在线固相萃取/液相色谱-串联质谱法检测饲料中5种喹噁啉药物残留量

建立了在线固相萃取/液相色谱-串联质谱法检测饲料中5种喹噁啉药物的方法。准确称取2 g饲料,用10 m L 0.1%盐酸-甲醇(1∶1)提取,提取液用0.2%甲酸稀释10倍,通过双三元液相色谱采用反相在线固相萃取柱在线富集净化,以0.2%甲酸与乙腈梯度洗脱,同时转移至C18色谱柱上进行分离,串联四极杆质谱检测。实验结果表明,5种喹噁啉药物在50~25 000μg/kg含量范围内线性良好(r0.999);方法的检出限为25μg/kg,定量下限为50μg/kg;方法回收率为72.6%~84.6%,批内和批间相对标准偏差(RSD)均小于10%。本方法较传统固相萃取柱净化法更简捷、经济和稳定。     

在线固相萃取/液相色谱-串联质谱法检测饲料中5种喹啉药物残留量

建立了在线固相萃取/液相色谱-串联质谱法检测饲料中5种喹(噁)啉药物的方法.准确称取2 g饲料,用10 mL 0.1％盐酸-甲醇(1:1)提取,提取液用0.2％甲酸稀释10倍,通过双三元液相色谱采用反相在线固相萃取柱在线富集净化,以0.2％甲酸与乙腈梯度洗脱,同时转移至C18色谱柱上进行分离,串联四极杆质谱检测.实验结果表明,5种喹(噁)啉药物在50～ 25 000 μg/kg含量范围内线性良好(r＞0.999);方法的检出限为25 μg/kg,定量下限为50 μg/kg;方法回收率为72.6％～84.6％,批内和批间相对标准偏差(RSD)均小于10％.本方法较传统固相萃取柱净化法更简捷、经济和稳定.     

液相色谱-串联质谱法测定水产品中麻醉剂MS-222残留

建立了液相色谱-串联质谱法测定水产品中麻醉剂3-氨基苯甲酸乙酯甲基磺酸盐(MS-222)残留量的方法。提取液为50%的甲醇及乙酸-乙酸钠缓冲溶液,提取液经C18固相萃取柱净化处理后用液相色谱-串联质谱仪进行测定,外标法定量。流动相为0.5%的甲酸溶液和乙腈(V:V=60:40),流速为0.2 mL/min。该方法的线性范围为0.001～1.0 mg/L,相关系数大于0.999,检出限为1μg/kg,定量限为2μg/kg。加标回收率可以达到80%～110%。     

在线固相萃取净化-液相色谱-串联质谱法测定猪肉中10种大环内酯类抗生素

建立了在线固相萃取净化-液相色谱-串联质谱检测猪肉中10种大环内酯类抗生素残留的方法。样品经过乙腈提取,提取液40℃旋蒸至干后,分析物用2 mL磷酸盐缓冲液溶解,溶解液经在线固相萃取柱(HLB柱)富集净化,甲醇洗脱,然后转移至XBridge BEH C18色谱柱上,以10 mmol/L乙酸铵水溶液和乙腈溶液为流动相进行分离,最后用串联四极杆质谱检测。结果表明,10种大环内酯类抗生素在0.1~200μg/L范围内呈现良好的线性关系,相关系数均大于0.990。方法的检出限范围为0.05~0.30μg/kg,定量限范围为0.10~1.00μg/kg;添加水平为0.10~10.0μg/kg时,方法回收率为69.6%~115.2%,相对标准偏差(RSD)10%。该方法可以作为猪肉中大环内酯类抗生素的检测方法。     

