摘要:

June, 19611 AND CERTAIN LOW-ALLOY STEELS BY CATHODE-RAY POLAROGRAPHY Polarographic Determination of Antimony in Refined 399 BY V. T. ATHAVALE, R. G. DHANESHWAR, M. M. MEHTA AND M. SUNDARESAN (Analytical Division, Atomic Energy Establishment, Tyombay, Bombay, India) A polarographic method has been developed for determining antimony in refined lead. Copper, iron and bismuth do not interfere and there is no interference from tin even if present in amounts equal to the antimony. However, results for antimony are lower if tin is present in higher ratios. The method can be used for determining as little as 10 p.p.m. of antimony on a l-g sample of lead; the error is within &5 per cent. in the concentration range above 25 p.p.m., but is greater in the lower range. The supporting electrolyte used is N sulphuric acid.THE concentration of antimony in refined lead is extremely low, and, according to Green,l if more than 100 p.p,m. are present, it seriously affects the rate of oxidation of the lead. Von Bayer12 and Kalousek3 studied polarographically the reduction of antimony in hydro- chloric acid medium and found that the results were only qualitative. Kraus and Novak* pointed out that the variations observed were due to changing acid concentration; Rourigan5 found that variations were also due to differences in lead concentrations. Hourigan and Robinson6 determined antimony in antimony-lead alloys and found that lead up to a concentration of 0 . 0 3 ~ could be tolerated. Besides copper, iron and equal amounts of bismuth interfere in this method, which is obviously not suitable for determining traces of antimony in refined lead.In a paper on the determination of traces of impurities in refined lead, Zotta' suggested the use of sulphuric acid - nitric acid medium as supporting electrolyte. Under the condi- tions she described it was observed that, owing to solution of mercury, good waves were not obtained. Moreover, Kolthoff and Lingane* had suggested that on dissolving lead in nitric acid Sb3+ may be oxidised to Sb5+ and, in presence of tin, it may remain undissolved as antimony pentoxide. The basis of the method described here is solution of the sample in nitric acid, removal of lead as lead sulphate, evaporation of an aliquot of the solution to remove excess of nitric acid and then determining the antimony with N sulphuric acid as supporting electrolyte.* Presented to the 48th Session of the Indian Science Congress held at Roorkee, India, January 3rd to 9th, 1961.400 ATHAVALE, DHANESHWAR, MEHTA AND SUNDARESAX [Vol. 86 EXPERIM:ENTAL A 0.01 M solution of antimony trichloride was prepared from the analytical-reagent grade salt, the acidity being kept at 5 per cent., and the solution was standardised iodi- metrically. Two solutions, one containing 100 and the other lOpg of antimony per ml, were prepared from this stock solution. Solutions of copper sulphate, bismuth nitrate, ferric chloride and stannous chloride containing 100 pg of the metal per ml were prepared from the analytical-reagent grade salts and standardised by conventional methods.Laboratory- reagent grade sulphuric acid was used. A Du Bellay polarograph was used. Temperature was maintained constant at 30" & 0.1" C by an electronically controlled thermostat. The rate of outflow (m) of the capillary was 1.217 mg per second and the drop rate (t) was 4.4 seconds. The mercury pool was used as anode. Different amounts of antimony (5 to 600 pg), as trichloride, were placed in beakers and 0.4 ml of concentrated sulphuric acid was ad.ded to each. The solutions were evaporated until fumes were evolved, and then polarograms were recorded with 3.0ml of N sulphuric acid as supporting electrolyte. In another set of experiments different amounts of antimony, as trichloride, were first treated with 5 ml of dilute nitric acid (1 + 4), and then the procedure described above was repeated.TABLE I RECOVERY OF ANTIMONY FROM LEAD AFTER TREATMENT WITH NITRIC ACID for the antimony (about 25 F1.p.m.) present in the lead A l-g sample of lead was used for each test. All results have been corrected Amount of antimony added, Clg 10 10 25 25 50 50 100 200 600 Amount of antimony recovered, PFLg 9.1 10.6 25.0 25.2 52.5 51.2 100.0 200.0 594.0 Difference, /O -9 + 6 0 + 0.8 +5 4 2-4 0 0 - 1 0' Proportionality was observed for 5 to 600 pg of antimony and the results were not affected by the treatment with nitric acid. Recovery experiments for antimony were carried out on l-g samples of lead to which different amounts of antimony, in solution, were added. The metal was dissolved in 5 ml of dilute nitric acid (1 + 4). The solution was transferred to a 25-ml flask, 1 ml of concentrated sulphuric acid was added to precipitate lead, and the solution was made up to 25ml.From this, XOml were placed, by pipette, in a beaker, and evaporated to the appearance of fumes; 3.0 ml of N sulphuric acid were then added, and the wave for antimony was recorded. The effect of tin was investigated by adding different amounts of tin, as stannous chloride, to the antimony solution and then carrying out the treatment with dilute nitric acid (1 + 4). Antimony was determined as described above and it was found that a ratio of tin to antimony of almost 2 to 1 could be tolerated. Recovery of antimony in presence of different amounts of tin, as stannous chloride, was tested on a 1.0-g sample of lead. The lead was dissolved by the nitric acid treatment; the results are shown in Table 11.The half-wave potentials of arsenic, antimony and bismuth in N sulphuric acid are reported as -0.7, -0.32 and -0.04 volt against the saturated-calomel electrode, respec- tively.9 These elements were also taken with antimony and the recoveries were tested on 1-0-g samples of lead. The half-wave potential for arsenic is much higher than that for antimony and therefore it does not interfere. The results are shown in Table 11; the original antimony content of the lead is corrected for. Antimony in two samples of refined lead was determined by the method described, and the results of duplicate and triplicate determinations at two sensitivites of the instrument are shown in Table 111. Results are shown in Table I.June, 19611 POLAROGRAPHIC DETERMINATION OF ANTIMONY IN REFINED LEAD TABLE I1 EFFECT OF DIFFERENT ELEMENTS ON THE DETERMINATIOK OF ANTIMONY IN LEAD A l-g sample of lead was used for each test 40 1 Amount of antimony Impurity Amount of impurity Amount of antimony Mean added, added added, recovered, recovery, Pg Pg % 100 Tin 100 { !) 100 100 Tin 200 { g:;:} 87.73 100 Tin 300 71-83 88-90 100 iiH) 100 { 95.4 E} 96.13 TABLE 111 DETERMINATION OF ANTIMONY IN REFINED LEAD Sample Sensitivity x Antimony found, Mean, No.amps per mm p.p.m. p.p.m. 6.3 24.4, 22.7, 24.4 ) 24.1 4.0 25.0, 22.8, 25.0 } 24.6 6.3 24.4, 24-4 4.0 24.6, 25.0 DISCUSSION OF THE METHOD As it is difficult to dissolve the sample in hydrochloric acid, dilute nitric acid (I + 4) is used.Zotta also used nitric acid, but, after precipitation of lead as lead sulphate, she suggested using the supernatant liquid for polarography. The supporting electrolyte was therefore a nitric acid- sulphuric acid mixture, in which it was found that the mercury from the drop as well as from the pool anode dissolved with the formation of mercuric nitrate. The mercuric nitrate so formed was reduced at the dropping electrode, thereby causing constant changes in height of the wave. Heating the test solution until fumes of sulphur trioxide were evolved removed nitric acid, and the wave could then be recorded in 3 ml of N sulphuric acid without any difficulty. It is reported that nitric acid may oxidise antimony to antimony pentoxide, which makes solution impossible, especially if tin is present. Different amounts of antimony were added to 1.0-g samples of lead, and the recoveries show that antimony is not lost as the pentoxide. When equal amounts of tin and antimony were added to lead the recovery was 100 per cent. For a ratio of antimony to tin of 1 to 2 the recovery was 87 per cent. and was much less for higher ratios. Bismuth, iron and copper in equal proportions do not interfere. 1. 2. 3. 4. 5. 6. 7. 8. 9. REFERENCES Green, F. A., “The Refining of Non-ferrous Metals,” The Institute of Mining and Metallurgy, Von Bayerl, V., Rec. Trav. Chim. Pays-Bas, 1925, 44, 514. Kalousek, M., Coll. Czech. Chem. Comm., 1939, 11, 592. Kraus, R., and Novak, J. V. A., Die Chemie, 1943, 56, 302. Hourigan, H. F., ,Inalyst, 1946, 71, 524. Hourigan, H. F., and Robinson, J. MT., Anal. Chim. Acta, 1954, 10, 281. Zotta, M., Gazz. Chim.. Ital., 1948, 78, 143. Kolthoff, I. M., and Lingane, J. J., “Polarography,” Second Edition, Interscience Publishers Inc., Received November 28th, 1960 London, 1950, pp. 281 to 325. New York, 1952, Volume 11, p. 606. , , ofi. cit., p. 547. --

ISSN:0003-2654    

DOI:10.1039/AN9618600399

出版商:RSC    

年代:1961

数据来源: RSC

摘要:

