GC-MS Determination of 1,2-Benzene Dicarboxylic Acid-Dialkyl Esters in Plastic Products

A method for the determination of DIHP and DHNUP in plastic products by gas chromatography-mass spectrometry (GC-MS) was proposed. DIHP and DHNUP in the sample (0.500 0 g) were extracted by microwave extraction at 100℃ for 30 min using 20 mL of ethyl acetate as extraction solvent, and then 2.0 mL of the extract was taken, made its volume up to 5.0 mL with ethyl acetate and filtrated. DIHP and DHNUP were analyzed by GC-MS under selected ion monitor (SIM) mode. The abundance ratio of the characteristic fragment ions was adopted for qualitative analysis, and the external standard method was adopted for quantification. As shown by the results, linear ranges of DIHP and DHNUP were both 0.40-4.0 mg·L^-1, with detection limits (3S/N) ranged from 1.0 mg·kg^-1 to 2.0 mg·kg^-1. Test for recovery was made by standard addition method, giving results in the range of 88.6%-115%, with RSDs (n=6) all less than 5.0%.