Use of 4-chloro-7-nitrobenzofurazane as a derivative reagent for the determination of amino acids by cathodic stripping square wave voltammetry in biological fluids

The rapid and simple reaction of 4-chloro-7-nitrobenzofurazane with amino acids allows the determination of amino acids in urine using cathodic stripping square wave voltammetry. The obtained compounds are adsorbed on a hanging mercury drop electrode for determination by voltammetric methods using phosphate buffer at pH 2.0 as supporting electrolyte. The proposed method allows determination with an error of less than or equal to 5.68%. A limit of detection (3 sigma) of 3.64 nM (0.766 ng ml(-1)) and a limit of determination (10 sigma) of 12.12 nM (2.55 ng ml(-1)) are obtained for arginine determination. The proposed method has been applied to the determination of amino acids in urine.