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In the last decade, the advancement of liquid chromatography mass spectrometry (LC/MS) techniques has enabled their broad application in protein characterization, both quantitatively and qualitatively. Owing to certain important merits of LC/MS techniques (e.g., high selectivity, flexibility, and rapid method development), LC/MS assays are often deemed as preferable alternatives to conventional methods (e.g., ligand-binding assays) for the analysis of protein biotherapeutics. At the discovery and development stages, LC/MS is generally employed for two purposes absolute quantification of protein biotherapeutics in biological samples and qualitative characterization of proteins. For absolute quantification of a target protein in bio-matrices, recent work has led to improvements in the efficiency of LC/MS method development, sample treatment, enrichment and digestion, and high-performance low-flow-LC separation. These advances have enhanced analytical sensitivity, specificity, and robustness. As to qualitative analysis, a range of techniques have been developed to characterize intramolecular disulfide bonds, glycosylation, charge variants, primary sequence heterogeneity, and the drug-to-antibody ratio of antibody drug conjugate (ADC), which has enabled a refined ability to assess product quality. In this review, we will focus on the discussion of technical challenges and strategies of LC/MS-based quantification and characterization of biotherapeutics, with the emphasis on the analysis of antibody-based biotherapeutics such as monoclonal antibodies (mAbs) and ADCs. © 2016 Wiley Periodicals, Inc. Mass Spec Rev 36:734-754, 2017.

1994). A mechanism of seed deterioration in relation to the volatile compounds evolved by dry seeds themselves. AbstractSome of the seed-evolved volatiles, which were mainly composed of methanol, acetaldehyde, ethanol and acetone, caused the loss of seed germmabihty during storage In general, the deleterious effects of the volatiles increased with increasing RH and temperature during storage Acetaldehyde had the strongest deleterious effect regardless of RH and temperature, while ethanol caused seed deterioration only at high RHs Acetone was slightly deleterious to some species, while methanol was almost inert in most seeds Various aldehydes applied during storage showed some toxicity to seed germmabihty, which decreased, except for 3-methylbutanal, with increasing molecular size, suggesting that the endogenous volatile compounds with an aldehyde group cause seed deterioration On the other hand, the contents of volatile compounds in seeds were higher when they were stored at 44% RH (water sorption zone 2), than when stored at 12% RH (water sorption zone 1) Acetaldehyde, the most deleterious volatile, was more abundantly accumulated within the seeds stored at -3 5°C than at 23°C Based on these facts, it is suggested that endogenous volatiles, especially acetaldehyde, may be an important factor that accelerates seed deterioration which often occurs under lower RHs and/or temperatures throughout long-term storage