Sensitivity Enhancement of the Formaldehyde Fluorimetric Determination by the use of a Surfactant

A sensitive method for the formaldehyde determination in aqueous samples by Flow Injection Analysis has been developed. Formaldehyde reacts with acetylacetone, acetic acid and ammonium acetate to form diacetyldihydrolutidine, detectable by its fluorescence; the effects of various surfactants upon this spectrofluorimetric method have been assessed. Fluorescence enhancements from 15-70% were observed in comparison with that without surfactant. The developed method has a detection limit of 55 ng/l and a precision of 2.5% at 1 µg/l level. The calibration graph is linear in over the range 0.1-3000 µ/l. The sensitivity, speed, ease of use and small volume of sample make this method ideal for formaldehyde determination in precipitation samples with concentration from very low to very high by continuous or semicontinuous analysis.