Tapiwa Chapupu, Anesuishe B Gatsi, Fidelis Chibhabha, Prince L M Zilundu
Self-regulated learning of anatomy during the COVID-19 lockdown period in a low-income setting
BMC medical education
knowledge molecular fraction contributing white wines oxidative stability still poorly understood however role ncontaining compounds like glutathione peptides source reductant many oxidation reactions acting heavy metals toxicity lipid polyphenol oxidation rosscavenger today well established respect aim present study introduce original analytical tool direct determination available nucleophilic compounds white wine acidic ph conditions one step derivatization nucleophiles realized directly wines using 4methyl12benzoquinone 4meq electrophilic probe derivatization conditions considering probe concentration ph reaction time ms ionisation conditions adducts stability optimized using model solutions containing standard sulfur amino compounds gsh cys hcys serapscysaspser aspmet met glu ultrahighperformance liquid chromatography coupled quadrupoletime flight mass spectrometer uhplcqqtofms analysis 92 white wines different cultivars chardonnay sauvignon semillon followed multivariate analysis pls da wilcoxon test allowed isolate 141 putative wine relevant nucleophiles 20 compounds essentially thiols detectable samples derivatization indicating importance quinone trapping revelation wine unknown nucleophiles moreover annotation using online database oligonet metlin kegg well elementary formula determined isotopic profile provided evidence presence amino acids val leu ile pro trp cys met peptides important antioxidant properties complimentary set msms spectral data greatly accelerated identification nucleophiles enabled peptides sequencing results show probing wines 4methyl12benzoquinone enhances thiols ionisation capacity gives better screening specific n containing functional compounds part white wines antioxidant metabolome