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Fluorimetric determination of cadmium with 8-hydroxyquinoline-5-sulphonic acid
SlIORT
COMMUNICATIONS
491
Reduction can also be utilized for the separation of micro amounts of elements on the ring oven. This can be seen from the results for the determination of tellurium in the presence of selenium. In this case selenium was reduced at the starting point by hydroxylarnine, while tellurium was washed out to the ring zone and reduced by hyclrazine. In order to show the applicability of the method described for the deterrninai.’ . tion of micro amounts of easily reducible elements, gold and tellurium were determined in electrolytic copper slime. Gold was determined in the hydrochloric acid solution obtained by treating the sample with aqua regia; the nitric acid was eliminated by heating the solution obtained with hydrochloric acid. For the determination of tellurium the solution was prepared in the usual manncra. The results obtained as well as the results of comparative analyses by standard methods are shown in Table IV. It can be seen that the results are in good agreement. From all these results it can be concluded that the reduction principle can be efficiently applied in ring calorimetry. This offers possibilities for the determination of micro amounts of easily reducible elements without prior separation from other elements. T. J. JANJIC G. JURISIC-MILOVANOVIC M. B. CELAP
Chemical Institute of the Faculty of Sciences, University of Belgrade, Belgrade (Yzrgoslavia) 1 z 3 4 5 6
B. C~LAF AND H. WEISZ, Mikrocirim. clcfa, (rg60) 706 B. CELAP AND T. J. JANJIC, Mikrochiwa. Ada, (1963) 313. J. SINCW AND A. IC. DEY, J. fndian C/rem Sot.. 40 (1963) 222. D. BISWAS AND A. XC.DI~Y, A?talysl, go (1965) 5G. WEISZ, fl~ikrockitn. Acta, (1954) 785. W. W. SCOTT, Standard Metkods of Chemical A~talysis. Van Nostrand, M. M. E. S. H.
(Received
London,
x939, p. 789.
July zoth, x965) Aural.
Fluorimetric determination &hydroxyquinoline-5-sulphonic
of cadmium acid
Clritn. Acla, 34 (1066) 48%4gr
with
In a recent study of solubility of cadmium hydroxide in basic solutions’, reliable measurements of small changes in solubility were necessary. A method based on the measurement of fluorescence developed when 8-hydroxyquinoline-3-sulphonic acid reacts with cadmium ion2 proved satisfactory. The factors influencing the determination are discussed in this paper.
Quantitative measurements were made with a Turner Fluorimeter model # 1x0; the general purpose filters supplied with the fluorimeter were used (360 rnp Corning #7-60; secondary filter passes wavelengths longer than 405 m,u, colour specification # 2A). Anal.
Ckitn. Acta,
34 (x966)
491-494
Sohr tio7ts 8-Hydroxyquinolinc-5-sulphonic acid was recrystallized from water and o.oo3o/Osolution prepared. A 0.01 M cadmium stock solution was prepared by dissolving pure cadmiu metal in a minimum amount of dilute nitric acid and excess nitric acid was eliminate This solution was diluted to prepare various cadmium standard by evaporation. Acctatc-acetic acid buffers were prepared by dissolving 20 g of sodium aceta in roe ml of water and adjusting to the desired pH with 6 A4 acetic acid. Ammonia-ammonium chloride buffers were prepared by dissolving 20 g ammonium chloride in IOO ml of water and adjusting to the desired PH with 6 A ammonia.
Constant maximum sensitivity was attained when the PH w
Porta Figr.
1-2.
Dctcrtninntion of Ccl in the p.p.111. range (I), at prr 6.7; (2). at p
1 Ports
Fig. 3. Anal.
per mIllton codmlum
par
2 Qllllon codmlum
3
4
Determination of Cd in the p.p.b. rnngc at pox7.9, Clrign.Acta, 34
(rgG6)
4gr-4g4
7.9.
