DNA-functionalized biosensor for riboflavin based electrochemical interaction on pretreated pencil graphite electrode.

The interaction of riboflavin with salmon sperm double-stranded DNA based on the decreasing of the oxidation signal of guanine and adenine bases was studied electrochemically with a pencil graphite electrode (PGE) using differential pulse voltammetry. The decrease in the intensity of the guanine and adenine oxidation signals after interaction with riboflavin was used as an indicator signals for the sensitive determination of riboflavin. Under the optimum conditions, a linear dependence of the guanine and adenine oxidation signals was observed for the riboflavin concentration in the range of 0.5-70 μg mL(-1) with a detection limit of 0.34 μg mL(-1) at ds-DNA modified PGE. The reproducibility and applicability of the analysis to pharmaceutical dosage forms and urine sample were also investigated. These results showed that this DNA biosensor could be used for the sensitive, rapid, simple and cost effective detection and determination of riboflavin-ds-DNA interaction. Pretreated pencil graphite electrode (PPGE) was also used for the determination of riboflavin by differential pulse adsorptive stripping voltammetry. With PPGE, a linear relationship was obtained for riboflavin over the concentration range of 0.003-0.88 μg mL(-1) with differential pulse adsorptive stripping voltammetric signal and with a detection limit of 0.076 ng mL(-1). Both determination methods were fully validated and applied for the analysis of riboflavin.