Rapid Determination of Aldehydes and Ketones in Cooking Fumes by 2£¬4-Dinitrophenylhydrazine Colorimetry

KeyWord:2,4-dinitrophenylhydrazine  colorimetric method  aldehydes and ketones  cooking fumes

Abstract:

      A 2£¬4-dinitrophenylhydrazine colorimetric method was developed for the rapid determination of aldehydes and ketones in cooking fumes£®The method was based on the formation of a yellow phenylhydrazone compound from the carbonyl groups of aldehydes and ketones£¬and 2£¬4-dinitrophenylhydrazine under heating and acid catalyzed conditions£¬which further produced a red or burgundy-coloured chromogenic substance under strongly alkaline conditions£®Separation of the chromogenic substance from 2£¬4-dinitrophenylhydrazine at the maximum absorption peak of UV-visible spectrum could be used for the detection of aldehydes and ketones£®The optimal conditions for the reaction were as follows£ºreaction temperature£º60 ¡æ£¬reaction time£º30 min£¬volume of concentrated hydrochloric acid£º45 ¦ÌL£¬ratio of aldehyde to hydrazine£º1¡Ã50£¬amount of alkali£º2.0 mL 60 g/L KOH solution£®Under the optimized conditions£¬the method could be carried out with simple operation£¬high sample throughput and wide linear range£¨2.5£­15 ¦Ìmol/L£©£®It was applied to the analysis of actual catering oil fume samples£¬with spiked recoveries of 80.0%¡«84.0% and relation standard deviations£¨RSD£© less than 5%£®This method provides a reference for the rapid and efficient determination of high-concentration aldehydes and ketones in cooking fumes.