摘要:

662 CORBETT: THE ESTIMATION OF OXYGEN [Vol. 76 The Estimation of Oxygen in Titanium Chlorination BY J. A. CORBETT An examination has been made of the chlorination technique for the estimation of oxygen in titanium metal. The results obtained are satisfactory for many purposes, although the accuracy is only about f6 per cent. Pure chlorine must be used and it is essential that the samples should be in massive form, not turnings or powder. THE estimation of oxygen in titanium is a problem that has caused considerable discussion and research. Two methods are suggested in the literature, the vacuum fusion method and the chlorination method. Neither appears to be entirely satisfactory, but the vacuum fusion method is generally considered superior to the chlorination technique and is used in most laboratories engaged in this work.As the erection of the vacuum fusion apparatus is a costly and time-consuming operation, it seemed that an examination of the chlorination technique was warranted. The chlorination method consists in converting the titanium and metallic impurities into volatile chlorides by treatment with chlorine at 400" C. The chlorides are carried away with the chlorine and condensed. The oxide residue is recovered and analysed, the oxygen being calculated from the analysis. The method is similar to the chlorination method used by Colbeck, Craven and Murray1 for the estimation of non-metallic inclusions in steel. Wartman2 investigated a chlorination technique for the estimation of oxygen in titanium but rejected the method because low results were obtained.Lilliendahl and Wrough3 successfully used a chlorination method for the estimation of oxygen in zirconium. EXPERIMENTAL Factors which may interfere with the results obtained by this method are- (a) Impurities in the chlorine supply, such as oxygen, carbon compounds, and water vapour. (b) Impurities in the titanium metal, e.g., dissolved nitrogen and carbon, and possibly titanium carbide. (c) Presence of moisture in the chlorination unit. (d) Form of sample-whether massive or otherwise. (e) Mechanical loss of the titanium dioxide residue. The significance of these factors was studied and this part of the investigation is outlined below. (a) Impurities in the chZorine-Wartmana listed the impurities in the chlorine as one of the important factors causing low results.The presence of carbon compounds could cause the loss of titanium dioxide by chlorination. Oxygen and water vapour would obviously cause high results. Chlorine of high purity is sold commercially and the chlorine used in this work was satisfactory, provided certain precautions were taken. The first fraction in the cylinder was passed into the air, as the bulk of the gaseous impurities are in this fraction.Nov., 19511 IIG TITANIUM BY CHLORINATION 663 High results were obtained until the first fraction of chlorine was removed. In this work a 10-lb chlorine cylinder was used and approximately 10 litres of chlorine were removed before consistent results were obtained. The gas was dried by sulphuric acid, calcium chloride and phosphorus pentoxide. (b) Impurities in the titaniztm-The titanium used in this work was prepared by the "Kroll" process.The carbon, nitrogen and oxygen are dissolved in the metal; if the carbon content is high some titanium carbide may be present. To study the effect of chlorine on these impurities a short investigation was made into the effect of chlorine at 400" C upon titanium nitride, titanium carbide, titanium dioxide plus titanium carbide and titanium dioxide plus free carbon. These materials, in various mixtures,. were chlorinated for 3 hours at 400" C under the conditions described under Procedure. Pure titanium nitride was not available. The material used was analysed and found to contain titanium in excess of the compound corre- sponding to TIN. The material was found by difference to contain 1.2 per cent.of oxygen, which was assumed to be combined with the excess titanium. The titanium carbide was prepared from pure carbon and pure titanium dioxide and contained 13.6 per cent. of free carbon and 4.0 per cent. of oxygen. The material contained titanium in excess of the compound corresponding to Tic, and the excess titanium was assumed to be combined with oxygen. The approximate analysis of these materials was as under- TITANIUM NITRIDE TITANIUM CARBIDE Titanium nitride . . Titanium dioxide THE EFFECT Test Titanium No. dioxide, 1 0.2288 2 0.0112 3 0.0341 4 0.4171 g Note- % % .. . . 97.0 Titanium carbide . . . . 76.4 .. .. 3.0 Titanium dioxide . . . . 10.0 Freecarbon .. .. . . 13.6 TABLE I TiN, Tic, TiO, AND CARBON OF CHLORINE AT 400°C FOR 3 HOURS ON MIXTURES OF Titanium Titanium Titanium Total dioxide in nitride, Carbon, carbide, residue, residue, f3 g g g g 0.3318 0-2287 0-1031 0.01 13 0.0464 0.2608 0.1 146 0.01 72 0.03 14 0.1686 0.4320 0.3678 0.3692 0-01 14 Test 2. Test 3 Test 4.The titanium dioxide figure is that calculated from the oxygen content of the titanium nitride. The carbon and titanium dioxide figures shown are those present in the titanium carbide Titanium dioxide was added to the carbide. The results in Table I show that- (1) Titanium dioxide is not affected by free carbon a t 400" C. (2) Titanium nitride is decomposed, and the titanium dioxide is not affected. (3) Titanium carbide is decomposed and causes chlorination of titanium dioxide. Calculations concerned with the total residues in tests 3 and 4 show that all the titanium dioxide did not react with the carbide as in equation (1)- TiO, + 2TiC + 6Cl, -+ 3TiC1, + 2CO .. .. - - (1) .. * (2) TIC + 2C1, -+ TiCl, + C . . .. . . but that the remaining carbide reacted as in equation (2) and no titanium carbide was present in the residue. For example, in test 3 the amount of titanium dioxide lost was O.O169g, so that the amount of carbide consumed (equation 1) = 0.0253 g . The remaining carbide reacted as in equation (2) yielding 0.0505 g of carbon in the residue. The residue consisted of- g Titanium dioxide unreacted - - 0.0172 Carbon from carbide - - 0.0505 Original carbon - 0.0464 Total .. .. .. . . 0.1141664 CORBETT: THE ESTIMATION OF OXYGEN [Vol.76 (c) Moisture in the chlorination unit-The presence of moisture will cause hydrolysis of the titanium tetrachloride and lead to high results. It is necessary that the reaction tube and the sample should be dry. The reaction tube is pre-heated to 400" C and the sample rinsed in ethyl alcohol before weighing. (d) Form of specime-High results were obtained when titanium powder or turnings was used, as is shown in Table 11. The larger the surface area, the greater will be the effect of surface oxidation, and of adsorbed moisture. Most of the titanium and titanium alloys used in this work were prepared by melting in an argon arc furnace. The buttons were forged and swaged down to #-inch rod. Samples cut from the rods in one piece were found to give satisfactory results.TABLE 11 EFFECT OF CONDITION OF SAMPLE "KROLL" TITANIUM. OXYGEN CONTENT 0.2 PER CENT. BY VACUUM FUSION Material Oxygen con tent Powder, - 60 + 240 mesh . . . . . . 0.38, 0.31, 0.35 Turnings from #-inch diameter rod . . . . 0.28, 0.23, 0.21 +inch diameter rod in one piece. . . . . . 0.19, 0.17, 0.19 (e) Mechanical loss of titanium dioxide-An investigation was performed to study the effect of varying the rate of flow of the chlorine. The residue of titanium dioxide is very light and it could be carried away by the flow of gas. Samples of Kroll titanium were analysed by the method outlined under Procedure with varying rates of gas flow. The flow rate was measured by a calibrated orifice gas-flow meter. The results are shown in Table 111. TABLE I11 EFFECT OF RATE OF FLOW OF CHLORINE Flow rate, litres/hour 6 10 12.5 15.0 Time, Oxygen content, hours % 6 0.17 4 0-15 3 0.19 3 0.17 The results show that the rate of gas flow in the range 5 to 15 litres per hour has no significant effect.CORRECTION FOR CARBOX REACTIONS- Tests have shown that the amount of titanium dioxide lost owing to carbon is not consistent. It is necessary to estimate the amount of carbon used during the reaction. The carbon content of the sample and also that of the final residue is determined. The carbon used up is thus known and its equivalent in titanium dioxide or oxygen is calculated from equation (1). The carbon content of the metal is estimated in our laboratory by burning turnings of the metal at 1100" C in oxygen. The carbon dioxide is absorbed and measured in a Strohlein type of apparatus.The carbon in the final residue is burnt at 1000" C in oxygen and estimated by the method outlined by Lilliendahl, Wrough and Greg~ry,~ in which the carbon dioxide is absorbed in standard barium hydroxide solution and the unused barium hydroxide titrated with standard hydrochloric acid and phenolphthalein indicator. Slight traces of chlorine have been found in the residues. The titanium contains small amounts of magnesium and the magnesium chloride formed would not be volatile at 400" C . The combustion gases from the estimation of carbon in the residues are passed through mercury to remove the chlorine and then to the barium hydroxide solution. METHOD APPARATUS- The apparatus is shown in Fig. 1. The chlorine is led from the cylinder through con- centrated sulphuric acid in the wash bottle A, and through calcium chloride and phosphorus pentoxide in the drying towers B and C.The titanium sample is placed in a silica boat and chlorinated in the Pyrex glass reaction tube D. This tube has a Quickfit B.24 jointNov., 19511 I N TITANIUM BY CHLORINATION 656 at E, which allows for insertion and removal of the sample. The reaction tube fits into a tube furnace F, which has no lagging, to allow for fast cooling. The volatile chlorides pass through a water condenser G and the titanium tetrachloride is collected in the vessel H. The vessel H is fitted with an outlet tube for the excess chlorine gas. PROCEDURE- A 2 to 3-g sample of titanium is cut from #-inch diameter rod. The sample is rinsed in alcohol, dried, weighed and chlorinated immediately.A sample of turnings is prepared and in this the carbon content is estimated. TO CHLORINE SUPPLY D F H C B Fig. 1. Chlorination apparatus b The reaction tube D, condenser G and the vessel H are rinsed with alcohol and dried in an air oven. The apparatus is assembled and the temperature of the furnace is raised to 400" C. The furnace is switched off, and the reaction tube brought to room temperature. This is speeded up by cooling the furnace with a blast of air. The weighed sample is placed in a silica boat which has been freed of moisture by recent ignition. The sample and boat are introduced into the reaction tube immediately and the flow of chlorine is started at once. The chlorine is passed through the apparatus for 30 minutes at the rate of 15 litres per hour.At approxi- mately 300" C the reaction begins, and the furnace is held at this temperature for 15 minutes to prevent the reaction from becoming violent. The temperature is then gradually raised to 400" C and the sample glows at a dull red heat. The chlorine is passed until the reaction is completed, which takes about 24 hours for a 2 to 3-g sample. The furnace is then switched off and cooled to room temperature, the flow of chlorine being continued. The chlorine flow is then stopped, the boat removed immediately and the drying train stoppered at E to exclude moisture. The boat and residue are then placed in a tube furnace and the carbon content estimated by burning gently in oxygen a t 1000" C.The combustion gases are passed through mercury to remove the chlorine and the carbon dioxide is absorbed in standard barium hydroxide solution. The carbonate precipitated is estimated by titrating the unused barium hydroxide with standard hydrochloric acid and phenolphthalein indicator. ANALYSIS OF THE RESIDUES- The furnace is then switched on, and the temperature raised gradually. The amount of silicon and iron found in the residues is small enough to be ignored. The contents of the boat are washed out with water, and the residae is filtered through a 9 cm No. 42 Whatman filter-paper. The residue and filter-paper are ignited and fused with potassium bisulphate in a platinum crucible. The melt is leached out with diluted sulphuric acid and filtered. The titanium is precipitated with cupferron in a 10 per cent.v/v sulphuric acid solution. The precipitate is ignited and weighed as titanium dioxide in a tared platinum crucible. To the weight of the oxide is added an amount equivalent to the difference between the carbon content of the metal and the carbon left after chlorination. RESULTS AND DISCUSSION The results obtained in the analysis of several oxygen alloys and six samples of Kroll titanium are shown in Table IV. The latter contains 0-10 per cent. of carbon, 0.04 per cent. of nitrogen and various metal impurities. The oxygen content is given as 0.20 per cent. by the National Physical Laboratory, Teddington, England, where the vacuum fusion method was used. The allovs were made by arc melting mixtures of titanium metal and pure titanium656 CORBETT: THE ESTIMATION OF OXYGEK [Vol.76 dioxide in an argon atmosphere. The calculated oxygen content of each alloy is derived from the amount of titanium dioxide added in addition to the oxygen present in the metal. CHLORINATION TESTS ON TITANIUM AND TITANIUM - OXYGEN ALLOYS Material Titanium metal . . Calculated oxygen content, YO - .. .. - - ,411oy 1 2 3 4 6 7 8 9 10 a .. .. .. .. .. .. .. .. .. . . .. .. .. .. .. .. .. .. .. .. - .. . . 0.84 .. .. 0.50 .. .. 1-17 .. . . 1-50 .. . . 0.33 .. .. 0-67 .. .. 1.00 .. .. 1-33 .. .. 1-66 .. .. 0-49 Oxygen found, 0.19 .0*17 0.19 0.15 0.16 0.17 0.86, 0-89 0.53, 0.81 1.22, 1.21, 1-25 1.54, 1-56 0.29, 0.30 0.64, 0-66 0.97, 0.95 1.29, 1.28 1.59, 1.62 0.51, 0.50 YO These results indicate that the method is satisfactory for checking the oxygen content The analytical A small strip of high-purity titanium refined by the iodide process was analysed for The titanium in the small residue was estimated colori- This figure can be of alloys in which limits of accuracy of the order of &5 per cent.are adequate. results are plotted against the calculated oxygen content in Fig. 2. oxygen by the above method. metrically. accepted as a satisfactory blank. The result was of the order of 0.01 per cent. of oxygen. r Synthetic oxygen content, per cent. w/w Fig. 2. Graph of analytical results obtained by the chlorination method against known oxygen content of synthetic samplesNov., 19511 I N TITANIUM BY CHLORINATION 657 After 4 hours chlorination at 400” C the reaction had not proceeded beyond the surface of the sample. A fresh sample was crushed to a powder, and chlorinated, but the result was no better. The dense coating of titanium dioxide apparently retarded very considerably the diffusion of gases to and from the metal surface. The maximum oxygen concentration that can be satisfactorilj- determined by the chlorination method has not yet been found. A test was performed on an alloy containing 5.0 per cent. of oxygen. REFERENCES 1. 2. 3. Colbeck, E. W., Craven, S. W., and Murray, W. J., “Seventh Report on the HeterogeneitySteel Ingots,” The Iron and Steel Institute, London, Special Report No. 16, 1937, p. 124. Wartman, F. S., Walker, J. P., Fuller, H. C., Cook, M. A., and Anderson, E. L., “Production of Ductile Titanium at Boulder City, Nev.,” U.S. Bureau of Mines, R.I., 4519, August, 1949. Lilliendahl, W. C., Wrough, D. M., and Gregory, E. D., Trans. Eleclvochem. SOC., 1948, 93, 236. COMMONWEALTH SCIENTIFIC AND INDUSTRIAL RESEARCH ORCANISATION PHYSICAL METALLURGY SECTION BAILLIEU LABORATORY UNIVERSITY OF MELBOURNE .Way, 1951

