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Spectrophotometric determination of antimony with vanillylfluorone in the presence of poly(vinyl alcohol)
Tahto,
vOl 38, NO 3, pp 343-345, 1w1
0039-9140/91$3 00 + 0 00 Pergamon Press plc
Printed in Great Britain
SPECTROPHOTOMETRIC DETERMINATION OF ANTIMONY WITH VANILLYLFLUORONE IN THE PRESENCE OF POLY(VINYL ALCOHOL) ITSUO MORI,+ YOSIUKAZU FUJITA, MINAKO TOYODA, Kam
KATO,
KAZUMIFUJITAand YUJIOKAZAKI Osaka University of Pharmaceutical Sciences, Matsubara-sht, Osaka 580, Japan (Recewed 12 June 1989 Rewed
26 January 1990 Accepted 30 August 1990)
Summary-Antimony m the range up to 2.5 pg/rnl m the final solution IS determmed spectrophotometncally wtth vamllylfluorone m the presence of poly(vmy1 alcohol) m acubc media The method is compared with that using o-hydroxyhydroqumonephthalem (Qnph) It is simple, rapid and sensitive, without need for heatmg or solvent extractton, and the apparent molar absorpttvity (E) LF5 0 x 104 1 mole-‘.cn--’ at 545 nm, for the Qnph method c 1s 2 8 x IO41 mole-’ cm-’ at 520 nm Tests with an artificial wastewater gave 99-103% recovery
High-purity antimony is used m the manufacture of semiconductors, and the antimony levels in the urine of workers in the factories should be monitored.’ Numerous xanthene and tnphenylmethane dyes such as phenylfluorone and its derivatives,2A Gallem, 5*6Bromopyrogallol Red7 and Brilliant Green, 8,9 have been used for spectrophotometric determination of antimony, and the effect of surfactants on some of these methods has been examined.s~7*‘0-‘2 However, the purity of commercial phenylfluorones is variable and their solutions in methanol are not always stable. Vanillylfluorone (2,6,7-tnhydroxy-9-vamllylxanthene-3-one, Vfl), is reported to be superior in ease of purification and stability in organic solvents I3 In this paper, the colour reaction of Vfl with antimony m the presence and absence of dispersion agents is compared with the corresponding reaction with ohydroxyhydroqumonephthalein (Qnph), which is also recommended’4s’s as superior to phenylfluorone. A simple, rapid and sensitive spectrophotometric method for the assay of antimony with Vfl in the presence of poly(vinyl alcohol), PVA, is proposed and compared with the corresponding method employing
Qvh. *Author for correspondence
EXPERIMENTAL Reagents
A 1.0 x 10e3M Vfl solution m methanol was prepared, and a Qnph solution as described earlier.14*15 Antimony stock solution (1.0 x lo-*M) was prepared by dissolving antimony metal (Mitsuwa Chemical Co., Ltd., 99.999% pure) m concentrated sulphuric acid, cooling and diluting with water to give 20% v/v sulphunc acid in the final solution. A 5.0 x 10m4M antimony working solution was prepared by dilution of the stock solution with 20% v/v sulphuric acid.16 A 1.0% solution of PVA (n = 500, I(lshida Chemical Co., Ltd.) in water was prepared, and 20% v/v sulphunc acid was used for adjustment of acidity. All reagents and materials were of analytical-reagent grade. Demmeralized water was used throughout Spectrophotometric procedure
Pipette various volumes of standard antimony solution, to give up to 25 pg of antimony, into a series of lo-ml standard flasks. Add 1.5-3.0 ml of 20% v/v sulphuric acid, 2 0 ml of 1.0% PVA solution and 1.5 ml of 1.0 x 10m3M Vfl solution. Mix thoroughly and dilute to the mark with water. After about 10 mm measure the absorbance at 545 nm against a reagent blank prepared m the same way. Analyse sample solutions similarly. A similar procedure can be used with Qnph, with measurement at 520 nm. 343
ITSUOMom
I
0’
.
