A major constraint in large-scale mass spectrometry (MS)-based metabolomic initiatives is the low sample throughput associated with chromatographic or electrophoretic separations. Herein, we introduce multisegment injection-capillary electrophoresis-mass spectrometry (MSI-CE-MS) as a multiplexed separation platform for metabolomics that increases sample throughput up to one order of magnitude while improving overall data fidelity. We demonstrate that serial injection of seven or more discrete sample segments can be performed within a single capillary while maintaining isomeric resolution without ion suppression when using a high mass resolution time-of-flight-MS. Customized injection sequences can be devised to encode information temporally within a separation based on signal pattern recognition, which enables unambiguous identification and accurate quantification (mean bias <10%) of polar metabolites in human plasma with good reproducibility (CV ≈ 10%, n = 70). False discoveries are avoided when using a rigorous dilution trend filter to reject spurious signals and background peaks that comprise the majority (≈65%) of total detectable features. MSI-CE-MS offers an unprecedented approach to enhance sample throughput analogous to direct infusion-MS (≈3 min/sample) while delivering far greater selectivity, quantitative performance, and data quality since the same ion from different samples migrates into the ion source within a short time interval (≈2-6 min). These distinct analytical and bioinformatic merits are achieved without column switching, isotopic labeling, hardware modifications, or costly infrastructure investments.

High efficiency separations are needed to enhance selectivity, mass spectral quality, and quantitative performance in metabolomic studies. However, low sample throughput and complicated data preprocessing remain major bottlenecks to biomarker discovery. We introduce an accelerated data workflow to identify plasma metabolite signatures of exercise responsiveness when using multisegment injection-capillary electrophoresis-mass spectrometry (MSI-CE-MS). This multiplexed separation platform takes advantage of customizable serial injections to enhance sample throughput and data fidelity based on temporally resolved ion signals derived from seven different sample segments analyzed within a single run. MSI-CE-MS was applied to explore the adaptive metabolic responses of a cohort of overweight/obese women (BMI > 25, n = 9) performing a 6-wk high-intensity interval training intervention using a repeated measures/cross-over study design. Venous blood samples were collected from each subject at three time intervals (baseline, postexercise, recovery) in their naïve and trained states while completing standardized cycling trials at the same absolute workload. Complementary statistical methods were used to classify dynamic changes in plasma metabolism associated with strenuous exercise and training status. Positive adaptations to exercise were associated with training-induced upregulation in plasma l-carnitine at rest due to improved muscle oxidative capacity, and greater antioxidant capacity as reflected by lower circulating glutathionyl-l-cysteine mixed disulfide. Attenuation in plasma hypoxanthine and higher O-acetyl-l-carnitine levels postexercise also indicated lower energetic stress for trained women.

Lutein and b-carotene are the major carotenoids in plant leaves, playing crucial roles in photosynthesis.These pigments also have important applications in human and animal health; therefore, it is essential to accurately determine their quantities in crops. A high-throughput RP-HPLC technique was developed for quantifying the levels of these carotenoids in leaf tissue using a piecewise gradient system. The analysis time was reduced to only 10 min, including column re-equilibration, through the use of a short, efficientPoroshell column with an HPLC-PDA instrument. The method was successfully validated, resulting in sub-mg mL À1 quantification limits for both analytes. To demonstrate the adaptability of the method, application to both saponified and unsaponified leaf samples was performed. The piecewise gradient allows for the customizability of the mobile phase selectivity towards specific sample components and can potentially be adapted to screen multiple tissues of plant varieties and mutants with more extensive carotenoid profiles.