402 KAKABADSE AND WILSON THE COMPLEX OF VANADYLV [Vol. 86 The Complex of VanadylV with Ethylenediaminetetra-acetic Acid BY G. KAKABADSE AND H. J. WILSON (Department of Chemistry, College of Science and Technology, Manchesttv 1) From conductimetric measurements, the existence of a 1 to 1 complex of vanadylv ions and ethylenediaminetetra-acetic acid is established, and its application to volumetric analysis is suggested. The ratio of hydrogen ions to vanadium in the initial solution is critical and must exceed 5 ; the pH must be above 1-8. Conductimetric end-point detection is compared with a method in which xylenol orange is used as indicator. COMPLEXOMETRIC investigations of the vanadylV ion, V02+, with phosphate, citrate, tartrate, oxalate and ethylenediaminetetra-acetic acid (EDTA) ions have revealed marked comples- ation around pH 2 with oxalate and EDTA, and an attempt was made to define the quant- itative character of the V02+ - EDTA complex1 by the titration technique.It is obvious that the existence of this complex will, to a large extent, depend on the hydrogen-ion concentration, i.e., the minimum acidity required for its quantitative formation from the vanadate ion2- whereas the maximum acidity will be determined by the general stability requirements of a metal - EDTA complex- With increasing acidity, this equilibrium will be displaced to the left and the stability of the complex decreased? In this investigation the ratio of hydrogen ions to vanadium was varied between 1 to 1 and 60 to 1 and the vanadium concentration between 0.015 and 0.009 gram-atom of vanadium per litre.Owing to a rather limited choice of low-pH complexometric indicator^,*^^^^ end- point determinations were in the first instance carried out conductimetrically. When the existence of the complex had been established the indicator method was tried, with xylenol orange as indicator. EXPERIMENTAL REAGENTS- . . - - (1) .. - - (2) V0,- + 2H+ + VO,+ + H20 . . . . Men+ + H,Y2- + (MeY)n-4 + 2H+ . . Ammonium metavanadate-Analytical-reagent grade. Perchloric acid, 60 per cent. w,h-Analytical-reagent grade. EDTA solution-A standard solution of the disodium salt of ethylenediaminetetra- acetic acid. XyZenoZ orange solution-A 0.1 per cent. solution in dilute ethanol. PREPARATION OF STOCK VANADYL SOLUTION- Dissolve 1.1699 g of ammonium metavanadate in approximately 400 ml of distilled water, heat to assist solution, add 60 ml of M perchloric acid, heat to boiling to ensure complete conversion of the polyvanadate to the pale-yellow vanadyl ion, and make up to 1 litre with distilled water.This stock solution is 0.01 M with respect to vanadium and 0.06 M in perchloric acid. Alternatively, the vanadyl stock solution has been prepared by passing ammonium metavanadate solution through a column containing Zeo-Karb 225 resin' and receiving the solution of polyvanadic acid in perchloric acid of the requisite concentration. For conducti- metric work the latter method has the advantage of eliminating ammonium ions. Its dis- advantage is the need for subsequently determining vanadium, some of which is lost by adsorption on the resin.TITRATION- Transfer 5 ml of the stock vanadyl solution to a conical flask, dilute to the volume shown in Table 111, p. 405, add 5 drops of xylenol orange solution,s and titrate in the cold withJune, 19611 WITH ETHYLENEDIAMINETETRA-ACETIC ACID 403 0.01 M EDTA solution until the colour changes from red to pure yellow. Pyrocatechol violetg did not show a colour change. For conductimetric titration (see Figs. 1 and 2), transfer 25ml of the stock solution to a conductivity titration flask, dilute to about 200ml with distilled water, and titrate at room temperature with 0-05 M EDTA solution to minimise dilution effects. 2-o c Volume of 0.01037 M EDTA, ml Fig. 1. Conductimetric titrations of solutions (200 ml) containing polyvanadic and perchloric acids (concentrations as shown in Table I) with 0 .0 5 0 ~ EDTA a t about 20" c 2.4c L I Volume of 0.05 M EDTA, mi Fig. 2. Conductimetric titrations of solutions (200 ml) containing ammonium metavanadate and perchloric acid (con- centrations as shown in Table 11) with 0.01037 M EDTA at about 20" C Accurate conductivity measurements (see Fig. 3) were made at 25" i 0.001" C on solutions prepared individually with conductivity water. In each test 10 ml of vanadyl stock solution (polyvanadic acid plus perchloric acid), being 0.01845 M in vanadium and having a ratio of hydrogen ions to vanadium of 6.57 to 1, were transferred to a 50-ml cali- brated flask. The required amount of 0-0104 M EDTA solution was then added, and the volume made up to 50ml.This solution was transferred to a conductance cell, and, after it had been set aside for about 2 hours in a thermostatically controlled bath, its resistance was measured until constant readings were attained. These solutions were then retained for 7 days to attain equilibriurn,l0 when their resistances were measured again.404 KAKABADSE AND WILSON: THE COMPLEX OF VANADYL~ [Vol. 6 EQUIPMENT- Conductimetric titrations were carried out with a Cambridge conductivity bridge and dip-type electrodes. Accurate conductance measurements were made with a Jones and Bollinger type cellll kept at constant temperature in a Townson & Mercer S200 thermostatically controlled bath containing Puremore 210 light oil. The bridge consisted of Muirhead decade resistance boxes, the null-point was detected on a Cossor oscilloscope and the alternating-current supply was obtained from an Airmac oscillator at 1500 cycles per second.RE su LTS Results based on conductimetric end-point determinations are shown in Tables I and 11. In Table I, for which polyvanadic acid was used, the vanadium concentration was varied, whereas in Table 11, for which ammonium metavanadate was used, it was kept constant (except for curve 2 E). The titration flask was fitted with, a stirrer. TABLE I CONDUCTIMETRIC TECHNIQUE WITH POLYVANADIC ACID AS THE SOURCE OF VANADIUM Concentration of Concentration of Ratio of Theoretical Experimental vanadium, hydrogen ions, * hydrogen ions end-point, end-point, Curve gram-atoms per litre gram-ions per litre to vanadium ml ml 1A 0.00382 0.00382 1 15-28 - 1B 0.001 84 0.01595 7-59 7.36 7.4 1c 0-00368 0.02808 7.59 14-72 14-0 1D 0.00736 0.05234 7.59 29.44 28.8 * Including protons obtained from ion-exchange column during formation of polyvanadic acid.10 13 16 19 22 25 Volume of 0.01037 M EDTA, rnl Fig. 3. Accurate conductance measurements:at 25' 4 0.001" C of solutions containing polyvanadic and perchloric acids (0.00369 gram-atom of vanadium per litre; ratio of hydrogen ions to vanadium = 6.57) and different volumes of 0.01037 M EDTA (total volume made up to 50 ml): curve A, after 2 hours; curve B, after 7 days. Theoretical end-point at117.79 ml Conductimetric titration curves are shown in Figs. 1 and 2. As the breaks in these curves are in general somewhat ill-defined, only approximate experimental end-points are quoted in Tables I and 11.Fig. 3 shows accurate conductivity measurements on solutions 0.00369 M in vanadium and having a ratio of hydrogen ions to vanadium of 6.57 to 1. After 2 hours, the experi- mental end-point was reached on addition of 17.60 ml of standard EDTA solution, but, when set aside for 7 days, this break occurred at 18.20 ml (theoretical end-point at 17.79 ml).June, 19611 WITH ETHYLENEDIAMINETETRA-ACETIC ACID TABLE I1 405 CONDUCTIMETRIC TECHNIQUE WITH AMMONIUM METAVANADATE AS THE SOURCE OF VANADIUM Concentration of vanadium, Curve gram-atoms per litre 2A 0.00088 2B 0.00088 2C 0.00088 2D 0.00088 2E 0.001 78 Concentration of hydrogen ions, gram-ions per litre 0.00188 0.00555 0-01 11 0.0175 0.0111 Ratio of hydrogen ions t o vanadium 2.14 6.3 12.6 20 6.3 Theoretical end-point, ml 17.0 17.0 17.0 17-0 34.0 Experimental end-point, ml 6-5 16.8 16.8 17.5 34.5 Table I11 shows titration results with xylenol orange as indicator and a stock vanadyl solution prepared from ammonium metavanadate.TABLE 111 INDICATOR TECHNIQUE Total volume, ml (a) 100 (b) 100 (d) 100 (e) 100 (6) 100 (f) 10 ["h', 1:: (2) 12.5 ( 3 ) 30 Concentration of vanadium, gram-atoms per litre 0-0005 0.0005 0*0005 0.0005 0-0005 0-005 0.00 1 0.0005 0-004 0.0025 Concentration of hydrogen ions, gram-ions per litre 0.003 0.0055 0.013 0.018 0-023 0.03 0.03 0.03 0-044 0-065 Ratio of hydrogen ions to vanadium 6 11 26 36 46 6 30 60 11 26 End-point ITheoretical,Experimentai, ml of 0.01 M ml of 0.01 M EDTA EDTA 5.07 5.12 6-07 5-09 5.07 5.10 5-07 4.8 5.07 - 5.07 6-05 5-07 5-10 5-07 - 5.07 5.14 5.07 - (f = 0.986) (f -- 0.986) Error, / O +1 + 0.4 + 0.5 -5 - 0.4 0' - $- 0.6 + 1-3 - - PH - - 1-94 1.90 1-80 1-80 1-70 1-33 - - DISCUSSION OF RESULTS By using the absorptiometric technique Ringbom, Siitonen and Skrifvarsl established the formation of two complexes between quinquivalent vanadium and EDTA-V02Y3- (pH 6 to 9) and V02HY2- (below pH 3-5).These findings are difficult to understand, since cations are com- plexed by EDTA and the vanadyl cation is formed in appreciable quantities only beyond the isoelectric point of quinquivalent vanadi~m,l~9~3 i.e., below a pH of about 2. In our investi- gation, solutions with a low ratio of hydrogen ions to vanadium gave very low vanadyl titres (see curves A in Figs.1 and 2), which are attributed to incomplete formation of vanadyl ions. To establish minimum acidity conditions, or rather the minimum ratio of hydrogen ions to vanadium required for the quantitative conversion of vanadate to vanadyl ion in the reaction expressed by equation (1) we studied the hydrolysis of a 0.0017 M aqueous solution of vanadium pento xide with perchloric acid by means of accurate conductivity measurements (see Fig. 4)- V20, aq. + 2H+ + 2V02+ + H20 . . .. . . - (3) In Fig. 4, curve A, denoting the change in conductivity of the aqueous vanadium pentoxide - perchloric acid system, becomes parallel to curve B-conductivity of perchloric acid-when the ratio of hydrogen ions to vanadium is about 4 to 1, indicating that on further addition of acid no changes occur in the reaction denoted by equation (3).Moreover, at point P, the fall in conductivity from theoretical corresponds approximately to the removal of one proton per vanadium atom. Although the lower hydrogen ions to vanadium limit is fixed by the minimum acidity requirements for the quantitative conversion of vanadate to vanadyl ions,* the upper limit is governed by the general instability of the metal - EDTA complex in the presence of excess of acid (equation 2), which can be particularly serious with a univalent cation.l* In addition, the oxidising power of the vanadylv cation increases with increase in hydrogen-ion concentration,l5 thus rendering the risk of a redox reaction between VO,+ and EDTA more pronounced. * This ratio would correspond to 5 to 1 for ammonium metavanadate.406 KAKABADSE AND WILSON: THE COMPLEX OF VANADYL~ [Vol.86 The quantitative character of complex formation between EDTA and the univalent vanadylv cation near the lower hydrogen ions to vanadium limit was established by a series of accurate conductivity measurements (see Fig. 3) and by volumetric experiments (see Table 111) by the indicator method. At the'higher acidity limit, complexation is still quantita- tive when the ratio of hydrogen ions to vanadium is 26 (experiment (c), Table 111), whereas for a ratio of 36 the experimental end-point is 5 per cent. low, and, for even higher ratios, the colour change is so gradual as to make the end-point undetectable. This is also true when the total acidity is high (experiment ( j ) , Table 111).If it is large enough to cause the minimum acidity to drop the pH below 1.8, a satisfactory end- point is not obtained. At the other extreme, for very small amounts of vanadium in solution the metal-indicator colour becomes too faint, even above pH 1.8. In the indicator method, the concentration of vanadium has an indirect effect. I P 7- - IE 4 - % 5 - - I E m 0 - x 4 - Q) c 2 3 - U 8 u 2 - E a e, tn I - 0 0 3 6 9 I Ratio of hydrogen ions to vanadium Fig. 4. Conductivity curves a t 25' f 0.001" C for: curve A, solutions of vanadium pentoxide in perchloric acid (0.001 7 gram-atom of vanadium per litre) ; curve B, solutions of perchloric acid The rather ill-defined breaks in the conductivity curves (Figs. 1 and 2) may be attributed to the low concentrations of the solutions, rendering the conductivity measurements less accurate. As regards the redox character of the vanadylv - EDTA system, we found that partial reduction to the blue vanadylIv ion occurs in solutions of high hydrogen-ion concentration, Around pH 2, this reduction appears to be slow and does not interfere with the titrimetric determination of the vanadylv ion.Even when the solution is set aside for 7 days, the conductivity break was only 2.2 per cent. high (see Fig. 3). Although the vanadylv - EDTA complex seems to be only moderately stable and involves a delicate balance between minimum and maximum acidity requirements, we suggest the method described below for the volumetric determination of vanadium. Place the vanadium compound, containing between 7.5 and 25 mg of vanadium, in a 250-ml conical flask together with 30 ml of 0.1 M perchloric acid, gently boil the solution, cool, and dilute to about 100ml. Add 3 drops of indicator solution, and titrate with 0.01 M EDTA until the last trace of orange disappears and the solution is pure yellow.50.95 g of vanadium 5 1000 ml of M EDTA :. 100 ml of 0.01 M EDTA = 51 mg of vanadium. We thank Dr. T. S. West for recommending the use of xylenol orange and for supplying We also thank the Manchester This is overcome to a large extent by the improved instrumentation (Fig. 3). us with samples of xylenol orange and pyrocatechol violet. Oil Refinery for a gift of Puremore 210 light oil.June, 19611 WITH ETHYLENEDIAMINETETRA-ACETIC ACID 407 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. REFERENCES Ringborn, A., Siitonen, S., and Skrifvars, B., Acta Chem. Scand., 1957, 11, 551. Ducret, L.-P., Ann. Chim., 1951, 6, 705. Barnard, A. J., Broad, W. C., and Flaschka, H., Chemist Analyst, 1956, 45, 86. Belcher, R., Lab. Practice, 1960, 9, 568. Belcher, R., Leonard, M. A., and West, T. S., J . Chem. Soc., 1958, 2390. Headridge, J. B., Analyst, 1960, 85, 379. Russel, R. U., and Salmon, J. E., J . Chem. Soc., 1958, 4708. Korbl, J., and Pfibil, R., Chemist Analyst, 1956, 45, 102. Flaschka, H., and Sadek, F., Mikrochim. Acta, 1957, 1. Martell, A. E., and Calvin, M., “Chemistry of Metal Chelate Compounds,” Prentice-Hall, New York, Jones, G., and Bollinger, G. M., J . Amer. Chem. Soc., 1931, 53, 411. Sidgwick, N. V., “The Chemical Elements and Their Compounds,” The Clareiidon Press, Oxford, Jander, G., and Jahr, K. F., 2. anorg. Chem., 1933, 212, 1. Genge, J. A. R., Lab. Practice, 1960, 9, 592. Kakabadse, G., and Wilson, H. J., J . Chem. SOC., 1960, 2475. 1952, p. 87. 1950, p. 812. Received January 12th, 1961

ISSN:0003-2654    

DOI:10.1039/AN9618600402

出版商:RSC    

年代:1961

数据来源: RSC

摘要:

