离子液体均相液液微萃取-高效液相色谱法测定水中痕量双酚A

建立了离子液体均相液液微萃取-高效液相色谱法测定水中痕量双酚A的分析方法。通过一定浓度的加标回收率实验,优化了离子液体均相液液萃取的条件和高效液相色谱仪的条件。对影响萃取和样品制备条件的因素进行了优化,其中萃取条件包括离子液体种类、体积、NH4PF6的量、萃取时间和离心时间,而样品制备的条件包括pH和NaCl含量。优化的最佳条件是:90μL离子液体1-己基-3-甲基咪唑四氟硼酸盐离子液体([C_6MIM][BF_4])作萃取剂,NH_4PF_6和[C_6MIM][BF_4]的摩尔比为6:1,萃取1.0 min,离心8.0 min,调节样品溶液的pH为8.0,NaCl质量分数为6.0%。在此条件下,双酚A在1.25~100μg/L范围内线性良好,相关系数大于0.999,回收率为86.5%~118.8%,相对标准偏差为2.5%~8.5%,定量限为1.25μg/L。     

分散液液微萃取富集土壤中的二嗪磷和甲拌磷残留

建立了基于离子液体1-辛基-3-甲基咪唑六氟磷酸盐的分散液液微萃取富集土壤中二嗪磷和甲拌磷的方法。实验确定了萃取优化条件:萃取剂为400μL 1-辛基-3-甲基咪唑六氟磷酸盐离子液体,分散剂为4mL甲醇,液固比(溶液体积与样品质量之比)为4∶1,微波温度为50℃,微波时间为8min。将建立的萃取方法与高效液相色谱法结合,应用于实际土壤样品的测定,结果表明该方法能对土壤中的二嗪磷和甲拌磷进行高效萃取与富集,方法快速简便。     

超声辅助离子液体分散液液微萃取光度法测定药物及人血清中氯诺昔康

本文提出了一种基于超声辅助离子液体分散液液微萃取紫外分光光度法测定药物及人血清中氯诺昔康含量的方法。疏水性离子液体1-辛基-3-甲基咪唑六氟磷酸盐([C8mim PF6])被用作萃取剂,在超声的帮助下,不使用分散剂离子液体即可萃取氯诺昔康,萃取率在85.0%以上。对实验条件如萃取剂的种类和用量、萃取时间、萃取温度、溶液p H、离心时间等进行了优化。在优化条件下,工作曲线的线性范围为0.2~15.0μg·m L-1,检测限为0.032μg·m L-1,加标回收率分别为94.5%~99.0%(药物)和92.2%~98.7%(人血清)。用本方法对氯诺昔康药片和加标后的人血清样品进行了测定,结果令人满意。     

离子液体-分散液液微萃取-比色法测定水样中痕量铁

建立了基于分散液液微萃取(DLLME)-数字成像比色(DIC)法测定水样中Fe的方法。在乙酸-乙酸钠缓冲溶液中,Fe(Ⅲ)被盐酸羟胺还原成Fe(Ⅱ)后与邻菲罗啉作用生成橙红色络合物。以离子液体[C6M IM][PF6]为萃取剂,乙腈为分散剂,采用涡旋辅助的分散液液微萃取方法对该络合物进行萃取和富集后,直接通过手机比色装置对Fe进行测定。优化了手机比色装置参数和分散液液微萃取的萃取剂种类及用量、分散剂种类及用量等条件。结果表明,在最佳条件下,方法的线性范围为24～200μg/L,相关系数(r~2)为0.9973,检出限为3μg/L,加标回收率为90.0%～108.0%,相对标准偏差(RSD)为0.8%～1.8%。该方法可用于测定环境水样中痕量Fe。     

离子液体分散液液微萃取/高效液相色谱法测定环境水样中7种萘二酚

建立了测定环境水样中7种萘二酚的离子液体分散液液微萃取/高效液相色谱(IL-DLLME-HPLC)分析方法。以1-丁基-3-甲基咪唑六氟磷酸盐([C4MIM][PF6])为萃取剂,水样体积为8.0 m L,研究了萃取剂用量、水相p H值、萃取时间及盐添加量对7种萘二酚萃取效率的影响。获得最佳萃取条件为:[C4MIM][PF6]体积为150μL,水相p H值为5.0~7.0,涡旋萃取时间为3 min,氯化钠添加量为0.20 g/m L。在优化条件下,7种萘二酚在一定质量浓度范围内线性关系良好,相关系数均不小于0.997 7;方法富集倍数为57倍,方法检出限(S/N=3)为0.3~1.0μg/L;阴性环境水样中3个加标水平的平均回收率为83.5%~103%,相对标准偏差(n=6)为1.1%~3.8%。该方法快速简单、准确灵敏、环保,适用于环境水样中痕量萘二酚的富集检测。     

涡旋辅助分散液液微萃取-悬浮固化/高效液相色谱法测定水样中7种萘二酚

建立了水样中7种萘二酚的涡旋辅助分散液液微萃取-悬浮固化/高效液相色谱(VA-DLLMESFO/HPLC)测定方法。以乙醚-十二醇为二元微萃取剂,通过涡旋分散方式协同萃取水样中的目标化合物,采用C18色谱柱分离,HPLC测定。优化了萃取剂及用量、萃取时间、氯化钠用量等条件。最佳萃取条件为:萃取剂为100μL乙醚和50μL十二醇,氯化钠用量为0.2 g/m L,涡旋萃取3 min。在优化条件下,7种萘二酚在一定质量浓度范围内线性关系良好,相关系数均大于0.997,方法检出限(S/N=3)为1.7~6.0μg/L;3个加标水平下的平均回收率为82.1%~106.0%,日内相对标准偏差(RSD,n=5)为1.2%~4.1%;中间添加水平的日间RSD(n=5)为2.5%~5.7%。该方法前处理简单,涡旋分散大大提高了物质传质速率,增大了萃取效率,缩短了萃取时间,是一种适用于水样中萘二酚类物质富集检测的绿色方法。     

