Catalytic flow injection determination of vanadium by oxidation of N-(3-sulfopropyl)-3,3′,5,5′-tetramethylbenzidine using bromate

• Published in: Talanta (Oxford) Vol. 49; no. 5; pp. 1083 - 1089
• Main Authors: Shiobara, Tsuyoshi, Teshima, Norio, Kurihara, Makoto, Nakano, Shigenori, Kawashima, Takuji
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 09.08.1999; Oxford Elsevier
• Subjects: Analytical chemistry; Catalytic flow-injection method; Chemistry; Exact sciences and technology; N-(3-sulfopropyl)-3,3′,5,5′-tetramethylbenzidine; Spectrometric and optical methods; Vanadium determination; Catalytic flow-injection method; Vanadium determination; N-(3-sulfopropyl)-3,3′,5,5′-tetramethylbenzidine; Water; Absorption spectrometry; Catalytic reaction; Sensitivity; Vanadium IV; Detection limit; Ultratrace compound; Standard deviation; Oxidation; Vanadium V; Spectrophotometry; Flow injection
• ISSN: 0039-9140; 1873-3573
• DOI: 10.1016/S0039-9140(99)00020-X

A catalytic flow-injection (FI) method was developed for the determination of 10 −9 mol l −1 levels of vanadium(IV, V). The method is based on the catalytic effect of vanadium(V) on oxidation of N-(3-sulfopropyl)-3,3′,5,5′-tetramethylbenzidine (TMBZ·PS) using bromate as oxidant to form a yellow dye ( λ max=460 nm). The use of 5-sulfosalicylic acid (SSA) as an activator enhanced the sensitivity of the method. The calibration graphs with a working range 0.05–8.0 ng ml −1 were obtained for vanadium(V). Vanadium(IV) was also determined, being oxidized by bromate. The detection limit (signal/noise, S/N=3) was 0.01 ng ml −1 (ca. 2×10 −10 mol l −1) vanadium. The relative standard deviations (R.S.D.) for 15 determinations of 0.5 ng ml −1 vanadium, and for ten determinations of 0.1 and 1.0 ng ml −1 vanadium were 0.41, 2.6 and 0.25%, respectively, with a sampling rate of 15 samples h −1. The proposed method was successfully applied to the determination of vanadium in natural waters.