June, 19611 WITH ETHYLENEDIAMINETETRA-ACETIC ACID 407 Colorimetric Determination of Copper with Zinc OO-Di-isopropyl Phosphorodithioate BY W. A. FORSTER," MRS. P. BRAZENALL? AND J. BRIDGE (Albright & Wilson (Mfg.) Ltd., P.O. Box hTo. 3, Oldbury, Birmingham) Zinc 00-di-isopropyl phosphorodithioate is recommended for the colori- metric determination of copper in the range 4 to 40 pg. Beer's law is obeyed, and both the solid reagent and its solution in carbon tetrachloride are stable. The method is rapid and precise, and large excesses of aluminium, antimony, arsenic, barium, cadmium, calcium, cobalt, chromium, ferrous and ferric iron, lead, magnesium, manganese, mercury, nickel, potassium, sodium and zinc do not interfere. Results are high when more than 0.1 mg of bismuth is present and erratic in presence of more than 5 mg of silver.OF the many reagents recommended for determining copper colorimetrically, cuproinel and zinc dibenzyldithiocarbamate2 are perhaps of most general use. Cuproine is specific, but requires careful control of pH ; zinc dibenzyldithiocarbamate (like zinc 00-di-isopropyl phosphorodithioate) is non-specific, but applicable over a wide range of acidity. Zinc 00-di-isopropyl phosphorodithioate is less subject to interference from antimony, mercury, nickel and silver than is zinc dibenzyldithiocarbamate, but more subject to interference from arsenic and chromium. Bismuth interferes seriously when either of the zinc compounds is used. Busev and Ivanyutin,3 in a short paper published in 1957, described the use of potassium 00-diethyl phosphorodithioate for the colorimetric determination of copper.We were interested in their paper, inasmuch as zinc 00-di-isopropyl phosphorodithioate had been used for several years in this laboratory as a reference substance for determining phosphorus in organic compounds and for the colorimetric determination of dialkyl phosphorodithioates. We therefore decided to investigate its suitability as a colorimetric reagent for copper. EXPERIMENTAL Acid solutions containing copper were extracted with a 0-04 or 0-004 per cent. solution The extracts obtained (;) Beer's law is obeyed over the range 4 to 40 pg of copper when a mercury-vapour The yellow complex with copper of zinc 00-di-isopropyl phosphorodithioate in carbon tetrachloride. were examined with a Spekker absorptiometer, and the results showed that- lamp and filters transmitting a t 4047 A are used.has an absorption maximum at approximately 4200 A. * Present address: B.I.P. Chemicals Ltd., Oldbury, Birmingham. t Present address : 58 Darnick Road, Sutton Coldfield, Warwickshire.408 FORSTER, BRAZENALL AND BRIDGE COLORIMETRIC DETERMINATION OF [VOl. 86 (ii) Bright sunlight causes the colour to fade slowly; in one experiment, the optical (iii) A single extraction for 30 seconds removes copper completely. (iv) Wide variation in acidity is permissible. density decreased by 36 per cent. in 3 hours. Experiments were carried out in which 50-ml portions of solutions of different acidity and containing 24pg of copper were extracted with 25-ml portions of a 0-004 per cent.solution of zinc 00-di-isopropyl phosphorodithioate. Twenty-two such experiments under the conditions of acidity listed below gave a standard deviation of only +_0-002 unit of optical density. Acid . . . . .. . . Sulphuric Hydrochloric Perchloric Orthophosphoric Nitric Acidity of extracted solution 0.1 to 5 N 0.1 t o 5 N 0.1 to 5 N 0.1 to 1.5 M 0.2 to 2 1 \ ~ The colour of the extract from a solution 3 N in nitric acid fades rapidly; for the other acids, no experiments were made at concentrations higher than the maximum values indicated above. (v) Wide variation in the concentration of the zinc 00-di-isopropyl phosphoro- dithioate solution is permissible. In most of the preliminary experiments we used a 0.004 per cent. solution, but studies on interfering ions showed that a 0.04 per cent.solution is better. (vi) Delay between the addition of the zinc 00-di-isopropyl phosphorodithioate solution and shaking should be avoided. Experiments were made in which intervals of 0, 2, 5 and 10 minutes elapsed, and the optical-density readings were 0.232, 0.224, 0.216 and 0.191, respectively. The probable explanation for this decrease in optical density is that dialkyldithiophosphoric acid slowly passes into the aqueous layer and there forms the cupric complex. It is known that the latter, in aqueous solution, rapidly changes to a colourless cuprous compound. Both 0.004 and 0.04 per cent. solutions of zinc 00-di-isopropyl phosphorodithioate were stored for 10 weeks in plain- glass bottles on the laboratory window-sill without deterioration. (vii) The stability of the reagent is excellent.METHOD REAGENTS- Carbon tetrachEoride, pwrified-The use of technical-grade carbon tetrachloride occasionally leads to low results, owing, we suspect, to the presence of traces of phosgene. Purify the solvent by shaking 600 ml of it successively with 100 ml of dilute ammonia solution (1 + 4) and two 100-ml portions of water. Dry the carbon tetrachloride over anhydrous sodium sulphate, and store in a dark-glass bottle. Zinc 00-di-isopropyl phosphorodithioate solution, 0.04 per cent. w/v-Dissolve the neces- sary amount of solid reagent, prepared as described below, in purified carbon tetrachloride. Hydrochloric acid, sp .gr. 1.18-Analyt ical-reagent grade. Standard copper sohution-Dissolve 0.1964 g of hydrated copper sulphate, CuS0,.5H20, in water in a 250-ml calibrated flask, acidify with a little hydrochloric acid, and dilute to the mark with water.Dilute 10 ml of this solution, again acidified with hydrochloric acid, to 250 ml; prepare this solution freshly each day, as required. PREPARATION OF ZINC 00-DI-ISOPROPYL PHOSPHORODITHIOATE- Weigh 10 g of phosphorus pentasulphide into a Quickfit & Quartz 250-ml conical flask, attach a reflux condenser, add 100ml of isopropyl alcohol, and heat for 5 minutes or more on a water bath, with frequent agitation, to give a clear solution. Cool to about 40" C, and expel hydrogen sulphide by passing a stream of nitrogen through the liquid for 3 minutes. Add 4 g of analytical-reagent grade zinc oxide, heat on the water bath for 10 minutes, and filter the hot mixture through a sintered-glass funnel (porosity No.4). Chill the filtrate, separate the crystals that form, and wash them with two small portions of cold isopropyl alcohol. Recrystallise twice from hot isopropyl alcohol, and dry the white crystalline product in air ; this procedure yields about 6 g of zinc 00-di-isopropyl phosphorodithioate. Each melted at 145" "I 2" C and contained proportions of carbon, hydrogen and phosphorus that agreed well with the values calculated from the formula [(C,H,O),PSS],Zn. All four samples gave satisfactory results in the colorimetric determination of copper. 1 ml E 8 pg of copper. Four samples were prepared in this way.June, 19611 COPPER WITH ZINC 00-DI-ISOPKOPYL PHOSPHORODITHIOATE 409 PROCEDURE- Place an aliquot of solution containing 4 to 40 pg of copper in a Pyrex-glass 125-ml separating funnel, and dilute with water to approximately 50 ml, adding sufficient hydro- chloric acid, sp.gr.1.18, to make the diluted solution approximately 4~ in this acid. By pipette, add 25 ml of 0.04 per cent. zinc 00-di-isopropyl phosphorodithioate solution to the contents of the separating funnel; fill the pipette by means of suction from a water pump. Without delay, shake the separating funnel vigorously for 30 seconds, and allow the layers to separate. Dry the stem of the separating funnel with a roll of filter-paper, and insert a loose plug of cotton-wool. Measure the optical density of the extract in a 2-cm cell with a Spekker absorptiometer; use a mercury-vapour lamp and a filter transmitting at 4047 A.,\lternatively, use any system permitting measurements to be made in the vicinity of 4200 A. TABLE I EFFECTS OF VARIOUS CATIONS The amount of copper taken for determinations by the proposed method was 24 pg; amounts from 10 to 40 pg were used in the zinc dibenzyldithiocarbamate method, as recommended by Johnson.2 The figures for each cation are the maximum amounts that may be present if the error is not to exceed &2 pg of copper Maximum amount permissible in- I A 1 zinc dibenzyldithio- Cation added proposed method, carbamate method, g !? ~ 1 3 + 0.5 0.5 Sb3 + 0.05" <0.01 -\s3+ 0.17 0.5 Ra2L 0.5 - Ri3f < 0-000 1 < 0.002 Cd2+ 0.3 0.5 Ca2 + 0.5 0.5 co2+ 0.01 0.0 1 0.5 Cr3 + - CrsL 0.01 - Fe2'- 0.5 0.5 Fe3 + 0.01 < 0.5 Pb2+ 0.5 0.5 Mg2+ 0.5 - Mn2+ 0.5 0.5 Hg2+ 0.05 0~0001 Ni2 + 0.5 0.05 K" 0.5 - Ag+ 0.005 0~0001 Na+ 0-5 - Zn2+ 0.5 0.5 * Colour fades in the presence of antimony, and the optical t Solution and reagent shaken for S minutes.density must be read with dispatch. CALIBRATION- Transfer portions of the standard copper solution ranging from 0 to 5 m l to separate 125-ml separating funnels, and add to each portion, from a measuring cylinder, 17.5 ml of hydrochloric acid, sp.gr. 1-18. Dilute each solution with water to approximately 50 ml, add reagent, extract, and measure the colour as described above. INTERFERENCES CATIONS- The effects of twenty cations were studied, and the amounts that may be present when determining 24 pg of copper are listed in Table I, which also shows comparative results for zinc dibenzyldithiocarbamate.Bismuth interferes seriously with the proposed method by forming a complex that absorbs strongly in the near-ultra-violet region ; this interference could perhaps be overcome by using a prism or grating spectrophotometer. Silver must not be present in amounts greater than 5mg.410 FORSTER, BRAZENALL AND BRIDGE [Vol. 86 The effects of the twenty cations were also investigated by means of a modified method, the concentration of hydrochloric acid being decreased from 4 to 0.1 N and that of the zinc 00-di-isopropyl phosphorodithioate solution from 0.04 to 0.004 per cent. Several cations interfered to a greater extent when the modified method was used, as shown by the results below.Cation . . . . . . . . . . . . Sb3+ Fez+ Fe3+ Hg2+ Ni2+ Maximum amount permissible for error of 2 2 pg of copper, g . . . . .. . . . . 0.0005 0.05 t0.005 0.0001 0.01 Only arsenic interfered less, the permissible amount being 0.5 g. Interference from bismuth-As much as 0.01 g of bismuth may be present if the acidity of the test solution is kept at 4~ in hydrochloric acid and the concentration of the zinc 00-di-isopropyl phosphorodithioate solution is decreased to 0.004 per cent. Interference from ferric iron also disappears under these conditions, and as much as 0.5 g of this ion may be present. AWONS- are summarised in Table 11; only molybdate and iodide interfered to a marked extent. The results of experiments carried out in presence of nine sodium and potassium salts TABLE I1 EFFECTS OF VARIOUS SALTS The figure for each salt is the maximum amount that may be present if the error in determining 24 pg of copper is not to exceed +2 pg Maximum amount permissible g Sodium acetate .. . . .. .. .. 0.5 Potassium bromide . . .. .. .. 0.5 Trisodium citrate . . .. .. . . .. 0.5 Potassium iodide . . .. . . .. 0.0 1 Sodium molybdate dihydrate . . . . .. 0.05 Sodium nitrite . . .. .. .. . . 0*25* Potassium oxaIate monohydrate . . .. 0.5 Potassium permanganate . . .. .. 0.5t Salt added in proposed method, Potassium sodium tartrate tetrahydrate . . 0.5 * Add 0.5 g of potassium permanganate, boil until pale brown in colour, t Boil until pale brown in colour, and cool before extraction. and cool before extraction with reagent solution. CONCLGSION In developing this method, we had in mind its eventual application to calcium phos- phates and decided on that account t o use hydrochloric acid solutions. It seems probable from the information under “Experimental” that other acids could equally well be used in determining copper colorimetrically. We thank Mr. S. F. Holder for suggesting this investigation and for his interest in its progress and the Directors of Albright &Wilson (Mfg) Ltd. for permission to publish this paper. REFERENCES 1. 2. 3. Diehl, H., and Smith, G. F., “The Copper Reagents: Cuproine, Neocuproine, Bathocuproine,” Johnson, W. C., Editor, “Organic Reagents for Metals, and Other Reagent Monographs,” Fifth Busev, A. I., and Ivanyutin, M. I., Vestn. Moskov. Univ., 1957 (5), 157; Chem. Abstr., 1958, 52, Received December 30th, 1960 G. Frederick Smith Chemical Co., Columbus, Ohio, 1958. Edition, Hopkin & Williams Ltd., Chadwell Heath, Essex, 1955, Volume I, p. 188. 19,676.

