Extraction-Chromogenic System for Silver(I) Based on Tetrazolium Violet and Semicarbazide Hydrochloride
- Authors: Hristov D.G.1, Divarova V.V.1, Mancheva R.D.1, Gavazov K.B.1
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Affiliations:
- Department of Chemical Sciences, Faculty of Pharmacy
- Issue: Vol 89, No 10 (2019)
- Pages: 2136-2142
- Section: Article
- URL: https://journals.rcsi.science/1070-3632/article/view/223130
- DOI: https://doi.org/10.1134/S1070363219100232
- ID: 223130
Cite item
Abstract
In the presence of semicarbazide hydrochloride (SCH) and traces of AgI, the tetrazolium salt 2,5-diphenyl-3-(1-naphmyl)-2H-tetrazolium chloride (Tetrazolium violet, TV) is reduced in alkaline medium to intensely colored chloroform-extractable 3,5-diphenyl-1-(1-naphthyl)formazan (Tetrazolium violet formazan, TVF). The following experimental parameters have been examined for finding optimal conditions for color development and extraction-spectrophotometric determination of AgI: concentration of reagents, extraction time, volume of the two phases, presence of dissolved oxygen, and light. Under the optimal conditions (cTV = 4.0 × 10−5 mol/dm3, cSCH = 2.4 × 10−3 mol/dm3, cNaOH = 4 × 10−1 mol/dm3, Vaq.phase = 25 cm3, Vchloroform = 4 cm3, extraction time t = 5 min) an isomer of TVF with λmax = 511–512 nm is predominantly extracted. The calibration curve (at 512 nm) is linear in the concentration range of 0.013–0.028 µg cm−3 of AgI. The following ions do not interfere in determination of 0.65 µg of AgI; Li+, Na+, K+, \(\rm{NH}_4^+\), \(\rm{H}_2PO_4^-\), F−, Cl−, \(\rm{SO}_4^{2-}\), \(\rm{B}_4O_7^{2-}\), \(\rm{ReO}_4^-\), tartrate, and citrate (5000-fold excess); MgII and EDTA (1000-fold excess); PbII and BaII (500-fold excess); AlIII (300-fold excess); ZnII and CaII (100-fold excess); VV (50-fold excess); HgII, HgI, MoVI and FeIII (25-fold excess); and CuII and WVI (10-fold excess). CrIII interferes in the process at a mass ratio of 1 : 1, however small amount of this cation (1.5-fold excess) can be masked by EDTA.
About the authors
D. G. Hristov
Department of Chemical Sciences, Faculty of Pharmacy
Email: kgavazov@abv.bg
Bulgaria, Buxton Brothers st. 120, Plovdiv, 4004
V. V. Divarova
Department of Chemical Sciences, Faculty of Pharmacy
Email: kgavazov@abv.bg
Bulgaria, Buxton Brothers st. 120, Plovdiv, 4004
R. D. Mancheva
Department of Chemical Sciences, Faculty of Pharmacy
Email: kgavazov@abv.bg
Bulgaria, Buxton Brothers st. 120, Plovdiv, 4004
K. B. Gavazov
Department of Chemical Sciences, Faculty of Pharmacy
Author for correspondence.
Email: kgavazov@abv.bg
Bulgaria, Buxton Brothers st. 120, Plovdiv, 4004