DETERMINATION OF FORMALDEHYDE IN AIR BY ION-EXCLUSION AND ION-EXCHANGE CHROMATOGRAPHY WITH PULSED AMPEROMETRIC DETECTION

A method is presented for the determination of formaldehyde in air sam ple extracts containing aqueous sodium hydrogensulfite, Utilizing the unique properties of its hydrogensulfite complex, formaldehyde is sepa rated from other sample components by ion-exclusion and ion-exchange c hromatography, then selectively detected by amperometry at a silver el ectrode, Optimum sensitivity of detection was found to occur at +0.10 V versus a silver mire reference electrode using a strongly basic back ground electrolyte, Using those as an internal standard, a linear resp onse (r(2) >0.99) was observed for aqueous formaldehyde concentrations in the range 0.02-10.0 mg l(-1); detection limits of <1 ng for formal dehyde were obtained using a 50 mu l sample loop, The short-term repro ducibility was better than 5% (as RSD). Analysis of laboratory air by collection in impingers containing aqueous NaHSO3 yielded results cons istent with previous literature values.