GERI-BP002-A

Synthetic phenolic antioxidants (SPAs) have been identified as an emerging group of contaminants in recent years. However, there are significant gaps in our knowledge of human prenatal exposure to these synthetic chemicals. In this study, a set of eight SPAs and four major transformation products (TPs) were systematically analyzed in matched samples of maternal plasma, cord plasma, and placenta from a population of pregnant women. Five of the eight target SPAs and all four target TPs were frequently detected in the maternal-placental-fetal unit, indicating prenatal exposure to SPAs and the transfer of SPAs across the placenta. In the three matrices, 2,6-di-tert-butyl-hydroxytoluene (BHT), 2,4-di-tert-butylphenol (DBP), and 2,2'-methylenebis(4-methyl-6-tert-butylphenol) (AO 2246) were identified as the most abundant SPAs, while 2,6-di-tert-butyl-1,4-benzoquinone (BHT-Q) and 2,6-di-tert-butyl-4-hydroxy-4-methyl-2,5-cyclohexadienone (BHT-quinol) were identified as the predominant TPs of BHT. In the maternal plasma, concentrations of both BHT-Q and BHT-quinol were significantly correlated with BHT (p < 0.001), suggesting that the two TPs mainly originated from the biotransformation of BHT itself in pregnant women. The transplacental transfer efficiencies (TTEs) of the SPAs and TPs were structure-dependent and generally less than 1. Significantly higher TTEs for four target TPs than their parent BHT were identified. To our knowledge, this study provides the first evidence that SPAs and TPs transfer across the placenta in pregnant women.

Background: According to WHO, Hepatocellular cancer (HCC) was the second leading cause of death in 2019 and is gradually increasing. The lipid peroxidation mechanism in cancer cells causes the emission of VOCs in the breath. Volatile organic compounds (VOCs) in breath are becoming favorable biomarkers, especially for cancers, for their sample retrieval and specific association with early metabolic changes. Since both diagnosis and prognosis of the disease depend on the quantity and kind of circulatory biomarkers to be detected, sensitive and selective biosensors with the possibility for portability are constantly in demand. Results: In this study, breath samples of HCC patients were screened for identification of VOCs via GCMS and later verified by applying unsupervised machine learning models. Phenol 2,2 methylene bis [6-(1,1-dimethyl ethyl)-4-methyl] (MBMBP) was found to be significant VOC in the breath of HCC patients, with a minimum concentration of 2100 ppm. Thiol-modified AuNPs were synthesized, as we reported earlier, and immobilized on the working electrode surface to electrochemically sense MBMBP in purified form and later from clinical breath samples. During the electrochemical experiment of AuNPs with MPMBP, the analyte gets electro-oxidized, whereas the Au (III) ions get reduced to the phenoxy radical's species. The electrochemical analysis of MBMBP detection using hexane thiol AuNPs showed a LOD of 0.005 molL 1. The thiolated AuNPs-based biosensor for HCC diagnosis via VOC detection confirmed MPMBP in lab standards and raw clinical breath samples of HCC patients. Significance: This study reveals that GCE modified with hexanethiol AuNPs for the adsorption of significant breath biomarker, is a potential platform for the development of e-nose sensor for the detection of HCC at early stage.

Composite magnetic oxide at cow dung ash, nano-Fe3O4@cow dung ash (nano-Fe3O4@CDA), was used as catalytic material for the degradation of 2, 2'-methylenebis (4-methyl-6-tert-butylphenol) (AO 2246) in real biologically pretreated landfill leachate. The Fe3O4@CDA composite exhibited catalytic ozonation activity and allowed material separation and magnetic recovery. The effects of several operating parameters including O3 concentration, catalyst dosage, temperature and scavengers were evaluated in parallel. Over 70% of AO 2246 were removed by the nano-Fe3O4@CDA/O3 system under optimum conditions within 120min reaction time. The EPR, GC-MS and free-radical quenching experiments expatiated the mechanism of this degradation process. It was confirmed that the AO 2246 was degraded efficiently in this catalytic micro-ozonation process, Additionally, GC-MS analysis state clearly that the 3,5-bis(1,1-dimethylethyl)phenol, 4-(1,5-dihydroxy-2,6,6-trimethylcyclohex-2-enyl)but-3-en-2-one, ethanone, 1-(1,4-dimethyl-3-cyclohexen-1-yl)-, 5-tert-butyl-6-3, 5-diene-2-one, 2-hydroxyhexanoic acid, 2-propenoic acid 1,1-dimethylethyl ester, butanoic acid, 2-methyl-, methyl ester and propanoic acid, 2, 2-dimethyl- were the dominant oxidation products (OPs) during the degradation of the AO 2246. The EPR results showed that the catalytic ozonation over Fe3O4@CDA led to produce more hydroxyl radicals, which were in favor of AO 2246 degradation. The toxicity evolution was also performed through a QSAR analysis calculated by the ECOSAR program which further demonstrated the different responses toward the AO 2246 and its OPs.