Search

Vinyl acetate is a restricted substance in food products. The quantification of the organic impurities in vinyl acetate is a major problem due to its activity, instability, and volatility. In this paper, while using the mass balance method to determine the purity of vinyl acetate, an improved method was established for the determination of the content of three impurities in vinyl acetate reference material, and the GC-FID peak area normalization for vinyl acetate was calibrated. The three trace organic impurities were identified by gas chromatography tandem high-resolution mass spectrometry to be methyl acetate, ethyl acetate, and vinyl propionate. The content and relative correction factors for the three organic impurities were measured. The purity of vinyl acetate determined by the mass balance method was 99.90% with an expanded uncertainty of 0.30%, and the total content of organic impurities was 0.08% with a relative correction factor of 1.23%. The vinyl acetate reference material has been approved as a national certified reference material in China as GBW (E) 062710. [ABSTRACT FROM AUTHOR]

BACKGROUND: Polycyclic aromatic hydrocarbons (PAHs), organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) have teratogenic, carcinogenic and mutagenic effects, which are priority pollutants. The formulation of pollution investigation and treatment measures depends on accurate analysis and test data, and certified reference materials (CRMs) are an important guarantee for data quality control. However, the existing relevant reference materials cannot meet the actual needs of pollution monitoring in China. OBJECTIVES: To prepare four CRMs of sediments for analysis of PAHs, OCPs and PCBs, and to meet the needs of environmental monitoring and scientific research for the monitoring of priority pollutants in China. METHODS: In this study, according to the specifications of certified reference materials (JJF 1006-1994, JJF1343-2012 and JJF 1646-2017),4 CRMs of PAHs, OCPs and PCBs in different sediments (GBW07352 - GBW07355) have been developed for Chinese environmental monitoring and scientific research. In the development process, in order to solve the technical difficulties of the stability of organic compound reference materials, the effects of 6° Co sterilization and temperature on the stability of organic compounds were investigated. In view of the complex characteristics of the sediment sample matrix, different extraction and purification technologies were adopted to reduce or eliminate the influence of the complex matrix on the extraction solution and reduce the matrix effect of instrument measurement. Nine laboratories' collaborative analysis was carried out by using traditional methods including high performance liquid chromatography (HPLC), gas chromatography - electron capture detector (GC - ECD), gas chromatography - mass spectrometry (GC - MS) and new techniques of gas chromatography - isotope dilution mass spectrometry (GC - IDMS). RESULTS: The sediment candidates have good homogeneity and stability. The certified values and expanded uncertainty for 16 PAHs, 3 OCPs and 3 PCBs are given, and the concentrations range from 9. Ong/g to 5. 7μg/g, which meets the requirements of quality assurance and quality control for analysis of P AHs, OCPs and PCBs. CONCLUSIONS: This series of reference materials has been approved as a national first - class reference material, numbered from GBW07352 to GBW07355. This series of CRMs can be used in analytical method validation, laboratory quality control, laboratory analysis ability assessment. [ABSTRACT FROM AUTHOR]

In 2009, the genetically modified (GM) rice event TT51-1 with an engineered insect resistance trait became the first GM rice event to be granted certification for safe production in China, and its derivative lines Bt 63 and Huahui No.1 are expected to be commercialized soon. The development of certified reference material (CRM) for TT51-1 is necessary to monitor and inspect the TT51-1 event and its derivates. In this work, we developed four matrix-based TT51-1 rice CRMs (TT51-1, TT51-1, TT51-1, and TT51-1) with different TT51-1 mass fraction ratios by blending seed powders of homozygous TT51-1 and its recipient cultivar Minghui 63. The between-bottle homogeneity and the within-bottle homogeneity were tested, and good results were obtained. The potential degradation during transportation and shelf life were evaluated, and demonstrated an expiration period of at least 36 months. The characterization values of the four TT51-1 CRMs based on the mass fraction ratio were 1000.000 ± 51.430 g/kg, 49.940 ± 4.620 g/kg, 9.990 ± 1.110 g/kg, and 4.990 ± 0.620 g/kg, respectively. The characterization values based on the copy number ratio were certified by digital PCR analysis as 97.442 ± 5.253 %, 4.851 ± 0.486 %, 1.042 ± 0.135 %, and 0.556 ± 0.073 %, respectively. These results suggested that the TT51-1 matrix-based CRMs developed are of high quality and can be used as potential calibrators for TT51-1 GM rice inspection and monitoring. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]