以N-十二烷基二甲基铵基乙酸为增敏剂催化光度法测定锰

基于存在增敏剂N-十二烷基二甲基铵基乙酸（DDMAA）和活化剂氨三乙酸,锰（Ⅱ）催化高碘酸钾氧化萘酚绿B的反应,拟定了测定痕量锰的新催化光度法。本法在两性表面活性剂DDMAA存在下,灵敏度提高10．3倍（Mn~(2+)量为0~6．0μg/L）和5．3倍（Mn~(2+)量为6．0~14μg/L）,相对标准偏差为0．5％,检出限为5．6×10~(-8)g/L,可用于酒样和谷物制品中锰的测定。     

测定尿中痕量碘的高锰酸钾-亚砷酸体系催化光度法

在硫酸和磷酸的介质中,碘离子催化高猛酸钾与亚砷酸反应生成的锰（Ⅲ）氧化砷酸的反应,据此建立了催化光度法测定痕量碘的新方法。该法的检出限为0．4μg/L,测定的线性范围为1．0－25．0μg/L。应用该法测定了尿样中痕量碘的含量,获得了满意的结果,测定样品的相对标准偏差（n＝6）为2．5％－3．7％,加标回收率为96．4％－102．6％。     

以十二烷基硫酸钠为增敏剂催化光度法测定痕量锰

报道了以阴离子表面活性剂十二烷基硫酸钠(SDS)为增敏剂,高碘酸钾氧化茜素绿催化之度法测定衣量锰的方法。方法中添加了阴离子表面活性剂SDS,灵敏度提高4．3涪(锰含量0-0．6ns·ml-1)和5．7倍(锰含量0．6-1．6ng·ml-1),相对标准偏差为2．6%(n=11),检出限为4．06×10-11g·ml-1。     

偶氮胂I-高碘酸钾催化光度法测定痕量Mn(Ⅱ)

研究了在HAc—NH4Ac介质中，以1，10-菲啰啉为活化剂，锰(Ⅱ)催化高碘酸钾氧化偶氮胂I褪色反应的条件及影响因素，建立了动力学光度法测定痕量Mn(Ⅱ)的新方法。方法线性范围为0-80μg/L，检出限为6．3ng/mL，对60μg/L,Mn(Ⅱ)测定的相对标准偏差为2．6％。导出了动力学方程，该催化反应的表观活化能为130．4kJ／mol。已用于野菜、水果样品中锰(Ⅱ)的测定。     

耐尔蓝-高碘酸钾-溴代十六烷基吡啶-氨三乙酸体系催化动力学光度法测定锰

在增敏剂溴代十六烷基吡啶和活化剂氨三乙酸存在的条件下，锰（Ⅱ）对高碘敢钾氧化耐尔蓝的反应具有催化作用，据此建立了测定锰的新方法。该法具有很高的灵敏度和选择性。在最优化的实验条件下，其线性范围为O．4--5．6μg/L；检出限为0．054μg/L(n=8)；相对标准偏差为3．8％。用于水样、蔬菜样品中锰含量的测定，结果令人满意。     

催化动力学光度法测定井水中痕量锰

研究了在 NH3· H2 O- NH4 Cl介质中锰催化过氧化氢氧化苋菜红的褪色反应及其动力学条件 ,测定了反应级数和表观活化能 ,建立了测定痕量锰的新方法。该方法的检出限为 2 .7× 1 0 -4 μg/m L Mn,线性范围为 0～ 2 .4μg/2 5m LMn。用于测定井水中痕量 Mn,与原子吸收法的测定结果一致。     

用锰(Ⅱ)-氨三乙酸-溴代十六烷基三甲胺-高碘酸钾-灿烂甲酚蓝体系催化光度法测定锰

基于存在活化剂氨三乙酸和增敏剂溴代十六烷基三甲胺，锰（Ⅱ）催化高碘酸钾氧化灿烂甲酚蓝的反应，拟定了测定痕量锰的催化光度法，讨论了有关反应机理。本法由于添加了溴代十六烷基三甲胺，灵敏度揭高2．5倍，测定锰含量线性范围为8．0×10－4～8．0×10－3mg／L，检出限为7．0×10－5mg／L，相对标准偏差为4．7％（n＝11），可用于测定茶叶和水样中的锰。     

高碘酸钾氧化酸性铬蓝K催化光度法测定痕量锰

研究了测定痕量锰的新催化光度法，在pH11.90的条件下，锰（Ⅱ）催化高碘酸钾氧化酸性铬蓝K的反应。测定锰的线性范围为0—8．0ng／mE，检出限为0．05ng／mL。用于饮用水中锰的测定，方法的回收率在94．3％-102．7％范围内，结果令人满意。     

催化光度法测定粮食中的痕量锰

研究了测定痕量锰的新催化光度法,方法基于氨三乙酸为活化剂,锰（Ⅱ）催化高碘酸钾氧化溴酚蓝的反应。测定锰的线性范围为0．4－10ng/mL,检出限为0．082ng/mL,对于4.0ng/mL Mn(Ⅱ）的测定,相对标准偏差为3．4％（n=9),其方法已用于粮食中锰的测定。     

催化过氧化氢氧化铬黑T褪色光度法测定痕量锰(Ⅱ)

在pH11.0的Na2B4O7-NaOH缓冲溶液中十二烷基磺酸钠（DBS）可增敏Mn(II）催化过氧化氢氧化铬黑T（EBT）的褪色反应，据此建立了催化褪色光度法测定痕量锰（Ⅱ）的新方法，锰（Ⅱ）浓度在5．0－12．0ug/L范围内服从比耳定律，回归方程ΔA=-0.014 0.32CMn(Ⅱ）（μg/L),r=0.9999检出限0．5ng/mL，应用该法测定人发和茶叶中的Mn(Ⅱ），测定结果满意。     

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.     

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。     

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。     

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).