1984 Volume 19 Issue 5 Pages 387-391
Low-molecular-weight carbonyl compounds react with O (2, 3, 4, 5, 6-pentafluorobenzyl)-hydroxyiamine (PFBOA) under weak acidity and the derivatives are volatile. This reaction was applied to gas chromatographic determination of small amount of formaldehyde in air.
Sample gases (1-5 l) were collected in absorption solution of distilled water at the flow rate of 1l/min. The absorption solution was made up to 25ml with water. To a portion of this solution, 0.2ml of PFBOA aqueous solution (0.5 mg/ml) was added and the mixture was allowed to stand for 40min. After the mixture was sat urated with sodium chloride and acidified with 2ml of 2 N sulfuric acid, fi derivative of formaldehyde was extracted with 5 ml of n-hexane for 1 min. An internal standard was added to the n-hexane extract after dehydration. The extract was made up to 10ml with n-hexane and was injected into gas chromatograph with ECD.
A calibration curve was linear to about 80 ng as formaldehyde in 25 ml of aqueous solution and the detection limit was about 2 ng. Then, at a size of 5l of air, the lower limit of determination was about 0.3 ppb for formaldehyde. The recovery of standard gas was 94% and its coefficient of variation was 3.7%(n=5).
The method presented above can be used for the determination of formaldehyde in urban air and indoor air.
