Determination of Trace Formaldehyde in Hydro-Products by Catalytic Spectrophotometry with KIO4-methyl Red

Based on the catalytic effect of trace formaldehyde on the reaction between high potassium iodate and methyl red in sulfuric acid,a new catalytic spectmphotometric method for the determination of formaldehyde was established in this paper. The formaldehyde concentration within a range of 2.25×10-4～1.35×10-2 μg·mL-1 has a good linear relation in the optimal conditions. The detection limit was 4×10 -5 μg·mL-1 with a relative standard deviation (RSD) of 0.1% for 0.004 1 μg·mL-1 formaldehyde solution (n=11) and a recoveries of 94%～103%. The results indicated that this method was sensitive and selec- tive for detecting formaldehyde in hydro-products.