GC-ECD和LC-MS/MS测定垃圾焚烧飞灰中氯苯和氯酚的方法

氯苯和氯酚是生活垃圾焚烧过程产生的重要污染物,目前对垃圾焚烧炉飞灰中氯苯和氯酚的研究较少。本文采用超声萃取法结合GC-ECD、LC-MS/MS,建立了飞灰等固体介质中的氯苯氯酚的定量检测方法,通过实验确定出较优的前处理条件,飞灰样品中滴加少量浓硫酸,以正己烷/丙酮(1∶1)为萃取溶剂,40℃超声萃取20 min,萃取3次,然后液相萃取分离氯酚氯苯,分别净化,浓缩,最后进机检测,对三、四、五、六氯代苯和所有的氯酚均获得较好的回收率。应用建立的检测方法测试了3座正常运行过程中的生活垃圾焚烧炉飞灰的氯苯和氯酚含量,样品中一到四氯代氯酚的含量都在定量限以下,五氯酚含量范围为5~11 ng·g-1,三氯苯、四氯苯、五氯苯和六氯苯的含量在3~70 ng·g-1的范围。     

水中微量弱极性内分泌干扰物测定方法的研究

使用ENVITM Chrom P固相萃取小柱、双(三甲基硅烷基)三氟乙酰胺(BSTFA)衍生剂及气质联机,系统研究了水中弱极性内分泌干扰物(EDCs)的测定方法.通过正交试验,得到最佳固相萃取条件为:水样流速5 mL/min,洗脱剂为二氯甲烷,洗脱速率0.5 mL/min,洗脱剂体积6 mL.最佳衍生化条件为:BSTFA 100 μL,60 ℃,反应时间30 min.结果表明,双酚A、五氯酚、2,4-二氯苯酚、4-壬基酚、雌二醇、雌三醇、雌酮、炔雌二醇的回收率在82.4%～101.9%,检出限为0.01～0.06 μg/L.     

粉末活性炭对水中氯酚的吸附

2,4-二氯酚、2,4,6-三氯酚、五氯酚是氯酚类污染物的典型代表,鉴于其对人类身体健康的危害和对环境所造成的污染,已被很多国家列为环境优先控制污染物。研究粉末活性炭(PAC)对该3种氯酚的吸附过程以及投炭量、p H值和水质对PAC吸附性能的影响。结果表明:粉末活性炭可以有效去除水中的80%以上的氯酚;吸附行为符合Freundlich吸附等温线和Langmuir吸附等温线;以分子状态存在的氯酚比电离状态更容易被活性炭所吸附。     

天然锰矿催化臭氧氧化降解水中4-氯酚的研究

以天然锰矿为金属催化剂,研究了锰矿催化臭氧氧化水中4-氯酚的降解效果。采用毛细管电泳方法及色质联用技术．分别对反应的中间产物和终产物进行了分析。推测了锰矿催化臭氧氧化水中4-氯酚的降解反应机理可能为：锰矿的吸附氧化与锰矿生成的Mn^2 催化臭氧分解．产生更多高活性的羟基自由基．从而提高了臭氧的氧化能力。     

微波辅助光催化降解氯酚类污染物的研究

研究了溶液中4-氯酚(4CP)、2-氯酚(2CP)、4-氯-3-甲基酚(4C3MP)、2,4-二氯酚(2,4-DCP)、2,4,6-三氯酚(2,4,6-TCP)和五氯酚(PCP)的微波辅助光催化降解(MW/PCO).结果表明,6种氯酚(CPs)光降解速率与分子中Cl原子取代的数目、位置等分子结构性质有关,单氯酚比多取代氯酚易光解.MW/PCO降解4CP的主要中间产物为苯酚、氯苯、对苯醌、对苯二酚等,降解PCP的主要中间产物为2,3,5,6-四氯对苯醌、2,3,4,6-四氯对苯二酚、四氯酚.CPs降解的机制是紫外光降解和羟基自由基 (·OH)亲电子加成脱氯过程.     

