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Determination of gallium by displacement substoichiometric extraction with labeled indium-oxinate in chloroform
ARTICLE IN PRESS
Applied Radiation and Isotopes 66 (2008) 317–319 www.elsevier.com/locate/apradiso
Determination of gallium by displacement substoichiometric extraction with labeled indium-oxinate in chloroform M. Mandala, S. Banerjeeb, S. Basub, a
Department of Chemistry, Tamralipta Mahavidyalaya, Tamluk, Purbamedinipur 721636, West Bengal, India b Department of Chemistry, The University of Burdwan, Burdwan 713104, India Received 14 May 2007; received in revised form 13 July 2007; accepted 12 September 2007
Abstract A radiochemical displacement method for the determination of small amounts of gallium has been developed. The method involves the displacement of spiked (114mIn) indium from its oxinate in chloroform. The effects of various ions on the extent of displacement have been reported. By this process 6–28 mg of Ga(III) can be determined. Results are highly reproducible in the proposed method. r 2007 Published by Elsevier Ltd.
1. Introduction Gallium is a widely distributed element. The amount of gallium in the earth’s crust is 5–15 ppm. Most of the gallium in the lithosphere is in association with aluminum and zinc in their minerals and can be obtained as a by-product in the extraction of the metals. Again, gallium is found as a liquid over a wide range of temperature and for this reason it is used in high-temperature thermometers and manometers. In nuclear reactors, it has received considerable attention as a heat exchange medium. It can also be used as a positive electrode in a generative battery, as a temperature rectifier and intransistors in solar batteries, etc. (Sheka et al., 1966). It is also used as an activator in glowing paints. As a radiopharmaceutical, 72Ga isotope is used for the diagnosis of bone cancer because bone can absorb the metal. The increasing use of Ga in industries and in other fields demands the development of a simple and rapid method of its estimation. For the determination of gallium, various methods have been reported. These include ETAAS (Shida and Matsuzaki, 1997; Lopez-Garcia et al., 2004), spectrophotometric (Lucena et al., 1994; Dzherayan et al., 2006), graphite furnace atomic absorption spectrometry (Shan et al., 1985), and solvent extraction with different Corresponding author.
E-mail address: [email protected] (S. Basu). 0969-8043/$ - see front matter r 2007 Published by Elsevier Ltd. doi:10.1016/j.apradiso.2007.09.013
phosphorous containing compounds such as di(2-ethyl hexyl)phosphoric acid (Lee et al., 2002; Lee and Lee, 1998; Sato et al., 1997), and oxygenous extractants such as triphenyl arsine oxide (Vartak and Shinde, 1998), MIBK (Venkaji et al., 1994), 2,4-pentane dione, and 3,5-dichlorophenol (Imura et al., 1998). Besides these, use of high molecular weight amines (Mukherjee and Bag, 1997; Gutierrez et al., 1997; Ohto et al., 1997) and 5-sulpho8-quinolinol (Hiroshi et al., 1998), n-octyl aniline from succinate media (Shilmkar et al., 2005) have also been reported for the extraction and determination of gallium in different matrices, adopting ICP-MS and ICP-AES (Even et al., 2001). Recently, a high-resolution ICP-MS procedure (Ghazi et al., 2000) for the study of Ga diffusion in human teeth has been reported using 69,71Ga isotopes. All the reported works are direct methods for determination of gallium. The purpose of the present work is to develop a radiochemical displacement method for the determination of gallium using spiked indium-oxinate in chloroform as the radioreagent. Such an indirect determination (Braun et al., 1969) needs the preparation of labeled indium-oxinate, totally free from oxine, the condition of which was obtained by preliminary study of substoichiometric extraction of indium (Zmuewska, 1974). Secondly, the metal complexes should be less stable than the complex of displacing cations. The present work is developed on the basis of fulfillment of these two essential conditions.
