Browsing: LC-MS

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Bile acids are an important class of biological molecules that are generated in the liver and play a central role in various biological functions, including cholesterol homeostasis. Quantitative analysis for research of bile acids using LC-MS is complicated by the presence of many isomeric compounds.Historically, this has meant that throughput has been compromised in order to separate these isomeric compounds. Here we demonstrate how these compounds can be separated, without compromising throughput, using Waters® CORTECS UPLC Technology combined with negative mode electrospray ionization mass spectrometry. This application note is also part of a MetaboQuan-R method package.

Large molecule quantification by LC–MS PPD IMage

Monoclonal antibody (mAb) based biotherapeutics have emerged as a dominant class of approved medicines during the past decade in both market share and variety of target diseases. Ligand binding assays (LBAs), such as enzyme-linked immunosorbent assays (ELISA), have been the gold standard for the bioanalysis of mAbs in support of non-clinical and clinical trials. While conventional LBAs provide highly sensitive and specific detection for the quantitation of mAbs, combining an LBA with liquid chromatography tandem mass spectrometry (LC-MS/MS) detection offers additional orthogonal dimensions of selectivity/specificity, extending the assay utility to a multiplexed format otherwise not achievable by LBA alone.

Large molecule quantification by LC–MS LGC_Glu-c_an_orthogonal_and_alternative_enzyme_for_protein_quantitation_SS

To date, almost all protein LC-MS/MS based bioanalysis has involved the use of trypsin to cleave biopharmaceuticals into manageable peptides for quantitation. In some cases, where trypsin does not generate useful peptide sequences, a different cleavage agent is required. Glu-C is an enzyme that is frequently used for protein characterisation, and cuts proteins on the C-terminal side of the aspartic and glutamic acid residues. These two molecules are acidic amino acids, whereas the ubiquitous trypsin cleaves at the basic residues (lysine and arginine), therefore making this an orthogonal cleavage enzyme.

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