沉积物中痕量氯代酚与氯代愈疮木酚的测定

沉积物表面吸附态的氯代酚与氯代愈疮木酚被提入缓冲溶液。于沉积物—缓冲液混合物中同时加入正己烷与酸酐,使溶解态的酚乙酰化,并将其酰化物萃取。萃取物随之用玻璃毛细管GC—ECD进行分析。测定ppb级浓度氯代酚仅需1克试样。总分析时间30分钟。污染严重的样品需进行预处理,此时分析时间为35分钟。     

A/O/O生物流化床处理焦化废水中酚类组成及降解特性分析

为了研究实际焦化废水处理工程中酚类污染物的组成及降解特性,实验中采用HLB小柱固相萃取水样,GC-MS选择性离子扫描方法检测环境中15种酚类污染物,除苯酚的平均回收率为72.6%以外,其他14种酚类的回收率在87.6%~102.3%之间,平行测定标准偏差均小于7.62%,能够满足环境中酚类污染物测定的需要。实验结果表明,焦化废水中含有高浓度的苯酚、甲基酚和萘酚,同时存在微量的氯酚和硝基酚。在生物流化床A/O/O组合工艺处理焦化废水的过程中,厌氧阶段高浓度酚类(苯酚、甲基酚和萘酚)、氯酚类去除率分别为29.3%和31.6%;一级好氧阶段分别为99%和92.4%;二级好氧阶段分别达到89%和6%;最终出水中酚类污染物浓度0.045 mg/L,满足钢铁行业废水达标排放要求。     

紫外光与超声波耦合对氯酚水溶液的降解研究

选择超声波(US)、紫外光(UV)、紫外光与超声波耦合(UV/US)3种方式对不同位置取代基的单氯酚和不同数目取代基的氯酚进行降解研究。结果表明,UV、US、UV/US对取代基位置不同的单氯酚的降解率大小均为3-氯酚4-氯酚2-氯酚;UV、UV/US对不同取代基数量的氯酚的降解率大小为2-氯酚2,4-二氯酚2,4,6-三氯酚,US单独作用下的降解率大小为2,4,6-三氯酚2,4-二氯酚2-氯酚;UV与US的耦合呈现出较优的协同效应,且耦合降解均以US的降解作用占主导;UV、US、UV/US对氯酚的降解均符合表观一级反应动力学。     

电-Fenton法处理4-氯酚废水

采用电解法对4-氯酚废水进行了处理。以活性炭纤维(ACF)为阴极，铁为阳极，并向阴极不断通入空气，电解过程中生成的H2O2与阳极溶解的Fe^2 形成Fenton(芬顿)试剂，Fenton试剂在电解的过程中可以产生大量活性羟基 OH，能够很好地氧化降解废水中的4-氯酚。在最佳试验条件下：室温，氯酚浓度为50mg／L，电解时间为60min，pH值为4．5，电流密度为15．38A／m^2，Na2SO4浓度为3g／L时，4-氯酚去除率为85．70％。     

维生素B_(12)协同纳米Fe/Cu双金属对五氯酚的催化降解与机理

针对水中含氯有机物的脱氯降解,制备了Fe/Cu双金属纳米颗粒,并引入维生素B12,研究铜负载率和维生素B12的剂量对以五氯酚为典型污染物的脱氯效果。结果表明:维生素B12和纳米零价铜能够有效提升五氯酚的脱氯速率及脱氯程度,脱氯率从4.52%增加到78.55%,降解产物从四氯酚进一步降解为苯酚。实验发现增加铜负载率可使双金属比表面积增大,催化活性位增多;增加维生素B12浓度可促进体系电子传递,使体系还原反应活性提升。铜负载率和维生素B12浓度过大均会使体系反应速率减缓甚至抑制。实验优化铜负载率为10%(质量分数),维生素B12浓度为20 mg·L~(-1)。探讨纳米零价铜和维生素B12的催化机理,以期对降解含氯有机物提供可操作性的参考。     

Fast determination of sulfonamides and their acetylated metabolites from environmental water based on magnetic molecularly imprinted polymers

Group-selective magnetic molecularly imprinted polymers (MMIPs) that can extract four widely used sulfonamide antibiotics and their acetylated metabolites from environmental water were synthesized in this study. The MMIPs with saturation magnetization value of 16.7 emu g^-1 could be separated from the environmental water samples easily by the application of an adscititious magnetic field, reducing the time consumption of pretreatment. The extraction conditions were evaluated, and optimal extraction conditions were as follows: extraction time, 25 min; amount of polymers, 90 mg; washing solvent, 30 % methanol aqueous solution; and elution solvent, methanol–acetic acid (95:5, v/v). The target analytes were detected by liquid chromatography–tandem mass spectrometry, and the detection limits of the method are in the range of 0.38–1.32 ng L^-1. The relative standard deviations of intra- and inter-day are in the range of 1.3–6.8 % and 1.7–9.1 %, respectively. The proposed method is suitable for the analysis of environmental water samples.     

