共查询到20条相似文献,搜索用时 62 毫秒
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以铅笔芯为吸附基质的顶空-固相微萃取法测定酒中的甲醇 总被引:1,自引:0,他引:1
固相微萃取(SPME)是以固相萃取(SPE)为基础发展起来的新方法。在多次实验后发现,主要成分为碳的铅笔芯在经过一定的物理,化学处理后对被分析物能产生定量吸附,因此可用作SPME的萃取基质。对该吸附基质,选择了其萃取、解吸的最佳条件如:萃取时间,水浴温度,搅拌速度,解吸时间及温度等。在选定的最佳条件下,以铅笔芯作吸附基质对甲醇进行顶空 固相微萃取测定,其线性范围是5×10-6~2×10-7g/mL,线性相关系数r=0.9975。富集20min后,检出限为0.5×10-7g/mL。使用该法测定了5种酒中的甲醇含量,回收率在95%~110%之间。在对同一样品的3次平行测定中,其相对标准偏差在6%以下。 相似文献
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模拟唾液浸泡塑料玩具溶出的邻苯二甲酸二(乙基己基)酯的固相微萃取-气相色谱法测定 总被引:4,自引:0,他引:4
利用新型溶胶 -凝胶富勒烯C60 涂渍的萃取头 ,采用顶空固相微萃取 -气相色谱法 ,研究了用模拟唾液浸泡塑料玩具溶出的邻苯二甲酸二(乙基己基)酯(DEHP)的固相微萃取(SPME)条件 ,并对聚氯乙烯玩具制品的模拟唾液浸泡液中增塑剂进行了分析和测定 ,方法的检出限为1.02μg/L ,实际样品的检出限为10.2×10-6(w) ,相对标准偏差RSD=10.5 %(n=7)。 相似文献
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离子液体键合固相微萃取涂层用于水样中五氯酚的测定 总被引:1,自引:0,他引:1
合成了1-甲基-3-三乙氧基硅基丙基咪唑二(三氟甲基磺酸酰)亚胺盐([TPMIM][NTf2])离子液体, 其热稳定性可达480 ℃, 并用其通过溶胶-凝胶法制备了一种含键合离子液体的固相微萃取(SPME)涂层. 该涂层的使用温度可达340 ℃. 优化了萃取温度、萃取时间、溶液的pH、盐效应、解析温度以及解析时间. 在最优条件下, 采用顶空固相微萃取结合GC/FID的方法测定水样中五氯酚(PCP)的检出限为1 ng/L, 线性范围为10-3~102 μg/L, 线性相关系数为0.9994, 相对标准偏差(RSD, n=5)为3.5%, 加标回收率为84.5%. 相似文献
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以咪唑改性的苯乙烯型大孔树脂填料制备固相萃取小柱,进行固定化离子液体固相萃取,结合β-环糊精修饰离子液体碳糊电极,发展痕量双酚A的电化学联用快速检测技术。实验优化影响萃取效率的因素,获得最佳萃取条件(萃取填料用量0.4 g,样品体积200 m L,上样液p H 7.0,5 m L甲醇为洗脱溶剂,萃取流速4.5 m L/min)。测得固定化离子液体树脂对双酚A的最大吸附容量为10.1 mg/g,富集倍数为40倍。双酚A的浓度线性范围在2.3~228μg/L,检出限为0.95μg/L。联用方法灵敏、实用性强,用于实际样品中双酚A分析,结果与HPLC方法一致。 相似文献
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本文研制了一个野外快速联合测定化探样品中金、银、铜的新方法。采用黄原酯棉(CCX)富集分离,以金试剂-TBP液珠萃取比色法进行测定,检出限分别为Au:0.2×10~(-9),Ag:50×10~(-9),Cu:0.1×10~(-6)。利用该法制备了野外快速分析箱,可在野外无电无排风条件下进行测定。 相似文献
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微液液提取或固相萃取法净化、气相色谱-质谱联用检测葡萄酒中19种农药多残留 总被引:2,自引:0,他引:2
建立了红葡萄酒中19种农药多残留的气相色谱-质谱联用选择离子模式进行监测的检测方法,比较了固相萃取(SPE)和微液液提取(MLLE)两种前处理方法并考察了基质效应。两种方法在0.01~10 mg/L范围内线性关系良好,相关系数大于0.997。在0.01~1.0 mg/kg添加水平范围内,SPE法的平均添加回收率在77.8%~109.1%之间(四螨嗪为137.5%);MLLE法的平均添加回收率在83.3%~116.7%之间(四螨嗪为43%)。SPE法的最低检出限(LOD)0.001~0.01 mg/kg之间,定量检出限(LOQ)为0.005~0.05 mg/kg,相对标准偏差小于10%;MLLE法为LOD在0.02~0.10 mg/kg,LOQ为0.06~0.30 mg/kg,相对标准偏差小于14%。所有目标化合物均存在基质增强效应,可用基质匹配标准溶液来减少其对测定结果的影响。 相似文献
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Lei Zhang Chenyang Zhang Xin Dong Zeyuan Dong 《Angewandte Chemie (International ed. in English)》2023,62(6):e202214194
Lithium ions have been applied in the clinic in the treatment of psychiatric disorders. In this work, we report artificial supramolecular lithium channels composed of pore-containing small aromatic molecules. By adjusting the lumen size and coordination numbers, we found that one of the supramolecular channels developed shows unprecedented transmembrane transport of exogenous lithium ions with a Li+/Na+ selectivity ratio of 23.0, which is in the same level of that of natural Na+ channels. Furthermore, four coordination sites inside channels are found to be the basic requirement for ion transport function. Importantly, this artificial lithium channel displays very low transport of physiological Na+, K+, Mg2+, and Ca2+ ions. This highly selective Li+ channel may become an important tool for studying the physiological role of intracellular lithium ions, especially in the treatment of psychiatric disorders. 相似文献