ISSN:0003-2654    

DOI:10.1039/AN9517600652

出版商:RSC    

年代:1951

数据来源: RSC

摘要:

Nov., 19511 I N TITANIUM BY CHLORINATION 657 Micro-Determination of Nitrogen in Organic Matter without Distillation BY H. N7. HARVEY A method is described by which 5 to 30-microgram quantities of nitrogen are estimated in test or centrifuge tubes without distillation. After digestion with sulphuric acid and hydrogen peroxide, in presence of a mercury catalyst, the resulting ammonium sulphate is treated with an excess of hypobromite. The residual hypobromite is determined by titrating the iodine liberated on addition of potassium iodide and acetic acid with standard sodium thiosulphate solution. IT was required to determine the quantity of organic nitrogen in small quantities of unicellular algae, which can be separated from suspension bjv centrifugation, and to complete sis to eight analyses within 3 hours.For this purpose an attempt was made to shorten the elegant and precise method of Conwaj.,' which involves both wet combustion and micro-diffusion. An investigation, made in this laboratory by Buljan,2 of the reaction between hypo- bromite and ammonia, suggested a suitable method and defined the limits of its application. This reaction was later found to have betm used by Rappaport and Pistine? to estimate nitrogen in blood. The reaction 3NaBrO + 2NH, --f Nz + 3h'aBr + 3H20 proceeds rapidly, but by stages, to completion at pH Lralues above 8-5, at room temperature, provided there is a small excess (10 per cent.) of hypobromite present. (A similar reaction also takes place, but less rapidl!., with amide, amino and at least some polypeptide nitrogen).In order to avoid loss of ammonia to the atmosphere from strongly alkaline solution, it is necessary to carry out the reaction between pH 8.5 and about 9-6. After reaction with ammonia the excess hypobromite can be determined by adding iodide, acidifying with a weak acid and titrating the iodine set free. The reaction between ammonia and hjypobromite was esamined and found to be complete under the condition described in the recommended procedure. Measured quantities of a 0.00975 Af solution of ammonium sulphate (delivered by sj-ringe burette) were treated with an excess of alkaline hj-pohromite and the excess determined by titrating the iodine set free on addition of potassium iodide and acetic acid with 0.0194 N thiosulphate, as described on p.659. Because hypobromite in the presence of excess ammonia forms intermediate products, such as hydroxylamine, which are themselves reducing agents and interfere with the estima- tion of hypobromite (Buljan2), it is essential to know either that the organic matter contains less nitrogen than is equivalent to the hypobromite added, or to make sure that an excess of hypobromite has been added. This precaution is included in the recommended procedure.658 HARVEY: MICRO-DETERMINATION OF NITROGEIS [Vol. 76 The presence of nitrite, copper or of some other heavy metals would interfere, either by destroying ammonia, or by oxidising the iodide added later. Although the amounts of interfering substances present in vegetable and animal tissues are so small that their effect TABLE I EXAMINATION OF THE REACTION BETWEEN AMMONIA AND HYPOBKOMITE Amount of 0.00976 M ammonium sulphate added to 2 ml of Ammonical dilution water, nitrogen taken, Titration, Nitrogen found, ml Pg ml Pg nil 0 3.60, 3.60, 3.61 - 0.05 13.65 2.06, 2.05, 2.05 14.0 0.10 27.3 0.57, 0.65, 0.66 27-6 may be neglected, the method is unsuitable for samples of unknown origin, which might be heavily contaminated. METHOD REAGENTS- Combustion acid-Dilute concentrated nitrogen-free sulphuric acid with an equal volume of 0.4 per cent.mercuric chloride solution. To keep the reagent blank constant from day to day it is necessary to keep this combustion acid and the following two reagents in an ammonia- free atmosphere, and out of contact with rubber, which may evolve ammonia.It is satisfactory to keep the combustion acid, together with the 0.2-ml pipette used for measuring it, in a flask whose neck is provided with a male cone joint, kept moist with acid, on which is fitted a test tube with a female ground joint. Hydrogen peroxide-A 100-volume, nitrogen-free solution. Cover the bottle containing this solution and a glass dropping tube with an inverted beaker, whose inner surface is moist with acid and glycerin, resting on filter-paper or cotton wool moistened with acid and glycerin. Dilution water-Distilled water kept, with a 2-ml immersion pipette, below a beaker as for the hydrogen peroxide solution. Alkaline hypobromife solution-Prepare by diluting a stronger solution to about 0.0075 N . Keep in a brown bottle with a glass (not rubber or plastic) stopper. There is but little change in titre after the first day.The stronger solution is made by dissolving 1 g of sodium hydroxide, 23 g of sodium carbonate monohydrate and 0.5 ml of bromine in a litre of water. This should be about 0.02 N if neither the water nor the reagents contain ammonia, amino or amide nitrogen, but it is usually necessary to add a further one or two drops of bromine in order to adjust it to about 0.02 N . Bufler solution-Prepare a solution containing 40 g of potassium hydroxide and 6 g of boric acid in 100 ml of water; boil to free it from possible ammonia. Potassium iodide solution-A 50 per cent. w/v aqueous solution. Acetic acid solution-Dilute 2 parts by volume of pure glacial acetic acid with 1 part ThiosuZphate solution-An approximately 0.002 N solution, the exact titre of which is One millilitre of 0.002 N thiosulphate is of water.determined against 0.002 N potassium iodate. equivalent to 9.33pg of nitrogen. PROCEDURE- The size of the centrifuge available to collect the algae necessitated using straight test tubes, which are ill adapted to the operation of wet combustion, owing to the risk of loss by spattering; test tubes with the ends bent over or micro-Kjeldahl flasks would have reduced this risk. Two of the tubes served a s reagent blanks and duplicate determinations were made in the other six. Provided the first three reagent solutions listed are stored in an ammonia-free atmosphere, The combustions were made in sets of eight Pyrex test tubes, 16 x 125 mm.Nov., 19511 IN ORGANIC MATTER WITHOUT DISTILLATION 659 there is practically no change in the reagent blank from day to day and one determination in duplicate daily should suffice.To each tube 0.2ml of combustion acid is added, followed by 2 drops of hydrogen peroxide. Heat the tubes slowly at first until all moisture and peroxide are driven off. This operation cannot be hurried owing to danger of loss by spattering; about 15 minutes heating are usually necessary. Of several methods of heating the tubes the most satisfactory has been in the oven shown in Fig. 1. After driving off all moisture, and when the upper parts of the tubes are hot and dry, increase the heat and continue until fumes of sulphuric acid start to emerge. At this temperature (340" C) any remaining peroxide (b.p.152" C) is driven off or per-acids decomposed. If heterocyclic nitrogen compounds, which are difficult to decompose, are likely to be present, more than 15 minutes heating will be necessary. After cooling, roughly 2 ml of dilution water are added to each tube from a pipette filled by dipping into the water. Then, tube by tube, the following operations are carried out- (;) Add a precise quantity of alkaline hypobromite from a syringe pipette, preferably such as that described by Krogh? which is set to deliver about 1 ml. The pipette used in this work is shown in Fig. 2. Bromine is set free. (22) Add buffer solution from a blood pipette fitted with a rubber teat. Determine the quantity to add (about 0.78 ml) beforehand by finding how much is necessary to turn 0.2 ml of the combustion acid blue to thymol blue or very faintly blue to thymolphthalein.\ M e c ~ d J Fig. 1. Section (scale about &rd) of oven hold- Fig. 2. Diagram of construction of simple syringe pipette made from an all-glass Pyrex hypo- dermic syringe held in a block of Perspex, as used in these determinations ing eight test-tubes. D, cylinder of sheet copper; T, copper tube with wire handle for lifting; MM, sheet copper with holes t o hold test-tubes; AA, asbestos pads. Thc apparatus is heated by a bunsen burner placed underneath If there is any doubt that the quantity of hypobromite is not in excess of the equivalent of nitrogen in the sample, add a second volume of alkaline hypobromite from the syringe pipette to one of the duplicate test solutions.Allow a quarter to half a minute, or more as convenient, to complete the reaction between hypobromite and ammonia. (2;;) Add 3 drops of iodide solution and about 1 ml of acetic acid. (iu) Titrate the iodine set free with thiosulphate from a 5-ml burette with sodium I t is convenient to pour most of the test solution into a small starch glycollate as indicator.[Vol. 76 white glass beaker or 3 x l-inch specimen tube, run in thiosulphate solution from the burette until it is colourless, wash out the original test tube with this partly titrated solution, and complete the titration. 660 HARVEY EXAMPLES AND CALCULATION OF RESULTS As an example of working rapidly with a minimum of care, the following experiment was made. Test tubes were charged from an Agla micrometer syringe with 0.050, 0.100 and 0.200 ml of a 0.2 per cent.solution of acetanilide and the recommended procedure carried out. Table I1 shows the results and method of calculation. TABLE I1 DETERMINATION OF NITROGEN IN ACETANILIDE Nitrogen taken, as acetanilide, Pg 0 0 10.32 10.32 20.65 20.65 41.3 41.3 41.3 NaBrO solution, ml 1 1 0.002 N thiosulphate, ml 3.44 3.46 mean 3.45 - 2.37 2-36 1.39 6.00 2.6 2-85 2.77 Xitrogen found, Pg (3.46 - 2.37) x 9-33 = 10.1 10.2 19.2 (3.46 + 3-76. - 6.0) x 9.33 = 20.6 40.7 41.4 8 t * One millilitre of NaBrO solution delivcred by syringe pipette required, after addition of iodide and t One millilitre of NaBrO solution was less than the equivalent of the nitrogen present. The method is capable of giving precise results, provided that there is no loss by spattering (which could be reduced by using small Kjeldahl flasks) and the titrations are made in a good light (a north window and overcast sky). Table 111 shows quadruplicate estimations of reagent blank and of 0.1 ml of a 0.2 per cent. solution of acetanilide introduced into test tubes by micrometer syringe, where particular care was taken in both the combustion and the titrations. acetic acid, 3.76 ml of thiosulphate solution. TABLE 111 QUADRUPLICATE DETERMINATIONS OF NITROGEN IN ACETANILIDE 0.001 N Thiosulphate solution, ml -_____\ Reagents only, after combustion . . . . 6.80, 6-82, 6.84, 6.80 Acetanilidc . . . . . . .. . . 2-39, 2.37, 2.38, 2.37 Nitrogen taken, as acetanilide .. . . 20.65 pg Nitrogen found . . .. .. .. . . 20.7 $9 mean 6.815 mean 2.377 REFERENCES 1. 2. 3. 4. Conway, E. J., “Microdiffusion Analysis and Volumetric Error,” Van Nostrand Co., New York, Ijuljan, M., Ackiv Zu Kenizju, Zugveb, in the press. Itappaport, I:.. and Pistiner, R., Micvochem., 1935, 18, 43. I<rogh, A,, Ind. Eng. Chew., Anal. Ed., 1933, 7, 130. 1940. JIARINE BIOLOGICAL ASSOCIATION PLY MOUTH :May, 1961

