查看更多>>摘要：We evaluated the performance of three different single-phase extraction methods to be used before untargeted lipidomics analysis by Liquid Chromatography High-Resolution Mass Spectrometry. Lipids were extracted from a pool of healthy human donors' plasma in triplicates and run in both positive and negative ESI. The most satisfactory results were attained using methanol/chloroform (2:1, v/v) mixture. Eventually, we evaluated whether a filtration of the samples could be beneficial to yield cleaner and more mass-friendly extracts. Instead of using syringes, we set up a method we called tip-tip filtration, which requires the usage of a filtrating pipette tip. This way of purification led to superior results than the solvent extraction method alone. This additional procedure not only increased reproducibility but also allowed the same lipid coverage. In addition, it permitted to spare time and money, as tip-tip filtration is not particularly expensive nor time-consuming and hopefully it may be useful to increase analytical column lifetime.
查看更多>>摘要：Yellow catfish (Pelteobagrus fulvidraco) is commonly contaminated by protease inhibitors because of the illegal use of antiviral drugs in aquaculture, so the determination of antiviral drugs is essential in food safety supervision. In this study, a novel sorbent, graphene and silica nanospheres composite (G/KCC-1), was synthesized for pipette-tip-based solid-phase extraction (PT-SPE) and purification of ritonavir, saquinavir, and indinavir in yellow catfish, followed by ultra-performance liquid chromatography and tandem mass spectrometry (UPLC-MS/MS) analysis. The wrinkly structure of G/KCC-1 with center-radial nanowrinkles enlarged the surface area and increased the capacity of absorbing the target analyte. With the proposed G/KCC-1 based PT-SPE UPLC-MS/MS method, the pH of sample solution, aspirating/dispensing cycles for extraction and elution were optimized to be 4.0, 25, and 10 respectively, and the eluting solvent was methanol/ammonia (95:5, v/v) with 0.02 M sodium chloride. This new method was further validated to be linear (correlation coefficient R-2, 0.9993-0.9996), sensitive (limit of detection, LOD <=& nbsp;0.8 ng mL(-1)), accurate (89.3-114.2%), and precise (relative standard deviation, RSD <=& nbsp;6.23%). These results indicated that the proposed method is qualified in bioanalytical method validation and meets the requirements for detecting illegally used antiviral drugs in yellow catfish. The demonstrated G/KCC-1 based PT-SPE UPLC-MS/MS method is a potential analytical method in food and drug administration.
NSTL
Elsevier