ISSN:0003-2654    

DOI:10.1039/AN9618600407

出版商:RSC    

年代:1961

数据来源: RSC

摘要:

June, 19611 NOTES 41 1 Notes THE COMBUSTION OF ORGANIC COMPOUNDS BY IGNITION IN OXYGEN: THE DETERMINATION OF CARBON AND HYDROGEN THIS Note is a preliminary report of an investigation in which the flask combustion technique was used to determine carbon and hydrogen in organic substances. The first serious attempt to determine carbon and hydrogen involved igniting a mixture of the weighed sample with a known weight of potassium chlorate. This ignition process, de- veloped by Gay-Lussac and Thenard in 1810, was carried out by dropping the pelleted mixture into a closed tube held in the vertical position and heated a t its lower end by the flame of a spirit lamp. When the pellets came into contact with the hot end of the tube, ignition occurred, with the production of oxygen, carbon dioxide and water vapour.These products were collected over mercury, and the amounts of carbon and hydrogen in the sample were determined by gasometric analysis of the mixture. The obvious drawback to this method was the crude way in which the weights of products were obtained, and it was by no means certain that the carbon dioxide had been quantitatively collected. Because of this, the principle of combustion now in common use was evolved by Liebig from earlier work by Berzelius and has not changed, even with its application by Pregl to the combustion of a few milligrams of material. Over the years, the simple operation of direct ignition has been lost, and the method has become one of a rather complex nature, in which com- plicated and expensive apparatus is used to burn the few milligrams of substance involved.On the micro scale, great effort has been, and still is being, directed towards hastening the method of analysis and making the combustion operation less tedious; rapid combustion,l the use of catalysts, such as thermally decomposed silver permanganate,2 and automation of the combustion procedure are typical examples of the means used to achieve these aims. At the turn of the century, some workers attempted to establish a method in which the sample was ignited in a Berthelot bomb under pressure of oxygen (20 atmospheres) by means of an electrically heated platinum wire. After combustion, the mixture of carbon dioxide and water vapour was swept out with a current of purified air and analysed. This method did not become established because it had some faults; for example, the presence of nitrogen oxides and oxidation products of the halogens and sulphur caused complications. In view of the success of Hempel's oxygen flask combustion technique, a s adapted to the micro scale by Schoniger3 and now an established procedure, an attempt has been made to adapt this technique to the determination of carbon and hydrogen.Some preliminary experiments have established a simple and rapid method of determining carbon and hydrogen on the micro scale, and this method has overcome the need for using a baffle-chamber combustion tube.1 In the first instance, the weighed sample (about 3 mg) was ignited by passing an electric current through a platinum-wire coil placed round the sample boat held in a spherical 200-ml flask filled with oxygen.After ignition, the carbon dioxide and water were swept out by passing a stream of purified oxygen at the rate of 30 to 35 ml per minute and determined gravimetrically. The results were not satisfactory, being low and inconsistent; the losses were not caused by leakage from the flask, but by incomplete combustion. Malissa* recently described a method in which the sample was decomposed in a fast flow of oxygen a t a high temperature. The carbon dioxide formed was absorbed in sodium hydroxide solution and determined by means of a conductivity measurement. In the light of this work, further experiments were carried out in which the sample was introduced directly into a combustion chamber heated by a furnace (at about 750" C), oxygen being allowed to flow through the chamber a t 35ml per minute.After continued sweeping for 15 minutes, the carbon dioxide and water collected in weighed absorption tubes were determined. In these experiments, the results for hydrogen were satisfactory, but those for carbon were low by about 2 per cent. Finally, it was established that correct results for carbon and hydrogen could be obtained with the required accuracy by introducing the sample into the oxygen-filled chamber, but without maintaining the flow of oxygen during combustion. As soon as the sample had burned, a matter of a few seconds after its introduction into the hot zone, oxygen was passed into the chamber to sweep out the water and carbon dioxide, which were absorbed in the conventional manner for subsequent gravi- metric determination.412 NOTES [Vol.86 DESCRIPTION OF COMBUSTION APPARATUS The combustion tube had the shape shown in Fig. 1 and was constructed from quartz tubing having a wall-thickness of 1.8 to 2 mm. The chamber, A, was 150 mm long and about 33 mm in internal diameter; it had a volume of about 130 ml at room temperature and contained about 50ml of oxygen at its operating temperature. The length of tubing from the chamber to the ground joint was 150 mm, and its bore was about 14mm. Oxygen was admitted via a side- arm, B, 150mm in length, sealed to the tube just below the ground joint. The exit from the chamber consisted of a 90-mm length of tubing, C (8 to 9 mm bore), provided with a "beak" 30 mm long and 3-6 mm in diameter.A roll of silver gauze was placed in the exit tube to retain halogen and sulphur oxidation products. The chamber was heated by an electric furnace at 720" to 750" C, and the temperature of the silver gauze was maintained a t about 550" C by another electric furnace. Water and carbon dioxide were absorbed in Flaschentrager tubes packed with suitable reagents ; when nitrogen-containing compounds were analysed, the oxides of nitrogen were retained by manganese dioxide in an absorber1 placed between the two Flaschentrager tubes. A = Combustion chamber B = Side-arm F = Platinum-wire coil C = Exit tube containing silver gauze D = Flaschentrager tube for absorbing water E = Sample holder G = Borosilicate-glass sleeve Fig. 1. Diagram of combustion apparatus The oxygen was purified by passing it through a pre-heater and a large U-tube containing soda asbestos and anhydrone and was passed into the combustion tube via a stopcock attached with rubber tubing to side-arm B.The flow of gas was controlled a t 50 ml per minute by means of a precision screw-clip and a pressure regulator. The flow was measured with a Rotameter reading to 200 ml of oxygen per minute. The sample was introduced into the combustion chamber by means of a special holder, E. This consisted of a quartz tube, 330 inm long and 6 mm external diameter, having a coil of platinum wire, F, sealed into one end. The coil was made from a piece of 16 s.w.g. wire about 170 mm in length formed into a spiral (about 25 mm long) by winding it round a piece of glass rod 8 to 8-5 mm in diameter.The other end of the quartz tube was provided with an iron core of length 70mm kept in position by an indentation in the wall of the tube. The holder was placed inside an elongated borosilicate- glass sleeve, G, sealed into the ground-joint cap closing the mouth of the combustion tube. The sleeve projected 20 mm beyond the edge of the joint, as shown in Fig. 1. Tube E fitted into sleeve G in a way such that it would slide in and out easily, without friction. The sample was moved into the centre of the combustion chamber in one operation by application of a magnet to the iron core. In preliminary experiments, the holder was pushed into the chamber by hand, the tube being fixed in a rubber sleeve attached to the ground cap. It was found, however, that high blank values were obtained after the apparatus had been used because of a leak through the rubber sleeve.The sample boat was placed in the coil for introduction into the chamber. METHOD The absorption tubes were conditioned as for a rapid combustion1 for 10 minutes, with oxygen Blank determinations were carried out, and it was established that flowing a t 50 ml per minute. the blank value for water was 0.05 mg; the blank r d u e €or carbon dioxide xvas negative.June, 19611 NOTES 413 COMBUSTION- The weighed absorption tubes were attached to the combustion tube, and the ground cap was carefully removed from the mouth of the tube. Oxygen was allowed to escape via the open tube, and then the sample boat was placed in the platinum spiral of the holder, which was still completely in the sleeve.The holder was replaced, and the joint was secured with springs. Oxygen was passed through the apparatus at 50 ml per minute for 1 minute, the stopcock was turned off, and, after a few seconds, the inlet tap - stopper of the water-absorption tube was closed. With the aid of a magnet, the sample holder was then pushed, in one movement, into the centre of the combustion chamber. As soon as the sample had burned, the stopcock connected to the side-arm was opened to permit oxygen to enter the combustion tube, the inlet tap - stopper of the water-absorption tube was opened, and the apparatus was swept out with oxygen for 13 minutes at the rate of 50ml per minute. The absorption tubes were then disconnected as described for the rapid-combustion meth0d.l TABLE I RESULTS FOR CARBON AND HYDROGEF BY THE PROPOSED METHOD Compound Anthracene .. Naphthalene . . Benzene . . Octan-2-01 . . Benzoic acid . . Succinic acid . . Sucrose . . * . Phenacetin . . p-Nitroaniline . . p-Chlorobenzoic acid Sulphonal . . Triphen ylphosphine Weight of s a m p 1 e , mg 2.127 2.200 3.745 3.545 4.283 3.675 3.900 2.481 3.154 3.227 3-230 3.896 4.678 3.748 3.886 3-313 3.498 3-061 3.493 2.684 3.573 3.642 4.685 3.184 3.847 Carbon content found, 94.62 94-46 94-25 93.62 93-84 92.35 92.18 73.70 73.97 68.75 69.02 40.87 40.50 42.01 42.20 67.09 67-21 52-24 52-26 53.76 53.75 36.92 36.74 82-60 82.52 Yo Hydrogen content found, % 5.78 5-59 5-54 6.30 6-22 7-88 7-92 13.75 13.97 5.06 4-95 5.09 5.03 6-38 6.36 7-29 7-37 4.36 4.59 3.32 3.28 7.13 7-10 5.82 5.70 Calculated carbon content, % 94.36 93-75 92.26 73.78 68-90 40.68 42.10 67.04 52.13 53.68 36.81 82.41 Calculated hydrogen content, % 5-66 6-26 7.74 13-93 4-96 5.08 6.48 7.26 4-38 3-22 7.06 5-76 DISCUSSION OF THE METHOD The method has been tested with several types of organic compounds, and typical results are shown in Table I.Samples containing carbon, hydrogen, oxygen and nitrogen (the last-named present as NH,, NO or NO,) have been analysed satisfactorily by using a combustion tube without the exit tube containing silver gauze attached; the chamber was heated with the flame of a large bunsen burner, giving an operating temperature of 725" to 75OOC. In these experiments, the chamber was enclosed in a sheath of nickel foil, the ends of which were encased in plates of thick asbestos sheet.No difficulty was experienced in analysing liquids, e.g., benzene. Liquid samples were weighed in the usual form of capillary tube and placed in a short piece of quartz tubing 65 mm long and 6.5 to 6 mm in bore. The quartz sleeve was placed in the platinum spiral for introduction into the combustion chamber.414 NOTES pol. 86 Triphenylphosphine has been analysed satisfactorily by covering the sample in the boat with tungstic oxide: and the analysis of organo-metallic compounds is being investigated. Promising results have been obtained with fluorine-containing substances, e.g., m-trifluoromethyl- benzoic acid; such samples were covered with magnesium o ~ i d e . ~ When a flux or reagent was used, the sample was weighed in a long narrow boat, which was then placed in a quartz sleeve before insertion into the platinum spiral.Initially, tests were carried out in which the sample was introduced into the hot zone by means of a short form of the holder E, which was placed immediately behind the cap of the tube, so eliminating sleeve G. However, this simple method of moving the sample holder into the hot zone was not always satisfactory, as the holder tended to rotate when moved forward by means of the magnet, and sample or added reagent was tipped out into the combustion tube. It is hoped that this simple combustion procedure will eventually be able to cope with all types of compounds difficult to analyse by other established methods, and work is proceeding with this aim in mind.The method of combustion provides a means of analysing the “difficult” organo-metallic compounds now being prepared, because suitable reagents can be sought to assist decomposition; the use of such reagents, coupled with a high temperature of combustion, permits quantitative oxidation. The possibility of increasing the rate of flow of oxygen to 100 ml or more per minute is being considered, as such an increase would cut the sweeping-out period by half. Other aspects being investigated are the determination of the water and carbon dioxide mano- metrically, so that the method could be extended to the determination of compounds containing carbon-14. The method of combustion also provides a simple way of decomposing samples for the determination of the halogens and sulphur, particularly when combustion is found to be difficult by the oxygen flask procedure.Work on these methods is in progress, and it is hoped that a full account of the investigations will be published later. REFERENCES Belcher, R., and Ingram, G., Anal. Chim. Acta, 1950, 4, 118. Korbl, J., Coll. Czech. Chem. Comm., 1955, 20, 948. Schoniger, W., Mikrochinz. Acta, 1955, 123; 1956, 869. Malissa, H., in “Proceedings of the International Symposium on Microchemistry, 1968,” Pergamon Belcher, R., Fildes, J , E., and Nutten, A. J., Anal. Chim. Acta, 1955, 13, 431. 