Determination of formaldehyde in aquatic products by a sensitive catalytic fluorescence method

A novel method for the determination of trace formaldehyde in food samples has been established using a catalytic kinetic fluorimetry technique. It is based on the fact that the oxidation of pyronine Y by sodium periodate is catalyzed by formaldehyde in phosphoric acid. When the excitation wavelength was set at 546 nm, it was observed that decreased intensity (Delta F) of fluorescence at 563 nm was proportional to the concentration of formaldehyde in the range 0 to 0.30 mu g mL(-1). The limit of detection and the average recovery for formaldehyde were 2.0 x 10(-2) ng mL(-1) and 101.3% (n = 6), respectively. The present method has been applied to the determination of trace formaldehyde in aqueous products and the results observed were in good agreement with those obtained by distillation-spectrophotometry. A review of recently published catalytic or inhibiting kinetic methods for the determination of HCHO is presented for comparison. The mechanism of reaction is studied.