建立全自动固相萃取-超高效液相色谱-串联质谱法同时测定大米中4种香精的分析方法.选用甲醇作为提取溶剂,经涡旋振荡和超声提取后,上清液加一级水稀释通过亲水亲脂平衡型固相萃取柱HLB净化,氮吹近干后补液过膜上机,使用Atlantis T3色谱柱分离,以甲醇-0.1％甲酸水为流动相.结果表明,4种香精在质量浓度为1～500 ng·mL-1时线性关系良好,相关系数R均大于0.999,平均加标回收率在80.1％～89.3％,RSD为1.7％～3.9％.该方法具有前处理简便、自动化、检测速度快等优点,适用于大米的批量检测.

建立了基于QuEChERS技术结合固相萃取(Solid-phase extraction,SPE)的气相色谱/四极杆-飞行时间串联质谱法(Gas chromatography-quadrupole time of flight mass spectrometry,GC-Q-TOF/MS)对牛奶中的11种有机磷农药(速灭磷、甲拌磷、二嗪磷、甲基对硫磷、杀螟硫磷、水胺硫磷、溴硫磷、杀扑磷、p,p'-DDE、三唑磷、p,p'-DDT)残留量进行测定.称取牛奶,以10 mL乙腈提取后,盐析离心,氮吹,乙酸乙酯复溶,氮吹浓缩.乙酸乙酯层用石墨化炭黑(Graphitized carbon black,GCB)固相萃取柱净化后,供GC-Q-TOF/MS测定.采用电子轰击离子源(Electron ionization,EI)进行电离,质谱飞行时间模式对目标母离子和子离子进行测定.结果表明,11种有机磷类农药在浓度为10～500μg/L的基质曲线范围内呈良好线性关系.该方法具有操作简便、快速高效、回收率高、灵敏度高、重复性好等优点,可用于测定牛奶的11种有机磷类农药残留量.

目的 建立分散固相萃取结合液相色谱-串联质谱法检测淡水鱼中9种磺胺类和3种喹诺酮类药物的分析方法.方法 淡水鱼肉样品用1％甲酸乙腈提取,提取液经盐析后取乙腈层,用分散固相萃取净化包净化,目标物用C18色谱柱(2.1 mm×50 mm,1.7μm)分离,采用0.1％甲酸水-乙腈作为流动相进行梯度洗脱,利用电喷雾离子源正离子多反应监测模式进行测定,内标法定量.结果 9种磺胺和3种喹诺酮类药物在1～50 ng/mL浓度范围内线性关系良好,相关系数均大于0.999.检出限和定量限分别为0.1～1.0μg/kg、0.5～5.0μg/kg,在3个不同浓度添加水平下的平均回收率为84.4％～114.6％,相对标准偏差为1.0％～7.8％(n=6).结论 该方法操作简单、快速、灵敏度高,适用于淡水鱼中常见9种磺胺和3种喹诺酮类兽药残留测定.

目的 建立超高效液相色谱-串联质谱法同时测定糕点中6种常用合成甜味剂的分析方法 .方法 选用超纯水作为提取溶剂,涡旋和超声提取后,低温离心,取部分上清液加入正己烷除脂,Waters Atlantis?T3色谱柱、甲醇-5 mmol/L甲酸铵(含0.1％甲酸)作为流动相、亲水亲脂平衡型固相萃取柱HLB(hydrophile-lipophile balance)净化.结果 6种甜味剂在质量浓度为10～200 ng/mL的曲线范围内呈良好线性关系,相关系数r均大于0.999,平均加标回收率在85.0％～98.2％之间,相对平均偏差(relative standard deviation,RSD)为1.3％～6.7％.结论 该方法 具有前处理简单、灵敏度高、检测速度快等优点,适合糖精钠、甜蜜素、三氯蔗糖、阿斯巴甜、阿力甜、纽甜的检测,但不适用于安赛蜜的检测.

对食用油中苯并(a)芘分子印迹固相萃取法测定过程中的试剂及耗材进行污染溯源分析.结果 表明:分析纯试剂及一次性注射器中的橡胶是污染的主要来源,二氯甲烷(分析纯)、正己烷(分析纯)、橡胶的苯并(a)芘平均峰面积分别为0.261、0.710、2.550 mV·min,分别是国标方法检出限的0.9、2.4、8.7倍,对检测结果准确性带来严重影响.因此,提出使用高速离心替代过滤膜方式除杂以除去样液中微小颗粒物,该方案既能避免注射器带来的污染,又能保证高效液相色谱系统稳定运行,提高检验结果准确性.

目的:通过高效液相色谱-串联质谱法(HPLC-MS/MS)建立一种快速测定市售凉茶中非法添加化学药的分析方法.方法:样品经甲醇-乙腈(1∶1)及流动相逐级稀释后,采用反向色谱C18柱(2mm×100mm,3μm)进行非法添加化学药物的分离.再通过质谱的多反应监测(MRM)模式进行正离子扫描,采用标准曲线外标法定量分析.结果:20种化学药物在其各自的质量浓度范围内,均表现出良好的线性关系,相关系数均大于0.9962,检出限为1～30 mg/mL,定量限为5～50 mg /mL.在3个不同添加水平下的平均回收率为88.13％～114.60％,RSD为1.18％～9.00％,并运用该方法对市售200种凉茶进行了检测.结论:该方法操作简便快捷,准确度和灵敏度高,可用于市售凉荼中非法添加20种化学药物的定量定性测定.