IH 5, but close control of solution px-i was essential. The results shown in Fig. I are ypical. Figures 2 and 3 illustrate the sensitivity of the method; these results were btained with solutions buffered at pH 7.9. Procedzwe. Transfer 0.01-2 pug of cadmium in solution to a xo-ml volumetric .ask. Add I ml of ammonia-ammonium chloride buffer to adjust the PH within .I-8.5. Add 4 ml of o.oo3°/o reagent for maximum sensitivity and dilute to IO ml rith doubly distilled water. Prepare the blank by the same procedure. Tactors affecthtg fluomxcence Although the reagent itself fluoresces, the intensity is very small relative to Irecadmium species. The fluorescence intensity of the cadmium hydroxyquinoline species varied ttle with time; a 0.1 p.p.m. cadmium sample varied by only 1% over a pcriodof 5 11. A study of the effect of PH on fluorescence (0.1 p.p,m, Cd) showed that the uorescence was maximal and constant between PH 7.1 and 8.5. A study was also one on the effect of ionic strength on the fluorescence of the cadmium species (up I ,u=3.0) using sodium perchlorate. No changes in fluorescence intensity were obtrved. The fluorescence of the cadmium species is markedly affected by the quantity I excess reagent. Figure 4 shows, for 0.1 p.p.m. cadmium, that constant readings are btained when the mole ratio of reagent to cadmium is in excess of 60 to I. 55-
s+ I 20406080io0 6.
4. Effect
200
Reagent rotio of oxccss reagent (0.1 p.p.m. Cd).
I
I
I 300
lzrorescence
of other medals BISHOIB” and STEVENS~ have commented on the failure of transition metal ttions to give fluorescence with S-hydroxyquinoline-5-sulphonic acid. Using a 230-W .ercury ultraviolet lamp, Hanovian type 16106, 30 cations were tested for fluoresnce with the reagent. Strong fluorescence was observed between PH 7.x to 8.5 with dz+, Zn2+, Mg3+, Ca2+, Ala+, Las+, Ced+, Th4+ and !%a+. The following ions fluoresc1 weakly or not at aLl: Li +, Na+, K+, Ag+, Ba2+, Hgz+, Cu2+, Co2+, Ni2+, Sn2+, d2-)-,Ba+, A$+, Sb”+, Bi3+, Craf, Fe3+, Zr4+, TaS+, NbS+, Wo+. The fluorescence spectra for both the cadmium and zinc species have their axima at the same wavelength (520 mp). Zinc is therefore a positive interference
Anal. Chim. Acta, 34 (xg66)~4gr-494
SHUK-I’
494
LUMMUNlC;ATIU
in the determination of cadmium; for example, the amount of cadmium found in t presence of 0.1 p.p.m. of zinc was 0.13 p.p.m. when 0.x p.p.m. of cadmium was tak for analysis. This Canada.
work was supported
by a grant
from the Defence
Research
D. E. RY, A. R. PIT R. M. CASSII
Defiavtmed of Chemistry, Dalhozrsie University, Halifax, Nova Scotia (Canada) I D. ILRYAN, 2 JOHN
A.
DEAN AND Anal. Chint.
J. R.
BISHOP,
Board
R. M.CASSIDY,CCIII. J. Chewz., 43 (rgGg)ggg.
Ada, 29 (1963) 172.
3 M. M.S~15~15~s,nnal.Clrint. ~c:n,20(rg~r) 5432.
(Received
August znd, 1965)
A rrnl. C/rim. Ach,
BOOK
34 (1966) 491-49‘1
REVIEWS
H. BENNETT AND W. G. HAWLEY, Methods of Silicnte Analysis, 2nd Et Academic Press, London and New York, for the BritishCeramic Research Associatio 1965, x + 334 pp., price 63 s. Analysts appreciate an authoritative source of information on those occasion when materials outside their normal field are to be analysed, and experts in the fie’ like to keep abreast with current analytical practice. This revised and extends version of the rg$3 publication meets both of these requirements and, like its pred’ cessor, it is essentially a practical book for analysts engaged in ceramic and allic industries. Although the title of the book refers specifically to silicate analysis, procedure are included for the analysis of materials in which the silica content is low. In man respects the presentation of both editions is the same, e,g., the methods given in eat chapter are self-contained, without any undue cross references. The book is certain1 comprehensive, bearing in mind the prime purpose for which it is intended, but tl recommended procedures are, justifiably, restricted to those that have been succes: fully appIied in extensive laboratory trials to specified materials; with special a tention to current requirements. Whilst the approach to silicate analysis has not changed radically since tl last edition of the book appeared, the authors are to be congratulated for implemen ing timely changes based on further instrumentation, and new techniques current1 used in other analytical fields. W. T. ELWELL (Birminghan Anal. Chin. Actn, 34 (1966) 494