ARTICLE IN PRESS M. Mandal et al. / Applied Radiation and Isotopes 66 (2008) 317–319
318
2. Experimental
2.4. Displacement substoichiometry
2.1. Isotopes and instrument
In order to study the displacement reaction, 5 ml labeled indium-oxinate in chloroform was taken in a separatory funnel, to which was added increasing amounts of aqueous solution of GaCl3 kept at pH 4.6. After equilibration, 1 ml of aqueous phase of each system was counted for g-activity. Results were further checked by a set of blank experiments, i.e. without addition of any Ga(III) solution in aqueous phases. Radioactivities of 1 ml of 114mIn solution displaced in aqueous phase are plotted against the amount of Ga(III) added in Fig. 2.
2.2. Preparation of labeled indium-oxinate In order to prepare indium-oxinate, spiked with 114mIn in CHCl3 and containing no excess oxine, we carried out substoichiometric extraction of the metal. For this purpose, spiked indium(III) chloride solution containing 118 mg/ml of In(III), kept at pH 4.5, was extracted with increasing (0–10 ml) amounts of 0.41 mM oxine in chloroform. The radioactivity of the extracted labeled In(III) was plotted against the amount of reagent. An inflexion point was obtained for 8 ml reagent, which corresponded to a metal: reagent ratio of 1:3.15. Hence, in a 200 ml separatory funnel, 5 ml spiked indium solution containing 118 mg/ml was diluted with 25 ml deionised water and extracted with 30 ml 0.41 mM oxine in chloroform. This extracted metal complex was diluted to 50 ml with CHCl3 and kept reserved as stock solution of labeled metal-oxinate. 2.3. Selection of pH for displacement reaction In a separatory funnel, 28 mg Ga(III) was equilibrated for 5 min with 5 ml indium-oxinate in CHCl3; the pH of the aqueous solution (5 ml) was varied from pHs 2 to 7. After extraction, 1 ml aqueous solution was measured for radioactivity. Results are plotted in Fig. 1. A blank experiment was also performed.
2.5. Effect of foreign ions Effects of diverse ions on the extent of displacement of In(III) from its oxinate complex by Ga(III) were followed; the results are presented in Table 1.
9000 Counts/30sec of aqueous phase
Radioisotopes used in the present study were obtained from BRIT, Mumbai, India. A single channel g-ray spectrometer coupled with an NaI(Tl) detector of ECILmake was used for radioactivity measurement. All other reagents were of AR grade.
6000
3000
0
0
15 30 Amount of gallium in micro gram
45
Fig. 2. Substoichiometric displacement of In(III) by Ga(III) from indiumoxinate. Table 1 Effect of various metal ions on the displacement of indium
In presence of Ga(III) Blank set
Counts/30sec of aqueous phase
10000
7500
5000
2500
0 2
3
4
5
6
7
pH
Fig. 1. Influence of acidity on the substoichiometric displacement of indium.
Diverse ions
Amont taken (mg)
a/a0
Na(I) Mg (II) Mn(II) Co(II) Ni(II) Pb(II) Hg(II) Zn(II) Cd(II) Cu(II) Ti(IV) Ce(III) Al(III) Fe(III) Tl(I)
124 118 108 124 125 125 148 140 125 120 120 120 150 117 120
1.00 0.97 0.96 0.93 0.94 0.97 0.98 1.00 0.99 0.95 0.93 0.88 High interference Strong interference Strong interference
a0, activity extracted in absence of any diverse ion; a, activity extracted in presence of diverse ion; 25 mg, amount of Ga(III) taken; pH 4.6.
ARTICLE IN PRESS M. Mandal et al. / Applied Radiation and Isotopes 66 (2008) 317–319
3. Discussion The reproducibility of the displacement reaction shows (Fig. 2) that 1 mM of Ga(III) displaces 1 mM of In(III) from its oxine complex in chloroform:
319
organic molecules show any interference. The method is very simple and rapid and can be recommended for the estimation of the metal under substoichiometric condition.