高效液相色谱-串联质谱法测定养殖环境沉积物中多肽类抗生素残留量

建立了测定水产养殖环境沉积物中多肽类抗生素残留量的高效液相色谱串联质谱法。沉积物经10 mL甲醇-柠檬酸-Na2 HPO4溶液(3∶4, V/ V)超声提取2次,0.5 g 乙二胺四乙酸二钠络合除杂,5 mL 甲基异丁基甲酮净化,HLB 固相萃取柱进一步富集净化,MGII C18色谱柱分离,0.1%甲酸与0.1%甲酸-乙腈梯度洗脱,ESI+电离,多反应监测模式(MRM)监测,外标法定量。粘菌素和杆菌肽在10~10000μg/ L 范围内,维吉尼霉素 M1在4~4000μg/ L 范围内,线性回归系数均大于0.999,方法检出限为2~5μg/ kg,方法定量限为4~10μg/ kg。在3个浓度添加水平下,多肽类抗生素回收率79.7%~91.6%,相对标准偏差1.9%~10.8%。本方法具有良好的精密度和准确度,灵敏度高,适用范围广。     

固相萃取-液相色谱-串联质谱法检测小鼠肌肉组织中矮壮素

建立了快速检测小鼠肌肉组织中矮壮素的固相萃取-液相色谱-串联质谱(SPE-LC-MS/MS)方法。小鼠肌肉样品经乙腈提取,弱阳离子交换(WCX)固相萃取柱净化,3 mL甲酸-甲醇(1∶99,V/V)重力洗脱。采用亲水作用色谱柱(HILIC),含10 mmol/L乙酸铵、0.1%甲酸水溶液-乙腈(40∶60,V/V)为流动相,以电喷雾正离子(ESI+)、多反应监测模式(MRM)进行矮壮素的定性分析,采用基质标准曲线外标法进行定量分析。结果表明:矮壮素的线性范围为5.0～500.0μg/L,线性相关系数为0.9991。在10.0,100.0和200.0μg/kg添加浓度下的回收率为73.2%～82.3%;相对标准偏差小于9.3%;方法定量限为10.0μg/kg,能够满足小鼠肌肉组织中痕量矮壮素检测的要求。     

超高效液相色谱-串联质谱法测定婴幼儿配方乳粉中的丙烯酰胺

采用固相萃取净化-超高效液相色谱-串联质谱法(UPLC-MS/MS)测定婴幼儿配方乳粉中丙烯酰胺的含量。乳粉用水复溶后,用乙腈沉淀蛋白,MCX固相萃取柱净化,HSS T3色谱柱分离,甲醇-0.1%甲酸水(5∶95, V/V)等度洗脱,ESI+模式下,多反应监测模式(MRM)分析,内标法定量。结果表明,丙烯酰胺在5～200 ng/mL范围内线性关系良好,相关系数R²=0.9997。选用婴幼儿配方乳粉为基质,在10, 50,100μg/kg 3个含量水平进行加标回收实验,回收率在88.4%～104.6%,相对标准偏差在3.4%～5.8%。称样量为1 g时,方法检出限为6μg/kg。本方法适用于婴幼儿乳粉中丙烯酰胺的快速测定。     

高效液相色谱-串联质谱法测定加工肉制品中莱克多巴胺及克伦特罗的含量

建立了高效液相色谱串联质谱测定加工肉制品中莱克多巴胺和克伦特罗的方法。采用阳离子交换色谱柱(SCX)分离目标化合物,改进了前处理方法,采用PXC固相萃取柱净化,并对洗脱溶液和高效液相色谱串联质谱的各参数进行优化。高效液相色谱流动相流速为0.4 mL/min,进样量为10μL,柱温为40℃。样品均质后加入30μLβ-盐酸葡萄糖醛苷酶-芳基硫酸酯酶,并经0.02 mol/L乙酸铵溶液(pH 5.2)提取,离心,过固相萃取柱净化。两种目标化合物在0.1～100μg/L范围内线性关系良好,检出限和定量下限分别不超过0.04μg/kg和0.15μg/kg。样品平均加标回收率为72%～98%,RSD低于8.5%。结果表明,此方法适于加工肉制品中莱克多巴胺和克伦特罗的测定。     

