Determination of formaldehyde in Brazilian alcohol fuels by flow-injection solid phase spectrophotometry

摘要

In this work,a solid phase spectrophotometric method in association with flow injection analysis for formaldehyde determination has been developed with direct measurement of light-absorption in C_(18)material.The 3,5-diacetyl-l,4-dihydroIutidine produced from the reaction between formaldehyde and fluoral P was quantitatively retained on C_(18)support and the spectrophotometric detection was performed simultaneously at 412 nm.The retained complexwas quickly eluted from C_(18)material with the eluent stream consisting of a 50%(v/v)ethanol solution.The results showed that the proposed method is simple,rapid and the analytical response is linear in the concentration range of 0.050-1.5 mg L~(-1).The limit of detection was estimated as 30 mugL(-1)and the R.S.D.2.2%using a sample volume of 625 muL.The system presented an analytical throughput of 20 determinations per hour.The method was successfully applied in the determination of formaldehyde in ethanol fuel.