Abstract

A cloud point extraction-chromogenic system for vanadium determination containing 4-(2-thiazolylazo)resorcinol (TAR), H₂O₂, H₂SO₄, and Triton X-100 was investigated. Optimal conditions for the formation and extraction of a 1:2:1 (V^V:O₂²⁻:TAR) ternary complex with an absorption maximum at 569 nm were found: concentration of TAR (4 × 10⁻⁵ mol dm⁻³), concentration of H₂O₂ (1.2 × 10⁻⁴ mol dm⁻³), pH (ca 2), mass fraction of the surfactant (3.6%), and incubation time (40 min). The molar absorptivity (ε₅₆₉), Sandell’s sensitivity (SS), limit of detection (LOD) and linear working range (LWR) were 7.4 × 10⁴ dm³ mol⁻¹ cm⁻¹, 0.69 ng cm⁻², 1.7 ng cm⁻³ and 6–510 ng cm⁻³, respectively. The effect of foreign ions was studied. The developed procedure was applied for the spectrophotometric determination of the total vanadium content in spent silica-supported catalysts and a vanadium-containing dietary supplement.

Graphic abstract

中文翻译：

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使用4-（2-噻唑基偶氮）间苯二酚和H 2 O 2的简单浊点萃取-分光光度法测定总钒

摘要

研究了含4-（2-噻唑基偶氮）间苯二酚（TAR），H ₂ O ₂，H ₂ SO ₄和Triton X-100的浊点萃取-发色法测定钒。发现了形成和萃取在569 nm处具有最大吸收的1：2：1（V ^V：O ₂ ^2-：TAR）三元配合物的最佳条件：TAR的浓度（4×10 ^-5 mol dm ^-3），H ₂ O _2的浓度（1.2×10 ^-4 mol dm ^-3），pH（ca 2），表面活性剂的质量分数（3.6％）和孵育时间（40分钟）。摩尔吸收率（ε₅₆₉），Sandell的灵敏度（SS），检测限（LOD）和线性工作范围（LWR），分别为7.4×10 ⁴ 分米³摩尔^-1厘米^-1，0.69纳克厘米^-2，1.7纳克厘米^-3和6-分别为510 ng cm ^-3。研究了外来离子的作用。所开发的程序用于分光光度法测定用过的二氧化硅负载的催化剂和含钒的膳食补充剂中的总钒含量。

图形摘要