Optimization of a headspace solid-phase microextraction and gas chromatography/mass spectrometry procedure for the determination of aromatic amines in water and in polyamide spoons

Abstract

In this work, a headspace solid-phase microextraction and gas chromatography coupledwith mass spectrometry (HS-SPME-GC/MS) method for trace determination of primary aromatic amines was developed. The following analytes were investigated: aniline (A), 4,4′-diaminodiphenylmethane (4,4′-MDA) and 2,4-diaminotoluene (2,4-TDA) using 3-chloro-4-fluoroaniline (3C4FA) and 2-aminobiphenyl (2ABP) as internal standards. Prior to extraction the analytes were derivatized in the aqueous solution by diazotation and subsequent iodination. The derivativeswere extracted byHS-SPME using a PDMS/DVB fiber and analyzed by GC/MS. A D-optimal design was used to study the parameters affecting the HS-SPME procedure and the derivatization step. Two experimental factors at two levels and one factor at three levels were considered: (i) reaction time, (ii) extraction temperature, and (iii) extraction time in the headspace. The interaction between the extraction temperature and extraction time was considered in the proposed model. The loadings in the sample mode estimated by a PARAFAC (parallel factor analysis) decomposition for each analyte were the response used in the design because they are proportional to the amount of analyte extracted. The optimum conditions for the best extraction of the analytes were achieved when the reaction time was 20 min, the extraction temperature was 50 °C and the extraction time was 25 min. The interaction was significant. A calibration based on a PARAFAC decomposition provided the following values of decision limit (CCα): 1.07 μgL−1 for A, 1.23 μg L−1 for 2,4-TDA and 0.83 μg L−1 for 4,4′-MDA for a probability of false positive fixed at 5%. Also, the accuracy (trueness and precision) of the procedurewas assessed. Furthermore, all the analyteswere unequivocally identified. Finally, the method was applied to spiked water samples and polyamide cooking utensils (spoons). 3% (w/v) acetic acid in aqueous solution was used as food simulant for testing migration from polyamide kitchenware. Detectable levels of 4,4′-diaminodiphenylmethane and aniline were found in food simulant from some of the investigated cooking utensils.