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1.
The sorption and determination of mercury(II) on the solid phase of a fibrous polyacrylonitrile material filled with the AV-17 anion exchanger is studied. Mercury is adsorbed in the form of the chloride complex from a solution with pH 5–7.5; it is determined on the solid phase by the reaction with dithizone either visually or by the measuring the color hue. A procedure for the test determination of mercury(II) has been developed and tested in the analysis of fresh natural waters by the added–found method. The detection limit is 0.02 mg/L. The time of analysis of 5 or 6 samples is no more than 15–20 min. 相似文献
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A high-performance liquid-chromatographic method has been developed for the determination of five penicillin compounds (benzylpenicillin, phenoxymethylpenicillin, oxacillin, cloxacillin, and dicloxacillin) at trace levels in commercially available milk samples. This method comprises extraction of the lipids with ethyl acetate, clean-up and concentration on a C-18 solid-phase extraction column, and derivatization with 1,2,4-triazole and mercury(II) chloride solution, pH 8, at 65 degrees C for 10 min. The derivatized compounds are eluted from a C-2 column with a mobile phase containing acetonitrile and phosphate buffer loaded with sodium thiosulfate and tetrabutylammonium hydrogen sulfate as ion-pairing reagent. The limit of determination was found to be 4 microg L(-1) milk for benzylpenicillin and 10 microg L(-1) for the others. This meets EU criteria according to decision No. 93/256/EEC. 相似文献
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《Journal of separation science》2017,40(8):1644-1650
Microcystins (MCs), produced by freshwater cyanobacteria, can be serious water pollutants, so it is important to monitor their concentration in drinking water. We have developed a method for rapid and accurate determination of microcystin levels in environmental water, using magnetic solid‐phase extraction and high‐performance liquid chromatography with UV detection. The magnetic composite material, which was combined with cetylpyridinium chloride, was prepared by hydrothermal synthesis. The optimal extraction of microcystins in water sample was achieved by optimizing the amount of adsorbent, time of adsorption, ratio of eluting solvent, and volume of eluent. Under the optimal conditions, the limit of detection of MC‐LR was 0.001 μg/L, and the limit of quantification was 0.0028 μg/L. The limit of detection of MC‐RR was 0.001 μg/L, and the limit of quantification was 0.003 μg/L. These values are far lower than those established by the International Health Organization for the maximum concentration of microcystins in drinking water. The magnetic solid‐phase extraction adsorbent used in this method has the advantages of simple preparation, low price, and easy solid–liquid separation, and it can be used for the rapid and sensitive monitoring of trace microcystins in environmental water samples. 相似文献
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Selenium(IV) is determined by cathodic stripping voltammetry after the formation of a piazselenol with 3,3′-diaminobenzidine. The selenium is then accumulated as HgSe on a mercury electrode by deposition at ?0.45 V. The differential-pulse cathodic stripping peak allows a detection limit of 0.01 μg l?1. For the determination of selenium in natural waters, interferences can be avoided by extraction of the piazselenol into toluene followed by a back-extraction into 0.5 M hydrochloric acid. The accuracy of the overall procedure was checked by analyses of a standard reference material. The method was applied to the determination of selenium(IV) in sea-water samples at levels as low as 20 ng l?1 with a concentration factor of 10 during the extraction procedure. 相似文献