ISSN:0003-2654    

DOI:10.1039/AN9517600657

出版商:RSC    

年代:1951

数据来源: RSC

摘要:

Nov., 19511 S OTES 601 A SIMPLE METHOD FOR APPROXIMATE PARTICLE SIZE AXALYSIS PARTICLE size distributions of powders in the sub-sieve range are frequently investigated by sedimentation methods. Its main defect is that, a t concentrations that permit free falling, the small volume withdrawn a t various time intervals may not be large enough for accurate analysis or weighing. The method now to be described attempts to separate those particles that have a greater Stokes’ diameter than a pre- determined limit. The principle involved is not new,2t3 but is believed, in conjunction with the apparatus described, to be particularly well suited for routine control use. The simplicity of the apparatus and its ease of operation may, in manv types of work, more than compensate for the loss of some of the information obtainable by more elaborate methods.In practice it has been found that different laboratories working on parts of reputedly uniform samples obtained more consistent and significant results with the present method than with more elaborate ones. Experience of the method in this laboratory has so far been confined t o insecticide and rodenticide powders, b u t its use seems capable of extension to many other classes of powdered materials. It appears t o be generally applicable to products that have been reduced t o sub-sieve size by grinding and sifting or aspiration and to be capable, provided adequate means of chemical analysis are available, of dealing with two or more different substances in the same mixture. Of these the method of Andreason’ is probably the best known.APPARATUS AND METHOD- The apparatus is the well-known fat extraction tube recommended by the Milk Products Sub-C~rnmittee.~J The tube is used in the following manner to find the percentage by weight of particles of a powder that are above a certain limiting size. Make two horizontal marks on the side of the tube, one about 3 cm from the bottom of the tube and the other exactly 12 cm above the first. A tube with a total length of 21 cm, with a length of 18 cm between the base and shoulder and a capacity of 85 ml up t o the 15 cm mark, has been found suitable. Calculate from the following formula, derived from Stokes’ law, the time 1 in seconds required for a particle of the size limit chosen to travel down the tube from the top mark to the lower mark- The dimensions of the tube itself are not critical.where q is the viscosity in poises of the suspending medium (0.01 for water a t 20’ C), h is the distance in centimetres traversed (12 cm), d is the Stokes’ diameter of the limit-sized particle in microns, ‘ ( p , - po) is the difference in density between the suspending medium and the particles and g the gravitational constant (981). Wash a weighed sample of about 1 g of the powder into the t u b e with the suspending medium. The suspending medium should be a liquid of known viscosity at the temperature used and should readily wet and disperse the powder. It must also be a liquid in which the powder is not soluble or one in which the solution rate of the powder is so low that the coarse fraction of the powder does not dissolve appreciably during the experiment.The viscosity of the liquid should be such as to ensure a sedimentation time of longer than 2 minutes for a particle of limiting size. M’ater containing 0.2 per cent. of “Teepol” is suitable for many organic powders that are otherwise difficult to wet in aqueous suspensions, and it will be assumed for the purpose of the following description that water is used. The temperature of the liquid during the determination should be kept within & 1’ C of the temperature chosen. A constant temperature bath is not necessary, but the apparatus should not be used in surroundings where abrupt temperature changes are liable to occur. Add water to the powder in the tube to the level of the top mark.Stopper the tube with a plain cork, shake the tube vigorously until the powder is evenly dispersed, allow the tube t o stand in an upright position for exactly time t as predetermined by calculation, remove the cork, insert the blow-off device and quickly blow liquid to waste down to the lower mark. Refill the tube t o the top mark with water and repeat the procedure, shaking vigorously to mix the contents and then, after standing for time I, blowing off the supernatant liquid down to the lower mark. Repeat this procedure until the fine particles are all removed and the only ones left are those that will fall below the lower mark in the tube in time t . The size of the particles may at this stage be checked by microscopical examination. The fraction left in the tube should Sucrose solutions have been used.Four such extractions are usually sufficient.862 NOTES [Vol. 76 not contain any appreciable proportion of particles below the calculated size. Estimate the weight of the coarse particles in the tube by any convenient method. In the simplest instances, this will only require the washing of the particles into a tared evaporating dish and the evaporation of the suspending liquid. In others, e.g., where two or more types of particles are present, other analytical methods may be necessary. Use can sometimes be made of the fact that the particles are already in a tube specially designed for extractions with a light immiscible solvent. By a series of experiments as described, with different times of sedimentation, i t is possible to get a good idea of the proportions of the size ranges present in the powder.In most routine control checks of particle size this complete survey of the various size ranges present is unnecessary. In most powders made by normal industrial processes the range of distribution of sizes is such that one well chosen experiment will give sufficient information. RESULTS- by the Andreason pipette procedure and by the present method- Two a-naphthyl thio-urea powders produced for use as rodenticides gave the following results Weight of particles over 53 microns as a percentage of total weight L I I Sample Andreason method Present method Powder A .. .. .. . . 13.4, 17.3 15.3, 14.6 PowderB .. .. .. . . 30.3, 31.8 30.4. 31.5 The authors wish to express their thanks to the Government Chemist for permission to publish this note.REFERENCES 1. 2. British Pharmacopoeia, 1948. Monograph on Light Kaolin. 3. 4. 6. Andreason, A. H. M., and Lundberg, J. J. V., Bey. dlsch. Reram. Ces., 1930, 11, 249. Burchfield, H. P., Gullstrom, D. K.. and McNew, G. L., Anal. Chcm., 1948, 20, 1168. “Report of the Milk Products Sub-Committee of the Analytical Methods Committee,” Analyst, British Standard Specification No. 770, 1938. 1936, 61, 105. E. I. JOHNSON GOVERNMENT LABORATORY J. KING STRAND, LONDON, W.C.2 April, 1961 THE IDENTIFICATION OF AMBERGRIS AMBERGRIS is the calculus formed in the stomach and intestines of the Cachalot (Sperm Whale, Physeter Macrocefihulus) when the animal feeds on cuttle-fish. It is known to consist of ambreine, epicoprostanol, arachidic acid, ambroporphyrines, a ketonic fraction and a liquid paraffin.The purpose of this note is to record a simple chemical means of identifying genuine ambergris. The method used entails the chromatographic separation of ambreine and epicoprostanol. It is based on the work of Ledererl and Ru2icka.g An examination of the inorganic constituents of the ash also aids identification. METHOD PREPARATION OF SAMPLE AND TEST SOLUTION- Grind the sample and dry in a desiccator. Place 2 g of the dry material in a Soxhlet extractor and extract with ethyl ether until no more soluble matter is obtained. Cool the ethereal solution and transfer to a separating funnel; the volume of the solution should be about 1OOml. Shake first with 60 ml and then with 26-ml portions of N sodium hydroxide solution to remove fatty acids.Shake the alkaline portion with 10-ml portions of ether and transfer the ether extracts to the main ether solution. The extract should be a clear brown gummy material with a characteristic odour, especially when warm. The proportion of the ether extract may vary considerably in different samples of ambergris. Good quality material may have 66 to 95 per cent. of ether-soluble material, whilst an inferior quality may have as little as 10 per cent. Dissolve the residue in 26 ml of aromatic-free light petroleum, boiling range 40’ t o 60” C. The solution is now ready for transfer to the adsorption column. Evaporate the ether extract to complete dryness.Nov., 19511 NOTES 663 THE ADSORPTION COLUMN- A suitable adsorption column can be prepared in a glass tube of 1.7 cm internal diameter and 34 cm long.The tube is provided with a perforated metal disc that is just a sliding fit in the tube. This disc is held in place by two cotton-wool plugs pressed down hard. A cork or rubber bung is provided for closing the lower end of the tube during filling. Fill the tube with light petroleum, boiling range 40' t o 60" C, and after removal of the air bubbles from the cotton wool add 40 g of alumina specially prepared for chromatographic adsorption analysis (Brockmann Grade 111). Add the alumina slowly, tapping the tube t o ensure an even distribution of the material in the column. Allow the light petroleum to drain until the level of the solvent is just above the top of the column, which should be approximately 19.5 cm long.The column is now ready for use and may be kept ready by inserting the cork in the bottom of the tube. THE CHROMATOGRAPHIC SEPARATION- Pour the prepared solution gently on to the column and remove the cork from the lower end of the tube. Almost at once the solution begins to run down the column and coloured bands appear on the alumina. A narrow yellow band, fluorescing green in ultra-violet light, moves rapidly down the column. Continue the elution until this band is washed into the receiver. It will now be observed that the column and the liquid that is emerging from it have a whitish blue fluorescence in ultra-violet light. Change the solvent to a 1 + 1 mixture of ethyl ether and light petroleum.Immediately a separation of the broad yellow bands at the top of the column begins and a series of bands that are fluorescent in ultra-violet light appears, a green and a yellow one travelling rapidly down the column. Stop the elution just short of the point where the green fluorescent material leaves the tube, which should be when about 60 ml of ether - light petroleum mixture have run through. Continue the elution into another receiver and collect the green and yellow - green fluorescent fractions. This contains epicoprostanol, which can be eluted from the column with benzene. Finally, all remaining traces of the sample can be removed from the column with alcohol. Follow the original solution by 40 to 50 ml of light petroleum. Immediately change the receiver.Remove the receiver, which now contains the crude ambreine. Above these fractions on the column is a red fraction. The crude fractions so obtained are re-fractionated. An alternative procedure is to elute as above and then to extrude the column and divide it in ultra-violet light. A combination of the two methods may also be used. IDENTIFICATION OF AMBREINE- The ambreine, which gives a characteristic pale blue - white fluorescence in ultra-violet light, can be prepared in crystalline form by slow evaporation of the solvent; it may take some days to crystallise. The compound shows a positive optical rotation and gives a rose colour with the Liebermann reagent. It has a characteristic odour reminiscent of the ambergris from which it is derived. On oxidation in acetone solution with potassium permanganate ambreinolide3 is formed, m.p.142" C (crystallised from alcohol). The crystals are colourless needles, m.p. 83" C. IDENTIFICATION OF epiCOPROST-4XOL- The fraction from the chromatogram that contains this compound yields a white solid on removal of the solvent. This is epicoprostanol (3-a-hydroxycoprostane) . The identity of the ambreine, ambreineolide and epicoprostanol was confirmed both by mixed melting-points and by means of the infra-red spectro- graph. By the courtesy of Prof. Lederer and Prof. Shoppee, samples of ambreine and of 3-rx and 3- /?