Synergistic promotion of nitrogen vacancies and single atomic dopants on Pt/C3N4 for photocatalytic hydrogen evolution.

C3N4 is widely applied in the synthesis of single-atom catalysts. However, understanding on the active site and the reaction mechanism is not fully in consensus. Especially, bare studies have considered the coordination environment of the single-atomic dopant and the effect of nitrogen vacancy on C3N4. In this study, we found that the presence of nitrogen vacancies promotes the activation of water and reduces the activation energy barrier for hydrogen generation. The results show that a synergistic effect between single-atom Pt and nitrogen vacancies enables the catalyst to achieve a superior hydrogen production rate of 3,890 µmol/g/h, which is 16.8 times higher than that of pristine C3N4. Moreover, the catalyst is also applicable for photocatalytic hydrogen production from seawater without significantly decreased hydrogen production rate. This study paves the way for the rational design and optimization of next-generation photocatalysts for sustainable energy applications, particularly in solar-driven hydrogen production.

[Analysis of fatty acids in leaves of Loropetalum chinense and L. chinense var. rubrum by GC-MS].

OBJECTIVE: To extract and analyze fatty acids in leaves of L. chinense Oliver and L. chinense var. rubrum Yieh. METHODS: The fatty acids were extracted with Soxhlet extractor and identified by the GC-MS method. RESULTS: 31, 26 and 30 components were identified from the leaves of L. chinense, the green leaves and red leaves of L. chinense var. rubrum. There were 19, 14 and 16 kinds of fatty acid in the respective leaves, which accounted for 99.09%, 95.31% and 98.83% of the total extraction, respectively. The main components in the extraction were oleic acid (30.77%, 47.01%, 75.28%), linoleic acid (48.49%, 29.26%, 0%), hexadecanoic acid (9.83%, 8.87%, 11.71%), octadecanoic acid (3.86%, 3.18%, 4.88%) and docosanoic acid (2.37%, 2.17%, 2.58%). CONCLUSION: Many kinds of unsaturated fatty acids exist in leaves of L. chinense Oliver and L. chinense var. rubrum Yieh. The leaves of these two plants can be used as the traditional Chinese medicine.

Simultaneous determination of organophosphorus pesticides in Chinese herbal medicines by microwave-assisted extraction coupled with dispersive-solid phase extraction and gas chromatography.

A reliable, rapid and nontoxic analytical method was proposed for the simultaneous determination of 16 organophosphorus pesticides in Chinese herbal medicines. The pesticides were extracted by ethanol and the experimental variables, such as temperature, extraction time and volume of ethanol, were optimized through orthogonal array experimental design. Cleanup of extracts was performed with dispersive-solid phase extraction using primary secondary amine as the sorbent. The determination of pesticides in the final extracts was carried out by gas chromatography-flame photometric detection. Under optimized conditions the obtained recoveries, except for isocarbophos, were in the range 73.8-123%, with relative standard deviations equal to or lower than 15.2% and limits of detection ranging from 0.001 to 0.009 mg/kg.

[Simultaneous analysis of multi-elements in vegetation oils by inductively coupled plasma atomic emission spectrometry].

A simple, accurate and sensitive method for the simultaneous analysis of eleven trace elements (Fe, Cu, Co, Ni, Pb, Al, Zn, Cd, Cr, Mn and Mg) in vegetation oils by ICP-AES has been developed. The oils were digested by H2 SO4 ashing method. The detection limits (MDLs) of the method for the eleven elements were in the range of 0.1-3.6 microg x kg(-1). The average recoveries at three concentrations of 0.1, 0.5 mg x kg(-1) were between 70.4% and 113% with the RSD in the range of 1.01%-10.6%. The proposed method has been applied to the determination of the above elements in soy, peanut, sesame, rape, tea and blended oils with satisfactory results.

Simultaneous determination of five synthetic antioxidants in edible vegetable oil by GC-MS.

A simple, quick and nontoxic analytical method for the simultaneous determination of five synthetic antioxidants [t-butyl-4-hydroxyanisole (BHA), 2,6-di-t-butyl-hydroxytoluene (BHT), t-butyl hydroquinone (TBHQ), ethoxyquin (EQ) and 2,6-di-tert-butyl-4-hydroxymethyl-phenol (Ionox 100)] in edible vegetable oil has been developed. The analytes were extracted by ethanol, then separated and detected by GC-MS. Extraction conditions such as volume of ethanol required, mixing time and number of extractions were investigated and optimized by an orthogonal array experimental design. The five compounds behaved linearly in the 0.100 approximately 20.0 mg/L concentration range, and the limits of detection (LOD) for BHA, BHT, TBHQ, EQ and Ionox-100 were 1.00, 0.92, 11.5, 0.83 and 1.39 microg/L, respectively. The recoveries at the tested concentrations of 1.00, 20.0 and 100 mg/kg were 75.6 approximately 123%, with coefficients of variation<10.0%. The proposed procedure was successfully applied to the simultaneous analysis of the five antioxidants in soybean oil, tea oil, edible blended oil, rap oil, peanut oil, peanut blended oil and sesame oil samples purchased from local supermarkets.