1 . 2. 3. 4. 5. 6. Throckmorton W. H., and Hutton, G. H., Anal. Chem., 1952, 24, 2003. Press, Oxford, London, New York and Paris, 1960, p. 97. COURTAULDS LIMITED, RESEARCH LABORATORY MAIDENHEAD, BERKS.G. INGRAM Received January 5th, 1961 THE DETERMINATION O F NITRITE IN WATER MOST methods described for the determination of nitrite depend on diazotisation. The diazonium compound formed is usually determined colorimetrically, either by direct measurement1 or after being coupled with a suitable reagent. The latter principle is employed in the Griess - Ilosvay method, various modifications2 of which are commonly used in water analysis. This method, although reliable, suffers from a number of disadvantages : the colour formed is rather unstable, the reagent, I-naphthylamine, deteriorates when stored, and samples may require excessive dilution on account of the small range over which results are reproducible. The method described in this Note is largely free from these disadvantages. Garner, Baumstark, Muhrer and Pfander determined nitrate by a method: later improved by Hill, Pivnick, Engelhard and B ~ g a r d , ~ in which a bacterial culture was used to reduce the nitrate to nitrite; this ion was then determined as in the Griess - Ilosvay method, except that N-( 1-naphthy1)ethylenediamine was used instead of I-naphthylamine.Sulphanilic acid and N-( 1- naphthy1)ethylenediamine had previously been used for the indirect determination of nitrogen dioxide by Saltzman,S who found that these reagents were more satisfactory than the Gness - Ilosvay reagents or the combination of sulphanilamide and N-( 1-naphthy1)ethylenediamine introduced by Shinn.6 By modification of the conditions used by Garner and his co-workers, we have developed a convenient method for determining nitrite in water.The reagents are added separately, instead of together as in the earlier procedures, and the acidity of the solution is established with potassiumJune, 19611 NOTES 416 hydrogen sulphate, which has a greater buffering capacity than the acetic acid normally used. Beer's law is obeyed up to 2 pg of nitrite-N, and amounts up to 8 pg ca.n be determined with use of a calibration graph. (The official Griess - Ilosvay procedure2 formerly used in this laboratory does not give good reproducibility for amounts of nitrite-N greater than 1 pg.) The colour pro- duced is more intense by 13 per cent., and blank values are less than half of those obtained in the official procedure.The N-( 1-naphthyl) eth ylenediamine hydrochloride solution can be stored in the dark for at least 2 months. TABLE I COMPARISON OF RESULTS BY PROPOSED AND OFFICIAL Sample Percolating-filter effluent A Percolating-filter effluent B I Thames water from Tilbury (salinity 13.4 parts per thousand) -*I Percolating-filter effluent C . . i Digester effluent containing phenols r I Sea water from Worthing . . f . Nitrite added (as N), p.p.m. 0.0 4.0 6.0 8.0 0.0 0.1 0.2 0.3 0.0 0.2 0.4 0-6 0.0 0.2 0.4 0.6 0.0 0.1 0.15 0.2 0.3 0.0 0.1 0.15 0.0 0.4 0.8 1.2 0.0 0.4 0.8 1-2 0.0 0.05 0.1 0.15 0.0 0.05 0.1 0.15 Total nitrite (as N) found by- r proposed method, p.p.m. 3.0 7.0 9.1 0.13 0-23 0.33 0.43 0.15 0.36 0.56 0.77 0.15" 0.34" 0*53* 0.72" 0.042 0.142 0-194 0.241 0.042" 0.140" 0.183" 0.79 1-21 1.58 2.00 0.73" 1.11" 1-48" 1.88" 0-008 0-055 0.108 0.157 0.008" 0.060" 0.112" 0.162" - - official method, p.p.m.3.0 7-0 11.1 - 0-14 0.23 0.33 0-42 0.17 0.37 0.5 7 0.76 - - - - 0.040 0-135 0.234 0.339 - - - - 0-82 1-24 1.61 2.02 - - - - 0.004 *0*051 0.101 0.144 - - - - METHODS Bias (as N) of- - proposed method, p.p.m. 0.0 +0.1 - - - 0.0 0.0 0.0 + 0.01 + 0.01 + 0.02 -0.01 - 0-02 - 0.03 0.0 + 0.002 - 0.001 - - - - - - 0.002 - 0.009 + 0.02 - 0.01 + 0.01 - 0-02 - 0.05 - 0.05 - - - - 0.003 0.0 - 0.001 + 0.002 + 0.004 + 0-004 - official method, p.p.m. 0.0 + o w 1 -0.01 - 0.01 - 0.02 0.0 0.0 - 0.01 - - - - - - - - - - 0.003 - 0.006 - 0.00 1 - - I - - + 0.02 -0.01 0.0 - - - _- - - 0.003 - 0.003 - 0.010 - - - - * Large sample taken; optical density measured in 1-cm cells.NO quantitative statements on the stability of the colour produced in the Griess - Ilosvay method have been found in the literature, although there are reports of precipitation or intensi- fication of the colour. In a 24-hour test of the stability of the colour produced by the official procedure2 in this laboratory, the colour derived from a standard solution of pure nitrite decreased by 2 per cent. and those from sewage effluents showed increases ranging up to 6 per cent. Under similar conditions, the colours obtained in the proposed method remained within 2.5 per cent. of their initial intensities for 2 days. When typical samples were analysed by both methods, there was good agreement between the two sets of results, some of which are shown in Table I.The samples, which included sea416 NOTES [Vol. 86 water and water from the Thames Estuary, were then fortified with known amounts of standard nitrite solution and again analysed. The increments observed normally agreed with the calculated values, but certain samples initially extremely low in nitrite (less than 0.1 p.p.m. of nitrite-N) showed a bias towards low recovery by both procedures. For samples from the Stevenage Brook, this effect is associated with warm and dry weather conditions. -4 similar bias was observed with effluents from the biological treatment of farm wastes containing phenolic disinfectants ; for these effluents, however, the bias could be removed by taking much smaller samples for the determination. Although most of the optical-density measurements were made at 550 m p with a spectro- photometer, an identical calibration graph was obtained when a Spekker absorptiometer and a Spectrum Green No.604 filter were used. METHOD REAGENTS- sulphanilic acid in water, and dilute to 1 litre. PROCEDURE- Clarify the sample, if necessary, by filtration or centrifugation, measure a suitable volume (not more than 30 ml) into a 50-ml calibrated flask, and adjust the temperature to between 20" and 30" C. (For effluents containing phenols, use the smallest practicable sample; otherwise, take a sample containing between 0.2 and 1.0 pg of nitrite-N unless the concentration is high, when up to 8 pg may be tolerated.) Dilute to a t least 10 ml, add 2.5 ml of sulphanilic acid solution, and set aside for 10 minutes.Add 2.5 ml of N-( 1-naphthy1)ethylenediamine hydrochloride solution, set aside for 20 minutes, dilute to the mark, and measure the optical density at 550 mp against a reagent blank solution; use 4-cm cells unless the amount of nitrite-N present exceeds 1.5 pg, when 1-cm cells are satisfactory. For the most accurate work, or with turbid or highly coloured samples, prepare an additional blank solution by carrying out the procedure described above, but omit the N-( 1-naphthy1)ethylenediamine hydrochloride solution. Measure the optical density against distilled water, and subtract the value from the optical density found in the test. This correction is usually negligible. Ascertain the nitrite content of the sample by reference to a calibration graph plotted from the results obtained for standard solutions of nitrite; we have found that solutions of analytical- reagent grade sodium nitrite (previously dried at 110" C) in freshly distilled water are suitable for this purpose and are stable for a t least 1 month. The purity of the sodium nitrite was checked by titration against a standard solution of potassium permanganate.This Note is published by permission of the Department of Scientific and Industrial Research. Sul$hanilic acid solution-Dissolve 27.2 g of potassium hydrogen sulphate and 3.46 g of N-( 1-Waphthy1)ethylenediamine hydrochloride solution, 0.04 per cent.-Store in the dark. REFERENCES 1. Bark, L. S., and Catterall, R., Mikrochim. Acta, 1960, 563. 2. 3. 4. 5. 6. Ministry of Housing and Local Government, "Methods of Chemical Analysis as applied t o Sewage Garner, G.B., Baumstark, J. S., Muhrer, M. E., and Pfander, W. H., Anal. Chem., 1956, 28, 1589. Hill, R. M., Pivnick, H., Engelhard, W. E., and Bogard, M., J . d g r i c . Food Chem., 1959, 7, 261. Saltzman, B. E., Anal. Chem., 1954, 26, 1949. Shinn, M. B., Ind. Eng. Chem., Anal. Ed., 1941, 13, 33. and Sewage Effluents," Second Edition, H.M. Stationery Office, London, 1956, p. 15. DEPARTMENT OF SCIENTIFIC AND INDUSTRIAL RESEARCH WATER POLLUTIOX RESEARCH LABORATORY STEVENAGE, HKRTS. H. A. C . MONTGOMERY JOAN F. DYMOCK Received February 3rd. 1961 INTERFERENCE BY CHLORIDE ION IN THE DETERVINATION OF SHAW and McFarlane developed a convenient colorimetric method for determining tryptophan in proteins.1 The method is an adaptation of the Hopkins - Cole reaction2 and has in general proved satisfactory in this laboratory, where i t has been extensively used for analysing proteins and in studies on the preservation of tryptophan by sulphur dioxide during acid hydrolysis of proteins? TRYPTOPHAN BY SHAW AND McFARLANE'S METHODJune, 19611 NOTES 417 In work on the rates of hydrolysis of whole casein and the various fractions of the casein complex, by proteolytic enzymes and by acids, 4 g of Warner casein (containing 14.1 per cent.of nitrogen4) and 80 ml of 3 N hydrochloric acid were boiled under reflux. Samples (3 ml) of the mixture (casein hydrolysate No. 1) were taken a t various time intervals and were analysed for tryptophan by Shaw and McFarlane’s methodl and for total nitrogen by a micro Kjeldahl method.6 A sample of the casein used was also analysed and found to contain 0.10 g of tryptophan per g of nitrogen.This experiment was then repeated with 3 pa sulphuric acid instead of hydrochloric acid ; the results were- Time of heating, hours . . 0-25 0.5 0.76 1.0 1.25 1-5 2.0 2.25 2.50 2.75 3.0 Tryptophan found in HC1 hydrolysate, g per g of nitrogen.. . . . . 0.128 0.124 0.122 0.118 0.110 0.112 0.106 0.099 0.094 0.090 0.084 Tryptophan found in H,SO, hydrolysate, g per g of nitrogen . . 0.099 0.098 - 0.097 - 0.092 0.084 - 0.074 - 0.086 These figures show- that the tryptophan content of the hydrochloric acid hydrolysate was (a) higher than that of the sulphuric acid hydrolysate and (b) did not attain that of the unhydrolysed casein (0.10 g of tryptophan per g of nitrogen) until the casein - acid mixture had been heated for more than 1.5 hours.This indicated that the hydrochloric acid had interfered with the determination of tryptophan. Accordingly, a mixture of 1.0 g of casein and 20 ml of a 20 per cent. solution of sodium hydroxide was heated for 20 minutes on a steam-bath. (This is the first step in the determination of tryptophan in proteins by Shaw and McFarlane’s method.) The volume of the resulting solution was adjusted to 25 ml, and various amounts of sodium chloride were added to 1-ml portions of the solution, each containing 0.04 g of casein. Tryptophan was determined in these samples by Shaw and McFarlane’s method; the results were- NaCl added, millimoles . . .. . . 0.0 0.1 0.3 0.5 1.0 2.0 4-0 6.0 8.0 Tryptophan found, g per g of nitrogen .. 0.100 0.102 0.118 0.137 0.131 0.132 0.131 0.128 0.124 which suggested that the presence of chloride had increased the intensity of the Hopkins - Cole reaction. Lesuks has reported that chloride ions increase the intensity of the colour produced by the reaction of tryptophan with p-dimethylaminobenzaldehyde.’ Spies* was able to overcome inter- ference from chloride ions by treating the tryptophan-containing solutions with silver sulphate. Attempts were therefore made to remove chloride ion by adding silver sulphate to solutions pre- pared by treating casein with a 2.0 per cent. solution of sodium hydroxide according to Shaw and McFarlane’s procedure. However, removal of chloride ion in this manner was unsatisfactory in so far as it led to the precipitation of protein. A sample of casein hydrolysate No.1 prepared in the previous experiments was extracted with di-2-ethylhexylamine solution (1 part by volume of di-Bethylhexylamine plus 10 parts by volume of chloroform) ; this removed virtually all the chloride. The hydrolysate was extracted with freshly distilled chloroform to remove the di-2-ethylhexylamine and was then heated on a steam-bath to remove chloroform. The hydrolysate, which then contained no detectable chloride ion or chloroform, was analysed for tryptophan by Shaw and McFarlane’s method. It was observed that the blanks (extracted hydrolysate to which no glyoxylic acid had been added) were faintly pink in colour, so that it was impossible to obtain an accurate value for the tryptophan content of the hydrolysate.The pink colour appearing in the blanks had the same peak absorption as did that produced by the action of glyoxylic acid on tryptophan. These observations show that Shaw and McFarlane’s method is subject to interference from chloride ion and that this possible interference should be taken into account when the method is used. REFERENCES 1. 2. Winkler, S., Hopfie-Seyl. Z., 1934, 228, 50. 3. 4. 5. Shaw, J. L. D., and McFarlane, W. D., Canad. J . Res. B., 1938, 16, 361. Pedersen, J. W., and Baker, B. E., J . Sci. Food Agric., 1954, 5 , 549. Warner, R. C., J . Amer. Chem. SOC., 1944, 66, 1725. Lepper, H. A., Editor, “Official Methods of Analysis,” Seventh Edition, The Association of Official Agricultural Chemists, Washington, D.C., 1950, p.745.418 NOTES [Vol. 86 Lesuk, A,, U S . Pharmacopoeia Amino Acids Advisory Committee, “Report on Collaborative Study on Chemical Tests and Standards for Amino Acids,” Letter 135, November 26th, 1948. Spies, J. R., and Chambers, D. C., -4naZ. Chem., 1948, 20, 30. Spies, J. R., Ibid., 1950, 22, 1447. 6. 7. 