Determination of pesticides of different chemical classes in drinking water of the state of Santa Catarina (Brazil) using solid-phase microextraction coupled to chromatographic determinations

The evaluation of the concentration of pesticides in drinking water presents a real concern. In this study, a simple and rapid method based on solid-phase microextraction (SPME) followed by gas chromatography–mass spectrometry and electron capture detectors was developed aiming at multiclass determination of 23 pesticides regulated by the Brazilian legislation. The extraction was carried out by direct immersion mode (DI-SPME) using DVB/Car/PDMS fiber coating. In order to improve the extraction efficiency, parameters such as temperature, salting-out effect, and extraction time were optimized. The method was evaluated using drinking water samples spiked with the analytes at different concentrations, and it showed good linearity in the range studied. The values obtained for limits of quantification (LOQ) were below the limits established by Brazilian regulations. Accuracy and precision of the method exhibited satisfactory results, providing relative recoveries from 70 to 123.34% at three spiked levels, and the relative standard deviations ranged from 0.53 to 24.8%. The method was applied in 20 drinking water samples from 13 cities in the State of Santa Catarina, Brazil.

     

Development,validation and application of a method to analyze phenols in water samples by solid phase micro extraction-gas chromatography-flame ionization detector

In this work the development, validation and application of method using Solid Phase Microexctration (SPME) for the analyses of five pollutants (phenol, 2-nitrophenol, 2,4-dimethylphenol, 2,4-dichlorophenol and 4-chloro, 3-methyl phenol) in supplying water, using gas chromatography (GC) with flame ionization detector (FID) is described. The optimal conditions obtained for SPME were: fiber type: Poliacrylate (PA); extraction time: 40 minutes; extraction temperature: 70°C; amount of salt added to sample (NaCl): 15%; desorption temperature: 8 minutes. The parameters studied in the method validation were: limit of detection (0.3 and 3.5 μ g.L^{? 1}); precision, measured by the variation coefficient (between 2.1 and 8.8%); calibration curve and linearity, by using the external standardization method (between 1 and 50 50 μ g.L^{? 1}). After the methodology development, samples of water collected in Atibaia River (São Paulo - Brazil) were analyzed, using the optimized methodology. Three water samples collected in the rain season showed a peak with retention time close to 4-chloro, 3 methyl phenol further analyzed by Gas Chromatography-Mass Spectrometry for the identity confirmation. In spite of the fact that none target compounds were found in the river water samples analyzed, the presence of two phenols different from those investigated (p-terc butyl phenol; butylated hydroxytoluene) were detected. These results together with the results of the limit of detection (that showed to be lower than the maximum concentration of phenols demanded by different environment control agencies), and the results of the validation, indicate the applicability of this method for the analysis of selected phenols in river water samples.     

Development, validation and application of a method to analyze phenols in water samples by solid phase micro extraction-gas chromatography-flame ionization detector

In this work the development, validation and application of method using Solid Phase Microexctration (SPME) for the analyses of five pollutants (phenol, 2-nitrophenol, 2,4-dimethylphenol, 2,4-dichlorophenol and 4-chloro, 3-methyl phenol) in supplying water, using gas chromatography (GC) with flame ionization detector (FID) is described. The optimal conditions obtained for SPME were: fiber type: Poliacrylate (PA); extraction time: 40 minutes; extraction temperature: 70 degrees C; amount of salt added to sample (NaCl): 15%; desorption temperature: 8 minutes. The parameters studied in the method validation were: limit of detection (0.3 and 3.5 microg.L(- 1)); precision, measured by the variation coefficient (between 2.1 and 8.8%); calibration curve and linearity, by using the external standardization method (between 1 and 50 50 microg.L(- 1)). After the methodology development, samples of water collected in Atibaia River (S?o Paulo - Brazil) were analyzed, using the optimized methodology. Three water samples collected in the rain season showed a peak with retention time close to 4-chloro, 3 methyl phenol further analyzed by Gas Chromatography-Mass Spectrometry for the identity confirmation. In spite of the fact that none target compounds were found in the river water samples analyzed, the presence of two phenols different from those investigated (p-terc butyl phenol; butylated hydroxytoluene) were detected. These results together with the results of the limit of detection (that showed to be lower than the maximum concentration of phenols demanded by different environment control agencies), and the results of the validation, indicate the applicability of this method for the analysis of selected phenols in river water samples.     