½InðOXÞ3 org þ ½Ga3þ aq Ð ½In3þ aq þ ½GaðOXÞ3 org
References
The displacement process is therefore quantitative. It was previously ascertained that In(III) can form In-trisoxinate complex, as the chelating agent is bidentate and the variation of substoichiometric extraction of In(III) with oxine corresponds to a inflection point at 1:3 ratio. Preparation of 114mIn-oxinate stock solution was made on this basis. Under such condition, there cannot be any free oxine in the chloroform medium. Although there was almost no variation of displacement within pH range 2–5, all the reactions were carried out at pH 4.6, controlled by acetate buffer which itself was not found to strip any In(III) activity. The stoichiometry of the reaction indicates that the upper limit of determination of Ga(III) is 28 mg; a linear calibration was obtained in the range of 6–28 mg of Ga(III). The mode of displacement indicates that Ga(III) forms stronger oxinate than In(III); a result which is supported by their relative crystal ionic radii values (Cotton and Wilkinson, 1969). Although most of the foreign ions used in the present investigation showed only little influence on the extent of displacement (Table 1), Fe(III) and Al(III) ions were found to show serious reducing effects on the displacement reactions and these two cations must be removed in order to get reproducible results. As Tl(I) salts totally hinder the extraction of In(III)-oxinate, their effects on the displacement reaction could not be followed. Among the anions, only F– and PO3 interfere and the method is not promising in the 4 presence of these anions. No other anions including
Braun, T., Ladanyi, L., Marothy, M., Osgyani, I., 1969. J. Radioanalytical. Chem. 2, 263. Cotton, F.A., Wilkinson, G., 1969. Advanced Inorganic Chemistry, second ed. Wiley Eastern Private Limited, New Delhi, India. Dzherayan, T.G., Shkinev, V.M., Reznik, A.M., Mitronov, A.N., Karandeshev, V.K., 2006. J. Anal. Chem. 61 (6), 614. Even, Z.D., Liu, J., Li, Y., 2001. J. Anal. Sci. 17 (1), 25–28. Ghazi, A.M., Shuttleworth, S., Angulo, S.J., Pashley, D.H., 2000. J. Anal. At. Spectrom. 15, 1335. Gutierrez, B., Pazos, C., Coca, J., 1997. Waste Manage. Res. 15, 371. Hiroshi, K., Tokuo, S., Takashi, S., Yoshio, S., 1998. Bull. Chem. Soc. Jpn. 71, 647. Imura, H., Oshiro, A., Ohashi, K., 1998. Anal. Sci. 14, 1093. Lee, M.S., Lee, E.C., 1998. Taehan Kumsok Hakhoechi 36, 1859. Lee, M.S., Ahn, J.G., Lee, E.C., 2002. Hydrometallurgy 63, 269. Lopez-Garcia, I., Campillo, N., Arnau-Jerez, I., Hernandez-Cordoba, M., 2004. J. Anal. At. Spectrom. 19, 935–937. Lucena, R.B., Morales, E., Gomez-Ariza, J.L., 1994. Farmaco 49 (4), 291–295. Mukherjee, J., Bag, S.P., 1997. Indian J. Chem. 36A, 818. Ohto, K., Furukawa, S., Shinohra, T., Inoue, K., 1997. Solvent Extr. Res. Dev. Jpn. 4, 199. Sato, T., Sato, K., Noguchi, Y., Ishikawa, I., 1997. Shigen to Sozai 113, 185. Shan, X.-Q., Yuan, Z.-N., Ni, Z.-M., 1985. Anal. Chem. 57, 857–861. Sheka, I.A., Chaus, I.S., Mityureva, T.T., 1966. The Chemistry of Gallium. Elsevier, Amsterdam. Shida, J., Matsuzaki, S., 1997. Anal. Sci. 13, 41–45. Shilmkar, T.N., Kolekar, S.S., Anuse, M.A., 2005. J. Serb. Chem. Soc. 70 (6), 853–867. Vartak, S.V., Shinde, V.M., 1998. Talanta 45, 925. Venkaji, K., Naidu, P.P., Rao, T.J.P., 1994. Talanta 41, 1281. Zmuewska, W., 1974. J. Radioanalytical. Chem. 20, 521.
