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分散液相微萃取-气相色谱/质谱快速分析水中的硝基苯类化合物 总被引:4,自引:1,他引:3
建立了分散液相微萃取.气相色谱,质谱快速分析水中硝基苯、对硝基苯、1,3一二硝基苯和2,4-二硝基氯苯的新方法.将含有18μL氯苯(萃取荆)的0.25 mL丙酮(分散剂)作为萃取体系,快速注入到5.0 mL水溶液中.在4000r/min下离心2.0 min后,得到(10.0±0.5)μL沉积相(氯苯),取底部沉积相1.0μL进行气相色谱,质谱分析.方法线性范围0.5~50μg/L(r2=0.9986~0.9994),检出限0.2~0.5μg/L,相对标准偏差4.2%~7.3%(n=5).将该方法用于环境水样的测定,加标回收率72.9%~89.6%. 相似文献
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单滴微萃取-气相色谱-质谱联用测定水中的硝基咪唑类药物 总被引:1,自引:0,他引:1
建立了单滴液相微萃取(SDME)与气相色谱-质谱(GC-MS)联用技术快速检测水中的硝基咪唑类药物,对影响萃取的因素(溶剂的种类及用量、萃取时间、萃取温度及搅拌子的搅拌速度)进行优化。优化的萃取条件为:溶剂为2.5μL正辛醇,温度为50℃,搅拌速度为600 r/min,时间为20 min。萃取后,微液滴转移至衍生化试管,于70℃水浴中衍生45 min,进样分析。该方法在水中的线性范围为0.5~400μg/L,线性相关系数良好(r0.998),检测限为0.16~0.57μg/L。加标自来水和湖水中的相对平均回收率为80.9%~103.6%,相对标准偏差为1.7%~9.0%。 相似文献
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顶空固相微萃取-气相色谱-质谱法同时测定饮用水源水中24种VOCs 总被引:1,自引:0,他引:1
建立了同时测定饮用水源水中24种挥发性有机物(VOCs)的顶空固相微萃取-气相色谱-质谱法.用75 μm CarboxenTM-Polydimethylsiloxane(CAR-PDMS)固相微萃取柱顶空萃取水样中的VOCs,VOCs用气相色谱-质谱联用仪检测,采用内标法定量.对萃取柱涂层、样品盐度、萃取温度和萃取时间等样品前处理条件进行了优化,VOCs的检出限在0.03~0.31 μg/L之间,线性相关系数r>0.996(二氯甲烷和三氯甲烷除外).对饮用水源水实际水样0.50μg/L和1.00 μg/L两个加标浓度水平的回收率进行了测定,三氯甲烷回收率均值分别为104%和142%,其余VOCs回收率分别为90.0%~120%和88.0%~110%,除二氯甲烷和三氯甲烷外,其余VOCs测定结果的相对标准偏差均小于15.0%(n=6).该方法适用于饮用水源水中挥发性有机物的监测分析. 相似文献
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原位乙酰化-顶空固相微萃取测定水中酚类化合物 总被引:1,自引:0,他引:1
建立了原位乙酰化-顶空固相微萃取-气相色谱/质谱联用测定水中酚类及氯酚类化合物的方法,考察了对衍生化以及萃取过程有影响的相关因素.结果表明,采用65 μm PDMS/DVB涂层纤维效果最好.在10 mL样品中,搅拌速率600 r/min、100 μL乙酸酐、0.10 g Na2HPO4、4.0 g NaCl、60 ℃时各被测组分检出限在0 014~0 044 μg/L之间,相对标准偏差(RSD)≤13.7%,在考察的浓度范围(0.02~25 μg/L)内均呈线性变化.实际废水样品测定结果表明,相对标准偏差(9.24%)和回收率(86.4%)符合环境水体中痕量酚类化合物监测的质控要求. 相似文献
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中空纤维膜液相微萃取-气相色谱质谱法测定水中的百菌清 总被引:1,自引:0,他引:1
研究了用中空纤维膜液相微萃取-气相色谱质谱法测定水中的百菌清。通过实验确定最佳萃取条件为:萃取剂为甲苯,萃取剂用量3μL,水样体积10mL,萃取温度为45℃,萃取时间为15 min,搅拌速率为500 r/min,萃取后取1μL有机溶剂直接进样进行气相色谱质谱分离检测。在此条件下,百菌清的富集倍数为450倍,方法的线性范围为5~600μg/L,检出限为0.5μg/L。测定实际水样的加标回收率在92.3%~96.0%之间。该方法可以用于水中百菌清的快速检测。 相似文献
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中空纤维液相微萃取-气相色谱/质谱联用检测水中的氯化苄 总被引:2,自引:0,他引:2
建立了一种以中空纤维液相微萃取(HF-LPME)前处理样品,利用气相色谱/质谱(GC/MS)对水中痕量氯化苄进行检测的方法。优化的实验条件为:3.0μL甲苯为萃取溶剂,在中等搅拌速率下室温萃取15 min。方法的线性范围为1~100μg/L,线性相关系数r=0.9995;检出限为0.5μg/L(S/N=3);相对标准偏差为5.37%(n=5)。用于水库水和被污染河水的测定,加标回收率分别为95.7%和93.6%,结果满意。 相似文献
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赖永忠 《理化检验(化学分册)》2012,(5):550-551,555
采用顶空固相微萃取-气相色谱-质谱法对饮用水源水中1,3,5-三氯苯进行了测定。以1,2-二氯苯-d4为内标,用PDMS萃取头顶空萃取20min,萃取头于气相色谱进样口解析5min。采用DB-624色谱柱在程序升温条件下进行分离,质谱分析中采用电子轰击离子源(230℃,70eV)及选择离子监测模式测定。结果表明:1,3,5-三氯苯在0.100~2.50μg.L-1范围内呈线性,检出限(3S/N)为0.019μg.L-1。方法用于河流及水库水中的1,3,5-三氯苯的测定,加标回收率在91.5%~126.0%之间。 相似文献
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分散液相微萃取-气相色谱联用测定葡萄中百菌清、克菌丹和灭菌丹残留 总被引:8,自引:0,他引:8
