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PM2.5 is an important global air pollution issue. PM2.5 causes various problems on the environment and human health. Even though PM2.5 of the outdoor air is eliminated by particulate air filters, the chemicals adsorbed on the filtered PM2.5 can be outgassed and introduced into the semiconductor manufacturing facilities and processes, thus causing defects on the semiconductor chips by producing particles and haze as airborne molecular contamination. Therefore, estimating the amount of the outgassing from PM2.5 is a very important factor to control gaseous contaminants in the semiconductor industry. In this paper, the PM2.5 samples at different PM2.5 mass loadings were collected in Xi’an, China and evaluated using the soft X-ray radiolysis method for determining the relation between the outgassing and the PM2.5 mass loading. The PM2.5 samples were also analyzed by several methods for quantifying organic and elemental carbons, water soluble ions, and organic compounds in the PM2.5 samples. The outgassing measured by the soft X-ray method increased linearly with the PM2.5 mass loading, and the chemical analyses explained that the organic carbon (OC) was dominantly detected by the soft X-ray method in the current study. Moreover, the sampling location of the PM2.5 affected on the organic compounds of the PM2.5. [ABSTRACT FROM AUTHOR]

The application of disposable tableware has increased substantially in recent times due to the rapidly growing food delivery business in China. Synthetic phenolic antioxidants (SPAs) are widely used in food contact materials (FCMs) to delay the process of oxidation; however, their compositions, concentrations, and potential health hazards remain unclear. Therefore, FCMs comprised of five materials obtained from 19 categories (n = 118) in China were analyzed for SPAs concentrations. FCMs have been found to contain a variety of SPAs, with ∑SPAs concentrations ranging from 44.18 to 69,485.12 μg/kg (median: 2615.63 μg/kg). The predominant congeners identified in the sample include 2,4-di-tert-butylphenol (2,4-DTBP), 2,6-di-tert-butylphenol (2,6-DTBP), and 2,6-di-tert-butyl-p-benzoquinone (BHT-Q) with a median concentration of 885.75, 555.45 and of 217.44 μg/kg, respectively. Milky tea paper cups, instant noodle buckets, milky teacups, and disposable cups showed high levels of SPAs. 2,2′-methylenebis(4-methyl-6-tert-butylphenol) (AO 2246) was predominantly detected in polyethylene and polyethylene terephthalate-based products. The migration test identified disposable plastic cups and bowls as the predominant FCMs and 2,4-DTBP as the dominant SPA. The exposure risk of SPAs decreased with age. In children, the estimated daily intake of ∑SPAs from FCMs was determined to be 17.56 ng/kg body weight/day, which was 8.3 times higher than that of phthalic acid esters. The current findings indicate the potential ingestion risk of SPAs during the daily life application of multiple FCM categories. [Display omitted] • 2,4-DTBP and BHT-Q were the dominant SPAs and TPs in FCMs with high concentration. • Milky teacup, instant noodle bucket and disposable cup are major source of SPAs. • Disposable cup and bowl are the most used FCMs with the highest migrating levels. • Migration efficiency of SPAs increased as ethanol content in simulants increased. • The exposure risks for single SPAs decreased with age. [ABSTRACT FROM AUTHOR]

The abuse of new psychoactive substances has spread around the world. Synthetic cannabinoids (SCs) is an important group. Since the first discovery of JWH-018 in Europe in 2008, SCs have multiplied rapidly and become the focus of drug control worldwide. Statistics from the Drug Intelligence and Forensic Center of the Ministry of Public Security of China showed that the proportion of SCs in suspected drug samples seized had increased from 18.5% to 72% in 2017-2019. To this, our country drug control administration department makes positive response. A series of new anti-drug policies had been introduced since 2015. Fifty-three SCs were legally controlled until the end of 2018. China had issued total ban on SCs since July 1st, 2021. However, because of the great structural variability of SCs, it is of great significance to identify the key target structures and summarize the characteristics of the common spectrum of similar drugs in judicial practice. In this paper, 27 synthetic cannabinoids were selected, including the new synthetic cannabinoids with high prevalence in recent years and potential drug structures that had not been reported but were inferred based on the structural evolution trend of synthetic cannabinoids. The method of gas chromatography-mass spectrometry (GC-MS) was used to collect data of the selected SCs under electron ionization mode (EI). The results indicated that the SCs were mainly composed of core, linker, linked group and sidechain. Among them, the core of new SCs gradually changed from formyl indole to indole/indazolamide, which would produce characteristic fragments of m/z 144, 145, respectively. The fragmentation of the linker part mainly occurred on both sides of the carbonyl group. The tertiary carbon atoms, methyl butyrate and butylamide from the linked groups led to diversified fragmentation easily. Neutral loss frequently happened in the part of sidechain, which resulted in the formation of characteristic fragments such as fluoro-butyl (m/z 74), fluoropentyl (m/z 88) and pentenyl (m/z 68). The 7 SCs prepared according to the predicted structure shared similar fragmentation pathways with the 22 SCs abused both domestically and abroad. The variation of SCs based on the structures defined in law would gradually decrease and the structural stability would be enhanced after the total ban of SCs was issued. The mass fragmentation pathway mentioned above can provide technical support for the species identification of new SCs, as well as the prevention of drug variation. [ABSTRACT FROM AUTHOR]

