| A high performance liquid chromatographic method with fluorimetric detection was developed for the determination of six isocycanates in polymer material samples.The isocyanates in the polymer material samples were extracted with polar solvent and derivatived in the extraction system.The separation was performed on a C18 column using acetonitrile and triethylamine-phosphoric acid buffer as mobile phase by gradient elution.The external standard method was used for the quantitative analysis.Effects of extraction solvent,extraction methods,derivation time and compound of mobile phase on the separation efficiency were investigated.The results showed that polar extraction solvent dichloromethane and ultrasonic extraction were more suitable than nonpolar extraction solvent cyclohexane and shaking extraction.The optimal derivation time was 30 min.Under the optimal conditions,6 isocycanates were separated with a resolution more than 1.5.The calibration curves of 6 analytes were linear in the range of 10-100 μg/L with correlation coefficients not less than 0.999 1.The average recoveries of 6 isocycanates at the spiked levels of 0.1－1.0 mg/kg were in the range of 90%-95% with relative standard deviations(RSDs,n=5) of 2.2%-4.2%.The limits of detection(S/N=3) were in the range of 30.3 – 42.3 μg/kg for six isocycanates in polymer material.The proposed method was applied in the analysis of 4 kinds of polymer material and the results indicated that,except for phenyl isocyanate(PI),the other five isocycanates were found at different degrees in the practical polymer material samples with total concentrations of 79.7-326.3 μg/kg.This method was accurate,sensitive and highly reproducible,and was suitable for the analysis of residual isocycanates in polymer material. |