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离子交换柱富集分光光度法测定超微量铬Ⅵ 总被引:1,自引:0,他引:1
1 引 言Cr 的强毒性 ,引起了人们关注。测定Cr 的方法文献报道较多 ,国家标准方法是二苯碳酰二肼光度法。但该法受各种共存物干扰 ,并受检出限限制 (最低检出浓度为 0 0 0 4mg/L) ,故常需将水样浓缩后再测定。加热蒸发水样不能消除干扰离子 ;液膜富集法有文献报道 ,但液膜组成复杂 ,操作繁琐。本文采用离子色谱柱分离、富集进行Cr 的测定 ,通过各项条件试验 ,确立了阴离子色谱柱分离、富集Cr 的方法离子交换柱富集分光光度法测定超微量铬Ⅵ@邹容$四川大学轻工与食品学院!成都610065
@张新申$四川大学轻工与食品学院!… 相似文献
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示波催化极谱法测定钢中微量钼 总被引:1,自引:0,他引:1
采用EGTA-丙二酸复合掩蔽体系,苯羟乙酸-氯酸盐催化体系,示波极谱法直接测定了多种合金钢中的微量钼,方法操作简单,结果可靠,灵敏度高。 相似文献
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以DCTA为滴定剂时二苯羟乙酸是钛(Ⅳ)的专属性隐蔽剂.利用DCTA-二苯羟乙酸隐蔽法并用光度终点,可选择滴定低至90ppb的钛.应用本法,不用分离可滴定石英石和石英砂中的微量钛.与丙二酸联合使用,可作钛和铝或钛、铝和铁的联合滴定. 相似文献
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极谱催化波测定海水中超痕量钨 总被引:1,自引:0,他引:1
本文研究了钨(Ⅵ)在盐酸、α二苯羟基乙酸(简称二苯羟乙酸)和适量氯化钠体系中超痕量钨的直接测定方法。灵敏度可低达5×10~(-12)M。方法具有灵敏度高,选择性好,操作简便快速、准确、稳定等优点。可直接用于海水、淡水中超痕量钨的测定。单个样品可在5分钟内完成。 相似文献
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隐蔽剂在螯合滴定中的应用(ⅩⅢ)——二本羟乙酸隐蔽钛(Ⅳ)的研究 总被引:1,自引:0,他引:1
本文提出用DCTA-二苯羟乙酸隐蔽法滴定钛的新方法,本法选择性高,用于测定钛铁矿、铝土和硅酸盐等的钛,操作简便,结果准确. 相似文献
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Yang Sun Xiaoqing Wang Yilei Huang Zaifa Pan Lili Wang 《Journal of separation science》2013,36(14):2268-2276
Derivatization at the injection port following hollow‐fiber‐based liquid–liquid–liquid microextraction with tetramethylammonium acetate as a dual‐function reagent, i.e. an acceptor and derivatization reagent, for the determination of benzoic acid (BA) and sorbic acid (SA) in real samples by GC was developed. BA and SA were extracted from aqueous samples to an organic phase impregnated into the pores of the hollow fiber wall, and then back‐extracted to the acceptor solution located inside the lumen of the hollow fiber. Upon injection, the extracted analytes were quantitatively derivatized to their methyl esters with tetramethylammonium acetate in the GC injection port. Several parameters related to the derivatization and extraction efficiency were optimized. The linearity was satisfactory over a concentration range of 0.1–50 mg/L with r > 0.993 for both analytes. The LODs were 2.0 μg/L for SA and 20 μg/L for BA. The recoveries (83–116%) and precisions (RSDs of 1.2–11.4% (n = 3)) were examined by analyzing real spiked samples. The enrichment factors of BA and SA were 300 and 425. The results demonstrated that this is a simple, rapid, accurate, and sensitive method for the determination of BA and SA in various samples. 相似文献
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A new sensitive and precise method for the determination of lactic acid in plasmatic microsamples (50 microL) has been developed. Lactic acid was directly extracted from plasma by ethyl acetate in acidic conditions, and analysed as its di-t-butyldimethylsilyl derivative by capillary gas chromatography/electron-impact mass spectrometry (GC/MS). The internal standard was a previously synthesized deuterated compound, 3-[2H]-(2R)-lactic acid. The method gives good reproductibility and precision, the overall standard deviation being better than 3%. The GC/MS assay was in good agreement with the enzymatic determination. 相似文献
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应用毛细管气相色谱-质谱轮廓分析方法,测定了33例2.5~4.5岁健康儿童尿中有机酸种类及含量和8例拟诊为苯丙酮尿症儿童尿中的有机酸,结果表明患儿尿样中苯丙酮酸、苯乙酸、邻羟基苯乙酸、对羟基苯乙酸高于正常值10~470倍。为苯丙酮尿症的确诊提供了可靠方法。 相似文献
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H. Dieckmann M. Stockmaier R. Kreuzig M. Bahadir 《Fresenius' Journal of Analytical Chemistry》1993,345(12):784-786
Summary An analytical procedure for the simultaneous determination of fenpropimorph and its main metabolite fenpropimorphic acid in soil is reported. Extraction with acetone/water (2:1), liquid/liquid partition with dichloromethane and clean-up using gel permeation chromatography is employed to concentrate the analytes. Methylation of the polar metabolite is absolutely required for GC/MS and GC/NPD. The parent compound fenpropimorph is not influenced by this derivatization step. The detection limits are 0.005 mg/kg for fenpropimorph and 0.010 mg/kg for fenpropimorphic acid. 相似文献
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Antonella Casoli Piero Mirti Gerardo Palla 《Fresenius' Journal of Analytical Chemistry》1995,352(3-4):372-379
Proteinaceous organic materials used as ancient painting media were investigated by capillary gas chromatography (GC) and capillary gas chromatography — mass spectrometry (GC/MS). Medieval wall paintings made by the tempera technique were considered and their binding media were studied by the characterization of their main chemical components. The basic methodology is based on the determination of amino acids in samples of paint layers after hydrolysis and derivatization and on the comparison with reference proteinaceous materials. Multivariate chemometric techniques were used to facilitate the recognition of the protein source from chromatographic data. To characterize the binders further, a method was developed for the determination of fatty acids, present as minor components, by GC/MS. The use of fused-silica capillary columns coated with selected stationary phases allowed the separation of amino acid and fatty acid derivatives in a single analytical run. 相似文献