8. MACDONALD COLLEGE OF MCGILL UNIVERSITY QUEBEC, CANADA G. 0. HEHNEBERRY B. E. BAKER Received November 28th, 1960 DETERMINATION OF COPPER IN PLATINUM JEWELLERY ALLOYS HAYWOOD and Sutcliffe’s method1 for determining copper in steel with use of biscyclohexanone oxalyldihydrazone has been extended, with certain essential modifications, to the determination of 0.05 to 6 per cent. of copper in platinum jewellery alloys.As only a small amount of sample is required, the method is particularly suitable for application t o delicate articles of jewellery, for which binary alloys of platinum and copper are commonly used. The proposed direct procedure, based on spectrophotometric measurement of the blue copper - reagent complex, is simple in comparison with older methods. O S S O l t 0.510 0 20 40 60 80 100 120 140 Time after addition of reagent, minutes Fig. 1. Variation of optical density of the copper - biscyclohexanone oxalyldihydrazone complex with time. (The values are for a copper - platinum alloy containing approximately 5.5 per cent. of copper) EXPERIMENTAL It was established that- In preliminary experiments, it was found that Haywood and Sutcliffe’s method required (i) The addition of ammonia solution must be deferred until the final-aliquot stage to avoid precipitation of ammonium chloroplatinate.(ii) Accurate adjustment of pH is necessary. This can be achieved by using neutral red indicator as recommended by Wetlesen and Gran.2.s (iii) The biscyclohexanone oxalyldihydrazone solution must be freshly prepared and added after the final adjustment of pH. (iv) The blue colour of the complex attains a maximum in about 7 minutes, after which there is slight progressive fading (see Fig. 1). Results are satisfactory, however, provided that the optical density is measured after a fixed interval from the time that the reagent solution is added; the recommended interval is 20 minutes. The relationship between copper content and optical density found by the proposed procedure is linear; an optical density of 1.000 (4-cm cell) is equivalent to 105 pg of copper in the final s o h tion.certain modifications for our purpose.June, 19613 NOTES 419 METHOD REAGENTS- Hydrochloric acid, s$.gr. 1. I -. Nitric acid, sp.gr. 1-42?. Citric acid solution-Dissolve 10 g of citric acid in 200 ml of water. Ammoniu solution-Dilute 100 ml of ammonia solution, sp.gr. 0.880, to 400 ml with water. NeutraE red ilzdicator solution-Dissolve 0.05 g of neutral red in 100 ml of water. Copper reagent solution-Dissolve 0.1 g of biscyclohexanone oxalyldihydrazone in a mixture of 10 ml each of industrial methylated spirit and hot water, dilute to 200 ml, and filter if necessary. PROCEDURE- Weigh 0.02 g of sample in the form of fine powder or drillings into a 150-ml beaker, add 7.6 ml of hydrochloric acid and 2.5 ml of nitric acid, cover the beaker, and heat on a hot-plate until solution is complete; add further portions of hydrochloric and nitric acids if necessary.(Platinum - iridium alloys may require modified treatment to effect solution.) W e n the sample has dissolved, remove the cover-glass, evaporate almost to dryness, add about 0.05 g of sodium chloride and a few drops of hydrochloric acid, and evaporate to dryness. Dissolve the residue in a little water, add 5 ml of hydrochloric acid, and dilute to 100 ml in a calibrated flask. Transfer a suitable aliquot of this solution (5ml for samples containing 2 to 6 per cent. of copper) to a TABLE I COPPER CONTENTS FOUND IN STANDARD ALLOYS Alloy No.Nominal Aliquot of alloy Copper copper content, solution taken, content found, % ml % 1 3.5 5 3-47 2 3.0 5 2-96 3 2.5 5 2-55 4 1.0 5 1.00 5 6 7 8 0.5 0.2 0.1 0.05 {l: 25 25 0.50 0.5 1 0.23 0.21 0.11 0-057 second 100-ml calibrated flask, add 5 ml of citric acid solution and 2 drops of neutral red indicator solution, and dilute to about 70 ml. Add ammonia solution until the indicator just turns yellow, and then add 1 drop in excess. Add 20ml of freshly prepared copper reagent solution, with thorough mixing, dilute to the mark, set aside for exactly 20 minutes, and then measure the optical density at 5950 A in 4-cm cells with a Uvispek spectrophotometer or similar instrument. Carry out a reagent blank determination concurrently with the sample determination, and apply any necessary correction. Determine the copper content of the sample from the corrected optical density by reference to a graph previously prepared from measurements made on solutions of known composition.(The solutions used in preparing the graph should have approximately the same content of platinum as encountered in the determination.) RESULTS A series of single deter- minations carried out on a copper - platinum alloy on successive days gave results of 5-55, 5.53, 6-53, 5.52 and 5.55 per cent. of copper. Haywood and Sutcliffe found that only iron, nickel, chromium and cobalt interfered with their rneth0d.l With platinum jewellery alloys, iron and nickel would have negligible effect on the results, whereas chromium and cobalt are unlikely to be present in amounts sufficient to cause any significant interference.The effects of some other elements occasionally found in small amounts were, however, studied ; none was found to interfere. To each of five samples of a copper - platinum alloy containing approximately 5.5 per cent. of copper was added a solution of the The reproducibility of results by the proposed method is good.420 NOTES [Vol. 86 element to be tested, the amount of element added being equivalent to a concentration of 6 per cent. in the alloy; the results were- Element added . . . . None Gold Palladium Rhodium Ruthenium Iridium Copper content found, % . . 5.55 5.53 5.55 5.53 5.57 5.54 The results obtained when the proposed procedure was applied t o eight standard copper - This Note is published by permission of the Wardens of the Worshipful Company of Gold- platinum alloys are shown in Table I.smiths. REFER.ENCES 1. 2. 3. Haywood, L. J. A,, and Sutcliffe, P., Analyst, 1956, 81, 651. Wetlesen, C.-U., and Gran, G., Svensk Papperstidn., 1952, 55, 212. Johnson, W. C., Editor, “Organic Reagents for Metals, and Other Reagent Monographs,” Fifth Edition, Hopkin & Williams Ltd., Chadwsell Heath, Essex, 1955, p. 31. ASSAY OFFICE GOLDSMITHS’ HALL LONDON, E.C.2 J. S. FORBES D. B. DALLADAY Received Ja?zuary 13t12, 1961 THE PHOTOMETRIC DETERMINATION O F SILICA IN ROCKS AND REFRACTORY MATERIALS INVESTIGATIONS by Stricklandl and Ringbom, Ahlers and Siitonen2 have demonstrated the utility of the yellow a-form of molybdosilicic acid for the photometric determination of silica in rocks and refractory materials. At lorn acidity, the a-form is stable; the 8-form is developed a t high acidity and slowly changes to the a-form.Both forms yield blue solutions when reduced by l-amino-2-naphthol-4-sulphonic acid3 or p-methylaminophenol ~ulphate,%~ and optical-density measurements are made at about 810 mp. In general, the sensitivity of this method is much too high for rocks containing 35 to 95 per cent. of silica. The great dilution involved may be a source of error, and the strongly acid solution results in initial development of the 8-form of the acid. Further, the time elapsing between development of the yellow molybdosilicic acid and its reduction is critical, and errors may also arise from deterioration of the reducing solution and the addition of reagents to mask iron.In the procedure described below, the sample is fused with sodium hydroxide,3!6 and the cooled melt, instead of being dissolved in a solution of disodium ethylenediaminetetra-acetate: is taken up in dilute sulphuric acid. This leads to much clearer solutions, particularly for rocks rich in iron. The pH of a suitable portion of the solution is then adjusted to between 3.0 and 3.1, as previously recommended,* before the yellow molybdosilicic acid is developed. The effect of iron is overcome by measuring the optical density of each sample solution against a blank prepared from that sample rather than against distilled water or a “fusion” blank. A correction is made for P20,, which is seldom present to an extent greater than 0.5 per cent.in most rocks. METHOD SPECTROPHOTOMETRY- All optical-density measurements were made in matched 10-mm glass cells with a Unicam SPSOO spectrophotometer. In accordance with the method described by Ringbom and &terholm,S the concentrations of the final solutions were adjusted so that the optical densities were between 1.0 and 1.6 at a sensitivity of 1 to 10. GLASSWARE- thoroughly rinsed with water just before use. should be stored filled with water. REAGENTS- Calibrated flasks should be set aside overnight filled with diluted sulphuric acid (1 + 1) and They should never be allowed to become dry and All reagents should be stored in polythene bottles. Sodium hydroxide pellats. Sulphzrric acid, 2.5 N.June, 19611 NOTES 421 Buffeev solution-Dissolve 200 g of chloroacetic acid in water, and dilute to 1 litre.Slowly add diluted ammonia solution (1 f l), with stirring, until the pH of the cold solution is between 3-15 and 3.20 (approximately 160 ml of the ammonia solution will be needed). Ammonium mdybdate solution-Prepare a solution containing 35.3 g of (NH,),Mo,0,,.4H20 per litre. PROCEDURE- Place 150-mg portions of standard and samples (weighed to the nearest 0.01 mg) in separate 30-ml silver crucibles, add 1-5 g of sodium hydroxide pellets to the contents of each crucible, and heat the covered crucibles in a muffle furnace for 8 to 10 minutes at 800" C. When cool, half fill each crucible with water, and warm gently on the top of a steam-bath until most of the cake has broken up. Transfer the contents of each crucible to a 500-ml calibrated flask containing about 250 ml of water and 20 ml of 2.5 N sulphuric acid, scrub the crucible and lid with water and then with 5 ml of 2.5 N sulphuric acid to remove any adhering material, and add the rinsings to the contents of the flask.Dilute the solution to the mark with water, and shake thoroughly. Transfer the solution to a dry polythene bottle, insert a stopper, and set aside to clear for 3 or 4 hour s or overnight. TABLE I SILICA CONTENTS FOUND BY PROPOSED METHOD For N.B.S. samples certified values are shown in columns 2 , 3 and 4; for rocks G-1 and W-1 the values in these columns are those recommended by various w ~ r k e r s ~ ~ * ~ ~ Total iron SiO, found present, as p20, SiO, by proposed Sample Fe,O,, present, present, method, % % % % Burnt refractory (W.B.S.No. 76) . . 2.38 0.069 64-68 64*5(1) 5 4.6 (5) 54-6(0) 54.5 (8) 59*0( 7) 59*0(5) Granite, G-1 . . . . .. .. 1-96 0.09 72-66 72.4( 7) 72.5(1) 7 2.5 (8) 72*5(5) Diabase, W-l . . .. . . . . 11-10 0.126 62-64 52-5(1) 52-5(9) 52-5(7) 52*6( 1) Plastic clay (N.B.S. No. 98) . . .. 2.05 0.08 59.1 1 69.1 (9) By pipette, place 25-ml portions of standard and sample solutions in separate 150-ml beakers, add 15ml each of buffer and ammonium molybdate solutions, and mix thoroughly. Heat the beakers in a bath of boiling water for 20 minutes, cool to room temperature, transfer each solution to a 100-ml calibrated flask, and dilute to the mark with rinsings from the beaker. Set these solutions, which must all have the same pH (3.0 to 3.1), aside for 12 hours or overnight.Prepare blank solutions for the standard and each sample in exactly the same way, but omit the addition of ammonium molybdate solution and subsequent heating. Measure the optical density of each solution against the appropriate blank solution. RESULTS The standard used throughout was National Bureau of Standards sample Xo. 99 (soda feld- spar), which contains 68.66 per cent. of SO,, 0.067 per cent. of Fe,O, and 0-142 per cent. of P,O,; this standard gave an optical density of 1.498. The lowest working concentration was about 45 per cent. of silica (optical density of 1.0) and the upper limit about 75 per cent. (optical density of 1-6). This range of concentrations covers a large proportion of common igneous rocks, and suitable adjustments to the final concentration can be calculated for samples having silica contents outside this range. The effect of phosphorus pentoxide was determined by adding this constituent to the standard up to a concentration of 3 per cent. I t was found that the presence of 1 per cent. of phosphorus422 NOTES vol. 86 pentoxide increased the optical density by 0.015 (equivalent to 0.75 per cent. of silica), and the results for silica in the samples were corrected accordingly. The results of several separate determinations of silica in two National Bureau of Standards refractory samples and two thoroughly investigated rocks, G-1 and W-1, are shown in Table I. 1. 2. 3. 4. 5. 6. 7. 8. 9. REFERENCES Strickland, J. D. H., J . Amer. Chem. Soc., 1952, 74, 862. Ringbom, A., Ahlers, P. E., and Siitonen, S., Anal. Chirn. Acta, 1959, 20, 78. Shapiro, L., and Brannock, W. W., “Rapid Analysis of Silicate Rocks,” U.S. Geological Survey Mullin, J. B., and Riley, J. P., Anal. Chim. Acta, 1955, 12, 162. Riley, J. P., Ibid., 1958, 19, 413. Ringbom, A., and Osterholm, K., Anal. Chem., 1953, 25, 1798. Fairbairn, H. W., Schlecht, W. G., Stevens, R. E., Dennen, W. H., Ahrens, L. H., and Chayes, F., “A Cooperative Investigation of Precision and Accuracy in Chemical, Spectrochemical and Modal Analysis of Silicate Rocks,” U.S. Geological Survey Bulletin 980, 1961. Fairbairn, H. W., Geochim. Cosnzochirn. Acta, 1953, 4, 143. Stevens, R. E., Fleischer, M., Niles, W. W., Chodos, A. A., Filby, R. H., Leininger, R. K., Ahrens, L. H., and Flanagan, F. J., “Second Report on a Cooperative Investigation of the Composition of Two Silicate Rocks,” U.S. Geological Survey Bulletin 1113, 1960. Bulletin 1036-C, 1956. DEPARTMENT OF GEOLOGY UNIVERSITY COLLEGE SWANSEA T. W. BLOXAM Received September 7th, 1960