The compounds in volatile flavor substances in duck meats of three different body parts (breast, leg, and wing) were extracted by headspace solid‐phase micro‐extraction and determined by gas chromatography‐mass spectrometry. A total of 16 main volatile compounds including 4 hydrocarbons, 4 alcohols, 2 acids, 3 aldehydes, and 3 others (N‐containing, S‐containing) were identified in raw duck meats from three different body parts. The hydrocarbon compounds account for more than 50% of all volatile substances in all three body parts. And the percentage of hydrocarbon compounds in raw duck breast meat reaches 82.76%. A total of 81 volatile compounds including 15 hydrocarbons, 10 alcohols, 7 acids, 12 aldehydes, 4 esters, 19 S‐containing and N‐containing compounds, and 14 others were isolated and identified in 1 hr‐marinated and cooked duck meats. A total of 101 kinds of volatile flavor compounds including 13 hydrocarbons, 14 alcohol, 7 acids, 8 aldehydes, 12 esters, 23 S‐containing and N‐containing compounds, and 24 others were detected in 3 hr‐marinated duck meats of the three body parts. It was proved in this study that under the same conditions, the volatile compounds in duck legs are more than those in duck breasts and wings, and the types of volatile flavor substances increase significantly in duck meats after cooked. Practical applications: Prepared and cooked duck meat, especially wings and legs are popular food in China. The results suggest that Pickling makes duck meat more flavory while proper pickling time is less than 3 hr. Duck wings are better for marinating and cooking compared with duck breasts and legs. The acceptance study of duck meat from different body parts and the analysis of volatile flavor compounds are beneficial for optimizing utilization of whole parts of duck meat. [ABSTRACT FROM AUTHOR]

The aim of this study is to investigate the status of laboratory practice of organic acid (OA) analysis using gas chromatography–mass spectrometry in China. A survey, investigating details of laboratory practice of OA analysis, was issued on the website of the National Center for Clinical Laboratories of China. Nationwide external quality assessment participating laboratories of OA assay were informed to participate in this survey. A total of 36 laboratories completed this survey. Most laboratories started OA analysis during 2016–2020. Most (100%) labs reported semi-quantitative results, in which 79.4% of labs adopted the form of the ratio of peak area of OA and quantitative internal standard. Rare labs reported quantitative results. Few labs released reports in three days, most in 5–7 days. The source of control materials varied, 64.5% of labs adapted self-made materials. A total of 43.8% of laboratories directly used reference intervals (RIs) from published literature, 43.8% of laboratories established RIs themselves, but 21.2% of laboratories reported they didn't verify RIs. Appropriate supervision for the organic acid assay is needed in the aspect of the turnaround time of reporting results, the establishment validation and verification of reference ranges, and the quantification of results. [ABSTRACT FROM AUTHOR]

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The composition and physical properties of spilled oil have great changes during the seriously weathering process. It brings great difficulties to the source identification of oil spill. So the stable and trustworthy diagnostic ratios (DRs) for accurate identification of severely weathered spilled oils are very important. The explosion of Sinopec pipeline happened on November 22, 2013 at Qingdao, China. Local beaches at Jiaozhou Bay were polluted by spilled oils. We have collected original spilled oil samples from an area free from human interference near the oil leakage point after the accident. Synchronized with actual beach weathering, laboratory experiments were conducted to simulate oil weathering for 360 days by using the collected original spilled oil samples. Based on t test and the repeatability limit method, 50 diagnostic ratios (DRs) of adamantanes were screened. Four DRs, namely 1,3-dimethyladamantane/total dimethyladamantane, 1-methyladamantane/(1-methyladamantane + 1,3-dimethyladamantane), dialkyl diamantane/total diamantane, and diamantane/(diamantane + dialkyl diamantane), have maintained remarkable stability during the simulated weathering experiments and field weathering process. These stable ratios can retain the characteristics of oil source during weathering. They are very beneficial to improve the accuracy of identifying the source of severely weathered oil and can be used as an effective supplement to existing index system for source identification. [ABSTRACT FROM AUTHOR]

Although volatile organic compounds (VOCs) are major indoor air pollutants and ones which may affect human health it is rare to find a study about their types and distribution pattern in a university. To remedy this large-scale sampling of VOCs was conducted at different indoor environments on a university campus in Hong Kong when the HVAC system was turned on. The 54 sites selected for sampling included classrooms, offices, dining and kitchen area of canteens, workshops, laboratories and a library. All the buildings were served with mechanical ventilation and an air conditioning (MVAC) system. Samples were analysed by the USEPA's TO-14 method. VOCs discovered were divided arbitrarily into three categories: fluorinated compounds, non-aromatic chlorinated compounds and aromatic compounds. Among the VOCs detected by the TO-14 method, toluene and benzene were the most common compounds present on the campus and were present in all the samples taken. The main source for those two VOCs was ingress from outdoors. [ABSTRACT FROM AUTHOR]