采用分散液相微萃取与气相色谱-电子捕获检测联用技术建立了测定葡萄样品中百菌清、克菌丹和灭菌丹农药残留的新方法.对影响萃取和富集效率的因素进行了优化.萃取条件选定为在10 mL带塞离心试管中加入 5.0 mL葡萄样品溶液,并加入1.0 mL丙酮(分散剂),振荡摇匀后以5000 r/min离心5 min,然后将上层清液转移至另一离心试管中,加10.0 μL氯苯(萃取剂),分散混匀后再以5000 r/min离心5 min,萃取剂氯苯相沉积到试管底部,吸取1.0 μL萃取相直接进样分析.在优化的实验条件下,3种杀菌剂的富集倍数可达788~876倍;检出限在6.0~8.0 μg/kg(S/N=3∶ 1)范围内.以α-六六六为内标,测定3种杀菌剂的线性范围为10~150 μg/kg,线性相关系数在0.9990~0.9995范围内.本方法已成功应用于葡萄样品中百菌清、克菌丹和灭菌丹残留的测定,平均加标回收率在92.3%~106.1%范围内;相对标准偏差在4.5%~7.2%之间,结果令人满意. 相似文献
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Reactions in droplets in microfluidic channels 总被引:5,自引:0,他引:5
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. 相似文献
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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 (Asi). In order to document the methylation process in humans, the kinetics of Asi, MMA and DMA elimination were studied in volunteers given a single dose of one of these three arsenicals or repeated doses of Asi. 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 Asi 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 Asi 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. 相似文献
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G. den Boef 《Fresenius' Journal of Analytical Chemistry》1981,305(2):127-129
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.
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.相似文献
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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. 相似文献
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Advances in passive sampling in environmental studies 总被引:2,自引:0,他引:2
Kot-Wasik A Zabiegała B Urbanowicz M Dominiak E Wasik A Namieśnik J 《Analytica chimica acta》2007,602(2):141-163
Passive sampling is based on the phenomenon of mass transport due to the difference between chemical potentials of analytes in a given environmental compartment and the collection medium inside a dosimeter. The subsequent laboratory procedure (i.e. extraction, identification and determination of analytes) is the same as in the case of classic sampling techniques.Passive sampling techniques are characterized by simplicity with regard to the dosimeter's construction as well as its maintenance. Therefore, they find ever increasing application in the field of environmental research and analytics. When choosing a passive sampling method, one should not forget that some passive samplers require the time-consuming calibration step before being used in the field.Novel solutions and modifications of existing sampler designs have been presented. Practical application of passive dosimetry in environmental analytics, including sampling of water, soil, air and other atypical media are discussed. Some aspects of calibration methods in passive dosimetry are also described. The latest trends in the application of passive sampling are highlighted. 相似文献