I
550
450
350
Wavelength
tnm)
Rg 1 Absorptton spectra of Qnph, Vfl, and then antimony complexes m the presence of PVA Antimony 5.0 x IO-rM, Qnph or Vfl 5 0 x 10m5M, PVA 0 2%, reference water. A, Qnph solution, B, Vfl solution, C, Qnph-anhmony solutton, D, Vfl-antrmony solution RESULTS AND DISCUSSION
Of the reagents Pyrogallol Red, Bromopyrogall01 Red, phenylfluorone derivatives, Gallein, Xylenol Orange and Vfl, the last was best in terms of sensitivity, stability and reproducibility. Though Vfl gave good colour development in the presence of a cationic surfactant such as hexadecylpyridmium chloride, the product was somewhat lacking in stability and gradually precipitated. However, the colour developed in the presence of PVA (as a dispersion or stabilizmg agent) was more stable and reproducible than that in its absence. Figure 1 shows the absorption spectra of the Vfl-antimony and Qnph-antimony complexes and of Vfl and Qnph, and shows the greater sensitivity of the Vfl system.
ef al
Maximal and constant absorbance was obtained at 4-8% v/v final sulphuric acid concentration for the Vfl-antimony complex, and at pH 1.1-l 5 (obtained with 0.5-3.0 ml of 1.0% v/v sulphuric acid, for the Qnph-antimony complex. A final PVA concentration of 0.1% was optimal, and PVA was superior to Triton X-100, Brij 35, poly(N-vinyl-2-pyrrolidone) and gelatine for the purpose. Maximal absorbance for a fixed amount of antimony was obtained with 1.4-3.0 ml of 1.0 x 10v3M Vfl, so final concentrations of 2.8 x 10e4M Vfl and 0.1% PVA were selected for use. Beer’s law holds over the concentration range O-2.5 pg/ml antimony in the final solution with Vfl and O-6.0 pg/ml with Qnph. The apparent molar absorptivtty was 5.0 x lo4 l.mole-‘.cm-’ for Vfl, and 2.8 x lo4 l.mole-’ .cm-’ for Qnph. The relative standard deviation was 0.5% for 1.05 ,ugg/ml antimony (5 replicates). Interferences Tm(IV) interfered seriously in the assay of antimony with Vfl, giving a positive error, and thorium and bismuth gave negative errors. Other cations tested, such as aluminium, cobalt(II), indium, tantalum, manganese(II), iron(III), did not interfere, nor did anions such as Iodide, fluoride and cyanide, at lOO-fold molar ratio to antimony, but thiosulphate caused interference. Table 1 shows the tolerance levels for these ions. The Vfl method is less prone to interference than the Qnph method, and is more sensitive than the phenylfluorone, Bromopyrogallol Red, Gallein and Brilliant Green methods.3-9
Table 1. Effect of foreign tons on determmatron of 1 22 pg/ml antimony
Added, IOn
Sn(IV) BI(III) Th(IV) Al(II1) In(II1) Fe(II1) Mn(I1) Cu(I1) Co(B) WI;) 2_Q3Tartrate NTA
uelml 03 20 9 23 2 80 9 34 3 55.8 54 9 63 6 1768 176.1 3:: 1200 1711
Molar ratio (ion/antimony)
0 25 10 10 300 300 100 100 100 300 300 5 100 1000 1000
Absorbance at 520 nm
Tolerance ratio for Vfl method relative to Qnph method
0.500 0 499 0 488 0 459 0 501 0 505 0 514 0 510 0.490 0500 0 495 0 485 0.498 0 496 0491
10 10 20 10 20 1000 10 2 5 10 5 10 10 5
Determmation
The reaction between Vfl and antimony can be prevented by mashing the antimony with tartrate, but the reaction with tin(N) is not affected, so Vfl can be used for the determination of tin in the presence of antimony. The composition of the Vfl-antimony complex in the presence of PVA was found to be 1: 1 by the continuous-variation and molar-ratio methods. The molar ratio of Vfl to PVA was not investigated. The recovery of antimony from an art& cial wastewater containing antimony, cobalt(II), aluminium, magnesium, iron(III), was found to be 99-103%.