COMMUNICATIONS
491
Reduction can also be utilized for the separation of micro amounts of elements on the ring oven. This can be seen from the results for the determination of tellurium in the presence of selenium. In this case selenium was reduced at the starting point by hydroxylarnine, while tellurium was washed out to the ring zone and reduced by hyclrazine. In order to show the applicability of the method described for the deterrninai.’ . tion of micro amounts of easily reducible elements, gold and tellurium were determined in electrolytic copper slime. Gold was determined in the hydrochloric acid solution obtained by treating the sample with aqua regia; the nitric acid was eliminated by heating the solution obtained with hydrochloric acid. For the determination of tellurium the solution was prepared in the usual manncra. The results obtained as well as the results of comparative analyses by standard methods are shown in Table IV. It can be seen that the results are in good agreement. From all these results it can be concluded that the reduction principle can be efficiently applied in ring calorimetry. This offers possibilities for the determination of micro amounts of easily reducible elements without prior separation from other elements. T. J. JANJIC G. JURISIC-MILOVANOVIC M. B. CELAP
Chemical Institute of the Faculty of Sciences, University of Belgrade, Belgrade (Yzrgoslavia) 1 z 3 4 5 6
B. C~LAF AND H. WEISZ, Mikrocirim. clcfa, (rg60) 706 B. CELAP AND T. J. JANJIC, Mikrochiwa. Ada, (1963) 313. J. SINCW AND A. IC. DEY, J. fndian C/rem Sot.. 40 (1963) 222. D. BISWAS AND A. XC.DI~Y, A?talysl, go (1965) 5G. WEISZ, fl~ikrockitn. Acta, (1954) 785. W. W. SCOTT, Standard Metkods of Chemical A~talysis. Van Nostrand, M. M. E. S. H.
(Received
London,
x939, p. 789.
July zoth, x965) Aural.
Fluorimetric determination &hydroxyquinoline-5-sulphonic
of cadmium acid
Clritn. Acla, 34 (1066) 48%4gr
with
In a recent study of solubility of cadmium hydroxide in basic solutions’, reliable measurements of small changes in solubility were necessary. A method based on the measurement of fluorescence developed when 8-hydroxyquinoline-3-sulphonic acid reacts with cadmium ion2 proved satisfactory. The factors influencing the determination are discussed in this paper.
Quantitative measurements were made with a Turner Fluorimeter model # 1x0; the general purpose filters supplied with the fluorimeter were used (360 rnp Corning #7-60; secondary filter passes wavelengths longer than 405 m,u, colour specification # 2A). Anal.
Ckitn. Acta,
34 (x966)
491-494
Sohr tio7ts 8-Hydroxyquinolinc-5-sulphonic acid was recrystallized from water and o.oo3o/Osolution prepared. A 0.01 M cadmium stock solution was prepared by dissolving pure cadmiu metal in a minimum amount of dilute nitric acid and excess nitric acid was eliminate This solution was diluted to prepare various cadmium standard by evaporation. Acctatc-acetic acid buffers were prepared by dissolving 20 g of sodium aceta in roe ml of water and adjusting to the desired pH with 6 A4 acetic acid. Ammonia-ammonium chloride buffers were prepared by dissolving 20 g ammonium chloride in IOO ml of water and adjusting to the desired PH with 6 A ammonia.
Constant maximum sensitivity was attained when the PH w
Porta Figr.
1-2.
Dctcrtninntion of Ccl in the p.p.111. range (I), at prr 6.7; (2). at p
1 Ports
Fig. 3. Anal.
per mIllton codmlum
par
2 Qllllon codmlum
3
4
Determination of Cd in the p.p.b. rnngc at pox7.9, Clrign.Acta, 34
(rgG6)
4gr-4g4
7.9.
