A sensitive flow analysis system for the fluorimetric determination of low levels of formaldehyde in alcoholic beverages

A sensitive FIA method was developed for the selective determination of formaldehyde in alcoholic beverages. This method is based on the reaction of Fluoral-P (4-amine-3-pentene-2-one) with formaldehyde, leading to the formation of 3,5-diacetyl-1,4-dihydrolutidine (DDL), which fluoresces at lambda(ex)=410nm and lambda(em)=510nm. The analytical parameters were optimized by the response surface method using the Box-Behnken design. The proposed flow injection system allowed for the determination of up to 3.33x10(-5)molL(-1) of formaldehyde with R.S.D.<2.5% and a detection limit of 3.1ngmL(-1). The method was successfully applied to determine formaldehyde in alcoholic beverages, without requiring any sample pretreatment, and the results agreed with the reference at a 95% confidence level by paired t-test. In the optimized condition, the FIA system proved able to analyze up to 60 samples/h.