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An analytical method has been developed for the determination of residues of ethephon (2-chloroethyl phosphonic acid) in drinking and surface water. The procedure is based on de-ionisation with an anion/cation-exchange resin, solid phase extraction by means of anion-exchange polystyrene-divinylbenzene extraction disks, elution with a mixture of methanol and 10 M hydrochloric acid (98/2, v/v), redisolution into acetonitrile after evaporation and silylation with N-(tert-butyldimethylsilyl)-N-methyltrifluoroacetamide (MTBSTFA). Quantification is performed by gas chromatography with ion-trap cubic mass spectrometric detection in the electron impact mode (GC-EI-MS3). Method validation was conducted using samples of mineral, tap, and river water that were fortified with ethephon at concentration levels ranging from 0.1 to 1.0 microg/L. The mean recovery from all the fortified samples (n = 36) amounted to 88% with a relative standard deviation of 17%. The method, therefore, was shown to allow accurate determination of ethephon residues in drinking and surface water with a limit of quantification of 0.1 microg/L. 相似文献
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A high-performance liquid chromatographic multiresidue method was developed for the determination of 8 penicillin compounds (benzylpenicillin, phenoxymethylpenicillin, ampicillin, amoxicillin, nafcillin, oxacillin, cloxacillin, and dicloxacillin) at trace levels in muscle tissue. This method involves extraction of the penicillins with phosphate buffer pH 9 followed by cleanup and concentration on a C18 solid-phase extraction column and reaction with benzoic anhydride at 50 degrees C for 5 min and with 1,2,4-triazole and mercury(II) chloride solution pH 9 at 65 degrees C for 10 min. The derivatized compounds are eluted on a C8 column with a mobile phase containing acetonitrile and phosphate buffer (pH 6; 0.1 mol/L) loaded with sodium thiosulfate and ion-pairing tetrabutylammonium hydrogenosulphate. The method detection limit is approximately 3-11 micrograms/kg and the limit of determination was evaluated down to 25 micrograms/kg in line with the criteria of the EU decision No. 93/256/EEC. 相似文献
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固相萃取-离子色谱法测定地下水中痕量高氯酸根离子 总被引:1,自引:0,他引:1
建立了测定地下水中痕量高氯酸根(ClO~4)的固相萃取-离子色谱(SPE-IC)分析方法。0.7 L水样经预处理降低主要干扰离子Cl~、CO2~3和SO2~4的干扰后,使用Cleanert PWAX弱阴离子交换固相萃取小柱对地下水中痕量(μg/L级)的ClO~4进行富集,用6 mL 1%NaOH溶液洗脱,富集液经0.45 μm水膜过滤后,用IonPac AS20阴离子分离柱、50 μL进样环、40 mmol/L KOH溶液淋洗、抑制电导检测分离分析。结果表明,地下水样品中ClO~4的方法检出限和测定下限分别为0.15 μg/L和0.60 μg/L,进样质量浓度在1~15 μg/L范围内有很好的线性关系,线性相关系数为0.9992,回收率为99.7%~100.5%;该方法经济有效,可用于地下水中痕量ClO~4的检测。利用该方法测定了哈尔滨周边部分地区地下水中ClO~4浓度,检测结果与离子色谱-质谱联用法的检测结果的相对误差为1.85%~9.24%。 相似文献
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The sorption of Hg(II), Cd(II), and Pb(II) as anionic complexes on the solid phase of polyacrylonitrile fiber filled with the AV-17 anion exchanger from NaCl and KI solutions and their complexation with 4-(2-pyridylazo)resorcinol (PAR) and dithizone were studied. A test method was developed for the individual determination of Hg(II), Cd(II), and Pb(II) from one sample on three support disks. From the same solution, by the successive sorption on two disks from a 0.2 M NaCl solution, mercury was determined with dithizone and cadmium was determined with PAR. After the addition of a KI solution and sorption on the third disk, lead was determined with PAR. Using the added-found method, the procedure was approved in the analysis of natural sodium chloride water. The detection limit was 0.01 mg/L for Hg(II) and 0.02 mg/L for Cd(II) and Pb(II) for a volume of the analyzed sample of 25 mL. The time of the analysis of five or six samples (determination of three elements) is no longer than 50 min. 相似文献