IH 5, but close control of solution px-i was essential. The results shown in Fig. I are ypical. Figures 2 and 3 illustrate the sensitivity of the method; these results were btained with solutions buffered at pH 7.9. Procedzwe. Transfer 0.01-2 pug of cadmium in solution to a xo-ml volumetric .ask. Add I ml of ammonia-ammonium chloride buffer to adjust the PH within .I-8.5. Add 4 ml of o.oo3°/o reagent for maximum sensitivity and dilute to IO ml rith doubly distilled water. Prepare the blank by the same procedure. Tactors affecthtg fluomxcence Although the reagent itself fluoresces, the intensity is very small relative to Irecadmium species. The fluorescence intensity of the cadmium hydroxyquinoline species varied ttle with time; a 0.1 p.p.m. cadmium sample varied by only 1% over a pcriodof 5 11. A study of the effect of PH on fluorescence (0.1 p.p,m, Cd) showed that the uorescence was maximal and constant between PH 7.1 and 8.5. A study was also one on the effect of ionic strength on the fluorescence of the cadmium species (up I ,u=3.0) using sodium perchlorate. No changes in fluorescence intensity were obtrved. The fluorescence of the cadmium species is markedly affected by the quantity I excess reagent. Figure 4 shows, for 0.1 p.p.m. cadmium, that constant readings are btained when the mole ratio of reagent to cadmium is in excess of 60 to I. 55-
s+ I 20406080io0 6.
4. Effect
200
Reagent rotio of oxccss reagent (0.1 p.p.m. Cd).
I
I
I 300
lzrorescence
of other medals BISHOIB” and STEVENS~ have commented on the failure of transition metal ttions to give fluorescence with S-hydroxyquinoline-5-sulphonic acid. Using a 230-W .ercury ultraviolet lamp, Hanovian type 16106, 30 cations were tested for fluoresnce with the reagent. Strong fluorescence was observed between PH 7.x to 8.5 with dz+, Zn2+, Mg3+, Ca2+, Ala+, Las+, Ced+, Th4+ and !%a+. The following ions fluoresc1 weakly or not at aLl: Li +, Na+, K+, Ag+, Ba2+, Hgz+, Cu2+, Co2+, Ni2+, Sn2+, d2-)-,Ba+, A$+, Sb”+, Bi3+, Craf, Fe3+, Zr4+, TaS+, NbS+, Wo+. The fluorescence spectra for both the cadmium and zinc species have their axima at the same wavelength (520 mp). Zinc is therefore a positive interference
Anal. Chim. Acta, 34 (xg66)~4gr-494
SHUK-I’
494
LUMMUNlC;ATIU
in the determination of cadmium; for example, the amount of cadmium found in t presence of 0.1 p.p.m. of zinc was 0.13 p.p.m. when 0.x p.p.m. of cadmium was tak for analysis. This Canada.
work was supported
by a grant
from the Defence
Research
D. E. RY, A. R. PIT R. M. CASSII
Defiavtmed of Chemistry, Dalhozrsie University, Halifax, Nova Scotia (Canada) I D. ILRYAN, 2 JOHN
A.
DEAN AND Anal. Chint.
J. R.
BISHOP,
Board
R. M.CASSIDY,CCIII. J. Chewz., 43 (rgGg)ggg.
Ada, 29 (1963) 172.
3 M. M.S~15~15~s,nnal.Clrint. ~c:n,20(rg~r) 5432.
(Received
August znd, 1965)
A rrnl. C/rim. Ach,
BOOK
34 (1966) 491-49‘1
REVIEWS
H. BENNETT AND W. G. HAWLEY, Methods of Silicnte Analysis, 2nd Et Academic Press, London and New York, for the BritishCeramic Research Associatio 1965, x + 334 pp., price 63 s. Analysts appreciate an authoritative source of information on those occasion when materials outside their normal field are to be analysed, and experts in the fie’ like to keep abreast with current analytical practice. This revised and extends version of the rg$3 publication meets both of these requirements and, like its pred’ cessor, it is essentially a practical book for analysts engaged in ceramic and allic industries. Although the title of the book refers specifically to silicate analysis, procedure are included for the analysis of materials in which the silica content is low. In man respects the presentation of both editions is the same, e,g., the methods given in eat chapter are self-contained, without any undue cross references. The book is certain1 comprehensive, bearing in mind the prime purpose for which it is intended, but tl recommended procedures are, justifiably, restricted to those that have been succes: fully appIied in extensive laboratory trials to specified materials; with special a tention to current requirements. Whilst the approach to silicate analysis has not changed radically since tl last edition of the book appeared, the authors are to be congratulated for implemen ing timely changes based on further instrumentation, and new techniques current1 used in other analytical fields. W. T. ELWELL (Birminghan Anal. Chin. Actn, 34 (1966) 494