For alcohol use motives, there was a significant increase in depression coping motives and significant decreases in social, enhancement, and conformity motives. Boredom motives for marijuana use significantly increased, while celebration motives decreased. Using a prospective design with a sample initially recruited in Washington State, these data indicate that (a) young adults' patterns of alcohol use may have changed, (b) young adults tend to think that peers are engaging in heavier alcohol/marijuana use than before the pandemic, and (c) motives for using alcohol/marijuana may have changed during the pandemic.Using a prospective design with a sample initially recruited in Washington State, these data indicate that (a) young adults' patterns of alcohol use may have changed, (b) young adults tend to think that peers are engaging in heavier alcohol/marijuana use than before the pandemic, and (c) motives for using alcohol/marijuana may have changed during the pandemic.Despite the increased interest and great progress obtained on arsenic test, it is still a challenge to accomplish the on-site determination of arsenic in rice due to the expensive instrumentation and harsh digestion process. In this work, MnFe2O4 micromotors were found to retain high catalytic activity to simultaneously produce large amounts of hydroxyl radicals and O2 bubbles in the presence of H2O2. Interestingly, the generated bubbles autonomously propel the micromotors and prevent them from depositing, thus keeping their high catalytic activity. As a result, a MnFe2O4 micromotors enhanced digestion method was developed for the field digestion of rice samples within 100 min only using H2O2, which was further utilized to realize the on-site detection of arsenic in rice by coupling with the Gutzeit method followed headspace solid phase extraction. A quantification limit of 40 μg kg-1 was obtained for the determination of arsenic in rice. Owing to their capabilities of the efficient and rapid adsorption of arsenic and continuous movement, a MnFe2O4 micromotors enhanced solid phase extraction was also established for the sensitive determination of arsenic in water with a 1 μg L-1 of quantification limit. The accuracy of the developed method was validated via analysis of a Certified Reference Material of rice (GBW10043) and a series of rice and water samples with satisfactory results, showing promising potential in the sensitive on-site detection of arsenic in rice and water samples.Bottom-up proteomics provides often small amounts of highly complex samples that cannot be analysed by direct mass spectrometry (MS). To gain a better insight in the sample composition, liquid chromatography (LC) and (comprehensive) two-dimensional liquid chromatography (2D-LC or LC × LC) can be coupled to the MS. Low-flow separations are attractive for HRMS analysis, but they tend to be lengthy. In this work, a low-flow, online, actively modulated LC × LC system, based on hydrophilic-interaction liquid chromatography (HILIC) in the first dimension and reversed-phase liquid chromatography (RPLC) in the second dimension, was developed to separate complex mixtures of peptides. Miniaturization permitted the analysis of small sample amounts (1-5 μg) and direct coupling with micro-ESI MS (1 μL min-1). All components were focused and automatically transferred from HILIC to RPLC using stationary-phase-assisted active modulation (C18 traps) to deal with solvent-incompatibility or dilution issues. Optimization of the setup was performed for the HILIC columns and the RPLC columns to provide a more efficient separation and higher identification rates than obtained using one-dimensional (1D) LC. A 60% increase in peak capacity was obtained with the 2D setup compared to a 1D-RPLC separation and a 17-34% increase in the number of proteins identified was achieved for the samples analysed (2D-yeast-8280 peptides and 2D-kidney tissue-8843 peptides), without increasing the analysis time (2 h).Rotational ambiguity is a phenomenon with the potential of generating an uncertainty in the estimation of analyte concentrations in protocols based on matrix instrumental data processed by multivariate curve resolution - alternating least-squares (MCR-ALS). This is particularly relevant when the second-order advantage is to be achieved, i.e., when selected analytes are determined in unknown samples having unexpected constituents, not considered in the calibration set of samples. It is therefore imperative that analytical chemists developing second-order multivariate calibration methods using MCR-ALS acknowledge the relevance of this issue, and more importantly, have access to the required tools to size the relative impact of this potential source of uncertainty on the estimated analyte concentrations. The purpose of this tutorial is to provide a down-to-earth view of rotational ambiguity, by studying in detail a synthetic example mimicking a typical chromatographic-spectral experiment, where a set of calibration samples is joined with an unknown sample having an uncalibrated interference. AS2863619 After explaining the background information needed to understand the origin of the phenomenon, the available tools for the estimation of the feasible MCR-ALS solutions and the derived uncertainty on analyte predictions will be discussed. A multi-component experimental system will also be discussed, stressing the fact that rotational ambiguity uncertainties, however small, should always be estimated and reported.When analyzing large complex protein biopharmaceuticals, ion-pairing agents imparting low pH are widely used as mobile phase additives to improve the chromatographic performance. However, one of the most effective additives in RPLC and HILIC, trifluoroacetic acid (TFA), is known as a strong suppressor of the MS signal and limits its use in hyphenated techniques. In this study, we evaluated a wide range of acidic additives to find alternatives to TFA that provided comparable chromatographic performance and improved MS sensitivity. It was observed that stronger acidic additives were required for intact level analysis compared to subunit level analysis and that the additive nature had a larger impact on the chromatographic performance in HILIC mode compared to RPLC. Therefore, four additives were identified as valuable alternatives to TFA in RPLC mode, namely, difluoroacetic acid (DFA), dichloroacetic acid (DClAA), trichloroacetic acid (TClAA), and methanesulfonic acid (MSA). Only one of these additives provided acceptable performance in HILIC mode, namely, TClAA.