超声辅助离子液体分散液液微萃取/高效液相色谱法测定新型抗艾药ACC007

该文提出了一种基于超声辅助离子液体分散液液微萃取/高效液相色谱(HPLC)测定血清及药片中ACC007含量的新方法。在超声辅助下,无需分散剂即可将疏水性离子液体1-辛基-3-甲基咪唑六氟磷酸盐([C8mimPF6])形成的细小液滴分散于样品溶液中,从而有效萃取ACC007,萃取率在94.0%以上。实验对萃取剂种类、萃取剂用量、溶液pH值、萃取时间、冷却和离心时间等萃取条件进行了考察。在优化条件下,ACC007的线性范围为0.20~10.0μg/mL,检出限分别为0.062μg/mL(药片)和0.068μg/mL(血清)。采用该方法对药片和血清中ACC007进行测定,加标回收率为90.5%~103%,相对标准偏差为2.9%~5.1%,结果令人满意。     

离子液体液-液萃取高效液相色谱测定水中邻苯二甲酸酯类物质

采用1-辛基-3-甲基咪唑六氟磷酸盐[C8mim][PF6]离子液体液-液萃取高效液相色谱法测定水中邻苯二甲酸酯类物质。实验选择邻苯二甲酸二丁酯(DBP)、邻苯二甲酸二环己酯(DCHP)和邻苯二甲酸二正辛酯(DNOP)作为研究对象,对萃取时间、萃取体积比和盐的加入量进行了优化。实验表明最佳萃取条件为:萃取时间为20min、萃取体积比为1:150,而盐加入对萃取效率无显著影响。在最佳条件下离子液体对3种邻苯二甲酸酯的富集倍率在17～84之间,方法对DBP、DCHP和DNOP的检出限分别为0.98、0.91和6.6μg/L。将该方法用于河水、塑料瓶装矿泉水和一次性塑料袋浸出液中邻苯二甲酸酯类的检测,加标回收率为85.2%～110%。同时与正已烷在最佳萃取条件下的富集方法进行了对比,结果表明:离子液体液-液萃取法方法简便,试剂用量少,富集倍率高。     

苄基功能化离子液体对有机磷和苯环化合物的分散液-液微萃取性能研究

以苄基功能化的离子液体1-苄基-3-甲基咪唑双三氟甲烷磺酰亚胺(1-Benzyl-3-methylimidazolium bis [(trifluoromethyl)sulfonyl]imide,[BeMIM][Tf2 N])作为分散液-液微萃取的萃取剂,与高效液相色谱联用,用于环境水样中5种有机磷农药(辛硫磷、杀螟松、毒死蜱、甲拌磷和对硫磷)以及2种苯环化合物(氯化萘和蒽)的萃取与富集。并与其它离子液体([OMIM][Tf2 N])以及普通有机溶剂(CCl4和 C2 Cl4)的萃取效能进行了对比。萃取优化条件为：40μL [BeMIM][Tf2 N]作为萃取剂,1 mL 甲醇作为分散剂,离心时间5 min,样品溶液中不添加盐。在优化的条件下,本方法的线性关系良好(R2=0.9994~0.9998);对10,40和100μg/ L 不同添加浓度重复测定5次的日内和日间 RSD 分别为1.1%~4.3%和0.8%~4.8%,LOD 为0.01~1.0μg/ L (S/ N=3)。将本方法用于3种实际水样中目标分析物的测定,加标回收率和 RSD 分别为82.7%~118.3%和0.7%~5.6%。由于在咪唑环上引入了苄基基团,[BeMIM][Tf2 N]与目标分析物之间除存在疏水作用外,还存在π-π作用,故对目标物的萃取效率明显提高,富集倍数和回收率分别高达339和81.4%。测定了分析物在[BeMIM][Tf2 N]-DLLME 体系中的分配系数,对萃取机制进行初步探讨。     

分散液液微萃取-气相色谱法快速测定水中15种硝基苯类物质

建立了分散液液微萃取-气相色谱电子捕获检测器测定水中15种硝基苯类物质的方法.筛选出了具有高密度且能够适用于电子捕获检测器的萃取剂.优化了色谱条件,对萃取剂种类及用量、分散剂种类及用量、萃取时间、萃取温度等条件进行了优化.DB-35毛细管柱对15种硝基苯类物质具有最好的分离效果.使用程序升温,初始80℃ 保持2 min,以5℃/min速率升温至180℃,可以在22 min内完成分离.以100μL氯苯作为萃取剂、400μL甲醇作为分散剂,对5.00 mL水样在室温下进行萃取,仅需30 s即可达到萃取平衡,15种目标物的萃取率均可达到90%以上,富集倍数达到45.0~48.8.离心分离,取下层沉积相进行气相色谱测定,使用电子捕获检测器检测,方法的定量限为0.03~0.15μg/L,线性范围为0.20~50.0μg/L,相关系数不低于0.998.方法的相对标准偏差在3.3%~8.9%之间,加标回收率在86.0%~103.5%之间.     

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.     

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.     

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.     

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。     

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.

     

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。     

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).