Histidine Determination in the Presence of Copper in Diluted Alkaline Electrolyte by Adsorptive Stripping Voltammetry at the Mercury Film Electrode

Abstract

A stripping method for the determination of histidine at the submicromolar concentration levels is described. The method is based on controlled adsorptive accumulation of histidine-copper complex at mercury film electrode followed by linear cyclic scan voltammetry measurement of the surface species. Optimum experimental conditions were found to be the use of a 1.0 × 10⁻³ M NaOH solution, an accumulation potential of − 0.20 V, and a linear scan rate of 200 mV sec⁻¹. The response of histidine is linear over the concentration range 0.02–0.12 ppm. For an accumulation time of 20 min, the detection limit was found to be 0.5 ppb (3.2 × 10⁻⁹ M). The more convenient relation to measuring the histidine in the presence of metals, cysteine, tyrosine, and other amino acids was also investigated. The utility of the method is demonstrated by presence of casein, ATP, and ss DNA.

Keywords:

• ATP
• Casein
• Cysteine
• Histidine determination
• Linear scan stripping voltammetry
• Metals
• Other amino acids
• Thin-film mercury electrode
• Tyrosine
• ss DNA

The authors gratefully acknowledge the CNPq and CAPES of the Government of Brazil and PUC-Rio for support of this work. The experimental assistance of A.B. Neves is appreciated.