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Antonella Casoli Piero Mirti Gerardo Palla 《Analytical and bioanalytical chemistry》1995,352(3-4):372-379
Proteinaceous organic materials used as ancient painting media were investigated by capillary gas chromatography (GC) and capillary gas chromatography — mass spectrometry (GC/MS). Medieval wall paintings made by the tempera technique were considered and their binding media were studied by the characterization of their main chemical components. The basic methodology is based on the determination of amino acids in samples of paint layers after hydrolysis and derivatization and on the comparison with reference proteinaceous materials. Multivariate chemometric techniques were used to facilitate the recognition of the protein source from chromatographic data. To characterize the binders further, a method was developed for the determination of fatty acids, present as minor components, by GC/MS. The use of fused-silica capillary columns coated with selected stationary phases allowed the separation of amino acid and fatty acid derivatives in a single analytical run. 相似文献
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建立了尿中2,4-滴(2,4-D)、2,4-滴丙酸(2,4-DP)2、甲4氯(MCPA)和2甲4氯丙酸(MCPP)4种苯氧羧酸类除草剂的气相色谱-质谱(GC-MS)分析方法。尿样加氯化钠饱和,酸化后用乙醚萃取,萃取物进行特丁二甲硅烷基(TBDMS)衍生化后分析。尿中4种除草剂的浓度在3~3 000 ng/mL范围内工作曲线的线性关系良好,检出限在1 ng/mL以下,3、100和1 000 ng/mL水平加标回收率在97.0%~102.2%之间,精密度在6.2%~14.2%之间。该法灵敏,可用于中毒者和职业接触者尿中苯氧羧酸类除草剂的分析。 相似文献
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In this work, a novel technique of aqueous-phase derivatization followed by headspace solid-phase microextraction and gas chromatography-mass spectrometry was developed for the determination of organic acids in urine. The analytical procedure involves derivatization of organic acids to their ethyl esters with diethyl sulfate, headspace sampling, and GC/MS analysis. The proposed method was applied to the determination of methylmalonic acid and glutaric acid in urine. The experimental parameters and method validation were studied. Optimal conditions were obtained: PDMS fiber, extraction temperature 55 degrees C, extraction time 30 min, and 60 microL of diethyl sulfate as derivatization reagent with 2 mg of the ion pairing agent tetrabutylammonium hydrogensulfate. The method was linear over three orders of magnitude, and detection limits were 21 nM for methylmalonic acid and 34 nM for glutaric acid, respectively. Consequently, in-situ derivatization/HS-SPME/GC/MS is an alternative and powerful method for determination of organic acids as biomarkers in biological fluids. 相似文献
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Summary Although chlorinated paraffins are widely used and therefore produced in large amounts (about 250 kt/a) — with well known problems —, there is a lack of a selective, highly sensitive and reproducible analytical method for the determination of these substances. Such a method is presented using GC/MS with electron impact ionization for their quantitative determination. The samples, pretreated with conc. sulphuric acid, were cleaned up by solid-phase extraction on alumina, and the chlorinated paraffins were determined by GC/MS using highly selective ion clusters.By this method, determination limits of 3 ng (corresponding to about 1.5 ppb) were routinely obtained. In contrast to the general methods of maximum signal selection or the selection of molecule ions in mass spectroscopy, the presented approach leads to higher selectivity, less discrimination between different types of chlorinated paraffins and allows to obtain further information on the degree of chlorination. 相似文献
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For the determination of fenpropimorphic acid in soil samples, a derivatization step with pentafluorobenzylbromide has been established in order to perform GC/MS with negative chemical ionization. In spite of forming the electrophilic pentafluorobenzyl ester, only the fenpropimophic acid anion was detected. Additional derivatization reactions with diazomethane and 2,2,2-trichloroethanol showed that the formation of this acid anion was depending on the leaving group. In comparison with the determination of the methyl ester with GC/MS and electron impact ionization, the detection limit was however improved from 10 microg/kg to 2 microg/kg dry soil and the analytical quality was ensured due to higher stability of the pentafluorobenzyl ester standards. 相似文献