Determination of Melamine in Candies by Triple Quadurupole Liquid Chromatography-Tandem Mass Spectrometry

本文建立了高效液相色谱串联质谱检测糖果中三聚氰胺的方法。以糖果为基质,采用三氯乙酸水溶液超声提取目标分析物,提取液经过离心、净化处理后,用强阳离子交换与反相C18混合填料色谱柱分离,乙腈和l0MMOl/l乙酸铵作为流动相(1:1),用串联质谱在多级反应监测模式下定量检测。lC-MS/MS定量限为0.01Mg/kg,线性范围为10~500μg/l,相关系数r2>0.99,平均回收率为66.8%~98.7%,相对标准偏差为1.9%~7.6%(n=6)。A method to analyze melamine residue in candies was established by using triple quadurupole liquid chromatography-tandem mass spectrometry(LC-MS/MS).Trichloroacetic acid was used to extract the target analyte.The CAPCELL PAK CR column was used for separation and the multiple reaction monitoring(MRM) positive ion mode was used for the determination.The limit of detection was 0.01mg/kg for LC-MS/MS.The coefficient of linear calibration curve was over 0.99 within the melamine concentration range of 10～500μg/L.The average recoveries of melamine by this method were 66.8%～98.7%,and the RSDs ranged from 1.9%～7.6%(n=6

厌氧条件在不同Fe( II) 浓度测定方法中必要性的比较研究

厌氧是目前Fe(II)测定方法中常选择的处理方式,但是不可避免会给实验操作带来不便。为了方便、准确地测定铁还原体系中的Fe(II)浓度,对比研究了厌氧条件对草酸—草酸铵和盐酸两种典型浸提方法测定Fe(II)浓度的影响。结果表明:对于草酸—草酸铵浸提法,厌氧条件是必须的,以防止提取液中的Fe(II)被氧化,而且样品浸提1 h 便可用于Fe(II)的测定;然而对于盐酸浸提法,厌氧条件却并不是必须的,对Fe(II)浓度测定基本不产生影响。因此,为简化实验操作或在没有厌氧条件的情况,可利用盐酸浸提法测定铁还原体系中Fe(II)浓度

A Study on the mechanisms of eutrophication of a shallow upstream lake in the Jiulong River Catchment

基于对九龙江上游龙潭湖富营养化水体和沉积物现状的监测结果,通过与国内富营养化深水湖库和流域下游大型富营养化浅水湖泊进行对比,深入探讨了流域上游浅水湖泊富营养化发生的原因及主导机制.流域上游浅水湖泊具有外源污染物输入较少的特点,较下游大型浅水湖泊更易受温度等气候条件和沉积物氧化还原状态的影响,以及外源输入总磷控制具有较强的滞后效应,因此对流域上游浅水湖泊富营养化的控制必须重视内源营养盐释放,特别是结合态磷的内源释放问题.Based on site monitoring chemical data of lake water and sediments during an algal bloom in the Longtan Lake,causes and mechanisms of eutrophication in shallow upstream lakes were discussed by comparing the Longtan Lake in upstream of the Jiulong River with deep eutrophic lakes and large shallow downstream eutrophic lakes in China.The shallow upstream lake is characterized as relatively simple nutrient inputs and high susceptivity to climatic variability(such as temperature),redox conditions,and strong lag effects of the external total phosphorus inputs.Therefore,attention must be paid to the sediments nutrient releases,especially,the bound phosphorus of sediments when remediating eutrophication in shallow upstream lakes.国家自然科学基金资助项目(41175130);教育部新世纪优秀人才支持计

Promoting electrocatalytic CO2 reduction to formate via sulfur-boosting water activation on indium surfaces

一般认为，H2O还原析氢反应是CO2还原反应的竞争反应，若促进H2O活化将降低CO2还原反应的法拉第效率。因此，基于该认识设计出的高CO2还原法拉第效率的催化剂常常活性低。王野课题组打破这种认识，提出H2O分子活化在CO2还原中起着重要的作用，成功合成出硫修饰In催化剂来活化H2O分子而促进CO2还原制甲酸的新方法，该催化剂在非常宽的电流密度范围内（25~100 mA cm-2），均可以维持85%以上的甲酸法拉第效率。将硫拓展至硒和碲等其它硫族元素以及将金属铟拓展至铋和锡等其它p区金属，均实现很好的促进效果，表明通过促进水的活化来提高CO2电催化还原性能具有普适性。该工作为理性设计高效的CO2还原电催化剂提供了新策略。 该研究工作实验部分主要由王野、张庆红教授指导，能源材料化学协同创新中心iChEM2016级博士生马文超、固体表面物理化学国家重点实验室高级工程师谢顺吉（共同第一作者）完成；理论计算部分由吴德印教授指导，2015级博士生张霞光（共同第一作者）完成。醇醚酯国家工程实验室高级工程师康金灿参与了部分实验表征。上海光源姜政教授和孙凡飞博士为同步辐射表征提供了支持。【Abstract】Electrocatalytic reduction of CO2 to fuels and chemicals is one of the most attractive routes for CO2 utilization. Current catalysts suffer from low faradaic efficiency of a CO2-reduction product at high current density (or reaction rate). Here, we report that a sulfur-doped indium catalyst exhibits high faradaic efficiency of formate (>85%) in a broad range of current density (25–100 mA cm−2) for electrocatalytic CO2 reduction in aqueous media. The formation rate of formate reaches 1449 μmol h−1 cm−2 with 93% faradaic efficiency, the highest value reported to date. Our studies suggest that sulfur accelerates CO2 reduction by a unique mechanism. Sulfur enhances the activation of water, forming hydrogen species that can readily react with CO2 to produce formate. The promoting effect of chalcogen modifiers can be extended to other metal catalysts. This work offers a simple and useful strategy for designing both active and selective electrocatalysts for CO2This work was supported by the National Key Research and Development Program of the Ministry of Science and Technology of China (No. 2017YFB0602201), the National Natural Science Foundation of China (Nos. 21690082, 91545203, and 21503176). We thank staff at the BL14W1 beamline of the Shanghai Synchrotron Radiation Facilities (SSRF) for assistance with the EXAFS measurements. 研究工作得到科技部重点研发计划（批准号：2017YFB0602201）和国家自然科学基金（批准号：21690082、91545203、21503176）等项目的资助

明代福建科学技术发展浅探

福建地处我国东南，背山面海，风物独特．自唐宋以来，福建科技、经济 快速发展，至明代又得到了进一步提高．明初实施了恢复社会经济的政策，福 建工商业得到很大发展，对外贸易也相当活跃，加上社会秩序长时期的安定。 为科学技术的发展提供了必要的客观条件． 明代福建科学技术取得了一系列重大成就．商业数学，尤其是珠算得到普 遍推广应用．天文知识广泛用于航海，出现了航海天文星图。地学尤其是地理 学出观了许多学者和著作，城外地理著作《东西洋考》的出现以及徐霞客在福 建的地学考察，为福建地学宝增添了重要的内容．明代福建医家对《伤寒论》 的研究和古医书的整理刊刻，成就令人瞩目． 在作物生产及其加工...学位：哲学硕士院系专业：人文学院哲学系_科学技术哲学学号：1992030