Use of Variamine Blue as a Chromogenic Reagent for Rapid Spectrophotometric Determination of Nano Amount of Chromium

Trace amounts of Chromium have been determined using a newly developed simple, rapid and sensitive spectrophotometric method. Variamine blue is used as a chromogenic reagent and the proposed method is based on the reaction of chromium(VI) with potassium lodide in acid medium to liberate iodine that oxidizes variamine blue to produce violet‐colored substances having an absorption maxmium at 615 nm. The molar absorptivity and Sandel's sensitivity were found to be 8.12× 10³ L mol⁻¹ cm⁻¹ and 2.36×10⁻³ µg cm⁻², respectively. The for accurate determination of chromium was found to be 0.0003–15 µg mL⁻¹. Chromium(lll) can be determined after it is oxidized to Cr(lV) with bromine water in alkaline medium the optimum reaction conditions, other analytical condition and interference effect of several ions are reported. The method has been successfully used to analyze chromium in natural water effluents from homes and industries, liver, blood serum and some carbonated drinks samples.

Keywords:

• chromium determination
• traceamounts
• spectrophometric
• variamine blue
• interference ions

We wish to warmly thank Richard Kahn (GMI, IPCOMS, Strasbourg) for his valuable assistance. This work was supported by CONICET, Fundacion Antorchas and CICPBA of Argentina for international cooperation. CONICET and TWAS–Trieste Italy are also acknowledged for research fellowships awarded to FAS.