超高效液相色谱-电喷雾串联质谱测定蔬菜中喹诺酮类抗生素

建立了蔬菜中4种喹诺酮类抗生素的超高效液相色谱-电喷雾串联质谱(UPLC-ESI-MS/MS)分析方法。每克蔬菜样品(干重)以15 mL乙腈-HCl(125∶8,V/V)进行振荡-超声提取3次,用HLB固相萃取柱进行净化富集,以6 mL 1%酸化乙腈进行洗脱,用N2进行吹脱,最后用初始流动相进行定容。以0.1%甲酸-乙腈溶液和0.1%甲酸溶液作为流动相,采用梯度洗脱方式进行UPLC-ESI-MS/MS检测。蔬菜中4种喹诺酮类化合物不同浓度加标回收率为61%～90%;相对标准偏差(RSD)小于5%(个别除外);检出限为0.021～0.092μg/kg;定量限为0.065～0.312μg/kg。本方法能够满足实际蔬菜样品的分析要求。     

超高效液相色谱串联质谱法测定猪尿中22种β_2-受体激动剂残留量

建立了猪尿中22种β2-受体激动剂残留量超高效液相色谱串联质谱的测定方法。样品加入0.2 mol/L乙酸铵缓冲溶液和β-葡萄糖醛苷酶/芳基硫酸酯酶,在55℃酶解4 h后加入三氯乙酸调节pH,阳离子交换固相萃取小柱净化,依次用2%乙酸、甲醇、正己烷、甲醇、0.5%氨水溶液、甲醇淋洗,5%氨化甲醇洗脱,洗脱液在40℃下氮吹至干,用0.5 mL甲醇-0.1%甲酸溶液(V/V=1:9)溶解样品。22种β2-受体激动剂检出限在0.03~0.3μg/kg之间,加标回收率在70.1%~120.0%之间,相对标准偏差在0.87%~16%范围内。改进了β2-受体激动剂残留量检测前处理的酶解方法和固相萃取净化技术,方法的灵敏度高,也提高了方法的检测效率。     

国内光催化研究进展简述

分1975~1985, 1985~1995和1995~2012三个时期简要介绍了国内光催化研究进展, 主要侧重于光催化材料及其改性、应用和反应机理方面的研究进展, 并指出了当前光催化领域存在的一些重要问题和未来的发展趋势, 涉及到光解水、CO₂还原、环境净化和选择性有机合成等方面.     

青蒿素研究进展

青蒿素是目前治疗疟疾的特效药。本文对自青蒿素发现以来的最新研究进展进行了比较详尽的综述。内容包括: 青蒿素的发现及历史, 青蒿素的来源, 青蒿素的全合成,青蒿素的生物合成, 青蒿素衍生物以及植物组织培养生产青蒿素。     

Reactions in droplets in microfluidic channels

Fundamental and applied research in chemistry and biology benefits from opportunities provided by droplet-based microfluidic systems. These systems enable the miniaturization of reactions by compartmentalizing reactions in droplets of femoliter to microliter volumes. Compartmentalization in droplets provides rapid mixing of reagents, control of the timing of reactions on timescales from milliseconds to months, control of interfacial properties, and the ability to synthesize and transport solid reagents and products. Droplet-based microfluidics can help to enhance and accelerate chemical and biochemical screening, protein crystallization, enzymatic kinetics, and assays. Moreover, the control provided by droplets in microfluidic devices can lead to new scientific methods and insights.     

Interpretation of inorganic arsenic metabolism in humans in the light of observations made in vitro and in vivo in the rat

The toxicity of inorganic trivalent arsenic for living organisms is reduced by in vivo methylation of the element. In man, this biotransformation leads to the synthesis of monomethylarsonic (MMA) and dimethylarsinic (DMA) acids, which are efficiently eliminated in urine along with the unchanged form (As_i). In order to document the methylation process in humans, the kinetics of As_i, MMA and DMA elimination were studied in volunteers given a single dose of one of these three arsenicals or repeated doses of As_i. The arsenic methylation efficiency was also assessed in subjects acutely intoxicated with arsenic trioxide (As₂O₃) and in patients with liver diseases. Several observations in humans can be explained by the properties of the enzymic systems involved in the methylation process which we have characterized in vitro and in vivo in rats as follows: (1) production of As_i metabolites is catalyzed by an enzymic system whose activity is highest in liver cytosol; (2) different enzymic activities, using the same methyl group donor (S-adenosylmethionine), lead to the production of mono- and di-methylated derivatives which are excreted in urine as MMA and DMA; (3) dimethylating activity is highly sensitive to inhibition by excess of inorganic arsenic; (4) reduced glutathione concentration in liver moderates the arsenic methylation process through several mechanisms, e.g. stimulation of the first methylation reaction leading to MMA, facilitation of As_i uptake by hepatocytes, stimulation of the biliary excretion of the element, reduction of pentavalent forms before methylation, and protection of a reducing environment in the cells necessary to maintain the activity of the enzymic systems.     