-hydroxycoprostane were obtained. Infra-red absorption spectra between 3 and 16 mp were recorded and compared with those of the compounds separated by us. The spectrum of the ambreinolide agreed with that published by Lederer and that of the hydroxycoprostane showed that it was the a-isomer (epicoprostanol).This on recrystallisation from alcohol yields crystals, m.p. 11 1' C. The ambreine was identical with that supplied by Lederer.664 SOTES [Vol. 70 THE ;\SH OF -43lBERGRIS- The percentage of ash in ambergris varies considerably from one sample to another. The good qualities range from 0.5 to 5.0 per cent., whilst a very inferior material from the outside of a large mass was found t o contain as much as 57 per cent. of ash. The ash consists essentially of the phosphates of calcium and magnesium with a small proportion of sodium chloride and traces of copper, silicon, manganese and chromium. The ash is obtained by gentle ignition at 400" C.GENERAL CONCLCSIONS Samples of ambergris vary considerable in the proportions of their constituents, so that no The identification of ambreine is in itself The presence of epicoprostanol and of an hard and fast rule can be drawn as to composition. sufficient to show that a sample is genuine ambergris. ash of the composition indicated above are good confirmatory evidence. W'e wish to thank the Government Chemist for permission to publish this note. REFERENCES 1. Lederer, E., Helv. Chim. Acta., 1046, 29, 1354. 2. Iiuzicka, L., Ibid., 1946, 29, 912. 3. Lederer, E., and Stall, M., I b i d . , 1950, 33, F.V. GOVERKMENT LABORATORY STRAND, LONDON, W.C.2 P. J. HARDWICK E. Q. LAWS nruv, 1951 PHOTOMETRIC DETERMIlS4TIOX OF j3-INDOLYLBUTYRIC ACID OF the three plant growth promoters, 8-indolylacetic acid, j3-indolylpropionic acid and j3-indolyl- butyric acid, the first has received most attention analytically.Methods for its determination are based on two types of reaction involving either oxidation or condensation with an aldehyde. Various oxidants have been tried; for example, ferric chloride was used by Salkowski' and nitrite by Herter,2 Home? and Freibefl; the conditions necessarv to obtain quantitative results with ferric chloride have been described by Stoppanis and with nitrite by Holt and Callow.6 Hamence' has tried benzoyl peroxide, bleaching powder with ferricyanide, perchloric acid, and mercuric sulphate in the presence of sulphuric acid, as oxidants; with perchloric acid he developed a quantitative method for the determination of 8-indolylacetic acid in the presence of j3-indolyl- butyric acid and j3-indolylpropionic acid.An example of a reaction of the second type is the well-known Adanikiewicz - Hopkins reaction for tryptophan, which was modified by \?'inkler,A applied by M'inkler and Petersene to j3-indolyl- acetic acid, and later further modified for this purpose by Sutter.14 In this test glyoq*lic acid is used lvith copper sulphate as oxygen carrier. This Note describes a quantitative test for j3-indolyl- butyric acid that makes use of formaldehyde with mercuric sulphate, which probably involves a reaction of the same type. METHOD REAGENTS- 400 volumes with water. acid R.P. to 8 volumes with water.) Fovmaldehyde solution, 0.1 per cml.-Dilute 1 volume of solution of formaldehyde H.P.to Mevctrvic sulphate solution, 1 per cent. in suljlhuvic acid 1 in 8-(Dilute 1 volume of sulphuric Sulphuric acid, 60 per cent. v/v-Dilute 60 ml of sulphuric acid R.P. to 100 ml with water. PROCEDURE- To 5 ml of solution containing up to 0-2 mg of j3-indolylbutyric acid in a boiling tube add 1 mi of formaldehyde solution, 1 ml of mercuric sulphate solution and 10 ml of 60 per cent. sulphuric acid, and mix after the addition of each reagent. After 10 minutes cool to room temperature and measure the extinction of 1 cm, with Ilford 605 filters, against a reagent blank. Read the corre- sponding amount of j3-indolylbutyric acid from a calibration curve.Nov., 19511 SOTES EFFECT OF VARIATION OF CONDITIONS 665 The amounts of formaldehyde and mercuric sulphate specified give maximum colour ; one- tenth as much colour is produced if the formaldehyde is omitted and one-third as much if no mercuric sulphate is used.The mercuric sulphate probably functions as an oxygen carrier or oxidant, as do nitrous acid,12 peroxide,lo copper sulphate8 and ferric chloride13 in other indolc- aldehyde colour reactions. The colour fades rapidly a t first, but much more slowly after 5 minutes; on cooling after 10 minutes a colour is obtained that is constant for a t least 1 hour. The spectral absorption curve shows a single broad band with A,,,. a t 555 mp. There are two distinct ranges of sulphuric acid concentration, a higher and a lower one, over which variation of acid concentration has only a slight effect on the colour; greater sensitivity was obtained in the lower range, the reproducibility of results being indicated by the following extinction values of separate determina- tions: 0.976, 0.975, 0.9i6, 0.977, 0.976.SPECIFICITY OF THE DETEI<MIN.4TION- Indole gave about one-twentieth as much colour as p-indolylbutyric acid, whilst both 8-indolyl- acetic acid and /3-indolylpropionic acid gave colours with a similar absorption spectrum to that of ,!l-indolylbutyric acid but differing in intensity, solubility and stability (Table I ) . Froni none was the colour extracted by ether, chloroform, benzene, toluene or light petroleum. PROPEIITIES OF THE COLOUR Ol3TAINEU WITH DIFFERENT INDOLYL ACIDS Extinction of 1 cm Appearance after Solubility in .Acid obtained on 0.1 mg 18 hours amyl alcohol 8-indol ylbutyric 0.600 unchanged soluble 8-indol ylpropionic 0.5.54 unchanged soluble 8-ind d y lacetic 0.1 70 pale brownish insoluble SUMMARY .I\ rapid, sensitive and precise method for the photometric determination of 8-indolylbutyric acid is described.Under the conditions described, the test is not specific; 8-indolylpropionic acid gives a similar intensity of colour, /3-indolylacetic acid gives much less colour, which fades on standing, whilst indole gives negligible colour. The coloured compounds obtaincd from /?-indolylbutyric and p-indolylpropionic acid are soluble in aniyl alcohol, whereas that from 8-indolylacetic acid is insoluble. 1. 2. 3. 4. 5. 6. 7. 8. 9. 10 11. 12. 13. 14. REFERENCES Salkowski, E., Z . physiol. Chenz., 1884, 8, 417. Herter, C.A., J . Biol. Chem., 1908, 4, 2.53. Homer, A., Ibid., 1915, 22, 345. Freiber, W., Centralbl. Bakt. Orig., 1921, 64, 65. Stoppani, A. 0. hI., Anales. Asoc. Quim. Argentina, 1945, 33, 63. Holt, P. F., and Callow, H. J., .4nalysl, 1943, 68, 351. Hamence, J. H., Ibid., 1943, 68, 356. Winkler, S., Z . physiol. Chem., 1934, 50, 228. Winkler, S., and Petersen, S., Ibid., 193.5, 231, 210 Furth, O., and Lieben, F., Biochem. Z., 1920, 109, 103, 124. Konto, K., 2. physiol. Chem., 1906, 202, 185. Spies, J. R., and Chambers, D. C., :Inal. Chent., 1948, 20, 30. Allport, N. L., and Cocking, T. T., Quurl. J . Pharm., 1932, 5, 341. Sutter, E., Bey. schweiz. botan. Ges., 1914, 54, 197. .1\ N A LY TIC AL CONTROL D I v IS I o N D AG E N H A hi M A Y AND BAKER, LIJIITED C. W.BALLARD MISS S. SPICE ApviZ. 1951666 NOTES [Vol. 76 A COLOUR REACTION FOR NITRATES AND NITRITES THAT many substances in concentrated sulphuric acid give brilliantly coloured compounds in the presence of nitrates and oxidising agents is well known.’ Diphenylamine and diphenylbenzidine have been extensively used in testing for small quantities of nitrate.2 The production of a brilliant purple by nitrates with a sulphuric acid solution of the nitrite reagent, N( l-naphthy1)ethylenediamine hydrochloride, does not seem to have been recorded. For the purpose of the test, 2.25 ml of an aqueous solution were used and 2.75 ml of nitrogen- free sulphuric acid were added, followed by 1-0ml of a 0.02 per cent. solution of the reagent in sulphuric acid. The effect of a number of oxidising agents as well as nitrates was examined, together with the effect of the oxidising agent in the presence of nitrate.The results are summarised in-Table I. Substance KKO, .. NaSO, .. KClO, .. K,S,08 . . KMnO, . . Na.&O, NO, .. KBr .. HgCl, . . H202 FeN H, (SO,) *. 1 2H,O .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. TABLE I COLOUR REACTIONS OF VARIOUS OSIDISING AGENTS Interference of 200 pg of anion per ml on 10 pg of nitrate ion per ml 10 pg of anion per ml 200 p g of anion per ml Distinct purple colour in 90 seconds. Intense after three minutes Goes purple as reagent is added. Intense after one minute No purple colour. Yellow colour developed No colour produced Very transient pink as reagent is added, fades rapidly No colour produced Trace of purple colour, changes to a yellowish tinge in a few minutes No colour produced No colour produced Yellow colour developed, but no purple No colour produced Very transient pink as reagent is added, fades rapidly No colour produced Purplish-red colour de- \.eloped, but not as intense as that given by KNOS (10 pg of NO, per ml) No colour produced No colour produced No colour produced Pink colour produced but not as intense as that Kitrate colour is masked Nitrate colour is masked Transient pink on adding reagent, fades rapidly.Nitrate colour is masked Distinct purple colour produced Normal nitrate colour produced Normal nitrate colour Normal nitrate colour Nitrate colour is masked Normal nitrate colour produced produced Droduced given by KNO, (10 pg of NO, per ml) FeSO, (NH,),SO,.6H,O - No colour produced Nitrate colour is masked K,Fe(CN),.3HSO . . No colour Droduced A little cloudiness: no Normal nitrate colour K,Cr,O, . . I<SCN .. Cu SO,. 