Applications Of Tetraazacalix[2]Arene[2]Triazine Bonded Silica Gel SPE Material In Food Safety Analysis

Tetraazacalix[2]arene[2]triazine SPE sorbent (NCS) is a novel heteroatomiccalixarene bonded silica gel material based on mix-mode multi-interaction. Therelevant mechanism includes π-π，π electron transfer，inclusion, anion exchange andhydrophobicity. Consequently, NCS is a promising material in complex samplepretreatment and analysis. In this thesis, NCS SPE sorbent was used in samplepretreatment and three analytical methodologies were established in terms of threesocial issues of food safety.In the first work, a novel analytical method on capsaicin and dihydrocapsaicin as thespecific indicators of recognising swill-cooked dirty oil was developed. They wereextracted from oil matrix to aqueous phase via alkali hydrolysis. Then under thereverse solid phase extraction mode, the aqueous solution was purified and enrichedby NCS SPE prior to UPLC-MS/MS analysis with MRM, ESI+mode. LC-MS/MSconditions and SPE conditions including pH of the loading solution, loading speed,packing dosage, elution kinds and dosage all were optimized. Lastly, the establishedmethod was evaluated and employed to correctly recognise four kinds of oil samples.The limit of detection (LOD) of capsaicin and dihydrocapsaicin were0.5ng/mL and0.1ng/mL, respectively, the recoveries ranged from71.6%to116.8%, the relativestandard deviations(RSD) was lower than11%. This detection method is with goodsensitivity, speed and specific enough, can be recommended to recognizeswill-cooked dirty oil.In the second work, a simple and reliable method was established for determination ofacrylamide in starchy food by HPLC-UV based on NCS SPE sorbent. Thehomogeneous sample was extracted by acetonitrile，then the extracted solution wasloaded onto the NCS SPE column. In the SPE process, NCS was used to extractimpurities. And for the SPE process, it didn’t use hexane or lower temperature toremove grease, only using NCS SPE column can get dominant clean effect，therefore,it decreased the harm to the liquid chromatography separation column without losing recovery of acrylamide. In the whole, this method is regent commercial, simple,convenient and with good purifying effect, the LOD of acrylamide is20ng/g，therecoveries were in the range of73.1%~110%, RSD was lower than12.2%.In the last work, a feasible, simple and fully validated SPE-HPLC-UV method ispresented for qualitative analysis the concentration of formaldehyde in beer. Themethod was based on the strong retention ability of NCS to phenylhydrazone and2,4-dinitrophenylhydrazine, then NCS sorbent was selected to extract formaldehydefrom beer after the formation of phenylhydrazone with DNPH. The reactionconditions and SPE conditions both were optimized. For this method, it is free ofdistilling, the reaction conditions are mild, the SPE process is simple and reliable, andthe LOD of formaldehyde is3ng/mL，the recoveries ranged from70%to82%, RSDwas lower than10%. Meanwhile, the developed method was successfully applied todetermine formaldehyde of different commercially available beer samples, the resultsshowed the content of formaldehyde is among0~0.8mg/mL which is lower than2mg/mL (the permitted level of national standard).