Swill-cooked dirty oil contents a lot of toxic substances, which might be cause cancers. According to the widely use of cayenne in China catering business, capsaicin and dihydrocapsaicin can be potential evaluation marker for the identification of swill-cooked dirty oil. However, the content of capsaicinoids in most swill-cooked dirty oil samples is very low, it is difficult to detect directly. We present a rapid and effective method comprising SPE based on tetraazacalix[2]arene[2]triazine modified silica (NCS) as sorbent and analysis with HPLC for the determination of trace capsaicin and dihydrocapsaicin.
　　　In the previously studied, the retention factors between the NCS sorbent and the analytes were investigated on the NCS column and Agilent C18 column for HPLC, respectively.The results demonstrates that capsaicin and dihydrocapsaicin were more strongly retained on NCS than on ODS stationary phase. So, we choose this material as SPE adsorbent for oil capsaicin. In addition, Factors affecting the extraction efficiency including the eluent type and its volume, sample volume, sample pH and sample flow rate were optimized.
　　　Under the optimized extraction conditions, the method showed good extraction rate and repeatability. The recoveries of capsaicin and dihydrocapsaicin spiked in swill-cooked dirty oil samples ranged from 73.5% to 88.4% with RSD range from 7.6% to 17.8% (n=5). The developed method based on NCS-SPE-HPLC was successfully applied to the analysis of swill-cooked dirty oil samples.

The authors acknowledge the support of NSF of China (21275133)