Comparison of methods for the determination of formaldehyde in air
Abstract
Different methods have been employed for the determination of formaldehyde in air. The Hantzsch method uses derivatization with acetyl acetone and the fluorescence signal of the resulting chromophore is highly selective for formaldehyde. The 2, 4-dinitrophenylhydrazine procedure allows measuring of carbonyl compounds in combination with high-performance liquid chromatography. In contrast, the 3-methyl-2-benzothiazolonehydrazone method delivers the sum of aliphatic aldehydes, although it is reported to be selective for formaldehyde. In order to compare the performance of these methods, measurements of thirteen samples of wooden furniture were performed. Further characterization was performed with a formaldehyde source and one oriented-strand board. As expected, the results of the 2, 4-dinitrophenylhydrazine and Hantzsch methods provided excellent correlation. However, the formaldehyde concentrations obtained from the 3-methyl-2-benzothiazolonehydrazone method showed almost no correlation with the 2, 4-dinitrophenylhydrazine and Hantzsch values. The results demonstrate significant error using the 3-methyl-2-benzothiazolonehydrazone method for the determination of a specific aliphatic aldehyde in a mixture of volatile organic compounds in air. In addition, the formaldehyde source measurements revealed excessively high concentrations of formaldehyde using the 3-methyl-2-benzothiazolonehydrazone method. Therefore, the 3-methyl-2-benzothiazolonehydrazone method is not suitable for the determination of formaldehyde in air due to interferences with other organic compounds and systematic analytical artifacts.