Applied Radiation and Isotopes 66 (2008) 317–319 www.elsevier.com/locate/apradiso
Determination of gallium by displacement substoichiometric extraction with labeled indium-oxinate in chloroform M. Mandala, S. Banerjeeb, S. Basub, a
Department of Chemistry, Tamralipta Mahavidyalaya, Tamluk, Purbamedinipur 721636, West Bengal, India b Department of Chemistry, The University of Burdwan, Burdwan 713104, India Received 14 May 2007; received in revised form 13 July 2007; accepted 12 September 2007
Abstract A radiochemical displacement method for the determination of small amounts of gallium has been developed. The method involves the displacement of spiked (114mIn) indium from its oxinate in chloroform. The effects of various ions on the extent of displacement have been reported. By this process 6–28 mg of Ga(III) can be determined. Results are highly reproducible in the proposed method. r 2007 Published by Elsevier Ltd.
1. Introduction Gallium is a widely distributed element. The amount of gallium in the earth’s crust is 5–15 ppm. Most of the gallium in the lithosphere is in association with aluminum and zinc in their minerals and can be obtained as a by-product in the extraction of the metals. Again, gallium is found as a liquid over a wide range of temperature and for this reason it is used in high-temperature thermometers and manometers. In nuclear reactors, it has received considerable attention as a heat exchange medium. It can also be used as a positive electrode in a generative battery, as a temperature rectifier and intransistors in solar batteries, etc. (Sheka et al., 1966). It is also used as an activator in glowing paints. As a radiopharmaceutical, 72Ga isotope is used for the diagnosis of bone cancer because bone can absorb the metal. The increasing use of Ga in industries and in other fields demands the development of a simple and rapid method of its estimation. For the determination of gallium, various methods have been reported. These include ETAAS (Shida and Matsuzaki, 1997; Lopez-Garcia et al., 2004), spectrophotometric (Lucena et al., 1994; Dzherayan et al., 2006), graphite furnace atomic absorption spectrometry (Shan et al., 1985), and solvent extraction with different Corresponding author.
E-mail address: [email protected] (S. Basu). 0969-8043/$ - see front matter r 2007 Published by Elsevier Ltd. doi:10.1016/j.apradiso.2007.09.013
phosphorous containing compounds such as di(2-ethyl hexyl)phosphoric acid (Lee et al., 2002; Lee and Lee, 1998; Sato et al., 1997), and oxygenous extractants such as triphenyl arsine oxide (Vartak and Shinde, 1998), MIBK (Venkaji et al., 1994), 2,4-pentane dione, and 3,5-dichlorophenol (Imura et al., 1998). Besides these, use of high molecular weight amines (Mukherjee and Bag, 1997; Gutierrez et al., 1997; Ohto et al., 1997) and 5-sulpho8-quinolinol (Hiroshi et al., 1998), n-octyl aniline from succinate media (Shilmkar et al., 2005) have also been reported for the extraction and determination of gallium in different matrices, adopting ICP-MS and ICP-AES (Even et al., 2001). Recently, a high-resolution ICP-MS procedure (Ghazi et al., 2000) for the study of Ga diffusion in human teeth has been reported using 69,71Ga isotopes. All the reported works are direct methods for determination of gallium. The purpose of the present work is to develop a radiochemical displacement method for the determination of gallium using spiked indium-oxinate in chloroform as the radioreagent. Such an indirect determination (Braun et al., 1969) needs the preparation of labeled indium-oxinate, totally free from oxine, the condition of which was obtained by preliminary study of substoichiometric extraction of indium (Zmuewska, 1974). Secondly, the metal complexes should be less stable than the complex of displacing cations. The present work is developed on the basis of fulfillment of these two essential conditions.