Recent Advances in Analytical Methodology for in vivo Electrochemistry in Mammals

Electrochemistry is one of the most advanced techniques for monitoring neurochemical activities in the living brain because electrochemical approaches bear the advantageous features of high spatial and temporal resolutions, which facilitate its tremendous potential in investigating the highly spatially heterogeneous brain system and the fast dynamics of neurochemical activities. On the other hand, since brain is the most complicated organ in the sense of its numerous kinds of neurochemical species, high selectivity is always required for any analytical methods that approach the brain. In this review, we will discuss various electrochemical methodologies to achieve selective detection of neurochemicals in mammalian brain and the strategies developed mainly by our group towards selective monitoring of both electrochemically active and inactive neurochemicals. At the end, we will discuss possible solutions towards brain mapping of neurochemical species and combination of neurochemical detection strategy with electrophysiology as the direction of future development of electroanalysis in living brain.     

乙基香兰素研究前景

报导了近几十年来国内外关于乙基香兰素的研究进展与动态,并简单介绍了本文作者在该方面所取得的研究成果,参考文献33篇。     

Gemini表面活性剂合成进展

系统总结了近百种Gemini表面活性剂的合成路线和方法,并且按照其结构特点分门别类地进行比较和归纳,对今后Gemini表面活性剂的合成发展方向提出了一些看法,这对促进此类新颖表面活性剂的工业化进程将具有指导意义。     

钙与人体及临床

钙是宏量元素，是人体中含量较高的元素之一，体内99％的钙构成骨骼和牙齿以及维持骨骼结构，1％的钙调节人体重要生理功能。钙的含量过高或过低都与许多疾病有关，只有保持一种平衡状态，才能使机体处于正常环境。     

Trends in education in analytical chemistry

Summary At the session of the WPAC of Fechem on education in analytical chemistry it was concluded that it is now essential to include chemometrics and basic knowledge of computers in all courses on analytical chemistry.

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Tendenzen in der analytisch-chemischen Ausbildung

Zusammenfassung Bei einer Tagung der WPAC über die Lehre auf dem Gebiet der analytischen Chemie wurde bei der Betrachtung neuer Aspekte festgestellt, daß vor allem Chemometrie und Grundkenntnisse in Computertechnik in die Ausbildung aufgenommen werden sollten.

     

AGET ATRP in the Presence of Air in Miniemulsion and in Bulk

Summary: The recently developed initiation system, activators generated by electron transfer (AGET), is used in atom transfer radical polymerization (ATRP) in the presence of a limited amount of air. Ascorbic acid and tin(II ) 2‐ethylhexanoate are used as reducing agents in miniemulsion and bulk, respectively. An excess of reducing agent consumes the oxygen present in the system and, therefore, provides a deoxygenated environment for ATRP. ATRP of butyl acrylate is successfully carried out in miniemulsion and in the presence of air. During polymerization the radical concentration remains constant. The polymerization reaches over 60% monomer conversion after 6 h, which results in polymers with a predetermined molecular weight = 14 000 g · mol⁻¹ and a low polydispersity ( = 1.23). AGET ATRP of styrene is also successful in bulk in the presence of air, as evidenced by linear semi‐logarithmic kinetics, which leads to polystyrene with an of 13 400 g · mol⁻¹ and a low polydispersity index ( = 1.14).

Appearance of miniemulsion before and after the reducing agent ascorbic acid was added (left); and GPC traces representing molecular weights during the AGET ATRP of BA in miniemulsion in the presence of air (right).