Pico molar assay of riboflavin in human urine using voltammetry

Using a new type of DNA and carbon nano tube (CNT) mixed paste electrode using cyclic and square wave anodic stripping voltammetric (SWASV) methods, this study presents an assay of riboflavin (RF) under optimum conditions. Results of the experiment yielded a low working concentration range of nanograms with 1-10 and 10-170 ng L-1 and 5-105 mu g L-1, at an accumulation time of 80 s in a 0.1 M H3PO4 electrolyte solution. A relative standard deviation of 30 mu g L-1 was observed at an accuracy level of 0.1164% (n = 15) under optimum conditions. The detection limit (S/N) was pegged at 0.2 ng L-1 (5.31 x 10(-13) mol L-1 RF). The proposed method was successfully applied to an actual human urine and drug sample, and can be applied to assays of other biological samples. (C) 2011 Elsevier Ltd. All rights reserved.