Development of a Method for Preservation, Extraction, and Quantitation of 4,4’-Methylenedianiline in Soils of Varied Texture and Organic Matter Content

Abstract

ABSTRACT Despite the reactivity and degradability of 4,4’-methylenedianiline (4,4’-MDA) with organic matter in soils, the improvement of Brunet et al. method makes it possible to monitor the substance in the environment. In fact, 4,4’-MDA can be found in soils, used for agriculture for example, if 4,4’-methylene diphenyl diisocyanate (4,4’-MDI) based fertilizers and pesticides are used. The possible degradation of 4,4’-MDI-based polyurethane could result in formation of 4,4’-MDA. To have a soil where 4,4’-MDA could be uniformly distributed, an impregnation method was developed. The method was validated using 1 g of the impregnated soil ranging 2,4% to 10% of organic matter, and the addition of both internal and surrogate standard to correct any losses of the substance over the different steps of the method. The limit of detection (LOD) and limit of quantification (LOQ) for the determination of 4,4’-MDA in soil are 0.107 and 0.358 μg/kg (dry weight), respectively, with a dynamic range between 5 and 250 μg/kg. For the intra-day precision, the result was 4,28% and for the inter-day, it was 9,32%. The accuracy was 96,4% and the total recovery obtained was 82.02%. Moreover, the stability of 4,4’-MDA was demonstrated in dry soil samples or in samples completely immersed in methanol over a 14-day period.