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超纯气体制备和用超纯气体做保护气的许多工业部门,对气体中微量水是需要经常分析的。目前常用的大都是露点法,其缺点是仪器只能专用;而用高灵敏度热导检测器气相色谱仪,不但可方便地测出超纯气体中的微量水,而且还可以测定超纯气体中的微量气体杂质及作其它有机物分析之用。气相色谱仪操作简单,定量也较方便准确。 相似文献
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制备了聚二-(1,10-邻菲啰啉)(1,10-邻菲啰啉-5,6-二酮)合钌修饰玻碳电极,研究了在非水介质中与水反应后的电极反应,成功构建了一种检测微量水的电化学传感器,建立了在非水介质中检测有机物中微量水的电化学分析法.在含有0.05 mol/L六氟磷酸四丁基胺的乙腈溶液中,采用差分脉冲伏安法,在电位-0.12 V处测得的阳极峰电流与水含量在0.02%~5.66%范围内成正比,检出限为0.005%(S/N=3).将传感器分别应用于乙腈、丙酮、93号汽油、柴油4种有机物中微量水的测定,相对标准偏差小于3.6%,加标回收率为94.1% ~ 105.0%,测定结果与卡尔费休法相符. 相似文献
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有机碳氢微量分析法虽已有很多改进,但似尚缺一种既能用以测定挥发性又能测定非挥发性有机化合物中碳氢含量的装置.最近已有改进的测定固体及挥发性物质中碳氢的方法,但该装置专为测定含氟化合物中的碳氢含量而设计. 本文应用如图1的根据经验及综合前人方法制定的装置,分析若干挥发性及非挥发性液体与固体有机化合物以及元素有机化合物中碳氢含量,结果都令人满意(见表1). 相似文献
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The determination of trace water in gas samples, such as isobutene, chloromethane (polymeric staple gases) and SF6 by a conventional Karl Fischer coulometer is very difficult, because of the adsorption of trace water on the surface of sample pipe, the gasification of the liquefied samples, and the migration of moisture into the measuring cell from the surroundings. To solve these problems, we improved a device for coulometric determination of water by Karl Fischer method. The improved coulometer was used to determine the trace water in isobutene, chloromethane and SF6; RSD was less than 5%, and recoveries ranged from 94.1 to 109.1%, which is adequate for the analysis of industry. 相似文献
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炼厂气是炼油工艺产生的各种气体的混合物,采用四阀六柱将炼厂气分离分解为3部分,以双TCD+FID检测器3通道气相色谱法快速分析炼厂气.FID通道用于分析烃类,一个TCD通道分析永久性气体和硫化物,另一个TCD通道分析氢气,采用面积归一化法定量计算分析结果.用该法测定了3种标准气体,测定值与标准值基本一致,测定结果的相对标准偏差小于8%.该法适用于测定包括液化气、烟气、裂解气等组分相近的样品组成. 相似文献
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反吹-气相色谱法检测蔬菜中的有机磷农药残留 总被引:3,自引:0,他引:3
采用反吹技术改进了气相色谱检测大批量蔬菜样品中有机磷农药残留的方法。在样品中加入乙腈、氯化钠混合溶液振荡,离心分层,得到乙腈提取液。取部分提取液浓缩、定容,用配备火焰光度检测器及微流控装置的气相色谱仪进行有机磷农药检测。16种有机磷农药在0.040~3.20 mg/L内具有良好的线性关系(r>0.9996)。回收率为75.2%~111.5%,相对标准偏差为2.8%~10.4%,检出限为0.003~0.01 mg/kg。通过反吹可以有效降低基质效应影响,缩短每个样品的运行时间,减少停机维护和材料消耗,节约38%的检测时间。 相似文献
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Silica-based monolithic column material was synthesized and an enrichment device was fabricated with the material by assembling the material inside a glass column.The enrichment device was applied for the determination of micro-carbaryl with near-infrared spectroscopy(NIRS).The aqueous solutions of carbaryl passed through the device and the carbaryl was enriched on the surface of the material where diffuse reflection NIR spectra were measured.These procedures of enrichment and measurement ensured to conc... 相似文献
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Nahid Mashkouri Najafi Mohammad Eidizadeh Shahram Seidi Ensieh Ghasemi Reza Alizadeh 《Microchemical Journal》2009,93(2):159-163
Electrodeposition is known to be proper for separation and preconcentration of extremely low concentrations of analytes from the bulk sample which is instrumentally very simple. In the present research, a combination of electrodeposition with arc atomic emission spectrometry (ED-AAES) method has been developed in order to improve the analytical performance of this spectrometry technique. The results show that sensitivity and detection limits by using ED-AAES were improved 1000–2000 folds over those of normal arc atomic emission spectrometry in determination of the selected elements. The detection limits for measurement of Ni, Cr and Pb were 2.56, 3.05 and 2.11 µg L− 1 for monodeposition and 3.31, 3.72 and 3.25 µg L− 1 for simultaneously deposition, respectively. The precision of determination was in the range of 2–4% RSD. Typical calibration graphs for these elements were linear up to 100 µg L− 1, depending on the element and matrix.Application of this technique was also tested on determination of the studied elements in an electroplating plant's waste water. The accuracy of technique was verified by comparing the results of the waste water analysis with those of electrothermal atomic absorption spectroscopy as a reference standard method.The obtained results show that the combined technique (ED-AAES) has been progressed substantially toward the ultimate goal of direct interference-free determination of trace analysis in complex samples by AAES. 相似文献
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研究了717型阴离子交换树脂柱分离-富集钼的条件,建立了分光光度法测定尾矿中微量钼的方法。在pH 7.5的条件下,钼以MoO42-形式被树脂定量吸附后,采用体积比1:1的2 mol/L HNO3和0.5 mol/L NH4NO3混合溶液洗脱,消除了绝大部分共存离子的干扰。结果表明,采用硫氰酸盐光度法,体系的最大吸收波长为460 nm,线性范围为0~120.0μg/L,检出限为1.3μg/L。对实际样品测定结果与ICP-AES法相符,6次测定值的RSD=3.3%,加标回收率在96.2%~105.7%之间。 相似文献
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