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Objective: The study aimed to optimize the preparation process and investigate the quality of coix bran dietary fiber. Methods: The coix bran was used as raw material; the effects of solid-liquid ratio, the amount of amylase and alcalase on the extraction rate were analyzed by usingorthogonal experiments. The chemical composition and physicochemical properties of the dietary fiber obtained under the optimal preparation conditions was analyzed. Results: The optimal extraction parameters of dietary fiber were as follows: solid-liquid ratio was 1∶10 (g/mL), the amount of amylase and alcalase was 100 U/g, respectively, and the extraction rate was up to 84.39%. The insoluble dietary fiber (64.49%) was significantly (P ＜ 0.05) improved compared to coxi bran. And the soluble dietary fiber was 0%, the content of moisture, fat, starch, and protein was significantly decreased (P ＜ 0.05). When the temperature increased, swelling capacity, water holding capacity and oil holding capacity were improved. and was 3.12 mL/g, 4.02 g/g and 4.29 g/g, respectively. Conclusion: The method could be used as a reliable method to extract the coix bran dietary fiber.

An ultra performance liquid chromatography – electrospray ionization triple-quadruple tandem mass spectrometric(UPLC–ESI MS /MS) method was developed for determining Quinololine antibiotics (Carbadox,, Quinocetone, Mequindox, Olaquindox, Cyadox, Tilmicosin, Tylosin, quinoxaline-2-carboxylic acid, 3-methylquinoxaline-2-carboxylic acid) and aminoglycoside antibiotics(Tilmicosin, Tylosin) residues in Penaeus. vannamei, Samples were extracted with acidified acetonitrile, then cleaned up with hexane. The separation of targets was carried out on a Waters BEH C18 column using acetonitrile and 0. 1% fomicacid as mobile phase. Analyte identification and quantification were performed by MS/MS under multiple-reaction monitering(MRM) mode with the external standard method. The results showed that there were good linear relationships between peak area and concentrations of nine targets in the range of 2.5 ~ 50 μg/L, with correlation coefficients more than 0. 999 and The limits of detection(LOD) were in the range of 0. 1 ~ 0.9 μg/kg. the recoveries ranged from 80.2% ~ 94.0%, with RSDs of 1.7%~8.4%. The method is simple, accurate and precise, and It could satisfy the requirement of mass and fast analysis in the laborator.

It still remains a great challenge to selectively enrich and sensitively quantify the trace volatile organic compounds (VOCs) in real samples with complex matrix. In this study, an integration method combining a selective enrichment medium of reduced graphene oxide (rGO) with a specially designed micro thermal-assisted purge-and-trap sampling device was developed for efficient enrichment and sensitive quantification of trace tobacco VOCs coupling with thermal desorption (TD)-gas chromatography/mass spectrometry (GC/MS). The prepared rGO has been proved to possess excellent enrichment selectivity and capacity for tobacco polar VOCs with the multi-layer structure, good thermal stability and large specific surface area. The specially designed sampling device was efficient and suitable for enriching and sampling trace polar tobacco VOCs coupling with rGO medium. Under the optimized sampling and analytical conditions, the established analytical method could be actually applied for quantification of typical tobacco polar VOCs with the good recoveries of 72.9–128% and the satisfied RSDs of 1.8–19.9% (n = 3). The results suggested that the developed method was selective, sensitive and reliable for enrichment and quantification of trace tobacco polar VOCs. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Recent decades have witnessed a rapid development of the lanthanide silicon chemistry. In this research, by reacting [(THF)3LiSiPh3] with Cp3Ln(III)(THF) (Ln(III) = Sm(III), Tb(III), Dy(III), Yb(III)) or Cp2Lu(III)Cl(THF), a series of middle‐ and heavy‐lanthanocene monosilyl/disilyl ate‐complexes ([(DME)3Li][Cp3Ln(III)SiPh3] and [(DME)3Li][Cp2Lu(III)(SiPh3)2]) were synthesized. The structures of the obtained lanthanocene monosilyl/disilyl ate‐complexes were determined by single crystal X‐ray diffraction. Together with the previously reported [(DME)3Li][Cp3La(III)SiPh3] and [(DME)3Li][Cp3Ce(III)SiPh3], a complex group comprising silyl light‐, middle‐ and heavy‐lanthanocene with identical core coordination pattern are presented. The structure analysis of this group of complexes showed that their key geometric parameters, including the Ln(III)–Si bond lengths and Ln(III)–Si–Cph/Cph–Si–Cph angles, were linearly correlated with the ionic radii of Ln(III) centers. Computational studies based on density functional theory calculations suggested the strongly polarized nature of the Ln(III)–Si bonds in these ate‐complexes. The UV‐Vis spectroscopy measurements of this group of ate‐complexes showed that the characteristic absorptions were hypsochromically shifted for complexes with heavier Ln(III) centers. In addition, as revealed by the time‐dependent density functional theory analysis, the HOMOs, in which the Ln(III)–Si σ‐bonding orbitals were the dominant components, of these complexes acted as main donor orbitals in the major electron transitions. [ABSTRACT FROM AUTHOR]

In order to ensure the authenticity and reliability of the 3rd National Soil Survey data, the standard detection methods need to be repeatedly verified to optimize the method suitable for nationwide promotion. At present, the sensitivity of NY/T 1121.8--2006 methylimine-H spectrophotometric to test available boron in soil is low, and factors such as color rendering temperature and light are easy to interfere with the test results. In view of this, this paper analyzed the key factors such as leaching time, leaching method and color rendering conditions in the process of detection of soil available boron by boiling water bath leaching-methylenimine-H spectrophotometric, and explored the optimal conditions for the detection of the method. The results showed that with the conditions of leaching time 12 min leaching time, capping leaching and 23 °C dark environment in color rendering process, it could better reduce the error in the detection of available boron and obtained more accurate results. At the same time, the detection of soil available boron by inductively coupled plasma spectroscopy (ICP-OES) was verified. The detection limits of spectrophotometric and ICP-OES were 0. 012 mg/kg and 0. 009 mg/kg, respectively, which met the requirements of analysis and testing. The accuracy and precision verification results showed that both methods could be used for the detection of soil available boron, and there was no significant difference in the test results of actual samples. Among them, the spectrophotometric method was suitable for the determination of high content (>0. 5 mg/kg) samples, and the ICP-OES method was suitable for the detection of medium and low content samples. Based on the experience of the 3rd National Soil Survey pilot work, it is suggested that ICP-OES should be the first choice for the effective boron determination, which provides reference for The 3rd National Soil Survey. [ABSTRACT FROM AUTHOR]