and three on dynamic theory. Two papers not obviously in either of these categories are included in this section; one is concerned with anomalous X-ray reflection at crystal surfaces, the other with a double diffractometric method for the separation of thermal diffuse scattering. For those about to start work in the field of X-ray topography, a technique that is finding increasing application in industrial laboratories, four review papers, on experimental techniques, applications and the classification of the various types of contrast observed, should prove to be most helpful.There are sixteen papers on various applications of X-ray diffraction, mainly to metallurgical studies. These include determinations of residual stress and of the structure of Guinier - Preston zones. Of the remaining fourteen papers, four are concerned with electron-microprobe analysis and ten with X-ray fluorescence analysis. Emphasis here is on methods of detection of light elements. Several ingenious methods of specimen preparation are described, and flow counters and multi- layer soap films are considered as detectors for soft X-rays. Once again the latest volume in this series is recommended to the analyst using X-rays in his work.E. A. KELLETT R. L. MITCHELL A total of forty-four papers is presented. CHEMICAL YIELD DETERMINATIONS IN RADIOCHEMISTRY. By ELINOR F. NORTON. Pp. iv + 96. Springfield, Virginia : Clearinghouse for Federal Scientific and Technical Information, Sub- committee on Radiochemistry. National Academy of Sciences-National Research Council. 1967. Price $3.00. Classical radiochemical analytical methods have generally involved the use of gravimetry for determining chemical yields of carrier elements, the whole of the final precipitate being weighed and counted for radioactivity. If suitable precipitates are used such methods may be reasonably accurate under the best conditions, but if chemical yields are low, accuracy may be poor. In some cases compounds have been recommended that are of doubtful value as weighing forms for the elements in question, and, in the case of barium chloride precipitated from ether - hydrochloric acid solution, a completely unsuitable compound has been used.Thq formula of this compound has been given by different authors as BaCl,.H,O and BaC1,.2H,O, whereas it may, in fact, vary between these extremes.352 BOOK REVIEWS The replacement of gravimetry by more sensitive methods of analysis of proved reliability and accuracy overcomes these troubles and allows replicate determinations of chemical yield to be made on aliquots of the radiochemically purified solution of the element. The aliquots can be selected to give optimum accuracy with the particular technique used and such methods, which have been increasingly used over the past few years, have undoubtedly resulted in more reliable chemical-yield measurements and hence in more accurate radiochemical results.The main requirements for a suitable chemical-yield method are accuracy and ruggedness ; it should preferably also be reasonably quick and simple to carry out. Great sensitivity is not generally necessary as adequate amounts of material will be available. Except for the analysis of special samples, specificity is not important because the ratio of carrier added to interfering elements will generally be high and the radiochemical purification will effect sufficient purification. This monograph is a compilation of the chemical-yield methods used at Brookhaven National Laboratory over the last 15 years, and covers 62 elements (counting rare earths, other than cerium, as one element).Not surprisingly, spectrophotometry is the most favoured technique (59 methods), but methods based on flame photometry (9), polarography (12), titration (6) and even neutron activation (1) are also given. For sulphur, where everything else fails, gravimetry is recommended. Often alternative procedures are given, generally in less detail. In some cases X-ray fluorescence (13) and atomic absorption (8) are the recommended alternatives, but no details are given for these methods. This is a useful collection of well tried methods that generally fulfil the requirements outlined above; it provides an excellent starting point for anyone new to the field. It is, however, unfor- tunate that the minimum amounts of sample specified for the spectrophotometric methods, in which 1-cm cells are used exclusively, are too small for adequate accuracy. Absorbances of less than 0.10, and in two cases less than 0.05, are not enough for chemical-yield purposes.SELECTED READINGS IN CHEMICAL KINETICS. R. G. MONK Edited by MARGARET H. BACK and KEITH J. LAIDLER. F'p. vii + 175. Oxford, London, Edinburgh, New York, Toronto, Sydney, Paris and Braunschweig: Pergamon Press. Price (hard cover) 3Os., $5.50; (flexi- cover) 2Os., $4.00. This modest little book was intended as a supplement to Laidler's two-volume Reaction Kinetics, for student reading. It should reach a wider public than this. Every practising chemist, whether academic or industrial, would profit from reading, or re-reading if he has been properly educated, this collection of reprints from the papers, which may be said to have laid the basis for the field we now recognise as Chemical Kinetics. It includes an example of the collaboration between the chemist Harcourt and mathematician Esson, the first statement of Arrhenius on the variation of reaction rate with temperature, Eyring and Polanyi's classical paper and selections from the work of Semenov, Christiansen, Hinshelwood and Rice and Herzfeld. All are, in their several ways, scientific masterpieces and give the authentic feel of contact with an important field of research while it was in development. 1967. R. C. SEYMOUR VACUUM MICROBALANCE TECHNIQUES. VOLUME 6. PROCEEDINGS OF THE NEWPORT BEACH CONFERENCE OCTOBER 23-25, 1966. Edited by A. W. CZANDERNA. Pp. xiv + 178. New York: Plenum Press. 1967. Price $12.50. The volume includes only thirteen papers, of which a high proportion is by contributors to earlier volumes, and some are merely progress reports on work previously described. None of the papers appears to the reviewer to represent outstanding advances in either microbalance design or application, and one has the feeling of very little progress. There seems little justification for the publication of an annual volume in this series. The most valuable feature of the series is probably the rather detailed account of practical points, such as balance construction and weighing errors. The present volume contains a number of contributions of this type, but clarity is sometimes obscured by the excessive use of technical jargon, as on page 67, where one finds "the lower purity grog will form the donut a t 2000" c" (reviewer's italics). Other articles describe the application of microbalances in studies of adsorp- tion, thermal desorption, pressure measurement through the buoyancy effect, difision through liquids and the defect structure of oxides. As in the case of earlier volumes, this book represents extremely poor value for money. D. W. BASSETT

ISSN:0003-2654    

DOI:10.1039/AN9689300345

出版商:RSC    

年代:1968

数据来源: RSC