Development of microwave-assisted extraction and dispersive liquid–liquid microextraction followed by gas chromatography–mass spectrometry for the determination of organic additives in biodegradable mulch films

Abstract

Organic additives are extensively used as ingredients in biodegradable mulch films. They are swiftly released into the environment, which may have an ecotoxicological impact on plant growth and development, as well as on soil microbial community abundance and function. Herein, a method based on the application of microwave-assisted extraction (MAE) and dispersive liquid–liquid microextraction (DLLME) was developed to analyze eighty organic additives by gas chromatography-mass spectrometry in poly(butylene adipate terephthalate) (PBAT) biodegradable mulch films. This was a comprehensive study, including the identification of organic additives, optimization of MAE and DLLME methods, analysis of isocyanate conversion, and evaluation of the matrix effect (ME). Under the optimized experimental conditions, this method exhibited excellent detection capabilities for organic additives, except for 5 kinds of isocyanates and their reaction products, with coefficients of determination R2 > 0.999 and lack of fit P > 0.05 in linear regression parameters. A negligible ME was observed. The relative recoveries were 93.0–109.8%, and the repeatability and reproducibility varied within the ranges of 2.06–8.76% and 2.38–10.23%, respectively. The limits of detection and limits of quantitation were 0.0008–0.0586 μg g−1 and 0.003–0.195 μg g−1, respectively. The developed method was further successfully applied to the analysis of organic additives in PBAT biodegradable mulch films from four different manufacturers. Interestingly, the Venn diagram and principal component analysis showed that different manufacturing origins display obvious characteristic differences in the organic additive types and concentrations.