3H,O 31nS0,. 4H,O (NH,) ,>IO,O,4.4 colour produced . . Slight yellow colour pro- Yellow colour produced . . No colour produced No colour produced duced . . No colour produced Very slight trace of a yellow colour produced . . No colour produced No colour produced 1,O . . No colour produced No colour produced produced Nitrate colour is masked Normal nitrate colour Normal nitrate colour Normal nitrate colour Normal nitrate colour produced produced produced produced With 2.5 pg of nitrate nitrogen per ml in the test solution the liquid goes a distinct purple in 90 seconds and is a n intense purple in 3 minutes: the colour is stable for some time.The limit of sensitivity is about 0-25 pg of nitrate nitrogen per ml, but at these low concentrations the colour takes some time longer t o develop. Potassium iodate was the only other oxidising agent tested that produced a purple colour, and this fades t o yellow. Some other oxidising agents produce a yellow colour. Nitritts give the same reaction.Nov., 19511 KOTES 667 The nitrate (and nitrite) colour is masked in the presence of some of the stronger oxidising agents by further oxidation t o a yellow compound. REFERENCES 1. 2. MILLPORT, SCOTLAND April, 1951 Eitel, M., 2. anal. Chem., 1934, 98, 227. Kolthoff, I. M., and Noponen, G. E., J . Amer. Chem. Soc., 1933, 55, 1448.THE MARINE STATION H. BARNES APPLICATIONS OF THE NITROSOFERRICYAKIDE REACTION: THE DETECTION OF PROLINE AND HYDROXYPROLINE THE test provides a direct method for the detection of proline and hydroxyproline in protein hydrolysates and other mixtures of amino-acids. I t is based on Lewin's test' for acetaldehyde, in which the unknown solution is made alkaline with piperidine and treated with dilute sodium nitrosoferricyanide (nitroprusside), when the presence of acetaldehyde is shown by the appearance of a dark blue colour. Pyrrolidine and pyrrolidine derivatives, including the prolines, also yield blue colours with acetaldehyde, under specified conditions of pH. THE TEST Treat 5 ml of the approximately neutral solution with a drop of 25 per cent. aqueous aldol and adjust to about pH 9.3, by shaking well with a slight excess of powdered sodium tetraborate (borax).Add 2 drops of 1 per cent. sodium nitrosoferricyanide solution and, after mixing, allow the tube to stand at room temperature. If proline or hydroxyproline is present in concentrations above 0.05 per cent. of the final mixture, a blue colour will begin t o develop within a couple of minutes. Sarcosine, in concentrations down to 0.5 per cent., reacts similarly but more slowly. NOTE ON THE REAGENT- Aldol is used in preference to the much less stable acetaldehyde, and appears t o be equally reactive. The 25 per cent. aqueous solution keeps indefinitely, when stored in a brown glass bottle. The aqueous nitrosoferricyanide must be protected from light, otherwise it undergoes partial conversion to pentacyanoaquoferrate, and acquires different chromogenic properties ( Fearon*).SELECTIVITY- Amongst the components of protein so far esainined only proline and hydroxyproline give the blue reaction. In mixtures more alkaline than pH 10, glycine and methylamine develop violet colours; at pH 9.3, this reaction is slow, and is negligible in dilute solutions. Cysteine, reduced glutathione, and other free thiols, give an immediate violet colour with nitrosoferricyanide at pH 9.3, in presence or absence of aldol. This sulphydryl reaction can be suppressed by pre- treatment of the original solution with iodine, so as t o convert the thiol into the non-reacting disulphide. The aldol- nitrosoferricyanide test is negative with other amino-acids, including alanine, arginine, aspartic acid, asparagine, canavanine, citrulline, cystine, glutamic acid, histidine, the leucines, lysine, methionine, ornithine, phenylalanine, serine, threonine, tryptophan, tyrosine and valine.Unhydrolysed proteins in concentrations down t o about 3 per cent. develop colours ranging from blue to purple. These reactions are of interest in that they give additional evidence for the presence of pyrrolidine nuclei in the intact protein molecule. The aldol- nitrosoferricyanide test is negative with ammonia, amides, urea, substituted ureas and guanidines, creatine, creatinine, uric acid, nicotinic acid, nicotinic amide, thiamine, pyridoxine, p-aminobenzoic acid, pyridoxine, riboflavine and the folic acids. In general, the blue reaction at pH 9.3 appears to be selective for proline and hydroxyproline. In solutions more alkaline than pH 10, secondary amines, including diethylamine and un- substituted cyclic imines, including piperidine, give dark blue colours with acetaldehyde, as in Lewin's original test.'668 NOTES [Vol. 76 A SURVEY OF THE NITROSOFERRICY.4NIDE REACTIONS During the present investigation, a survey was made of the familiar colour reactions given by nitrosoferricyanide. These can be divided into three classes: (1) thiol tests, (2) methylene - carbinol tests and (3) miscellaneous tests.By controlling thc pH value and by using sensitisers, such as ammonia or amines, it is possible to distinguish between the different classes, and, in some cases, to identify particular members of a class.This is exemplified in Rothera's r e a ~ t i o n , ~ which develops a violet colour with acetoacetic acid and a blue Lvith pyruvic acid (Simon and Piauxq). REACTIOSS .4T pH VALUES ABOVE 10- Sulphw cotizpounds-Free thiols of the type I<-SH yield red - purple, acid-labile colours that soon fade, owing to atmospheric oxidation to non-reactive I<-S-S-1I systems, e.g., alkaline sulphides (B6champs), cysteine (rv10rner,6 Arnold;), ergothionine (Tanrets) and glutathione (Hopkins@). Thio-ethers of the type CH,-S-CH,- develop no colour in alkaline solution, but on subsequent acidification the mixture turns red, e.g., methionine (McCarthy and Sullivanlo). Sulphite gives a pink colour, intensified by zinc ions and bleached by acids. Thiosulphate, thiocyanate and thiourea gradually acquire colours ranging from greenish-blue to violet. This is not a true nitrosoferricyanide reaction, but depends on the formation of photo-chemical decom- position products (Fearon,2 Baudisch").AZelhyZene - cavbitiols-Aldehydes of the type -CH,.CHO yield orange - red acid-labile colours. Ketones of the type -CH,-CO-CH yield red to violet colours, the tint of which is shifted towards the violet end of the spectrum on acidification with acetic acid, and is discharged by strong acids. Cyclic methvlene - carbinol compounds and some unsaturated lactones give fugitive, acid-labile orange - red colours, e.g., acetone (Legal12), acetaldehyde, methyl ketones (von Bitto,13 Kothera3), creatinine (\Veyl14) and digitalis aglycones (Jacobs and Hoffmann,lS Paist et al.16).iMisceZZaneous compounds-H ydrazincs, pyrroles and indole develop violet colours that become blue on acidification (Lega1,12 DenigW'). REACTIOSS AT pH 9.3 5 0-1- are less fugitive, owing to the slower rate of oxidation. negative or very faint reactions. Sulphuv compounds-Thiols give reactions similar to those obtained a t pH -10. The colours ,%fethYlene - cavbinols-Aldehydes, methyl ketones, creatinine and other hydantoins give llliscellaneous compounds-The reactions are negative or vcry faint. REACTIONS I N PRESENCE OF SENSITISERS- Many subsequent workers have confirmed Le Sobel's18 observation that animonium hydroxide is preferable to sodium or potassium hydroxide for testing for acetone in presence of creatinine. If the mixture containing the nitrosoferricyanide is overlaid with concentrated ammonium hydroxide, acetone will develop a red - purple ring, in concentrations down to about 1 in 5000; while acetoacctic acid will develop a purple ring, in concentrations down to about 1 in 30,000.Creatinine doesnot react. In Rothera's3 modification of the test the mixture is saturated with ammonium sulphate which acts as an acidifying buffer and enables concentrations of acetoacetic acid as low as 1 in 400,000 to be detected. By the use of buffers in absence of ammonia it can be shown that the increased sensitivity of the tests is not due merely to a favourable pH range, but is dependent on a sensitising effect of the ammonia on the carbonyl system. Aliphatic amines, diamines and some cyclic imines also can act as sensitisers. The optimum pH value for a sensitised reaction is usually between 9.5 and 10.The sensitiser enables a reaction to take place a t a pH value insufficiently alkaline to allow of colour development with creatinine, indole and other miscellaneous compounds, other than thiols, which react equally wcll in presence or absence of sensitisers. A Zde?zjdes-\Yith ammonia as sensitiser, acetaldchyde and higher aldehydes yield relatively weak carmine colours. \Yith CH3.SH,, the colours are dark violet, and with diethylamine or piperidine, deep blue. Methyl kefones-The colour obtained depends both on the nature of the ketone and that of the sensitiser. For systems of the type -CH,.CO.R, with ammonia the colour is carmine to violet when R is -CH,, -CH,.CO.CH,, -CO.CH,, -CH,.COOH ; violet changing t o blue when 13 is -COOH ; and blue when R is -C,H,. No colour is obtained when R is -OH. With primary or secondary amines as sensitisers, the methyl ketones, in general, yield violet pigments.Nov., 19511 APPARATUS 669 We are indebted to the Medical Research Council of Ireland for the grant to one of us (Mi. A. B.), which enabled this work to be done. 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. REFERENCES 1-ewin, I..., Bev., 1899, 32, 3388. Fearon, \\’. I<., Analyst, 1946, 71, 562. Rothera, A. C. H., J . Physiol., 1908, 37, 491. Simon, L. J., and Piaux, L., Bull. Soc. Chim. Biol., 1924, 6, 273. Bkchamp, A., Compt. rend., 1866, 1087. Morner, I<. -4. H., Z . physiol. Chem., 189’3, 28, 611. Arnold, Y., Ibad., 1906, 49, 397. Tanret, C., Compt. rend., 1909, 149, 222; J. pharnt. Chin!., 1909, 30, 143. Hopkins, F. G., Biochem. J . , 1921, 15, 286. JIcCarthy, T. E., and Sullivan, 31. X., J . Biol. Chem., 1041, 141, 871. I3audisch, G., Science, 1948, 108, 443. Legal, E., “The Jlerck Index,” 5th Ed., Iiahway, New Jersey, 1940, p. 806. von Bitto, B., A n n . Chem., 1892, 267, 374. \Veyl, T., Bey., 1882, 11, 2175; Z. anal. Chem., 21, 575. Jacobs, W. A., and Hoffmann, A., J . Biol. Chetn., 1926, 67, 333. Paist, W. D., et al., J . Org. Chena., 1941, 6, 273. Denigks, G., “PrCcis de Chimie Analytique,” 6th Ed., Maloine, Paris, 1930, p. 279. Le Nobel, C., Z . anal. Chem., 1885, 24, 148. W. R. FEAROX DEPARTMENT OF BIOCHEMISTRY TRINITY COLLEGE, DUBLIS W. A. BOGGUST June, 1951

