Electrochemical Determination of Riboflavin by an Ionic Liquid Modified Carbon Paste Electrode as a Sensitive Sensor

In this research, an ionic liquid modified carbon paste electrode was prepared by incorporating 1-hexyl-3-methylimidazolium hexafluorophosphate (HMHP) to a carbon paste. The preconcentration and electroanalysis of riboflavin were employed using the HMHP modified carbon paste electrode (HMHP/CPE). The overall analysis involved a two-step procedure: an accumulation step at open circuit, followed by medium exchange to a pure electrolyte solution for the voltammetric measurement. During the preconcentration step, riboflavin was adsorbed onto HMHP surface. The influence of various experimental parameters on the HMHP/CPE response was investigated (i.e. pH, accumulation time, pulse time and pulse amplitude). Under the optimized conditions, the reduction peak showed that the peak height was found to be directly proportional to riboflavin concentration in the range comprised between 3.5×10-8 M and 1.5×10-6 M. With this, it was possible to determine limit of detection, which resulted in 11 nM. Common interfering species did not interfere in the determination. The method was successfully applied to the measurement of riboflavin in pharmaceutical formulations.