A study of riboflavin determination by square wave adsorptive stripping voltammetry on mercury film electrodes

Abstract

In this work riboflavin was determined by square wave adsorptive stripping voltammetry (SWASV): riboflavin was initially adsorbed on a mercury film electrode (MFE) at a potential of 0.0 V (vs. Ag/AgCl) and at pH 12; the subsequent reductive stripping step was carried out by applying a square wave potential-time waveform on the electrode. Both a batch method (based on the rotating disk electrode configuration) and a flow approach [based on the wall-jet flow-through electrode and flow injection analysis (FIA)] were employed. Both instrumental and chemical parameters were investigated and optimized for analytical use of the technique. The limit of detection was 0.5 nmol L-' (for 10 min of preconcentration), the precision was 8 % for the batch system (at the 10nmolL-' level) and 6% for the flow system (at the 100nmol L-' level); the linear range depended on the preconcentration time and the mass transfer conditions during the accumulation step. Both methods were automated and applied to the determination of riboflavin in commercial pharmaceutical products with recovery values at over 90%.

Sono-Adsorptive Stripping Voltammetry: Its Application to the Analysis of Metals and Organic Compounds in Aqueous Media

“…The procedure followed was a modified version of that described by Economou and Fielden for silent conditions [28] in which preplating of the mercury film was conducted in the same solution as the preconcentration of the target. In the procedure 250 mL of a solution containing 0.01 M NaOH and 82 mM Hg 2+ were placed in the electrochemical cell described above.…”

Selective Determination of Vitamin B2 at Electrochemically Activated Glassy Carbon Electrode

“…VB 2 did not show signi®cant adsorption on solid electrodes including carbon, gold and platinum [9]. Electroanalytical determination of VB 2 at mercury ®lm electrodes also suffered from rapid decomposition in alkaline medium under ambient light [12].…”

Simple, Rapid and Selective Chronopotentiometric Method for the Determination of Riboflavin in Pharmaceutical Preparations Using a Glassy Carbon Electrode

“…18,19 Among electrochemical methods, those based on voltammetry and voltammetric stripping analysis are mostly used for riboflavin assays. 1,[18][19][20][21][22] Various types of electrodes were considered in analysis of riboflavin, including mercury electrodes, 22,23 gold electrode, 18 different types of carbon paste electrode, 2,22,24 glassy carbon electrodes, 25,26 and bismuth based electrodes. 27,28 Most of the mentioned electrodes are complicated to prepare, often with low reproducibility of fabrication.…”