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The ion-trapping ion cyclotron resonance spectrometer, or Fourier transform mass spectrometer, provides a powerful and convenient environment for the study of photodissociation of gas-phase ions. This capability has been explored for about 30 years in a number of laboratories including our own. A variety of developments and applications, historical and current, are organized here under five broad headings: (1) optical spectroscopy of ions; (2) kinetics of the dissociation process; (3) dynamics of the dissociation process; (4) thermochemistry of dissociation; and (5) probing the structure and energy of the ions. 相似文献
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GUO Li-li WANG Dong-xia Roger W. Roeske 《高等学校化学研究》2006,22(2):265-266
Introduction PeptidesmadeupofalternatingL andD amino acidscanformβhelicesasingramicidinAorcyclic peptidesthataggregatetoformtubes[1].Inbothcases thestructuresarehollowwithallthesidechainspro jectingoutwards.Kennedyetal.[2]postulatedthat peptideshavingthe… 相似文献
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A solid state copper(II) ion sensor is reported based on the application of electropolymerized undoped (neutral) polycarbazole
(PCz) and polyindole (PIn) modified electrodes. The new sensor shows high selectivity to Cu2+ ions with a detection limit of 10–5 M. PCz and PIn are formed respectively by the anodic oxidation of 50 mM carbazole and 5 mM indole monomers in dichloromethane
containing 0.1 M tetrabutylammonium perchlorate on a platinum electrode using a single compartment cell. Potentiostatic polymerization
of both the monomers are carried out at 1.3 V and 1.0 V vs. Ag/AgCl, respectively. Perchlorate ions were electrochemically
removed from the polymer films by applying – 0.2 V vs. Ag/AgCl. Polymer-coated electrodes are incubated in 1 M KCl solution
for 8 h followed by incubation in distilled water for 2 h before using as a metal ion sensor. The undoped PCz and PIn electrodes
were found to be highly selective and sensitive for Cu2+ ions with little selectivity for Pb2+ and negligible response towards Ag+, Hg2+, Cu+, Ni2+, Co2+, Fe2+, Fe3+ or Zn2+. Potentiometric responses for Cu2+ ions are recorded for both the sensor electrodes together with a double-junction Ag/AgCl reference electrode. Calibration
curves for Cu2+ are reported for both ion sensors. The polymer-modified electrodes were found to be stable for several weeks.
Electronic Publication 相似文献
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柱后衍生离子色谱法同时测定水中Fe^3+,Fe^2+,Cu^2+,Zn^2+方法研究 总被引:5,自引:0,他引:5
将Dionex 4000i离子色谱仪和国产721分光光度计组合联用,建立了一种同时测定水中Fe~(3+)、Fe~(2+)、Cu~(2+)、Zn~(2+)四种金属离子的柱后衍生离子色谱法。以磺基水杨酸/酒石酸/草酸为络合剂,质子化的二价乙二胺离子(EnH_2~(2+))为淋洗离子,在Dionex HPIC-CS2分离柱上先实现混合金属离子的分离,之后,各被分离的离子依次进入柱后反应器,与PAR在此反应显色生成有色络合物。借助国产721分光光度计,在500 nm的固定波长下依次检测流出的各离子。Fe~(3+)、Fe~(2+)、Zn~(2+)三种离子仅需6 min就可全部淋洗出。Cu~(2+)在切换淋洗液后检测,也仅需10 min。本法可用于同时测定天然水(mg/L级浓度)和电站高纯水(μg/L级浓度)以及金属腐蚀产物中的Fe~(3+)、Fe~(2+)、Cu~(2+)、Zn~(2+)。进样分析前,仅需将水样酸化和过滤即可。 相似文献