气相色谱法测定饮水中1,2,3-三氯苯的方法研究

建立了液液萃取-气相色谱法测定饮用水1,2,3-三氯苯的方法。根据测定研究,得出其方法检出限为0.05ug/L,建立的曲线回归系数高于0.995,回收率在91.17%-106.25%之间,符合要求。     

Experimental and statistical validation of SPME-GC-MS analysis of phenol and chlorophenols in raw and treated water

A procedure based on solid-phase microextraction (SPME) and gas chromatography coupled with mass spectrometry (GC-MS) was developed and validated in order to analyse 10 phenols in water samples. The optimised conditions were obtained using polyacrylate fibre (PA), 20ml of sample volume, 10% NaCl, pH 4.0 and direct extraction at 35 degrees C and 1000rpm, for 40min. The linear range and quantification limits for these compounds by SPME-GC-MS were defined. An evaluation of the main uncertainty sources of this method is included, which allows expanded uncertainties in the 9.4-35% range for the majority of the compounds. The main source of uncertainty is associated with matrix effects. The validated method is suitable for monitoring the production and distribution of potable water and was used, in field trials, for the analysis of samples from main intakes of water (surface or underground) and from water supply system of a large area (Lisbon and neighbour municipalities).     

Packed in-tube solid phase microextraction with graphene oxide supported on aminopropyl silica: Determination of target triazines in water samples

On-line in-tube solid phase microextraction (in-tube SPME) coupled to high performance liquid chromatography and tandem mass spectrometry (HPLC-MS/MS) was successfully applied to the determination of selected triazines in water samples. The method based on the employment of a packed column containing graphene oxide (GO) supported on aminopropyl silica (Si) showed that the extraction phase has a high potential for triazines extraction aiming to its physical-chemical properties including ultrahigh specific surface area, good mechanical and thermal stability and high fracture strength. Injection volume and loading time were both investigated and optimized. The method validation using Si-GO to extract and concentrate the analytes showed satisfactory results, good sensitivity, good linearity (0.2–4.0 µg L^?1) and low detection limits (1.1–2.9 ng L^?1). The high extraction efficiency was determined with enrichment factors ranging from 1.2–2.9 for the lowest level, 1.3–4.9 intermediate level and 1.2–3.0 highest level (n = 3). Although the analytes were not detected in the real samples evaluated, the method has demonstrated to be efficient through its application in the analysis of spiked triazines in ground and mineral water samples.     

Analysis of chlorothalonil and degradation products in soil and water by GC/MS and LC/MS

We present a method using gas chromatography (GC) and liquid chromatography (LC) coupled to a mass selective detector to measure concentrations of the fungicide chlorothalonil and several of its metabolites in soil and water. The methods employed solid-phase extraction using a hydrophobic polymeric phase for the isolation of analytes. In lake water, average analyte recoveries ranged from 70% to 110%, with exception of pentachloronitrobenzene that gave low recoveries (23%). The method detection limits were determined to be in the range of 1 and 0.1microg l(-1) for the LC and GC methods, respectively. In soil samples, recoveries ranged from 80% to 95% for 4-hydroxy-2,5,6-trichloroisophthalonitrile (metabolite II) and 1,3-dicarbamoyl-2,4,5,6-tetrachlorobenzene (metabolite III). Limits of detection (LOD) were 0.05 and 0.02microg g(-1), respectively. Chlorothalonil and other metabolites were analyzed by GC giving recoveries ranging from 54% to 130% with LOD of 0.001-0.005microg g(-1).     

太湖水源地水体中半挥发性有机物的监测

太湖某水源地水样经C18柱富集、气相色谱-质谱法(GC-MS)分离,定性测定其中的有机物.在丰水期、平水期、枯水期分别采样,在检测到的近百种有机化合物中有40种出现频率很高,同时运用内标法对其进行相对含量的比较,结果表明脂肪族化合物、邻苯二甲酸酯、2,6-二叔丁基-4-甲基苯酚和异氰尿酸三甲酯的相对含量较高,值得引起关注.     

Decomposition of dihaloacetonitriles in water solutions and fortified drinking water samples

An investigation of the decomposition of dihaloacetonitriles (DHANs) in water solutions and fortified drinking water samples was conducted. The concentrations of dichloroacetonitrile (CHCl2CN, DCAN), bromochloroacetonitrile (CHBrClCN, BCAN) and dibromoacetonitrile (CHBr2CN, DBAN) were determined by a gas chromatography mass spectrometry (GC-MS) method at regular time intervals and different temperatures. The effect of sodium thiosulfate (Na2S2O3), which is used as a preservative in water samples, was also examined. The rates of decomposition were determined for each compound. The results show that the reactions are faster in fortified drinking water samples than in ultrapure water solutions. They are also favored at higher temperature, especially when sodium thiosulfate is present. The highest decomposition rate is shown by DCAN, followed by BCAN and DBAN, while at the presence of sodium thiosulfate the decomposition of DBAN is the fastest.