Normal and reverse flow injection-spectrophotometric determination of thiamine hydrochloride in pharmaceutical preparations using diazotized metoclopramide.

Simple and sensitive normal and reverse flow injection methods for spectrophotometric determination of thiamine hydrochloride (THC) at the microgram level were proposed and optimized. Both methods are based on the reaction between THC and diazotized metoclopramide in alkaline medium. Beer's law was obeyed over the range of 10-300 and 2-90 μg/mL, the limits of detection were 2.