ISSN:0003-2654    

DOI:10.1039/AN9618600411

出版商:RSC    

年代:1961

数据来源: RSC

摘要:

422 NOTES vol. 86 Book Reviews MASS SPECTROMETRY AND ITS APPLICATIONS TO ORGANIC CHEMISTRY. By J. H. BEYNON. Amsterdam, London, New York and Princeton: Elsevier Publishing Co.; Various combinations of atoms of the elements can be found to give, as is well known, indi- vidual molecules having the same nominal mass number, to the nearest whole number. In fact, since the nuclear packing fraction is different for each isotopic species, the exact mass numbers of these molecules differ to a small extent from each other according to the particular atomic combination making up the molecule. The author of this new book on mass spectrometry observed some years ago that, if the mass spectrometer could be used to distinguish such small differences in mass, it should not be difficult to devise semi-empirical rules for determining the molecular formula of an unknown organic compound.Having obtained the molecular formula, one could then proceed further to an elucidation of the structural formula by a study of the type and abundance of the fragment ions observed in the mass spectrum of the compound. With more complicated molecules, one might have also to consider the information supplied by formation of metastable ions, the possible existence of doubly-charged ions, appearance-potential studies and so on to describe the structure. Nevertheless, it would appear that the mass spectrometer could be applied on a wider basis to chemical analysis, for qualitative as well as quantitative determination. The author’s observation was opportunely made, at a time when the mass spectrometer had already established itself as a powerful analytical instrument in hydrocarbon chemistry and when considerable pressure was being exerted by the users of these instruments on those concerned with instrument design to extend considerably the available mass resolution.In these instances, all the compounds present in the samples could be identified in other ways. The desire was for facility to undertake quantitative analysis in a region of higher molecular weight. In the development of this field of application-qualitative analysis-the author has made considerable contributions. It is to be expected, then, that in his book on mass spectrometry qualitative analysis would receive high priority in treatment; this is indeed so. The chapters (2, 8 and 9) dealing with the measurement of malss and qualitative analysis, together with the relevant appendixes-No.1 giving the masses and isotopic-abundance ratios for various com- binations of carbon, hydrogen, nitrogen and oxygen, No. 2 giving nomograms for determining the origin of metastable ions, No. 5 giving possible peaks in the mass spectra of fluorocarbons and their composition, No. 6 giving the mass spectrum of Fluorolube residues (above mass 69) Pp. xii + 640. London: D. Van Nostrand Co. Ltd. 1960. Price 120s.June, 19611 BOOK REVIEWS 423 and No. 7 giving some common mass doublets-occupy more than one-third of the book. However, it is valuable t o have, for the first time, a full and authoritative exposition of this relatively new field of work.All the usual features of mass-spectrometric technique and instrumentation are described in other chapters on instruments, abundance measurement, sources of positive ions, sample hand- ling, recording of positive-ion beams and types of ions in mass spectra. All the other applications of mass spectrometry are condensed into one final chapter. In addition, two further appendixes are added: No. 3 giving a table of the masses and abundances of naturally occurring isotopes and No. 4 giving international atomic weights. Inevitably, the quality of presentation in all these fields is bound to be somewhat variable, since no one person could claim to have special knowledge in all aspects of the subject. In fact, with a subject growing so rapidly, one wonders at what point in time an all-embracing book ceases to be a worth-while exercise.I t is apparent that, even in this book, some decisions have had to be taken as to what to include and what to exclude. For example, on pp. 11 to 15, dealing with the now common double-iocusing instruments, in which simultaneous correction is made for direction and energy inhomogeneities, the basic equations of Herzog and of Mattauch and Herzog have been omitted. This was probably a wise decision, but it does mean the reader cannot so readily grasp that a series of data may be chosen at will and that better combinations of electric and magnetic fields may yet be devised. Again, on p. 98, where the powerful isotope-dilution technique for determining trace elements is described, the stages involved in the derivation of equation (32) are omitted.This is a pity, because I think that the newcomer would gain much from their inclusion, particu- larly with regard to insight into and appreciation of the method. It becomes easier in this way to realise that many of the elements can be detected with as little as 10-l2 g of material present. As a final example, one may refer to quantitative analysis of multi-component mixtures in the petroleum industry (pp. 424-432). Here, only brief reference is made to the computation problems involved in dealing with the available linear simultaneous equations derived from a comparison of the mixture spectrum with each pure-component spectrum. I would have thought that this work is sufficiently extensive to have merited a much fuller treatment.However, although a number of examples of this kind can be chosen, it is clear that the author had to set a limit to the size of his book, and the main text already covers some 480 pages. The book is excellently produced, and hardly any errors have been noticed a t a first reading. It will prove to be a valuable addition to the rapidly growing library of books on mass spectrometry for two main reasons: (u) for the work on qualitative analysis and (b) as a source of reference for all the other aspects of mass spectrometry. A price of 120s. for a work of this nature is not surprising in view of the existing costs of publication, but it tends to place the volume in the luxury class for the junior research worker. This is regrettable, for there is a great deal of value here for all workers in this field.Finally, some 2200 references are listed. To deal with all this work has clearly demanded immense effort from the author. G. P. BARNARD X-RAY MICROSCOPY. By V. E. COSSLETT, M.A., Ph.D., and W. C . NIXON, M.A., Ph.D. Pp. xiv An examination of the contents of this volume shows that the authors have used the term X-ray microscopy to cover a number of distinct techniques in the fields of radiography, crystallo- graphy and X-ray emission spectroscopy. The several properties of X-rays rendering them of special value in micro-scale investigations are their short wavelength, their great power of pene- tration into matter, the simple spectral character of X-ray emission and the rapid variation in absorption coefficient with the atomic number of the absorbing element.The various methods described include contact micro-radiography, in which an X-ray negative on fine-grain emulsion is enlarged by optical microscopy, point-projection X-ray microscopy and reflection X-ray micro- scopy with either mirror systems or curved crystals. A second group of techniques comprises X-ray absorption micro-analysis, X-ray emission micro-analysis and X-ray micro-diff raction, and it is with the applications of these methods that the analyst will be principally concerned. It is less than ten years ago that Castaing first investigated the use of a fine beam of electrons to bring about direct excitation of X-rays in micro regions of a specimen, with consequent informa- tion about the distribution of elements therein.Cosslett and his colleagues have extended this idea to a scanning system in which a television technique is used to display a picture of the specimen in terms of variation in characteristic X-ray emission. By this means the distribution + 406. London: Cambridge University Press. 1960. Price 80s.424 BOOK REVIEWS [Vol. 86 of a particular element is made directly visible down to below the micron scale. Already there are available several commercial versions of these “electron probe analysers,” and their potential value in metallurgical analysis cannot be over-emphasised. X-ray absorption micro-analysis is another exciting development that has been used with significant results in the biological field. Cosslett and Nixon have arranged their account so as to provide detailed treatment of the several aspects of X-ray microscopy, covering in each instance the general principles, practical details of their use and examples of applications.The book is comprehensive, authoritative and readable, is provided with a good bibliography and contains thirty-two plates, with excellent reproductions of representative X-ray micrographs. It will undoubtedly qualify as the standard text on a subject to which the authors, in spite of a mc lest disclaimer in their preface, have made such notable contributions. B. s. COOPER ANALYTICAL CHEMISTRY OF THE RARE EARTHS. By R. C. VICKERY. Pp. xiii -+ 139. Oxford, Information on the analytical chemistry of the rare earths is widespread, like the rare earths themselves, but the author has gathered together reliable analytical information on this subject and presented it, without unnecessary detail, in a clear and concise way.With such an extensive subject it would be unreasonable to expect to find answers to all related problems in a book of this size, but emphasis has been placed where it is most needed. The author, who is an expert in this field, has obviously given considerable forethought to lay-out, referring first to the historical aspect of the subject then to gravimetric, volumetric, spectrophotometric, spectrographic, X-ray, polarographic and solvent-extraction methods; for good measure a chapter is devoted to radiochemical techniques. On page 11, the reference to pentavalent chromium should read sexavalent chromium, but, with this exception, no errors are apparent, although the values given for the accuracies of the polarographic procedures on pages 132 and 133 lose their significance in the absence of any indication of the levels of europium and ytterbium involved, unless the author is really referring to “sensi- tivities.” In future editions the author should include typical compositions; information that could conveniently be included in Table 2-1.With a book like this available, no analyst having an interest in these fascinating and challeng- ing Group I11 (sub-group A) elements can claim to be up-to-date unless this publication is at his right hand. London, New York and Paris: Pergamon Press. 1961. Price 40s. W. T. ELWELL ORGANIC ELECTRONIC SPECTRAL DATA. Volume I, 1946-1952. Edited by MORTIMEK J.KAMLET. Pp. xiv. + 1208. New York and London: Interscience Publishers Inc. 1960. Price (single volume) 215s. ; (subscribers to whole series) 188s. T’olume 11, 1953-1955. Edited by HERBERT E. UNGNADE. Pp. x + 919. Price (single volume) 132s. ; subscribers to whole series) 113s. This venture aims at providing a comprehensive catalogue of ultra-violet spectral data for organic compounds. Volume I11 will cover 1966-1957, Volume IV 1958-1959 and Volume V 1960-1961. The first two volumes contain the work of fifty abstractors who went through 10,000 papers in seventy journals and reported 45,000 sets of data. The project was aided financially by various interests, and the publications, although expensive, are evidently subsidised. The arrangement of compounds is according to molecular formulae; the symbols are in alpha- betical order, e.g., C,H,,N,O,S, and the compound name is given below the formula.When possible, the solvent used is stated, and the data are given as A,,,. in millimicrons, with log,, of the molecular extinction coefficient (log E ) in brackets, stated to 0-01 logarithmic unit if the data justify it. Many papers contain absorption curves without numerical data, and in these instances the abstractors have estimated the values of A,,,. and loge and the figures given are underlined. When the published absorption curves exhibit fine structure, only the main maximum or the centre of the fine-structure system is entered and is labelled with the letter f after the wavelength. The final column lists the code number of the journal, the page number of the paper and the last two ciphers of the year in which it was published.The complete reference is obtained by turning to the section at the end of the book that lists all articles abstracted. The journals are arrangedJune, 19611 BOOK REVIEWS 425 in order of their code numbers, the articles in order of volume, year and page. “Errors” have been dealt with by correcting matters of nomenclature, but those apparently depending on techniques or unknown chemical or photochemical processes are reported faithfully. The literature of the period before the second World War was in the main based on Photographic spectrophotometry, and the task of tracing studies on particular compounds is not an impossible one in a good library.There is a good index for 1930-1954, which gives references only (Ultra- violet and visible absorption spectra, H. M. Hershenson, Academic Press, 1956). Photoelectric spectrophotometry became widespread just after the War, and the editors are fully justified in beginning at 1946, although it is by no means safe for research workers to neglect the older literature. The plan of the present work is eminently sound, and the abstracting and checking have obviously been done well. In testing the coverage, I looked for a paper on pyridoxin and related compounds read before an International Congress on Analytical Chemistry (Lunn, A. K., and Morton, R. A., Analyst, 1952, 77, 718), which I thought contained useful data. For the editors, it is sheer bad luck that The Analyst is not on their list of journals abstracted and that I should be the reviewer! Combining truth and kindness, it is safe to predict that these reference books will be heavily used and that in most research laboratories they will soon pay for themselves in saving unnecessary labour.They are to be welcomed warmly. R. A. MORTON SYNTHESIS AND ORGANISATION IN THE BACTERIAL CELL. By E. F. GALE. Pp. viii + 110, Like so many current books on biochemistry, and doubtless on other subjects as well, this one depends on the activities of analysts to a far greater extent than their interest in its subject matter might indicate. For without the application of pretty difficult analytical procedures- many of which might equally well be described as difficult pretty analytical procedures-most of the results described by Dr.Gale in this concise, but informative, little monograph could not have been got. Without the results there could have been no interpretation, and without the inter- pretation none of the three CIBA Lectures at Rutgers (The State University of New Jersey) forming the substance of this book would or indeed could have been given. In chapter I, on Structure and Organisation in the Bacterial Cell, and in chapters I1 and 111, on Amino Acid Incorporation and on Nucleic Acid and Protein Synthesis, respectively, everything, or almost everything, depends directly or indirectly on a mass of analytical results got by workers who, mainly for reasons of space, maybe, are not mentioned and may indeed be in danger of oblivion.For this Dr. Gale is himself in no way to blame; he had, in all conscience, already overmuch to crowd into his three lecture - chapters. It seems to me, all the same, that analysts might be more encouraged to interest themselves in the sometimes apparently remote results and conclusions that have arisen from their arduous laboratory toils if those who almost unconsciously make use of the analysts’ methods would a little more often and a little more openly give credit to them when it is due. A practical advantage would also be gained from closer understanding between analyst on the one hand and biochemist or microbiologist on the other. The latter might then enquire a little more closely into the validity of the methods that have given him his results; the former might be more inclined to look critically at the methods he is proposing to use.London and New York. John Wiley & Sons Ltd. 1960. Price 28s.; $3.50. A. L. BACHARACH ANALYSE QUALITATIVE RAPIDE DES CATIONS ET DES ANIONS. By G. CHARLOT. Third Edition. The industrial chemist asked to review a book on qualitative analysis approaches his task with diffidence. Books on this subject are almost always written for colleges, and this is no exception. It is an introduction to the system of identifying inorganic substances by spot tests. The classical “group system” of qualitative analysis remained almost unchanged for a long time; Pp. xiv + 82. Paris: Dunod. 1961. Price 9.50 NF.426 BOOK REVIEWS [Vol. 86 given a large enough sample and the requisite skill, it could yield satisfactory results.Admittedly, the elements covered were rather arbitrarily selected; even so, a competent analyst with a reason- able knowledge of inorganic chemistry in its more factual aspects could cope with most of the samples presented to him. Based on the kind of spot test popularised by Feigl, qualitative analysis, always on a semi-micro or micro scale, becomes a series of tests for individual elements or small groups of elements, and separations are avoided. I t is a variant of this scheme that is advocated by Professor Charlot, and the fact that his booklet has now passed through three editions indicates the interest it has aroused. Charlot’s scheme is not intended to deal with traces; it is a system for identifying any of a series of elements or ions present to more than 0-1 per cent.of the whole, the size of sample being, perhaps, 50 mg, and, as presented in this booklet, it covers rather more than sixty inorganic ions. The instructions are generally clear, although there are occasional signs of hasty writing or revision: for example, on p. 60, the “Remarks” under the heading of reactions with barium belong really to the paragraph above, dealing with silver nitrate. This is a teaching manual and not a handbook for the professional laboratory, but it deserves to be read by both lecturers and professional analysts. Qualitative inorganic analysis has acquired a reputation as a dull mechanical subject, mostly because it was taught in a dull mechanical way. There is nothing dull or mechanical in the school of analytical chemistry at the Xkole Supbrieure de Physique et de Chimie Industrielles; on the contrary, its ideas are stimulating, and serious teachers of analytical chemistry cannot fail to be stimulated by reading them.They may strongly disagree with these ideas, but what matters is that they give fresh thought to the contents of their courses. I do not know how qualitative analysis should be taught, nor how much should be taught, but I do regard it as rather important. Tn a large establishment well equipped with physical apparatus, it may not often be necessary, but there are few laboratories, large or small, where from time to time a knowledge of this art is not essential. To an outsider it appears that, within academic walls, analytical chemistry is fighting a losing battle, and it certainly will not regain any lost ground with weapons designed-although no doubt refurbished here and there in the interval-a hundred years ago.In the industrial laboratory, although the question “What is it?” is sometimes asked, more often one hears “Does it contain x?” or “Is it y or is it z?” Here, well designed spot tests are more useful than the traditional scheme, and Charlot’s text-book is an excellent introduction; if the analyst wishes to cover every possibility he will need a much fuller treatment. To-day cz totally different system is emerging. This will not worry a teacher, but might confuse a student. H. N. WILSON ADVANCES IN ANALYTICAL CHEMISTRY AND INSTRUMENTATION. Volume I. Edited by CHARLES N. REILLEY. Pp. viii + 445. New York and London: Interscience Publishers Inc. 1960. Price $12.00; 90s. In this new venture an attempt is being made to bring new analytical developments into working practice and, moreover, to discuss critically, from time to time, conventional classical procedures in analytical chemistry. I t is suggested that the volumes will appear annually, and the first volume certainly caters for the most diverse tastes. There are chapters on tetraphenylboron and thioacetamide as analytical reagents, and new ideas are presented on organic micro-analysis and on the determination of fluorine. Gas-chromato- graphic detectors, near-infra-red spectrophotometry and theories of electrode processes all find a place, and the individual articles are written by experts in the form of critical reviews. There is no doubt that this innovation will appeal to those analytical chemists who, while ordinarily engaged in specialised activities, are sufficiently wide-awake to want to keep abreast of new developments and wish, moreover, to do so by reading articles that present the essential ideas in small compass. J . HASLAM