ISSN:0003-2654    

DOI:10.1039/AN9517600661

出版商:RSC    

年代:1951

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Nov., 19511 APPARATUS 669 Apparatus A SIMPLE CIRCULATING PUMP IT is sometimes necessary to maintain gentle flow in a fluid circuit in a closed system, as, for example, with the continuous recycling of a liquid through a fibrous plug. For this purpose a new pump has been devised. An alternating pressure, generated by a rocking U-tube containing mercury, is supplied to two tubes, and liquid is alternately sucked out and Fig. 1 shows the pump in its simplest form. I Fig. 1. The pump in its simplest form forced into the system through jets that point in a similar direction. In this way a continuous flow is maintained. In the original model the frequency of the alternating pressure was 60 cycles per minute and the volume of the liquid sucked out a t each half cycle was 2 to 3 ml: the optimum frequency will vary with the size of the apparatus.670 BRITISH STASDARDS ISSTITUTION [Vol. 76 In larger tubes the jets can be arranged to be parallel and side by side. Circulation can in this way be maintained in closed systems without the use of moving parts, mercury seals, etc.; the apparatus will also function under slightly reduced or increased pressures. Gentle circulation of air in a desiccator can be effected by the use of the rocking tube in conjunction with two parallel vent jets passing through the desiccator lid. The author is indebted to the Director and Council of this Association for permission to publish this note. BRITISH LAUNDERERS’ RESEARCH ASSOCIATION HILL VIEW GARDENS HENDON, N.lV.4 D. G. STEVENSON June, 1951

ISSN:0003-2654    

DOI:10.1039/AN9517600669

出版商:RSC    

年代:1951

数据来源: RSC

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670 BRITISH STASDARDS ISSTITUTION [Vol. 76 British Standards Institution MEMORANDUM AND AMENDMENT TO SPECIFICATION THE following Memorandum and Amendment to B.S. 1425:1961, “Cleanliness of fillings and stuffings for bedding, upholstery, toys and other domestic articles.” have been issued. PD 1276-Memorandum : October, 1951. Part 1. Owing to the present difficulty of complying with the limit of 1.5 per cent., with the raw materials available, the maximum content of soluble matter may be increased to 1.8 per cent. PD 1277-Amendment No. 1 : October, 1951. Appendix A, page 26. filter tablet.” Clause 3. e. Soluble impurities. Line 5. Delete the words “or a 44cm x 4 mm Whatman DRAFT SPECIFICATIONS A FEW copies of the following draft specifications, issued for comment onIy, are available to interested members of the Society, and may be obtained on application to the Secretary, Miss D.V. Wilson, 7-8, Idol Lane, London, E.C.3. Draft Specification prepared by Technical Committee LBC/ 1-Volumetric, Mouldblown and Lamp- blown Glassware. CN(LBC) 4349-Draft B.S. for Sugar Flasks (Revision of B.S. 675). CN(LBC) 4989-Fourth Draft B.S. for Dean and Stark Apparatus for the Determination of Water. Draft Specifications prepared by Technical Committee OSC/3-Soaps for Domestic Use. CN(0SC) 4692-Draft B.S. for Genuine Hard Soap. CN(0SC) 4693-Draft B.S. for Carbolic Soap. CN(0SC) 469ADraft B.S. for Soft Soap. CN(0SC) 4695-Draft B.S. for Soap Flakes. CN(0SC) 4696-Draft B.S. for Toilet Soap. Draft Specifications prepared by Technical Committee CHE/36-Chemicals and Chemical Plant for CN(CHE) 41 1 l-Draft B.S. for Cyanides for Electroplating (Revision of B.S. 622). CN(CHE) 41 12-Draft B.S. for Nickel Anodes and Nickel Salts for Electroplating (Revision Electroplating. of B.S. 558 and 564).

ISSN:0003-2654    

DOI:10.1039/AN9517600670

出版商:RSC    

年代:1951

数据来源: RSC

摘要:

Xoi*., 19511 SPECIFICATIONS FOR MICRO-ASALYTICA~ REAGEKTS 67 1 Specifications for Micro- Analytical Reagents HITHERTO there have been no published quantitative specifications for chemical reagents supplied in this country for niicro-analytical use, though the malwrs have applied to micro-analytical reagents such tests as are described or recommended in the literature by Pregl and others. I n a number of respects these tests, apart from the fact t h a t they are qualitative, are not fully appropriate t o the needs of micro-analysts to-day, and as manufacturers of "M.A.R." reagents The British Drug Houses Ltd. some two years ago invited advice and comments from the Micro- chemistry Group of the Society of Public Analysts and Other Analytical Chemists on a new series of specifications that the B.D.H.Laboratory Chemicals Group proposed t o issue for reagents for micro-analytical work. .4 Sub-committee of the Microchemistry Group has since considered draft specifications drawn up by the British Drug Houses and a number of additions and improvements have been suggested by the Sub-committee and the Company. The specifications finally agreed were submitted to the Committee of the Microchemistry Group and approved b y them. Publication in Tkc .4naZyst was approved by the Council of the Societv at its meeting on July 24th, 1951. They have also been published by The British Drug Houses Ltd. in the form of a booklet and copies may be obtained from the B.D.H. Laboratory Chemicals Group, Poole, Dorset, on request. ANHYDRONE (MAGNESIUM PERCHLORATE) 14 TO 22 MESH h1.A.R.- Moisture .. . . . . . . .. . . 6 to 8 per cent. Particle size . . . . . . . . . . All should pass 14 B.S. mesh; not more than 6 per cent. should pass 22 B.S. mesh. Reaction . . .. . . . . .. . . Five grams shaken with 20 ml of 95 per cent. ethyl alcohol should not be alkaline to phenol- phthalein. The loss in weight on extraction with 10 per cent. hydrochloric acid on a water-bath for ten minutes The approved specifications are given below. ASBESTOS M.A.R.- should not exceed 0.25 per cent. CAZIPHOR M.A.R.- Appearance . . . . .. .. . . Colourless crystals. Particle size . . . . .. .. . . All should pass 30 B.S. mesh. Solution (10 per cent. in alcohol) Clear, colourless and free from extraneous particles. Meltingpoint (Rast method) .. . . . . 179" to 179-5" C. The material should show no darkening after thirty minutes a t meltingpoint. . . . . COPPER OXIDE, WIRE FORM, M.A.R.- Length . . .. . . . . .. . . 2 to4mm. Particle size . . .. . . .. . . None should pass 36 B.S. mesh. Carbon (C) . . . . . . . . . . Not more than 10 p.p.m. COPPER OXIDE "POWDER" h1.A.R.- Prepared by grinding copper oxide fvont wire M. A.R. Particle size . . . . .. .. . . Carbon (C) .. . . .. . . Solution (10 per cent. in water) .. . . Chloride (Cl) . . .. .. .. . . Iron (Fe), . . .. . . .. .. . . Nitrogen (N) . . . . .. . . .. Assay (CuS04.5H,0) . . .. .. . . Distillation range. . .. .. .. .. Distillation range. . .. * . . . .. Appearance . . .. .. .. .. Distillation range. . .. .. .. .. Ether peroxide . . .. .. .. ..COPPER SULPHATE M.A.R.- p-CYMENE M.A.R.- DEKALIN (DECA-HYDRONAPHTIIALENE) M.-4.R.- ETHER M.A.R.- Non-volatilc matter . . .. . . .. IVater . . .. .. .. .. .. ,411 should pass 30 B.S. mesh; none should pass Kot more than 10 p.p.m. 85 B.S. mesh. Clear and free from extraneous particles. Not more than 10 p.p.m. Not more than 10 p.p.m. Not more than 10 p.p.m. Not less than 99 per cent. and not more than 17.5' to 177°C (at 760mm). 101 per cent. 190" to 192" C (at 760 mm). Clear, colourless and free from extraneous particles. Not less than 95 per cent. should distil between Not more than 5 p.p.m. Not more than 0.16 p.p.m. Not more than 80 p.p.m. 34" and 35" C (at 760 mm).672 SPECIFICATIONS FOR MICRO-ANALYTICAL REAGENTS [Vol. 76 D( +)GLUCOSE M.A.R.- Solution (10 per cent.in water) Chloride (Cl) . . .. .. .. . . Not more than 20 p.p.m. Iron (Fe) . . .. .. .. .. . . Not more than 1 p.p.m. Phosphate (PO,) . . .. .. .. . . Not more than 20 p.p.m. .. . . Clear, colourless and free from extraneous particles. Sulphate (SO,) . . .. . . . . .. Not more than 20 p.p.m. HYDRIODIC ACID M.A.R.- Specific gravity . . .. .. .. . . 1.7 (constant boiling mixture). Nitrogen (N) . . .. .. .. . . Not more than 5 p.p.m. Sulphur (S) . . .. .. .. . . Not more than 20 p.p.m This reagent may be stabilised by the addition of 0.03 per cent w/v of H,PO,. HYDROCHLORIC ACID MAR.- Specific gravity . . .. .. .. . . 1.18. Non-volatile matter . . . . .. . . Not more than 5 p.p.m. Free chlorine (Cl) . . .. .. .. . . Not more than 1 p.p.m. Iron (Fe) . . .. .... .. .. Not more than 1 p.p.m. Lead (Pb) . . .. .. .. .. . . Not more than 1 p.p.m. Sulphate (SO,) . . .. .. .. . . Not more than 1 p.p.m. HYDROGEN PEROXIDE 100 VOLUMES M.A.R.-- Acidity (to phenolphthalein) - Halogens (as C1) . . .. .. .. . . Not more than 5 p.p.m. Nitrogen (N) . . .. .. .. . . Not more than 10 p.p.m. Phosphate (PO,) . . .. .. .. . . Not more than 10 p.p.m. Sulphate (SO,) . . .. .. .. .. Not more than 5 p.p.m. Total . . .. .. .. .. . . Not more than 0.5 ml of N acid per cent. Steam volatile . . .. .. .. . . Not more than 0.1 ml of N acid per cent. LEAD CHROMATE 14 TO 22 MESH M.A.R.- Particle size . . .. .. . . . . All should pass 14 B.S. mesh; none should pass 25 B.S. mesh. Carbon (C) .. .. .. .. . . Not more than 20 p.p.m. Nitrogen (N) . . .... .. . . Not more than 10 p.p.m. MERCURIC SULPHATE M.A.R.- Nitrogen (N) . . .. .. .. . . Not more than 5 p.p.m. Assay (HgS0,) . . .. .. .. . . Not less than 99 per cent. NITRIC ACID, SP.GR. 1.42, M.A.R-- Chloride (Cl) . . .. .. .. . . Not more than 0.5 p.p.m. Lead (Pb) . . .. .. .. .. . . Not more than 1 p.p.m. Sulphate (SO,) . . .. .. .. . . Not more than 1 p.p.m. Non-volatile matter . . .. .. . . Not more than 10 p.p.m. POTASSIUM NITRATE M.A.R.- Solution (10 per cent. in water) .. .. Chloride (Cl) . . .. .. .. .. Iron (Fe) . . .. .. .. .. .. Iodate (10,) . . .. .. .. .. Nitrite (NO,) . . .. .. . . . . Phosphate (PO,) . . .. .. .. .. Sulphate (SO,) . . .. .. .. .. Solution (10 per cent. in water) .. .. Calcium (Ca) . . .. .. .. .. Chloride (Cl) . . .. .. .. ..Iron (Fe) . . .. .. .. .. .. Lead (Pb) . . .. .. .. .. .. Magnesium (Mg) . . .. .. .. .. Total nitrogen (N) . . .. .. .. ' Assay (K,SO,) . . .. .. .. .. Assay ( A d .. .. .. .. .. POTASSIUM SULPHATE M.A.R.- SILVER WOOL M.A.R.- SILVER GAUZE M.A.R.- Mesh size . . .. .. .. .. .. Assay (Ad .. .. .. .. .. Clear, colourless and free from extraneous particles. Not more than 5 p.p.m. Not more than 2 p.p.m. Not more than 0.5 p.p.m. Not more than 1 p.p.m. Not more than 10 p.p.m. Not more than 20 p.p.m. Clear, colourless and free from extraneous particles. Not more than 25 p.p.m. Not more than 5 p.p.m. Not more than 5 p.p.m. Not more than 10 p.p.m. Not more than 50 p.p.m. Not more than 5 p.p.m. Not less than 99.5 per cent. 99.99 per cent. 36 to 60 B.S. mesh. 99-99 per cent.Nov., 19511 SPECIFICATIONS FOR SODA ASBESTOS 14 TO 22 MESH M.A.R.- Particle size .. .. .. .. CO, absorption . . .. .. .. SODIUM BISULPHITE SOLUTIOI;, 35 PER CENT., Solution .. .. .. .. Chloride (Cli . . .. .. .. SODIUM CARBONATE, ANHYDROUS, 31.A.R.- Solution (10 per cent. in water) Halogens (as C1) . . .. .. .. Nitrogen (N) . . .. .. .. Phosphate (PO,) . . .. . . .. Silica (SiO,) . . .. . . .. Sulphate (SO,) . . .. .. .. Solution (10 per cent. in water) Ammonia (NH,) . . .. . . .. .. SODIUM SULPHIDE M.A.R.- .. Sulphite and thiosulphate (as SO,) Solution (10 per cent. in C0,-free water) . . SODIUM THIOSULPHATE M.A.R.- Calcium (Ca) . . .. .. .. Iron (Fe) . . .. . . .. . . Lead (Pb) . . .. .. .. .. Nitrogen (N) . . .. .. .. Sulphate and sulphite (as SO,) . .Sulphur ( S ) .. .. .. .. Assay (N+S,03.5H;O) . . .. . .. SULPHATE - MOLYBDATE REAGENT 1I.A.R.- Concentration . . .. .. .. SULPHURIC ACID, 98 PER CENT., 3I.A.R.- Xon-volatile matter . . .. .. Total nitrogen (N) . . .. .. Iron (Fe) . . .. . . .. .. Lead (Pb) . . .. .. .. .. Oxygen absorption (in five minutes) P-TOLUENE - SULPHONIC ACID hLA.R.- . . Solution (25 per cent. in water) .. Volatile acidity (to phenolphthalein) . . MICRO-AXALYTICAL REAGESTS 673 . . All should pass 14 B.S. mesh; not more than 5 per cent. should pass 22 B.S. mesh. . . The material should absorb not less than 30 per cent. of its weight of CO,. 3l.A.R.- .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. . . .. . . .. .. .. .. .. .. .. .. .. Clear and free from extraneous particles. Not more than 1.5 p.p.m. Clear, colourless and free from extraneous particles. Not more than 10 p.p.m. Not more than 5 p.p.m. Not more than 10 p.p.m. Not more than 10 p.p.m. Not more than 10 p.p.m. Clear, colourless and free from extraneous particles. Not more than 20 p.p.m. Not more than 0-05 per cent. Clear, colourless and free from extraneous particles. Not more than 50 p,p.m. Not more than 5 p.p.m. Not more than 10 p.p.m. Not more than 2 p.p.m. Not more than 100 p.p.m. Not more than 5 p.p.m. Not less than 99 per cent. and not more than 101 per cent. Approximately 15 per cent. of ammonium molyb- date. h’ot more than 10 p.p.m. Not more than 2 p.p.m. Not more than 1 p.p.m. Not more than 2 p.p.m. Not more than 1 p.p.m. Clear and almost colourless. Not more than 0.02ml of hT acid per 1OOg of p-toluene - sulphonic acid. August 71h, 1951