of anttmony
5. W Car, Y Chtyang, L. He and J. Xu, Fenxr Huaxue, 6 1987, 15, 828; Anal. Abstr., 1988, So, 4B106
L. Naruskevtcms, R Kazlauskas and J Skadauskas, Llet TSR A&t, Mokyklu Mokslo Darb., Gem. Technol, 1979, 21, 13, Anal Abstr, 1980, 39,4B115 7. D H Chrtstopher and T S West, Talanta, 1966, 13, 507 * L A. Soldatova, Z G Ktlma and G A. Kataev, Zh Anaht Khwn, 1964, 19, 1267 ,-, A G Fogg, J. Jdlmgs, D. R Mamott and D T Bums, Analyst, 1969, 94, 768. 10 V. P Antonovtch, E N. Suvorova and E L Shehkhma, Zh. Anaht Khun., 1982, 37, 429 l1 H. Li, Q Pan, Q Rong and D. Tan, Ceshl Tongao Fenxl, 1986, 5, No 6, 6; Chem. Abstr , 1987, 107, 69819u. IL. X Wu and H. Ding, Fenxi Shryanshl, 1986, 5, No. 11, 34; Anal Abstr., 1987, 49, lOB132. 13 W. Lin and M. Chen, Fenxl Huasue, 1988, 16, 202; Chem. Abstr., 1989, 110, 87560u 14. I. Mori, Y FuJita, Y. Kamada and T. Enokt, Bunseki Kagaku, 1976, 2S, 388. 15 I. Mori, Y. Fujita, K. Fujita, A. Usarm, H. Kawabe, Y Kosmyama and T. Tanaka, Bull. Chem Sot. Japan, 1986, S9, 1623. 16 I Mot-t, Yakugaku Zasshr, 1969, 89, 475 .L
REFERENCES 1. S Costantim, R Gtordano, M Rizzlca and F Benedeth, Analyst, 1985, 110, 1355 2 0. G Koch, Z Anal Chem., 1973, 265, 29 3 V P Antonovtch, E M. Nevskaya, E N Suvorova and V A Nazarenko, Zh Analrt. Khzm , 1978, 33, 458 4 E Asmus and K Brandt, Z Anal Chem, 1965, u)8, 189
345
vOl 38, NO 3, pp 343-345, 1w1
0039-9140/91$3 00 + 0 00 Pergamon Press plc
Printed in Great Britain
SPECTROPHOTOMETRIC DETERMINATION OF ANTIMONY WITH VANILLYLFLUORONE IN THE PRESENCE OF POLY(VINYL ALCOHOL) ITSUO MORI,+ YOSIUKAZU FUJITA, MINAKO TOYODA, Kam
KATO,
KAZUMIFUJITAand YUJIOKAZAKI Osaka University of Pharmaceutical Sciences, Matsubara-sht, Osaka 580, Japan (Recewed 12 June 1989 Rewed
26 January 1990 Accepted 30 August 1990)
Summary-Antimony m the range up to 2.5 pg/rnl m the final solution IS determmed spectrophotometncally wtth vamllylfluorone m the presence of poly(vmy1 alcohol) m acubc media The method is compared with that using o-hydroxyhydroqumonephthalem (Qnph) It is simple, rapid and sensitive, without need for heatmg or solvent extractton, and the apparent molar absorpttvity (E) LF5 0 x 104 1 mole-‘.cn--’ at 545 nm, for the Qnph method c 1s 2 8 x IO41 mole-’ cm-’ at 520 nm Tests with an artificial wastewater gave 99-103% recovery
High-purity antimony is used m the manufacture of semiconductors, and the antimony levels in the urine of workers in the factories should be monitored.’ Numerous xanthene and tnphenylmethane dyes such as phenylfluorone and its derivatives,2A Gallem, 5*6Bromopyrogallol Red7 and Brilliant Green, 8,9 have been used for spectrophotometric determination of antimony, and the effect of surfactants on some of these methods has been examined.s~7*‘0-‘2 However, the purity of commercial phenylfluorones is variable and their solutions in methanol are not always stable. Vanillylfluorone (2,6,7-tnhydroxy-9-vamllylxanthene-3-one, Vfl), is reported to be superior in ease of purification and stability in organic solvents I3 In this paper, the colour reaction of Vfl with antimony m the presence and absence of dispersion agents is compared with the corresponding reaction with ohydroxyhydroqumonephthalein (Qnph), which is also recommended’4s’s as superior to phenylfluorone. A simple, rapid and sensitive spectrophotometric method for the assay of antimony with Vfl in the presence of poly(vinyl alcohol), PVA, is proposed and compared with the corresponding method employing
Qvh. *Author for correspondence
EXPERIMENTAL Reagents
A 1.0 x 10e3M Vfl solution m methanol was prepared, and a Qnph solution as described earlier.14*15 Antimony stock solution (1.0 x lo-*M) was prepared by dissolving antimony metal (Mitsuwa Chemical Co., Ltd., 99.999% pure) m concentrated sulphuric acid, cooling and diluting with water to give 20% v/v sulphunc acid in the final solution. A 5.0 x 10m4M antimony working solution was prepared by dilution of the stock solution with 20% v/v sulphuric acid.16 A 1.0% solution of PVA (n = 500, I(lshida Chemical Co., Ltd.) in water was prepared, and 20% v/v sulphunc acid was used for adjustment of acidity. All reagents and materials were of analytical-reagent grade. Demmeralized water was used throughout Spectrophotometric procedure
Pipette various volumes of standard antimony solution, to give up to 25 pg of antimony, into a series of lo-ml standard flasks. Add 1.5-3.0 ml of 20% v/v sulphuric acid, 2 0 ml of 1.0% PVA solution and 1.5 ml of 1.0 x 10m3M Vfl solution. Mix thoroughly and dilute to the mark with water. After about 10 mm measure the absorbance at 545 nm against a reagent blank prepared m the same way. Analyse sample solutions similarly. A similar procedure can be used with Qnph, with measurement at 520 nm. 343
ITSUOMom
I
0’
.
I
550
450
350
Wavelength
tnm)
Rg 1 Absorptton spectra of Qnph, Vfl, and then antimony complexes m the presence of PVA Antimony 5.0 x IO-rM, Qnph or Vfl 5 0 x 10m5M, PVA 0 2%, reference water. A, Qnph solution, B, Vfl solution, C, Qnph-anhmony solutton, D, Vfl-antrmony solution RESULTS AND DISCUSSION
Of the reagents Pyrogallol Red, Bromopyrogall01 Red, phenylfluorone derivatives, Gallein, Xylenol Orange and Vfl, the last was best in terms of sensitivity, stability and reproducibility. Though Vfl gave good colour development in the presence of a cationic surfactant such as hexadecylpyridmium chloride, the product was somewhat lacking in stability and gradually precipitated. However, the colour developed in the presence of PVA (as a dispersion or stabilizmg agent) was more stable and reproducible than that in its absence. Figure 1 shows the absorption spectra of the Vfl-antimony and Qnph-antimony complexes and of Vfl and Qnph, and shows the greater sensitivity of the Vfl system.
