Acesulfame and other artificial sweeteners in a wastewater treatment plant in Alberta, Canada: Occurrence, degradation, and emission.

Acesulfame (ACE), sucralose (SUC), cyclamate (CYC), and saccharin (SAC) are widely used artificial sweeteners that undergo negligible metabolism in the human body, and thus ubiquitously exist in wastewater treatment plants (WWTPs). Due to their persistence in WWTPs, ACE and SUC are found in natural waters globally. Wastewater samples were collected from the primary influent, primary effluent, secondary effluent, and final effluent of a WWTP in Alberta, Canada between August 2022 and February 2023, and the artificial sweeteners concentrations were measured by LC-MS/MS. Using wastewater-based epidemiology, the daily per capita consumption of ACE in the studied wastewater treatment plant catchment was estimated to be the highest in the world. Similar to other studies, the removal efficiency in WWTP was high for SAC and CYC, but low or even negative for SUC. However, ACE removal remained surprisingly high (>96%), even in the cold Canadian winter months. This result may indicate a further adaptation of microorganisms capable of biodegrading ACE in WWTP. The estimated per capita discharge into the environment of ACE, CYC, and SAC is low in Alberta due to the prevalent utilization of secondary treatment throughout the province, but is 17.4-18.8 times higher in Canada, since only 70.3% of total discharged wastewater in Canada undergoes secondary treatment.

Multiplexed separations for biomarker discovery in metabolomics: Elucidating adaptive responses to exercise training.

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.

Multisegment injection-capillary electrophoresis-mass spectrometry: a high-throughput platform for metabolomics with high data fidelity.

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.