1.
Covalent Triazine Framework Sorbent for Solid Phase Extraction of Fipronil and its Metabolite in Eggs with Ultra-High Performance Liquid Chromatography-Tandem Mass Spectrometry.
Ba, X, Yun, G, Hou, Y, Zhang, W, Zhao, W, Yuan, H, Zhang, S
Food additives & contaminants. Part A, Chemistry, analysis, control, exposure & risk assessment. 2021;(9):1495-1505
Abstract
A solid-phase extraction (SPE) method was established for fipronil and its metabolite residues (fipronil desulfinyl, fipronil sulphone and fipronil sulphide) in eggs with a covalent triazine framework (CTF) porous material as the adsorbent followed by ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) detection. Multiple probes and quantum chemistry theory calculations were conducted to describe the versatile adsorption property directly and quantifiably. The conjugated structure of CTF and N-containing triazine generated π-π interactions and hydrogen bonds between the CTF and the targets, which led to high extraction efficiency and recoveries. The solid-phase extraction parameters, including amount of the adsorbent, type of eluent, amount of eluent and loading rate were investigated. Under the optimal experimental conditions, the recoveries of the analytes were between 85.5% and 103.2%, and the RSD (n = 5) was between 1.8% and 3.6%. The LODs and LOQs were 0.13-0.2 ng g-1 and 0.5-0.8 ng g-1, respectively. The sorbent can effectively reduce the interference of the matrix and meet the detection requirements of fipronil and its metabolites in eggs. These results imply that the CTF as adsorbents have great potential in the analysis of trace targets in samples with complex matrices.
2.
Regeneration and Reuse of Immunoaffinity Column for Highly Efficient Clean-Up and Economic Detection of Ochratoxin A in Malt and Ginger.
Liu, X, Liu, X, Huang, P, Wei, F, Ying, G, Zhang, S, Lu, J, Zhou, L, Kong, W
Toxins. 2018;(11)
Abstract
Immunoaffinity columns (IACs) are most popularly used for mycotoxin clean-up in complex matrices prior to chromatographic analysis. But, their high cost has limited their wide application and the regeneration of IACs for multiple instances of reuse is important. This study aimed to investigate the feasibility of regeneration and reuse of IACs for purification of ochratoxin A (OTA) in spiked raw malt and dried ginger samples followed by high performance liquid chromatography-fluorescence detection. After each use, the IACs were filled with phosphate buffer saline (PBS) as the preservation solution and stored at 8 °C overnight for regeneration and reuse until the recovery rate was <70%. The results showed that matrix type, preparation procedure, and pH value of sample extraction exhibited major effects on the reuse of IACs for OTA clean-up. While, after modifying the sample preparation procedure using water as the diluent and the solution at a pH of 7 to 8, the IACs could be used eight and three times for the spiked raw malt and dried ginger samples with OTA after regeneration. Regarding the traditional procedure recommended in Chinese Pharmacopoeia (2015 edition), the IACs could be used for three and two times for the spiked raw malt and dried ginger samples with OTA, respectively. Therefore, the corresponding experimental cost could be reduced to one-eighth and one-third of the original cost. This is the first study on the regeneration and reuse of IACs for OTA clean-up in complex Chinese herbal medicines, providing a green and economical tool for a large number of samples analysis with low cost.