ef al
Maximal and constant absorbance was obtained at 4-8% v/v final sulphuric acid concentration for the Vfl-antimony complex, and at pH 1.1-l 5 (obtained with 0.5-3.0 ml of 1.0% v/v sulphuric acid, for the Qnph-antimony complex. A final PVA concentration of 0.1% was optimal, and PVA was superior to Triton X-100, Brij 35, poly(N-vinyl-2-pyrrolidone) and gelatine for the purpose. Maximal absorbance for a fixed amount of antimony was obtained with 1.4-3.0 ml of 1.0 x 10v3M Vfl, so final concentrations of 2.8 x 10e4M Vfl and 0.1% PVA were selected for use. Beer’s law holds over the concentration range O-2.5 pg/ml antimony in the final solution with Vfl and O-6.0 pg/ml with Qnph. The apparent molar absorptivtty was 5.0 x lo4 l.mole-‘.cm-’ for Vfl, and 2.8 x lo4 l.mole-’ .cm-’ for Qnph. The relative standard deviation was 0.5% for 1.05 ,ugg/ml antimony (5 replicates). Interferences Tm(IV) interfered seriously in the assay of antimony with Vfl, giving a positive error, and thorium and bismuth gave negative errors. Other cations tested, such as aluminium, cobalt(II), indium, tantalum, manganese(II), iron(III), did not interfere, nor did anions such as Iodide, fluoride and cyanide, at lOO-fold molar ratio to antimony, but thiosulphate caused interference. Table 1 shows the tolerance levels for these ions. The Vfl method is less prone to interference than the Qnph method, and is more sensitive than the phenylfluorone, Bromopyrogallol Red, Gallein and Brilliant Green methods.3-9
Table 1. Effect of foreign tons on determmatron of 1 22 pg/ml antimony
Added, IOn
Sn(IV) BI(III) Th(IV) Al(II1) In(II1) Fe(II1) Mn(I1) Cu(I1) Co(B) WI;) 2_Q3Tartrate NTA
uelml 03 20 9 23 2 80 9 34 3 55.8 54 9 63 6 1768 176.1 3:: 1200 1711
Molar ratio (ion/antimony)
0 25 10 10 300 300 100 100 100 300 300 5 100 1000 1000
Absorbance at 520 nm
Tolerance ratio for Vfl method relative to Qnph method
0.500 0 499 0 488 0 459 0 501 0 505 0 514 0 510 0.490 0500 0 495 0 485 0.498 0 496 0491
10 10 20 10 20 1000 10 2 5 10 5 10 10 5
Determmation
The reaction between Vfl and antimony can be prevented by mashing the antimony with tartrate, but the reaction with tin(N) is not affected, so Vfl can be used for the determination of tin in the presence of antimony. The composition of the Vfl-antimony complex in the presence of PVA was found to be 1: 1 by the continuous-variation and molar-ratio methods. The molar ratio of Vfl to PVA was not investigated. The recovery of antimony from an art& cial wastewater containing antimony, cobalt(II), aluminium, magnesium, iron(III), was found to be 99-103%.
of anttmony
5. W Car, Y Chtyang, L. He and J. Xu, Fenxr Huaxue, 6 1987, 15, 828; Anal. Abstr., 1988, So, 4B106
L. Naruskevtcms, R Kazlauskas and J Skadauskas, Llet TSR A&t, Mokyklu Mokslo Darb., Gem. Technol, 1979, 21, 13, Anal Abstr, 1980, 39,4B115 7. D H Chrtstopher and T S West, Talanta, 1966, 13, 507 * L A. Soldatova, Z G Ktlma and G A. Kataev, Zh Anaht Khwn, 1964, 19, 1267 ,-, A G Fogg, J. Jdlmgs, D. R Mamott and D T Bums, Analyst, 1969, 94, 768. 10 V. P Antonovtch, E N. Suvorova and E L Shehkhma, Zh. Anaht Khun., 1982, 37, 429 l1 H. Li, Q Pan, Q Rong and D. Tan, Ceshl Tongao Fenxl, 1986, 5, No 6, 6; Chem. Abstr , 1987, 107, 69819u. IL. X Wu and H. Ding, Fenxi Shryanshl, 1986, 5, No. 11, 34; Anal Abstr., 1987, 49, lOB132. 13 W. Lin and M. Chen, Fenxl Huasue, 1988, 16, 202; Chem. Abstr., 1989, 110, 87560u 14. I. Mori, Y FuJita, Y. Kamada and T. Enokt, Bunseki Kagaku, 1976, 2S, 388. 15 I. Mori, Y. Fujita, K. Fujita, A. Usarm, H. Kawabe, Y Kosmyama and T. Tanaka, Bull. Chem Sot. Japan, 1986, S9, 1623. 16 I Mot-t, Yakugaku Zasshr, 1969, 89, 475 .L
REFERENCES 1. S Costantim, R Gtordano, M Rizzlca and F Benedeth, Analyst, 1985, 110, 1355 2 0. G Koch, Z Anal Chem., 1973, 265, 29 3 V P Antonovtch, E M. Nevskaya, E N Suvorova and V A Nazarenko, Zh Analrt. Khzm , 1978, 33, 458 4 E Asmus and K Brandt, Z Anal Chem, 1965, u)8, 189
345