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Normalization is a crucial step in proteomics data analysis as it enables data adjustment and enhances comparability between datasets by minimizing multiple sources of variability, such as sampling, sample handling, storage, treatment, and mass spectrometry measurements. In this study, we investigated different normalization methods, including Z-score normalization, median divide normalization, and quantile normalization, to evaluate their performance using a case study based on renal cell carcinoma datasets. Our results demonstrate that when comparing datasets by pairs, both the Z-score and quantile normalization methods consistently provide better results in terms of the number of proteins identified and quantified as well as in identifying statistically significant up or down-regulated proteins. However, when three or more datasets are compared at the same time the differences are found to be negligible., Competing Interests: Declaration of competing interest All authors declare nor financial or personal relationships that may be perceived as influencing this work., (Copyright © 2023. Published by Elsevier B.V.)

In this paper, the development of efficient enantioselective HPLC methods for the analysis of five benzofuran-substituted phenethylamines, two substituted tryptamines, and three substituted cathinones is described. For the first time, reversed-phase (eluents made up with acidic water-methanol solutions) and polar-ionic (eluent made up with an acetonitrile-methanol solution incorporating both an acidic and a basic additive) conditions fully compatible with mass spectrometry (MS) detectors were applied with a chiral stationary phase (CSP) incorporating the (+)-(18-crown-6)-tetracarboxylic acid chiral selector. Enantioresolution was achieved for nine compounds with α and R S factors up to 1.32 and 5.12, respectively. Circular dichroism (CD) detection, CD spectroscopy in stopped-flow mode and quantum mechanical (QM) calculations were successfully employed to investigate the absolute stereochemistry of mephedrone, methylone and butylone and allowed to establish a (R)<(S) enantiomeric elution order for these compounds on the chosen CSP. Whole blood miniaturized samples collected by means of volumetric absorptive microsampling (VAMS) technology and fortified with the target analytes were extracted following an optimized protocol and effectively analysed by means of an ultra-high performance liquid chromatography-MS system. By this way a proof-of-concept procedure was applied, demonstrating the suitability of the method for quali-quantitative enantioselective assessment of the selected psychoactive substances in advanced biological microsamples. VAMS microsamplers including a polypropylene handle topped with a small tip of a polymeric porous material were used and allowed to volumetrically collect small aliquots of whole blood (10 μL) independently from its density. Highly appreciable volumetric accuracy (bias, in the -8.7-8.1% range) and precision (% CV, in the 2.8-5.9% range) turned out., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Diazepam is frequently used as an adjuvant during antidepressant therapy. Recently, some studies have suggested that the treatment with benzodiazepines could have different efficacy in depressed patients as opposed to non-depressed ones. To clarify the matter, a study is currently underway, regarding the drug metabolism in rats. In order to obtain a more complete and significant set of data, the main diazepam metabolites have also been considered, namely: nordiazepam, temazepam and oxazepam. A feasible and reliable HPLC method has been developed for the simultaneous determination of these compounds in plasma and brain tissue of rats. The method has been applied to "normal" rats and to genetic rat models of depression in order to estimate drug metabolism in different breeds. Analyte separation was achieved on a C8 reversed phase column using an acidic phosphate buffer/acetonitrile mixture as the mobile phase. The detection wavelength was 238 nm. An original sample pre-treatment, based on solid-phase extraction (SPE) was developed in order to eliminate endogenous interference, using only 250 microL of matrix (brain homogenate or plasma) for a complete analysis. The method has been validated with good results in terms of precision, extraction yield, sensitivity, selectivity and accuracy on both matrices and has been successfully applied to samples from some rats subjected to the preliminary study. The obtained data will hopefully contribute to the clarification of possible differences between depressed and non-depressed subjects with respect to benzodiazepine biotransformation.