ISSN:0003-2654    

DOI:10.1039/AN9517600671

出版商:RSC    

年代:1951

数据来源: RSC

摘要:

674 BOOK REVIEWS [Vol. 76 Book Reviews HANDBOOK OF ANTIBIOTICS. By A. L. BARON. Pp. viii + 303. New York: Reinhold Publishing Dr. Waksman’s definition of an antibiotic as “a substance produced by micro-organisms, which has the capacity of inhibiting the growth and even of destroying other micro-organisms’’ has the advantage of distinguishing between antimicrobial agents produced by micro-organisms on the one hand and antimicrobial agents elaborated by higher plants on the other. This distinction is of considerable practical importance because antibiotics as thus defined are made by fermentation and extraction of the active material from the culture fluid, processes so specialised that anti- biotic production now ranks almost as a separate industry with its own special techniques, personnel and jargon.The extraction of antimicrobial agents from plants, on the other hand, involves the use of methods that do not differ essentially from those developed years ago for the preparation of crude vegetable drugs. Dr. Baron, however, has elected to cast his net over a much wider area than that covered by \Vaksman’s definition and has included in his review antimicrobial agents produced by flowering plants and lichens as well as those produced by bacteria and fungi. He gives very good reasons for his choice and few will regret his decision, however much they may disagree with his reasons, as it has resulted in the incorporation of much useful information about a far wider range of substances than would otherwise have been legitimate. The “Handbook of Antibiotics” does not pretend to be a critical review of the subject.It is rather a compilation from the very voluminous literature of the most important data a L u t the methods of production, chemistry, bacteriology and pharmacology of the antibiotics. These are dealt with in alphabetical order and wherever possible in “telegraphic style, tabulations and statistical summaries.” The section dealing with each antibiotic includes a comprehensive biblio- graphy. Penicillin and streptomycin, i t should be noted, are purposely covered in an extremely cursory fashion as they have been discussed at great length in other readily accessible publications. The result is a handy encyclopaedia containing much essential information that would other- wise be very difficult to find.The bacteriological data alone, culled as they often are from many different sources, will save hours of tedious literature searching. The information given, in so far as it has been possible to check it, appears to be reliable, although one or two slips were noted by the reviewer. The constitution of clavacin (patulin) for example is now believed to be entirely different from that given; this constitution was shown to be incorrect over two years ago. The structure of streptomycin has likewise been known with certainty for some time and could with advantage have been given in a more precise form. Again, one of the most important applications of chloramphenicol is in the treatment of whooping-cough, but this is not mentioned among the clinical uses of this antibiotic. One is also a little surprised at the inclusion in a book on antibiotics of dicoumarol and even more so at the presence of indolylacetic acid and other synthetic plant hormones.On the whole, however, the book appears to have been prepared with great care and there is every indication that the proof-reading has been carefully carried out. Some minor errors occur, such as the spelling of Bebaryomyces on p. 36, “Skellysolve” on p. 44, Ustilago on p. 131 and helianthate on p. 226, whilst the formula on p. 55 contains a trivalent carbon atom, and Cholara quercina occurs in both lists on I>. 61. There is an author index and an index of organisms, and the printing and binding are excellent. This is a book that can be recommended to anyone who requires basic factual information about the antibiotics as quickly as possible and who is not very much concerned with the fin‘er details or with the theoretical aspects of the subject. Corporation; London: Chapman and Hall Ltd.1950. Price $6.50; 52s. F. A. ROBINSON MEDICINAL CHEMISTRY. Volume 1. By ALFRED BURGER. Pp. xviii + 577. New York and The scope of the work is better indicated by the sub-title, “Chemistry, Biochemistry, Therapeutic and Pharmaco- logical Action of Natural and Synthetic Drugs,” than by the main title. Chemistry is confined to structure and brief descriptions of the reactions used in the preparation of synthetic drugs, the main interest of the author being in the relation of chemical constitution to pharmacological action. The book is no less valuable on this account; indeed, to cover completely all the subjects mentioned in the sub-title would require many more volumes than the two contemplated, but London: Interscience Publishers Inc.1951. Price $10.00; 80s. This book is the first of two volumes to be published by Professor Burger.Sov., 19511 BOOK REVIEWS 675 those who go to this book expecting to find accounts of chemical and physical properties, reactions, tests or manufacturing processes will be disappointed. The main value of the book to the chemist will in fact be its contribution to his understanding of the biological mechanisms bv which the action of drugs can be explained. The contents of the first volume include, among othcr subjects, general and local anaesthetics, hypnotics and sedatives, anti-convulsants, analgesics, adrenergic drugs, curarising drugs, anti- spasmodics, anti-histamines and the vitamins.Hormones, sulphonamides, antibiotics and anti- malarials will be covered in the second volume. The drugs are grouped mainly according to pharmacological action, but this is abandoned in the chapters on “Vitamins” and on “Drugs for the Treatment of Cancer.” The title of the latter is, perhaps, hardly justifiable, as it conveys the suggestion that there are drugs in regular use for the treatment of cancer, whereas the chapter deals with carcinogenic substances and with some of the many drugs that have bccn tried for treatment of that disease. Incidentally, the Greek word for crab is KapKLvoq not XapKivoS. There is an interesting chapter on the historical development of medicinal chemistry, which includes a table of important dates during the last hundred years. The events that are regarded as important are strangely uneven.It seems unlikely that future generations will regard the isolation of the goitrogenic principle of cabbage in 1949 as an event of comparable importance to the isolation of vitamin B,, or the use of cortisone in rheumatoid arthritis, but one never knows. Chenopodizarn anthelminticum did not contain santonin (p. 9) even when used by the Romans. The chapter on physical properties and biological activity is mainly concerned with isosteric molecules and their pharmacological action. Such physical properties as surface phenomena or solubility are barely mentioned. Perhaps the most serious criticism of the book is that the author’s selection of material is too often inclined to be academic rather than practical. In reading the chapter on curare and curariform drugs, one gets a good summary of the work that has been done on curarising com- pounds, but little idea about which have been found valuable in practical anaesthetics.The author retains the old distinctions of “tube,” “calabash” and “pot” curare, but it is said that these have been replaced by one variety that should be known as “petrol-can” curare. The first reference to be checked (to Harington and Barger’s synthesis of thyroxine) proved to be wrong, but the experience was not repeated. Apart from these defects, most of which can be corrected in a later edition, the book contains a large amount of useful and interesting information that is well presented.The book is too often marred by careless statements and inaccuracies. N. EVERS LIXEAR POLYMERS. By ELIZABETH $1. FRITH and R. I?. TUCKETT. Pp. xi $- 355. London: This book, which deals with the physical chemistry of linear polymers, was written, for the greater part, whilst the authors were members of the Department of Colloid Science at Cambridge University. The volume is written for those who are taking or have taken a Final Honours course in chemistry at a major British university. The initial chapter deals with the X-ray and infra-red structure of polymers, after which there follow two chapters on double-bond polymerisation, principally concerned with the initiation, propagation and termination stages of the polymerisation of substituted ethylene monomers and the kinetics of such polymerisations.Condensation polymers, i . e . , polymers produce’d from monomers containing two or more functional groups, are then discussed, after which the authors have felt it necessary to introduce a chapter dealing with the first and second laws of thermodynamics in order to assist the reader to understand the theories underlying the solution properties of amorphous polymers. In many respects Chapter 7, which covers the cryoscopic, end-group, isothermal distillation, osmotic pressure, solution viscosity, ultra-centrifuge, light scattering and de-swelling methods of determining the molecular weight of high polymers in a comprehensive manner, is likely to be of considerable value to analytical chemists in the wider sense.Certainly it will assist them t o exercise caution in expressing opinions about the molecular weight of polymers. A final chapter is concerned with such physical properties of linear polymers as elasticity, plastic flow and relaxation. The book is well produced and the price, in these days, is satisfactory. This volume will doubtless serve the purpose for which it is intended and will, in particular, appeal to chemists possessing first-class mathematical ability. Longmans, Green & Co. Ltd. 1951. Price 18s.676 BOOK REVIEWS [Vol. 76 The criticism the reviewer would like to make is that this field of linear polymers is a highly controversial one, with fresh theories being put forward continually to account for observed facts.For that reason he believes it would have been a better plan to have tried to bring the first edition of this book up to date in the first place, rather than to restrict the subject-matter to work