Increase in functional groups for POSS by introducing branched phenylglycidylether

In the selected experimental conditions, firstly, the branched products with functional groups, N-(2-hydroxylpropylphenylether) (3-aminopropyl) triethoxysilane (APES-PGE,containing one hydroxyl group) and N-[di(2-hydroxylpropylphenylether)] (3-aminopropyl) triethoxysilane (APES-PGE2,containing two hydroxyl groups), were synthesized by reacting 1 mole of (3-aminopropyl)triethoxysilane (APES) with 2 mole of phenylglycidylether (PGE).Then the hydrolytic condensation of APES-PGE and APES-PGE2 was performed by dissolving 1g of the corresponding silane in 1.5ml tetrahydrofuran (THF), adding water and eventually a catalyst(molar ratios:[H2O]/Si=3,[NaOH]/Si=0.05),and heating at 50℃ for 24h, allowing continuous evaporation of volatiles. The final products with branches containing hydroxyl groups were polyhedral oligomeric silsesquioxanes (POSS).The products from two reactions were characterized by standard spectroscopic techniques,gel partition chromatography (GPC), Fourier-transformed infrared spectroscopy (FTIR) and matrix-assisted ultraviolet laser desorption/ionization time-of-flight mass spectrometry (UV-MALDI-TOF MS). Additionally, a narrow mass distribution of muhifunctionalized POSS was shown by UV-MALDI-TOF MS and assignments of the MS peaks.     

固相萃取-气相色谱/三重四极杆质谱法同时分析蔬菜中的50种农药残留量

采用固相萃取-气相色谱/三重四极杆质谱(GC/MS/MS)法测定蔬菜中50种农药残留量.样品经乙腈提取、固相萃取小柱净化,用气相色谱-质谱/质谱法测定,外标法定量.50种农药在10～500 μg/L范围内线性关系良好,加标回收率在77.30％～116.91％之间,相对标准偏差均小于15％,定性检出限和定量检出限分别为0.1～5.0 μg/kg和0.3～16.7 μg/kg,可以满足欧盟、日本等国对蔬菜中农药残留量的限定要求.该方法具有简单快速,准确度和精密度高,适用于各种蔬菜中农药多残留量的检测和确证.