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Determination of organophosphorus insecticides in natural waters using SPE-disks and SPME followed by GC/FTD and GC/MS 总被引:1,自引:0,他引:1
Lambropoulou D Sakellarides T Albanis T 《Fresenius' Journal of Analytical Chemistry》2000,368(6):616-623
Two methods for the analysis of ten organophosphorus insecticides in natural waters using solid phase extraction disks containing C18 and SDB and solid phase microextraction fibers containing polyacrylate (PA) are developed. Bromophos ethyl, bromophos methyl, dichlofenthion, ethion, fenamiphos, fenitrothion, fenthion, malathion, parathion ethyl and parathion methyl were determined by GC/MS and GC/FTD. The SPE-disks require only 1000 mL of sample and provide a method limit of detection in the range of 0.01-0.07 microgram/L and recovery rates from 60.7 to 104.1%. The solid phase microextraction (SPME) technique requires 2-5 mL of water sample and provides a method limit of detection in the range of 0.01 to 0.05 microgram/L for all detectors and the recoveries compared to distilled water ranged from 86.2 to 119.7%. The proposed methods were applied to the trace level screening determination of insecticides in river water samples originating from different Greek regions. 相似文献
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建立了一种简单快速测定三聚氰胺的方法. 在pH=7.0的磷酸盐缓冲溶液中, 三聚氰胺与巴比妥酸衍生物(DBA)形成稳定的氢键, 使三聚氰胺的荧光强度显著增强, 由此建立了巴比妥酸衍生物荧光增强测定牛奶中三聚氰胺的新方法. 在优化的条件下, 该方法的线性范围为12.5~1250 μg/L, 检出限为7.5 μg/L, 相对标准偏差为2.06%, 样品平均加标回收率为96.62%. 本方法简便、快速、准确, 可用于大量牛奶样品中三聚氰胺的快速检测. 相似文献
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Multiwalled carbon nanotubes functionalized by oxidation of original multiwalled carbon nanotubes with NaClO were prepared and their application as solid phase extraction sorbent for 2,4-dichlorophenoxyacetic acid (2,4-D) was investigated systemically, and a new method was developed for the determination of trace 2,4-D in water samples based on extraction and preconcentration of 2,4-D with solid phase extraction columns packed with NaClO-treated multiwalled carbon nanotubes prior to its determination by HPLC. The optimum experimental parameters for preconcentration of 2,4-D, including the column activating conditions, the amount of the sorbent, pH of the sample, elution composition, and elution volume, were investigated. The results indicated 2,4-D could be quantitatively retained by 100 mg NaClO-treated multiwalled carbon nanotubes at pH 5, and then eluted completely with 10 mL 3:1 (v/v) methanol-ammonium acetate solution (0.3 mol/L). The detection limit of this method for 2,4-D was 0.15 μg/L, and the relative standard deviation was 2.3% for fortified tap water samples and 2.5% for fortified riverine water sample at the 10 μg/L level. The method was validated using fortified tap water and riverine water samples with known amount of 2,4-D at the 0.4, 10, and 30 μg/L levels, respectively. 相似文献
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《Analytical letters》2012,45(2):395-404
Abstract A rapid determination method for trace bisphenol A in leachate by solid phase microextraction (SPME) coupled with high performance liquid chromatography (HPLC) was developed. The experimental condition of SPME, such as select operation, solid phase microextraction fibers, pH, extraction time, extraction temperature, desorption time, desorption solution, mode, and the analytical conditions of HPLC were optimized. As compared with the graph that was produced by HPLC alone, the graph by only HPLC couldn't analyze bisphenol A and compared to the results of three solid‐phase microextraction fibers. The linear range was between 0.0128 mg/L and 0.192 mg/L in this method, and the correlative coefficient was 0.9975. Limits of detection, repeatability, and reproducibility were also determined. The limit of detection of this method was 3.25 µg/L (3σ, n=11). The relative standard deviation (RSD, n=3) was 4.4%. The method was used for the determination of trace bisphenol A in leachate of Qingshan landfill and leachate of Liufang landfill. The recoveries were between 94.5% and 103.3%. This method is fast, convenient, sensitive, solvent free, and suitable for the determination of trace bisphenol A in leachate. 相似文献
