Isotope-dilution method for the determination of 1-vinyl-2-pyrrolidone-mercapturic acid as a potential human biomarker for 1-vinyl-2-pyrrolidone via online SPE ESI-LC/MS/MS in negative ionization mode

Applications of chromatographic methods in metabolomics: A review

Chromatography is a robust and reliable separation method that can use various stationary phases to separate complex mixtures commonly seen in metabolomics. This review examines the types of chromatography and stationary phases that have been used in targeted or untargeted metabolomics with methods such as mass spectrometry (MS) and nuclear magnetic resonance (NMR) spectroscopy. General considerations for sample pretreatment and separations in metabolomics are considered, along with the various supports and separation formats for chromatography that have been used in such work. The types of liquid chromatography (LC) that have been most extensively used in metabolomics will be examined, such as reversed-phase liquid chromatography and hydrophilic liquid interaction chromatography. In addition, other forms of LC that have been used in more limited applications for metabolomics (e.g., ion-exchange, size-exclusion, and affinity methods) will be discussed to illustrate how these techniques may be utilized for new and future research in this field. Multidimensional LC methods are also discussed, as well as the use of gas chromatography and supercritical fluid chromatography in metabolomics. In addition, the roles of chromatography in NMR- vs. MS-based metabolomics are considered. Applications are given within the field of metabolomics for each type of chromatography, along with potential advantages or limitations of these separation methods.

Simultaneous online SPE-HPLC-MS/MS quantification of gefitinib, osimertinib and icotinib in dried plasma spots: Application to therapeutic drug monitoring in patients with non-small cell lung cancer

Gefitinib, osimertinib and icotinib are the most commonly used tyrosine kinase inhibitors (TKIs) in non-small cell lung cancer (NSCLC) with EGFR mutation. Therapeutic drug monitoring (TDM) for these TKIs has become a standard and essential procedure. Dried plasma spots (DPS) was choosen for microsampling strategies for TDM, allowing easy and cost-effective logistics in many settings. This study developd and validated an assay for the simultaneous quantitative determination of gefitinib, osimertinib and icotinib in DPS by online solid-phase extraction-liquid chromatography-tandem mass spectrometry (online SPE-LC-MS) system. The TKIs were extracted from DPS with methanol and enriched on a Welch Polar-RP SPE column (30 × 4.6 mm, 5 µm), followed by separation on Waters X Bridge C18 analytical column(4.6 × 100 mm, 3.5 µm). The method achieved LLOQ of 2 ng mL^-1 for gefitinib and osimertinib (4 ng mL^-1 for icotinib), respectively (r² > 0.99). Precision (within-run 1.54-7.41 % RSD; between-run 3.03-12.84 % RSD), accuracy (range from 81.47 % to 105.08 %; between-run bias 87.87-104.13 %). Osimertinib and icotinib were stable in DPS stored at - 40 °C for 30 days, 4 °C, 42 °C and 60 °C for 5 days and well-sealed 37 °C,75 % humidity (except gefitinib). Lastly, the assay was applied to TDM of TKIs in 46 patients and the results were compared to SALLE assisted LC-MS analysis, it could be confirmed that the developed method achieves similarly good results as the already established one and no bias could be detected. It implies that this method capable of supporting clinical follow-up TDM of TKIs in DPS from poor medical environment.