A flexible nanocomposite of cobalt hexacyanoferrate (CoHCF) and commercial carbon cloth (CC) was prepared by facile electrodeposition of CoHCF on a flexible CC surface.

A simple and industrially scalable approach to prepare porous carbon (PC) with high surface areas as well as abundant nitrogen element as anode supporting materials for lithium-ion batteries (LIBs) was developed. Herein, the N-doped PC was prepared by carbonizing crawfish shell, which is a kind of food waste with abundant marine chitin as well as a naturally porous structure. The porous structure can be kept to form the N-doped PC in the pyrolysis process. The N-doped PC-Co3O4 nanocomposites were synthesized by loading Co3O4 on the N-doped PC as anode materials for LIBs. The resulting N-doped PC-Co3O4 nanocomposites release an initial discharge of 1223 mA h g(-1) at a current density of 100 mA g(-1) and still maintain a high reversible capacity of 1060 mA h g(-1) after 100 cycles, which is higher than that of individual N-doped PC or Co3O4. Particularly, the N-doped PC-Co3O4 nanocomposites can be prepared in a large yield with a low cost because the N-doped PC is derived from abundant natural waste resources, which makes it a promising anode material for LIBs.

A nonenzymatic glucose sensor was developed by using the reduced graphene oxide (rGO) and Co3O4 nanocomposites as the sensing material. The hybrid was prepared in a one-pot reaction process by hydrothermal method. The effects of time and temperature in the hydrothermal treatment on the Co3O4-rGO nanocomposites were explored. Co3O4 with size of 5-10 nm was successfully synthesized on the surface of rGO at 150 °C for 3 h. These Co3O4-rGO nanocomposites exhibited superior electrochemical activity towards oxidation of glucose. The catalytic current density is linear to the glucose concentration in the range of 0.0005 mM to 1.277 mM with a sensitivity of 1366 μA cm-2mM- 1 and a detection limit of 0.18 μM. The high sensitivity, low detection limit and good selectivity indicate that the newly developed sensor based on the Co3O4-rGO nanocomposites is a promising sensor for practical application.

A novel nonenzymatic glucose sensor was developed by electrodepositing dendritic copper-cobalt nanostructures (Cu-Co NSs) on glassy carbon electrode (GCE) which was modified by reduced grapheme oxide-chitosan (RGO-CHIT) nanocomposites. The electrochemical behaviors and electrocatalytic performances of the sensor towards oxidation of glucose were evaluated by cyclic voltammograms, chronoamperometry and amperometric method. Compared to sensors based on monometal Cu or Co NSs, the sensor based on bimetal Cu-Co NSs exhibits good electrocatalytic activity towards oxidation of glucose. The effects of electrodeposition time and the ratio of Cu2+ and Co2+ in an electrodeposition solution on the electrocatalytic performance of the Cu-Co NSs sensor were explored in detail. The best catalytic activity towards oxidation of glucose can be achieved under an optimized condition: electrodepositing time of 2600 s and the Cu2+/Co2+ molar ratio of 2:1. The catalytic current density is linear to the glucose concentration in the range of 0.015-6.95 mM (r = 0.9947) with a sensitivity of 1921 mu A cm(-2) mM(-1), and a detection limit of 10 mu M. The good catalytic activity, high sensitivity and good stability indicate that the newly developed sensor based on the dendritic Cu-Co NSs/RGO-CHIT/GCE is a promising sensor for application in real samples. (C) 2014 Elsevier B.V. All rights reserved.

Three kinds of hierarchical porous carbon were successfully fabricated in the absence of any templates by carbonizing kenaf-nickel ion stems complex and subsequently etching nickel-doped carbon composites with hydrochloric acid. The pore size was easily controllable by changing the concentration of nickel ion solution. The unique porous structure of the products resulted in high specific surface area of 1480 m2 g−1. The creation of mesopores and macropores and construction of hierarchical pores not only improve the accessibility of the active centers, but also provide highways for reaction species, which result in an enhanced performance in a supercapacitor. The resulting porous carbon electrode materials showed improved specific capacitance of 327 F g−1 at a scan rate of 2 mV s−1 in 1.0 M H2SO4. Furthermore, the electrode showed a super-long cycle life with 95.6% retention of the initial specific capacitance after 5000 cycles at a current of 1 A g−1. This research demonstrated that the hierarchical porous carbon derived from kenaf stems was a good potential material in energy conversion and storage devices.

Three-dimensional (3D) kenaf stem-derived porous carbon (PC) is considered to be a promising low-cost supporting material for application in energy storage devices. In this report, a simple and industry-scalable approach to prepare the hybrid (MnO2/3D-PC) of nanostructured MnO2 and 3D-PC has been developed. Such porous structures of the 3D-PC not only provided a conductive network to enhance the charge transport and mass transfer in the electrochemical process but also achieved a large MnO2 mass loading capacity of 11.5 mg/cm2, which resulted in a high areal capacitance of 2.77 F/cm2 at a scan rate of 1 mV/s. A specific capacitance of 416 F/g was obtained based on the mass loading of 2.52 mg/cm2 at scan rate of 1 mV/s. Furthermore, the symmetrical supercapacitor based on the MnO2/3D-PC exhibited outstanding cycle performance with only 14% degradation after 1000 cycles under a large specific current density of 16 mA/cm2. This research demonstrated that the 3D-PC was a good potential supporting material in energy conversion and storage devices.