RAPID MICROWAVE-ASSISTED HYDROLYSIS OF FORMETANATE

A fast microwave-assisted hydrolysis procedure has been developed for the derivatization of formetanate previously to the flow-injection spectrophotometric determination of m-aminophenol by reaction with p-aminophenol. Formetanate is quantitatively hydrolyzed with 0.1 M NaOH in 150 s using a closed polytetrafluoroethylene reactor with 115 ml internal volume and a radiation power of 390 W. The above procedure has been applied, as a previous step, for the flow-injection spectrophotometric determination of formetanate in spiked water samples and accurate and precise results have been found. The method permits to obtain a limit of detection of 0.025 mg l-1 of formetanate. The relative standard deviation of five independent analyses of a sample containing 6 mg l-1 formetanate was 0.5%.