中空纤维三相液相微萃取-高效液相色谱法测定水中的4种酚类化合物

建立了中空纤维液-液-液三相微萃取-高效液相色谱法测定水中4种酚类化合物的方法.实验系统地优化了影响萃取效率的因素(包括有机溶剂种类、接收相浓度、分散相pH值、加盐量、转速及萃取时间).得到的最佳萃取条件为:萃取剂为正辛醇,接收相NaOH溶液的浓度为0.09 mol/L,分散相的pH为4,萃取时间为40 min,搅拌速...     

超高效液相色谱-电喷雾三重四极杆质谱法测定中药中马兜铃酸A和B的含量

利用超高效液相色谱-电喷雾三重四极杆质谱仪建立了中药中马兜铃酸A和B的定性定量分析方法。选取柴胡、生甘草、桔梗、龙胆泻肝丸、消胖丸、减肥茶等14种代表性样品,用甲醇-水(70:30, v/v)溶液加热回流提取,经Oasis MAX固相萃取柱富集净化后,在Eclipse RP HD C18反相柱(150 mm×2.1 mm, 1.8 μm)上进行分离;流动相为5 mmol/L乙酸铵水溶液(pH 7.5)-乙腈(75:25, v/v)。采用电喷雾离子源正离子模式(ESI+)和多反应监测模式(MRM)进行质谱分析。马兜铃酸A和B的线性范围分别为0.5～200 μg/L和1～200 μg/L,相关系数(r2)均大于0.995;检出限(LODs)分别为5 μg/kg和7.5 μg/kg;定量限(LOQs)分别为12.5 μg/kg和25 μg/kg。在100 μg/kg和500 μg/kg添加水平下,马兜铃酸A和B的回收率(n=6)范围分别为60.3%～96.4%和61.3%～94.7%,相对标准偏差均不大于10.2%。该方法灵敏度高,重复性好,操作简便,适用于中药材、饮片及中成药中马兜铃酸A和B的痕量检测。     

基质固相分散萃取-高效液相色谱-串联质谱法分析拟南芥中的赤霉素

建立了基质固相分散萃取-高效液相色谱-串联质谱法(MSPD-HPLC-MS/MS)同时测定拟南芥中3种赤霉素GA1, GA3和GA4的分析方法。将拟南芥样品与C18填料混合研磨制成MSPD柱,并采用80%冷甲醇洗脱。采用反相C18色谱柱进行分离,以0.05%甲酸水溶液和乙腈为流动相进行梯度洗脱,采用电喷雾离子源负离子模式(ESI~)电离,多反应监测模式检测。对样品前处理条件、色谱分离条件和质谱检测条件进行了优化,结果表明,在最优条件下,3种赤霉素在10～300 ng/g范围内均呈良好线性关系,相关系数(r2)均大于0.98,检出限在1.1～4.1 ng/g之间。在10～50 ng/g添加水平下,平均回收率范围为54.7%～102.6%,相对标准偏差（RSD,n=3)为3.2%～12.8%。该方法操作简单、灵敏度高、选择性好、回收率高,适合拟南芥中GA1、GA3、GA4含量的测定。     

柱前衍生-反相高效液相色谱法测定不同方法煮制的猪肉及其汤汁中的游离氨基酸

建立了反相高效液相色谱(RP-HPLC)分离检测用不同方法煮制的猪肉及其汤汁中17种游离氨基酸的方法.样品经6-氨基喹啉基-N-羟基琥珀酰亚氨基甲酸酯(AQC)柱前衍生后,采用Nova- PakTMC18色谱柱分离,以AccQ·Tag Eluent A稀释液、乙腈和超纯水为流动相,梯度洗脱,检测波长为248 nm,在4...     

Al掺杂对正极材料LiNi0.33-xMn0.33Co0.33AlxO2结构和电化学性能的影响

以柠檬酸为螯合剂利用快速湿化学法合成了具有α-NaFeO₂型层状结构的LiNi_0.33-xMn_0.33Co_0.33Al_xO₂(x=0.00,0.01,0.02, 0.04)正极材料,并通过X-射线衍射、充放电测试、循环伏安和交流阻抗对材料的结构和电化学性能进行了系统研究。XRD结果表明此方法合成的材料具有很好的层状结构且阳离子的混排度随着Al³⁺含量的增加而下降。电化学测试表明,LiNi_0.31Mn_0.33Co_0.33Al_0.02O₂具有很好的电化学性能和和循环性能,1C放电倍率下首次放电比容量达到176.9 mAh·g^-1,且Al³⁺的掺杂能有效提高电荷在电极界面间转移并抑制了在高压循环过程中电荷转移阻抗的增加。     

