Workplace air sampling and polarographic determination of formaldehyde

A polarographic method has been developed for the determination of formaldehyde in workplace air. Samples are collected in midget fritted glass bubblers containing an aqueous solution of 10% methanol. The collected formaldehyde in the absorbent solution is derivatized with hydrazine reagent to form a formaldehyde hydrazone compound. An aliquot of the resulting solution is analyzed by differential pulse polarography at a dropping mercury electrode. The sample generation system, impinger collection, polarographic analysis, and precision and accuracy data are described. The method was validated over the range of 5.8 to 17.7 mg/cu m, which corresponds to 0.5 to 2 times the (peak) OSHA-PEL for a 30-liter sample at a flow rate of 1 Lpm. The average recovery was 103%. The pooled coefficient of variation or relative standard deviation was 0.08.