ISSN:0003-2654    

DOI:10.1039/AN9618600422

出版商:RSC    

年代:1961

数据来源: RSC

摘要:

June, 19611 PUBLICATIONS RECEIVED 427 Publications Received GAS CHROMATOGRAPHY. By ERNST BAYER. Pp. xii + 240. Amsterdam, London, New York and Princeton : Elsevier Publishing Company; London : D. Van Nostrand Company Ltd. 1961. Price 25s. POLYNUCLEOTIDES : NATURAL AND SYNTHETIC NUCLEIC ~ I D S . By ROBERT F. STEINER and Amsterdam, London, New York and Princeton: 1961. Price 85s. By CHARLES K. RErLLEY and DONALD T. SAWYER. New York, Toronto and London: McGraw-Hill Book Company Inc. By P. C. Washington, D.C.: National Academy ROLAND F. BEERS, jun. Elsevier Publishing Company; London: D. Van Nostrand Company Ltd. Pp. viii + 404. EXPERIMENTS FOR INSTRUMENTAL METHODS. Pp. xii + 412. 1961. Price 46s. THE RADIOCHEMISTRY OF THE RARE EARTHS, SCANDIUM, YTTRIUM, AND ACTINIUM. STEVENSON and W.E. NERVIK. of Sciences-National Research Council. 1961. Price $3.00. Pp. x + 282. Nuclear Science Series: N A S-NS-3020. THE RADIOCHEMISTRY OF TECHNETIUM. By EDWARD ANDERS. Pp. vi + 50. Washington, 1960. Price 50 cents, D.C. : National Academy of Sciences-National Research Council. Nuclear Science Series: N A S-NS-302 1. THE RADIOCHEMISTRY OF TIN. By W. E. NERVIK. Pp. x + 68. Washington, D.C.: National Academy of Sciences-National Research Council. 1960. Price 75 cents. Nuclear Science Seyies: N A S-NS-3023. THE RADIOCHEMISTRY OF THE RARE GASES. By FLOYD F. MOMYER, jun. Pp. vi + 55. Washington, D.C. : National Academy of Sciences-National Research Council. 1960. Price 75 cents. Nuclear Science Series: N A S-NS-3025. PROTIDES OF THE BIOLOGICAL FLUIDS.Proceedings of the Eighth Colloquium, Bruges, 1960. Amsterdam, London, New York and Princeton: 1961. Price 86s. London: Her Edited by H. PEETERS. Elsevier Publishing Company; London: D. Van Nostrand Company Ltd. Majesty’s Stationery Office. 1961. Price 17s. 6d. Ministry of Agriculture, Fisheries and Food. Pp. x + 356. THE MITES OF STORED FOOD. By A. M. Hughes, Ph.D., D.I.C. Pp. vi + 287. Technical Bulletin No. 9. ASSESSMENT OF THE ACTIVITY OF DISEASE. By J. s. LAWRENCE, M.D., M.R.C.P. Pp. viii + 252. London: H. K. Lewis & Co. Ltd. 1961. Price 42s. LIPIDE METABOLISM. Edited by KONRAD BLOCH. Pp. xiv + 411. New York and London: John Wiley & Sons Inc. 1960. Price 84s. Second Edition. Pp. viii + 395 + 26 Tables. Berlin, Gottingen and Heidelberg: Springer- Verlag.1960. Price DM 88. HANDBOOK OF CHEMISTRY AND PHYSICS. Edited by CHARLES D. HODGMAN, M.S., ROBERT C, WEAST, Ph.D., and SAMUELM. SELBY, Ph.D. Pp. xxvi + 3481. Cleveland, Ohio : Chemical Rubber Publishing Co. (Distributor in England : Blackwe1 I Scientific Publications Ltd., Oxford.) 1960. Price $12.00; 105s. FLAMMENPHOTOMETRIE. By Dr. Rer. Nat. R. HERRMANN and Dr. C. Th. J. ALKEMADE. Forty-second Edition. TABLES FOR IDENTIFICATION OF ORGANICOMPOUNDS. Edited by CHARLES D. HODGMAN, M.S., ROBERT C. WEAST, Ph.D., and SAMUEL M. SELBY, Ph.D. Compiled by Professor MAX FRANKEL, Ph.D. and Professor SAUL PATAI, Ph.D., with the assistance of ROBERT FARKAS- KADMON and ALBERT ZILKHA, Ph.D. Cleveland, Ohio: Chemical Rubber Publishing Co. (Distributor in England : Blackwell Scientific Publications Ltd., Oxford.) 1960.Price $7.00; 60s. Pp. viii + 241. Supplement to “Handbook of Chemistry and Physics.”428 PUBLICATIONS RECEIVED SPECTROCHEMICAL AXALYSIS. By L. H. AHRENS, M.A., D.Sc., F.R.I.C., and S. R. TAYLOR, M.A., M.Sc., Ph.D. Second Edition. Pp. xxiv + 454. Oxford, London, New York and Paris : Pergamon Press ; Reading, Mass., and London : Addison-Wesley Publishing Company Inc. 1961. Price 105s. LES METHODES DE LA CHIMIE ANALYTIQUE: ANALYSE QUANTITATIVE MIN~RALE. By G. CHA4RLOT. Fourth Edition. Pp. viii + 1024. Paris: Masson et Cie. 1961. Price (paper) 100 NF; (cloth boards) 110 NF. THE RADIOCHEMISTRY OF MAGNESIUM. By A. W. FAIRHALL. Pp. vi + 22. Washington, D.C. : National Academy of Sciences-National Research Council. 1961.Price 50 cents. Nuclear Science Series: NA S-NS-3024. THE RADIOCHEMISTRY OF COPPER. By F. F. DYER and G. W. LEDDICOTTE. Pp. vi + 54. Washington, D.C. : Sational Academy of Sciences-National Research Council. 1961. Price 75 cents. Nucleav Science Series: N A S-NS-3027. THE RADIOCHEMISTRY OF RHENIUM. By G. W. LEDDICOTTE. Pp. vi + 43. Washington, D.C.: National Academy of Sciences-National Research Council. 1961. Price 50 cents. Nuclear Science Series: NA S-NS-3028. THE RADIOCHEMISTRY OF MERCURY. By J. ROESMER and P. KRUGER. Pp. vi + 50. Washing- ton, D.C. : National Academy of Sciences-National Research Council. 1960. Price 50 cents. Nuclear Science Series: NAS-NS-3026. GAS SAMPLING AND CHEMICAL ANALYSIS IN COMBUSTION PROCESSES. By Prof. ing. G. TIN$. Pp. xvi + 94.Published for and on behalf of Advisory Group for Aeronautical Research and Development North Atlantic Treaty Organisation. Oxford, London, New York and Paris: Pergamon Press. 1961. Price 42s. SYNTHETIC ION-EXCHANGERS : RECENT DEVELOPMENTS IPT THEORY AND APPLICATION. By G. H. OSBORX, F.R.I.C. Second Edition. Pp. xi + 346. London: Chapman & Hall Ltd. 1961. Price 50s. SYSTEMATIC QUALITATIVE AXALYSIS : AN INTRODUCTION. By G. A. MORRISON, M.A., D.Phi1. Pp. x + 198. London: Butterworths Publications Ltd. 1961. Price 25s. Edited by I. M. KOLTHOFF and PHILIP J. ELVIPTG, with the assistance of ERNEST B. SANDELL. Part 11. Analytical Chemistry of the Elements. Vol. 1. Pp. xxii + 471. New York and London: Interscience Publishers Inc. 1961. Price (single volume) $16.00; 120s. : (subscribers to whole series) $14.00; 105s. the Commission on Molecular Structure and Spectroscopy of the International Union of Pure and Applied Chemistry. Pp. viii + 163. London: Butterworths Publications Ltd. 1961. Price 40s. TREATISE ON ANALYTICAL CHEMISTRY. TABLES O F WAVEXUMBERS FOR THE CALIBRATION OF INFRA-RED SPECTROMETERS. Issued by Reprinted from Pure and Applied Chemistry, Vol. 1, No. 4.

ISSN:0003-2654    

DOI:10.1039/AN9618600427

出版商:RSC    

年代:1961

数据来源: RSC