Determination of Ciprofloxacin in Human Plasma and Urine by Precolumn Derivatization High Performance Liquid Chromatography with Fluorescence Detection

A sensitive, simple and selective high‐performance liquid chromatographic (HPLC) method was developed for the determination of ciprofloxacin in biological fluids. The method is based on the reaction between the drug and 4‐chloro‐7‐nitrobenzofurazan (NBD‐Cl) in borate buffer of pH 9.0 to yield a highly fluorescent derivative that is measured at 535 nm after excitation at 464 nm. The calibration curves were linear over the concentration ranges of 25–3000 and 50–3000 ng·mL^?1 for plasma and urine, respectively. The mean recovery of ciprofloxacin from plasma and urine was 98.37% and 98.40%, respectively. The method was found to be sensitive, precise, accurate, and reproducible. All of the validation parameters were within the acceptance range.     

High performance liquid chromatography with immobilized Ru(bpy)_3~(2+)-KMnO_4 chemiluminescence detection and its application in metabolism of repaglinide in pig liver microsomes

A novel high performance liquid chromatography-chemiluminescence（HPLC-CL） method for investigation of in vitro metabolism of repaglinide in pig liver microsomes with microdialysis sampling technique was developed.The chromatographic separation was performed on a Hypersil BDS-C18 column with an isocratic mobile phase consisting of methanol and 0.01 mol/L KH₂PO₄（pH 3.0）（volume ratio 75:25） at a flow rate of 1.0 mL/min.The detection was based on the chemiluminescence reaction of repaglinide with acidic potassium permanganate（KMnO₄） and tris（2,2’-bipyridyl）ruthenium（Ⅲ）(Ru（bpy）₃³⁺),which was immobilized on the cationic ion-exchange resin for obtaining high sensitivity and reducing consumption of expensive reagent.     

Synthesis,characterization and catalytic performance of nanosized iron-cobalt catalysts for light olefins production

Nanosized Fe-Co catalysts were prepared by co-precipitation method and studied for the conversion of synthesis gas to light olefins.In particular,the effects of a range of preparation variables such as Co/Fe molar ratios of the precipitation solution,pH value of precipitate,temperature of precipitation,promoters and loading of optimum promoter on the structure and catalytic performance are investigated.The optimal nano catalyst for light olefins (C2-C4) production was obtained over the catalyst with Co/Fe molar ratio of 3/1 which promoted with 2 wt% K.The results show that the best operational conditions were GHSV=2200 h-1 (H2/CO=2/1) at 260℃ under atmospheric pressure.Characterization of catalysts were carried out using X-ray diffraction (XRD),thermal gravimetric analysis (TGA),differential scanning calorimetry (DSC),scanning electron microscopy (SEM),transmission electron microscopy (TEM) and N2 physisorption measurements such as Brunauer-Emmett-Teller (BET) and Barrett-Joyner-Halenda (BJH) methods.     

Gas sensing performance of polyaniline/ZnO organic-inorganic hybrids for detecting VOCs at low temperature

Polyaniline (PANI) was prepared by the chemical oxidative polymerization of aniline, and ZnO, with the mean particle size of 28 nm, was synthesized by a non-aqueous solvent method. The organic-inorganic PANI/ZnO hybrids with different mass fractions of PANI were obtained by mechanically mixing the prepared PANI and ZnO. The gas sensing properties of PANI/ZnO hybrids to different volatile organic compounds (VOCs) including methanol, ethanol and acetone were investigated at a low operating temperature of 90°C. Compared with the pure PANI and ZnO, the PANI/ZnO hybrids presented much higher response to VOCs. Meanwhile, the PANI/ZnO hybrid exhibited a good reversibility and a short response-recovery time, implying its potential application for gas sensors. The sensing mechanism was suggested to be related to the existence of p-n heterojunctions in the PANI/ZnO hybrids.     

1,3,5,7-四甲基-8-丙酰肼-二氟化硼-二吡咯甲烷柱前衍生高效液相色谱测定白酒中的脂肪醛

以合成的1,3,5,7-四甲基-8-丙酰肼-二氟化硼-二吡咯甲烷(BODIPY-丙酰肼)作为柱前荧光衍生试剂,用于高效液相色谱分离荧光法检测甲醛、乙醛、丙醛、丁醛、戊醛、己醛、庚醛、辛醛、壬醛、癸醛、十一醛、十二醛等12种脂肪醛.通过对衍生条件和分离条件进行优化,建立了测定脂肪醛的HPLC/FD新方法.衍生反应以H3P...