超高效液相色谱–电喷雾串联质谱测定蔬菜水果中27种常见农药残留

建立了蔬菜水果中27种常见农药残留超高效液相色谱–电喷雾串联质谱(UPLC–ESI–MS/MS)测定方法。样品用乙腈均质提取,加入无水硫酸镁和氯化钠盐析分层,经CARBON/NH2固相萃取柱净化,乙腈–甲苯(3∶1,v/v)洗脱,旋转蒸发浓缩,用乙腈–0.1%甲酸(1∶1,v/v)溶解,以电喷雾串联质谱在多反应监测模式(MRM)下进行测定。分析方法结果表明,多数组分在5～100μg/L范围内线性良好(r2=0.991～0.999),在10～50μg/kg范围内,27种农药的回收率为65.81%～124.7%,相对标准偏差为3.6%～19.2%。方法的检出限和定量限范围分别为0.05～5μg/L和0.2～18μg/L。该方法操作简便、快捷、灵敏,灵敏度、准确度和精密度均能满足农药多残留检测的技术要求,适用于蔬菜水果中常见农药残留的检测。     

Rhodamine-based fluorescent sensor for mercury in buffer solution and living cells

A novel fluorescent sensor based on thiooxorhodamine B has been prepared to detect Hg²⁺ in aqueous buffer solution. It demonstrates high selectivity for sensing Hg²⁺ with about 383-fold enhancement in fluorescence emission intensity and micromolar sensitivity (K_d = 7.5 × 10⁻⁶ mol L⁻¹) in comparison with alkali and alkaline earth metal ions (K⁺, Na⁺, Mg²⁺, Ca²⁺) and other transition metal ions (Mn²⁺, Ni²⁺, Co²⁺, Cu²⁺, Zn²⁺, Cd²⁺, Ag⁺, Pb²⁺, Cr³⁺, Fe³⁺). Meanwhile the distinct color changes and rapid switch-on fluorescence also provide ‘naked eyes’ detection for Hg²⁺ over a broad pH range. Moreover, such sensor is cell-permeable and can visualize the changes of intracellular mercury ions in living cells using fluorescence microscopy.     

高效液相色谱法测定化妆品中的双酚A

采用Themo BDS HYPERSIL C18色谱柱(100 mm×4.6 mm×2.4μm),以乙腈-水(35∶65,体积比)为流动相,流速1.0mL/min,检测波长228 nm,柱温40℃,进样量5μL,在前述条件下建立了测定化妆品中双酚A的高效液相色谱方法。结果发现,在0.05140~2.056μg/mL范围内,双酚A峰面积与其质量浓度呈良好线性关系(r=0.9999);低浓度水平下的平均加标回收率为98.9%~100.8%(相对标准偏差2%),高浓度水平下的平均加标回收率为100.6%~102.7%(相对标准偏差3%);检出限为0.015μg/mL,检出质量比为0.3μg/g。所建立的方法操作简便快捷,结果准确可靠,可用于化妆品中双酚A的测定。     

辽宁省生食水产品致病菌污染及安全性评价

目的了解辽宁省生食水产品的安全状况,及早发现食品安全隐患,为食品安全监管提供信息。方法在2013年12月~2014年1月于辽宁省的盘锦市、营口市和大连市三个港口城市,从不同规模的大中小型餐饮企业中共收集到生食水产品样品150批,采用国标方法,对生食水产品中沙门氏菌、志贺氏菌、金黄色葡萄球菌、单核增生李斯特氏菌、菌落总数、大肠菌群和寄生虫囊蚴进行检查。结果 150批样品中共检出副溶血性弧菌9批,单增李斯特氏菌1批,金黄色葡萄球菌(定量)10批,菌落总数(限定性包装)1批,总合格率为93.3%,结论辽宁省生食水产品中存在致病菌的污染,相应部门应加强进行食品卫生监管。     

Assessing and optimizing the economic and environmental impacts of cogeneration/district energy systems using an energy equilibrium model

Energy equilibrium models can be valuable aids in energy planning and decision-making. In such models, supply is represented by a cost-minimizing linear submodel and demand by a smooth vector-valued function of prices. In this paper, we use the energy equilibrium model to study conventional systems and cogeneration-based district energy (DE) systems for providing heating, cooling and electrical services, not only to assess the potential economic and environmental benefits of cogeneration-based DE systems, but also to develop optimal configurations while accounting for such factors as economics and environmental impact. The energy equilibrium model is formulated and solved with software called WATEMS, which uses sequential non-linear programming to calculate the intertemporal equilibrium of energy supplies and demands. The methods of analysis and evaluation for the economic and environmental impacts are carefully explored. An illustrative energy equilibrium model of conventional and cogeneration-based DE systems is developed within WATEMS to compare quantitatively the economic and environmental impacts of those systems for various scenarios.     

藜芦胺类似物的合成及体外抗肿瘤活性研究

以黎芦属植物中含量丰富的甾体生物碱藜芦胺(Ⅰ)为原料,经结构修饰,共得到5种藜芦胺类似物Ⅱ~Ⅵ。经核磁共振谱、质谱确定化合物结构。以已知的Hedgehog信号通路抑制剂环巴胺为阳性对照,采用人胃癌细胞SGC-7901和人胰腺癌细胞Aspc-1进行体外抑制肿瘤细胞增殖活性筛选。结果表明,化合物Ⅳ、Ⅴ、Ⅵ的抑制肿瘤细胞增殖活性优于环巴胺。初步构效关系研究表明,在藜芦胺的哌啶环上引入烟酸及对硝基苯甲酰基团,可显著提高其抗肿瘤活性。     

Optimizing an electronic nose for analysis of volatiles from printing inks on assorted plastic films

Volatiles from inks present in food packaging films could pose a quality problem in food products. The food industry is interested in determining a single set of optimum values for the system parameters to maximize detection levels on assorted plastic packaging films. Volatiles from ink used on nine plastic food-packaging films were analyzed using an electronic nose with six resonating quartz sensors. A response surface analysis was used to determine if the system parameters (sample temperature, equilibration time, sensor temperature and pressurization time) significantly affected the detection levels of volatile compounds. Sample temperature, equilibration time and sensor temperature were significant (α=0.05) for each of the sensors and the optimum settings for these parameters to maximize detection levels were 80 °C, 20 min, and 40 °C, respectively. The results of this study indicate potential for this electronic nose to be used as a discriminatory tool in quality control for packaging films.     

BAX Q7系统快速检测食品中金黄色葡萄球菌效果验证

目的验证BAX Q7全自动病原菌检测系统快速检测食品中金黄色葡萄球菌的效果,以强化食品检验机构对金黄色葡萄球菌的快速检测能力和推进快速检测技术的有效应用。方法通过BAX Q7全自动病原菌检测系统和GB 4789.10-2010《食品安全国家标准-食品微生物学检验-金黄色葡萄球菌检验》2种方法同步检测定量污染的样品,比较2种方法的检测结果的符合率和灵敏度。结果采用2种方法对24份样本检测的结果基本一致,金黄色葡萄球菌检测符合率均为100%,但BAX Q7实时荧光定量PCR法相比国家标准方法检出时间缩短4～6 h,具有更高的灵敏度,而且操作简便快速。结论 BAX Q7实时荧光定量PCR系统能在食品安全突发事件中快速锁定病原菌,为溯源调查指明方向,应用于食品中金黄色葡萄球菌的快速检测合理可行。