ARTICLE IN PRESS M. Mandal et al. / Applied Radiation and Isotopes 66 (2008) 317–319
318
2. Experimental
2.4. Displacement substoichiometry
2.1. Isotopes and instrument
In order to study the displacement reaction, 5 ml labeled indium-oxinate in chloroform was taken in a separatory funnel, to which was added increasing amounts of aqueous solution of GaCl3 kept at pH 4.6. After equilibration, 1 ml of aqueous phase of each system was counted for g-activity. Results were further checked by a set of blank experiments, i.e. without addition of any Ga(III) solution in aqueous phases. Radioactivities of 1 ml of 114mIn solution displaced in aqueous phase are plotted against the amount of Ga(III) added in Fig. 2.
2.2. Preparation of labeled indium-oxinate In order to prepare indium-oxinate, spiked with 114mIn in CHCl3 and containing no excess oxine, we carried out substoichiometric extraction of the metal. For this purpose, spiked indium(III) chloride solution containing 118 mg/ml of In(III), kept at pH 4.5, was extracted with increasing (0–10 ml) amounts of 0.41 mM oxine in chloroform. The radioactivity of the extracted labeled In(III) was plotted against the amount of reagent. An inflexion point was obtained for 8 ml reagent, which corresponded to a metal: reagent ratio of 1:3.15. Hence, in a 200 ml separatory funnel, 5 ml spiked indium solution containing 118 mg/ml was diluted with 25 ml deionised water and extracted with 30 ml 0.41 mM oxine in chloroform. This extracted metal complex was diluted to 50 ml with CHCl3 and kept reserved as stock solution of labeled metal-oxinate. 2.3. Selection of pH for displacement reaction In a separatory funnel, 28 mg Ga(III) was equilibrated for 5 min with 5 ml indium-oxinate in CHCl3; the pH of the aqueous solution (5 ml) was varied from pHs 2 to 7. After extraction, 1 ml aqueous solution was measured for radioactivity. Results are plotted in Fig. 1. A blank experiment was also performed.
2.5. Effect of foreign ions Effects of diverse ions on the extent of displacement of In(III) from its oxinate complex by Ga(III) were followed; the results are presented in Table 1.
9000 Counts/30sec of aqueous phase
Radioisotopes used in the present study were obtained from BRIT, Mumbai, India. A single channel g-ray spectrometer coupled with an NaI(Tl) detector of ECILmake was used for radioactivity measurement. All other reagents were of AR grade.
6000
3000
0
0
15 30 Amount of gallium in micro gram
45
Fig. 2. Substoichiometric displacement of In(III) by Ga(III) from indiumoxinate. Table 1 Effect of various metal ions on the displacement of indium
In presence of Ga(III) Blank set
Counts/30sec of aqueous phase
10000
7500
5000
2500
0 2
3
4
5
6
7
pH
Fig. 1. Influence of acidity on the substoichiometric displacement of indium.
Diverse ions
Amont taken (mg)
a/a0
Na(I) Mg (II) Mn(II) Co(II) Ni(II) Pb(II) Hg(II) Zn(II) Cd(II) Cu(II) Ti(IV) Ce(III) Al(III) Fe(III) Tl(I)
124 118 108 124 125 125 148 140 125 120 120 120 150 117 120
1.00 0.97 0.96 0.93 0.94 0.97 0.98 1.00 0.99 0.95 0.93 0.88 High interference Strong interference Strong interference
a0, activity extracted in absence of any diverse ion; a, activity extracted in presence of diverse ion; 25 mg, amount of Ga(III) taken; pH 4.6.
ARTICLE IN PRESS M. Mandal et al. / Applied Radiation and Isotopes 66 (2008) 317–319
3. Discussion The reproducibility of the displacement reaction shows (Fig. 2) that 1 mM of Ga(III) displaces 1 mM of In(III) from its oxine complex in chloroform:
319
organic molecules show any interference. The method is very simple and rapid and can be recommended for the estimation of the metal under substoichiometric condition.