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D. Lambropoulou T. Sakellarides T. Albanis 《Analytical and bioanalytical chemistry》2000,368(6):616-623
Two methods for the analysis of ten organophosphorus insecticides in natural waters using solid phase extraction disks containing C18 and SDB and solid phase microextraction fibers containing polyacrylate (PA) are developed. Bromophos ethyl, bromophos methyl, dichlofenthion, ethion, fenamiphos, fenitrothion, fenthion, malathion, parathion ethyl and parathion methyl were determined by GC/MS and GC/FTD. The SPE-disks require only 1000 mL of sample and provide a method limit of detection in the range of 0.01–0.07 μg/L and recovery rates from 60.7 to 104.1%. The solid phase microextraction (SPME) technique requires 2–5 mL of water sample and provides a method limit of detection in the range of 0.01 to 0.05 μg/L for all detectors and the recoveries compared to distilled water ranged from 86.2 to 119.7%. The proposed methods were applied to the trace level screening determination of insecticides in river water samples originating from different Greek regions. 相似文献
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《Journal of separation science》2017,40(21):4256-4263
Polypyrrole‐magnetite dispersive micro‐solid‐phase extraction method combined with ultraviolet‐visible spectrophotometry was developed for the determination of selected cationic dyes in textile wastewater. Polypyrrole‐magnetite was used as adsorbent due to its thermal stability, magnetic properties, and ability to adsorb Rhodamine 6G and crystal violet. Dispersive micro‐solid‐phase extraction parameters were optimized, including sample pH, adsorbent amount, extraction time, and desorption solvent. The optimum polypyrrole‐magnetite dispersive micro‐solid phase‐extraction conditions were sample pH 8, 60 mg polypyrrole‐magnetite adsorbent, 5 min of extraction time, and acetonitrile as the desorption solvent. Under the optimized conditions, the polypyrrole‐magnetite dispersive micro‐solid‐phase extraction with ultraviolet‐visible method showed good linearity in the range of 0.05–7 mg/L (R 2 > 0.9980). The method also showed a good limit of detection for the dyes (0.05 mg/L) and good analyte recoveries (97.4–111.3%) with relative standard deviations < 10%. The method was successfully applied to the analysis of dyes in textile wastewater samples where the concentration found was 1.03 mg (RSD ±7.9%) and 1.13 mg/L (RSD ± 4.6%) for Rhodamine 6G and crystal violet, respectively. It can be concluded that this method can be adopted for the rapid extraction and determination of dyes at trace concentration levels. 相似文献
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亚临界水萃取及气相色谱-串联质谱法检测红茶中多种农药残留 总被引:1,自引:0,他引:1
建立了亚临界水萃取及气相色谱-串联质谱(GC-MS/MS)检测红茶中21种有机氯和拟除虫菊酯农药残留的方法。在萃取压力为5 MPa条件下,样品经150 ℃的亚临界水提取15 min后,将目标物转移至丙酮-正己烷(1:1, v/v)中,经ENVI-Carb固相萃取净化小柱净化,DB-5毛细管气相色谱柱分离,在多反应监测(MRM)模式下进行MS/MS检测,基质匹配溶液内标法定量。各目标物在5.0~320.0 μg/L范围内线性关系良好,相关系数均大于0.99,其定量限(信噪比(S/N)>10)为50 ng/g,检出限(S/N>3)为10 ng/g。茶叶基质中添加50、100和200 ng/g的标准品时,21种农药的回收率为70.18%~119.98%,相对标准偏差(RSD)为5.01%~11.76%。该方法的灵敏度、准确度和精密度均符合农药残留测定的技术要求,适用于红茶中有机氯和拟除虫菊酯农药残留的检测。 相似文献
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通过对多壁碳纳米管(MWNTs)的表面酸氧化、表面共价接枝功能化,制备了改性MWNTs,将改性MWNTs作为一种新型的固相萃取吸附剂自制了固相萃取(SPE)柱,建立了以改性MWNTs作为SPE吸附剂测定农产品中痕量2甲4氯(MCPA)和2,4-滴(2,4-D)2种苯氧羧酸类除草剂的SPE/HPLC联用分析方法.考察了氧化处理、共价接枝、SPE柱操作和色谱条件等对实验结果的影响,并优化了实验条件.在优化实验条件下,2种除草剂在较宽质量浓度范围内线性关系良好,相关系数为0.9984~0.9995,检出限为0.020mg/L;对样品分别进行0.20、5.0、50 mg/L 3种水平的加标回收率实验,2种除草剂的加标回收率为81%~105%,RSD为3.2%~8.3%.该方法用于大豆、大米和茶叶等样品的净化,效果良好,测定结果准确、灵敏度高,符合农产品中低浓度农药残留的分析要求. 相似文献