published up to the year 1947, e.g., the section on the infra-red examination of polymers could very profitably have been extended in the light of modem knowledge of the subject. MELLOR’S MODERN INORGANIC CHEMISTRY. Revised by G. D. PARKES, M.A., There is little more that need be said in a review of the latest edition of this famous textbook. Although labelled only as a new edition, it is, in point of fact, the tenth of a work first published in 1912, the second in which Dr. Parkes has been concerned, and the first in which he is solely responsible for the work of revision.In the ninth edition, 1939, extensive changes were made and now it has been necessary only to supplement these to a minor extent. This has been judiciously done by adding new, short paragraphs on atomic transmutation, wave-mechanics and resonance, overvoltage and products of electrolysis, and on oil from coal, and by expanding the last chapter, on radio-activity and the radio-elements, to include some information on their separa- tion and properties and on nuclear reactions and fission. A new chapter on metals, in which mineral benefication, extraction of metals from their ores and the properties of metals and their compounds are dealt with in a general way, will certainly be of value to the hard-pressed examinee of to-day.This chapter also contains a useful table showing the occurrence of the principal metals. Here, curiously enough, the occurrence of iron as carbonate is listed as chalybite with no mention of the better-known alternative name siderite, and in the text itself the reverse is true. Pynhotite, by the way, is spelt “pyrrotite,” and sperrylite, which is mentioned in the text under platinum, is missing from this table. The two chapters on the atmosphere and fhe inert gases have now been combined in one, which seems a logical and sensible thing to do, and some of the questions at the end of the book have been altered. The diagrams have also received attention; a few have been omitted without loss to the clarity of presentation and many have been re-drawn on a larger scale to add much to the attractiveness of the book.It is good to see that notice has been taken of a review (B. S. Evans, Analyst, 1940,65, 479) of the last edition. The statement concerning the oxidation of manganese in a steel by the heating with sodium bismuthate, to which Dr. Evans so rightly took exception, has been corrected, but his further criticism concerning the “curious omission” of a description of cerium has not been met. Surely, a little more information about this element and a few of its compounds might well have been given. On glancing through this new edition for the first time several misprints meet the eye-there is one on the title-page-and one wonders whether this book has not more than its share. One error for which the printer cannot be wholly blamed is to be found in the table on p.57, where the ratio silver to fluorine, 70.05:29.95, gives fluorine an equivalent of 46.12-the ratio should be 170-05:29.95-and this error has been handed down from the first edition of 1912. It is, of course, all too easy to overlook misprints, but textbook writers should give this matter special care; they are writing primarily for students whose inexperience gives them a touching faith in the printed word. To end criticism of an admirable book, can one suggest that the time has come to abandon “C.C.” for “ml”? Whether we like it or not the term millilitre, with its abbreviation “ml,” has come to stay and the sooner “c.c.” disappears from our textbooks the better. This book desemes continued success; it is good value for money and, properly used, will see a student well past his intermediate year, but the professional analyst may want a larger book with more detail than this one can be expected to give.MELTING AND SOLIDIFICATION OF FATS. New York and He has lately been honoured by his fellow-workers with the presidency of the American Oil Chemists’ Society, and his eminence in the field of fat technology is as well recognised in this country as in his own. Sooner or later there was bound to be a book on phase changes in fats; we may be thankful that it was Bailey who decided to write it. He combines a very readable style with a capacity for compressing the maximum amount of useful information into what must be the smallest space possible, and the result is always stimulating.This J. HASLAM Tenth Edition. D. Phil. Pp. xxi + 967. London: Longmans, Green & Co. Ltd. 1951. Price 25s. L. S. THEOBALD By ALTON E. BAILEY. Pp. vii + 357. London: Interscience Publishers Inc. 1950. Price $7.00; 60s. Bailey continually excites admiration and wonder by his writings. Here it is, if anything, more stimulating than usual.Nov., 19511 BOOK REVIEWS 677 book should prove to be the best base for further operations that any future investigator could wish for. Oils and fats differ from most other organic substances by the complexity with which a comparatively few compounds are mixed, and this complexity confers distinctive physical pro- perties. Among the phenomena most affected are melting and solidification, variations in which are of basic importance in most aspects of oil and fat technology.The author has collected all available material from widely scattered sources and has sought to correlate and interpret the experimental data so as to reveal the relationships between different phenomena associated with phase changes. In addition he has dealt with the influence of molecular structure on these phenomena. By these means he emphasises a picture of remarkable unity and order, and shows that, because of it, even highly mixed commercial fats often behave almost exactly like the com- paratively simple ternary or binary systems. In developing his subject the author divides his book into six sections; in the first he deals with the theory of the subject and with general considerations. The second section is on laboratory technique; the third is on the melting and solidifying of pure compounds and is followed by a section on mixtures.The last two sections deal with solubility and with practical melting and solidification processes. The section on laboratory techniques is of outstanding interest to the fat chemist; those on practical aspects of the subject and on commercial fats also merit his profound attention. K. A. WILLIAMS INDUSTRIAL OIL AND FAT PRODUCTS. By ALTON E. BAILEY. Second Edition. Pp. xxiv + 967 New York and London: Interscience Publishers Inc. 1951. Price $15.00; 120s. The first edition of this book appeared in 1945 and received nothing but praise when it was reviewed in The Analyst (1945, 70, 437). Since then there have been remarkable advances in the processing of oils and fats and in the knowledge of their structure and properties.As a result the author has clearly not found it easy to do justice to all the complexities of the industry. Nevertheless it may fairly be said that with the assistance of the foremost workers in the field he has triumphed over his difficulties and has produced a detailed picture of the technology of the oil and fat industry that is quite unsurpassed in the literature of the subject. The general plan of the book is on the same lines as that of the first edition and, as before, the section dealing with unit processes in oil technology occupies almost half of it. The next longest section describes the industrial utilisation of oils and fats and includes sub-sections on cooking oils, salad oils, butter and margarine, bakery products, soaps, paints and miscellaneous products.Two more sections describe structure and composition, reactions and properties and deal individually with the various raw materials of the industry. As before, analytical methods are not described, although many analytical results are recorded. The numerous illustrations in the book are very clearly reproduced and merit the highest praise. MICRO-ANALYSIS IN MEDICAL BIOCHEMISTRY. K. A. WILLIAMS By E. J. KING, M.A., Ph.D., F.R.I.C. Second The new edition of Professor King’s book brings up to date the material treated in the previous Since that time there have been a number of notable advances in medical The book is a useful manual of methods primarily arranged for use in medical laboratories It begins with a chapter on normal values for body-fluid constituents, compiled as a result of recent statistical research into many hundreds of analyses.Also indicated are the likely clinical conditions that exhibit abnormal levels. The subsequent chapters give detailed procedures for analysis of whole blood, plasma, serum, cerebrospinal fluid, faeces, urine, calculi and gastro-intestinal contents. There is an extremely useful chapter on functional tests in which the latest procedure is outlined and explained. Next comes an outline of spectroscopic procedures for such substances as blood and bile pigments, and for the quantitative estimation of carbon monoxide. From a student’s point of view the portion of the book on hydrogen ion concentration and volumetric solutions should be most helpful. Descriptions are given of the most up-to-date type of photometric instruments, including Professor King’s own grey wedge photometer, which has proved so useful in practice. There is a sketchy reference at the end to the flame photometer, but no technique is described for its use. The book is very clearly written with a lucidity and care that one would expect from the author. The reviewer has used the methods for blood analysis in his own laboratory andcan recommend them to other analysts. Edition. Pp. viii f 222. London: J. & A. Churchill Ltd. 1951. Price 14s. edition issued in 1946. biochemical technique and these have been incorporated. . and in teaching hospitals. The book closes with a chapter on colorimetric and photometric measurements. R. F. MILTON

ISSN:0003-2654    

DOI:10.1039/AN9517600674

出版商:RSC    

年代:1951

数据来源: RSC

摘要:

678 PL'BLICATIOSS RECEIVED [Vol. 76 BIOLOGICAL METHODS GROUP THE Annual General Meeting of the Group will be held in the Anatomy Lecture Theatre, University College, Gower Street, London, W.C.l, on Thursday, December 13th, 1951, a t 6.15 p.m. This will be followed by an Ordinary Meeting of the Group for the reading of Original Papers.

ISSN:0003-2654    

DOI:10.1039/AN951760678c

出版商:RSC    

年代:1951

数据来源: RSC