½InðOXÞ3 org þ ½Ga3þ aq Ð ½In3þ aq þ ½GaðOXÞ3 org
References
The displacement process is therefore quantitative. It was previously ascertained that In(III) can form In-trisoxinate complex, as the chelating agent is bidentate and the variation of substoichiometric extraction of In(III) with oxine corresponds to a inflection point at 1:3 ratio. Preparation of 114mIn-oxinate stock solution was made on this basis. Under such condition, there cannot be any free oxine in the chloroform medium. Although there was almost no variation of displacement within pH range 2–5, all the reactions were carried out at pH 4.6, controlled by acetate buffer which itself was not found to strip any In(III) activity. The stoichiometry of the reaction indicates that the upper limit of determination of Ga(III) is 28 mg; a linear calibration was obtained in the range of 6–28 mg of Ga(III). The mode of displacement indicates that Ga(III) forms stronger oxinate than In(III); a result which is supported by their relative crystal ionic radii values (Cotton and Wilkinson, 1969). Although most of the foreign ions used in the present investigation showed only little influence on the extent of displacement (Table 1), Fe(III) and Al(III) ions were found to show serious reducing effects on the displacement reactions and these two cations must be removed in order to get reproducible results. As Tl(I) salts totally hinder the extraction of In(III)-oxinate, their effects on the displacement reaction could not be followed. Among the anions, only F– and PO3 interfere and the method is not promising in the 4 presence of these anions. No other anions including
Braun, T., Ladanyi, L., Marothy, M., Osgyani, I., 1969. J. Radioanalytical. Chem. 2, 263. Cotton, F.A., Wilkinson, G., 1969. Advanced Inorganic Chemistry, second ed. Wiley Eastern Private Limited, New Delhi, India. Dzherayan, T.G., Shkinev, V.M., Reznik, A.M., Mitronov, A.N., Karandeshev, V.K., 2006. J. Anal. Chem. 61 (6), 614. Even, Z.D., Liu, J., Li, Y., 2001. J. Anal. Sci. 17 (1), 25–28. Ghazi, A.M., Shuttleworth, S., Angulo, S.J., Pashley, D.H., 2000. J. Anal. At. Spectrom. 15, 1335. Gutierrez, B., Pazos, C., Coca, J., 1997. Waste Manage. Res. 15, 371. Hiroshi, K., Tokuo, S., Takashi, S., Yoshio, S., 1998. Bull. Chem. Soc. Jpn. 71, 647. Imura, H., Oshiro, A., Ohashi, K., 1998. Anal. Sci. 14, 1093. Lee, M.S., Lee, E.C., 1998. Taehan Kumsok Hakhoechi 36, 1859. Lee, M.S., Ahn, J.G., Lee, E.C., 2002. Hydrometallurgy 63, 269. Lopez-Garcia, I., Campillo, N., Arnau-Jerez, I., Hernandez-Cordoba, M., 2004. J. Anal. At. Spectrom. 19, 935–937. Lucena, R.B., Morales, E., Gomez-Ariza, J.L., 1994. Farmaco 49 (4), 291–295. Mukherjee, J., Bag, S.P., 1997. Indian J. Chem. 36A, 818. Ohto, K., Furukawa, S., Shinohra, T., Inoue, K., 1997. Solvent Extr. Res. Dev. Jpn. 4, 199. Sato, T., Sato, K., Noguchi, Y., Ishikawa, I., 1997. Shigen to Sozai 113, 185. Shan, X.-Q., Yuan, Z.-N., Ni, Z.-M., 1985. Anal. Chem. 57, 857–861. Sheka, I.A., Chaus, I.S., Mityureva, T.T., 1966. The Chemistry of Gallium. Elsevier, Amsterdam. Shida, J., Matsuzaki, S., 1997. Anal. Sci. 13, 41–45. Shilmkar, T.N., Kolekar, S.S., Anuse, M.A., 2005. J. Serb. Chem. Soc. 70 (6), 853–867. Vartak, S.V., Shinde, V.M., 1998. Talanta 45, 925. Venkaji, K., Naidu, P.P., Rao, T.J.P., 1994. Talanta 41, 1281. Zmuewska, W., 1974. J. Radioanalytical. Chem. 20, 521.