顶空固相微萃取法同时分析源水中5种极性挥发性有机物

建立了饮用水源水中5种极性挥发性有机物同时检测的顶空-固相微萃取-气相色谱/质谱法,目标物分别为丙烯腈、环氧氯丙烷、吡啶、苯胺和硝基苯;提出了延长样品保存期限的样品保存方式,将加入内标物和过量氯化钠的样品在冷冻箱内保存,保质期至少为72 h。通过试验对影响顶空-固相微萃取效率的主要因素进行了优化,包括微萃取柱涂层、萃取温度、水样盐度及p H值、搅拌速度和萃取时间等。结果表明,50/30μm二乙烯基苯/碳分子筛/聚二甲基硅氧烷最适合作为同时萃取这5种有机物的微萃取柱涂层,所有方法参数优化后,硝基苯的方法检出限为0.14μg/L,其余目标物介于0.80~3.2μg/L。HS-SPME-GC/MS用于实际样品的检测,回收率和RSD分别介于81.1%~120%和5.89%~12.7%。     

顶空固相微萃取法用于测定水中二甲基三硫醚

采用顶空固相微萃取一气相色谱/质谱联用的方法对水中嗅味物质二甲基三硫醚进行了测定.经优化试验,得到了二甲基三硫醚固相微萃取的最佳条件:采用CAR/PDMS(85 μm)纤维头、在水样中加入25%(W/V)的NaCl、65℃水浴下顶空萃取30 min.该方法的检出限为5 ng/L,相对标准偏差为2.2%～7.1%,加标回收率为71.5%～87.3%.利用该方法对不同实际水样的检测发现,不同水源水中均有一定程度的二甲基三硫醚检出(9～40 ng/L),值得关注.     

吹扫捕集气质联用法测定饮水中挥发性有机物

目的建立吹扫捕集气质联用(P&T-GC/MS)方法测定《生活饮用水卫生标准》(GB 5749-2006)中规定的12种挥发性有机物(VOCs)。方法饮用水中的微量有机物经吹扫捕集提取后,HP-VOC毛细管色谱柱进行程序升温分离,质谱选择离子监测方式分析检测饮用水中12种挥发性有机物,外标法定量。结果 12种挥发性有机物的线性范围为0.4μg/L~100.0μg/L,浓度范围内的线性相关系数为0.998~0.999,检出限为0.011μg/L~0.196μg/L,相对标准偏差(RSD)2.37%~6.29%(n=11),加标回收率为78.0%~119.5%。结论该方法适用于饮水中12种挥发性有机物的同时测定。     

HS-SPME/GC/MS法测定水中甲硫醚和二甲基三硫醚

采用顶空固相微萃取/气相色谱/质谱联用的方法对水中两种嗅味物质——甲硫醚和二甲基三硫醚进行测定。经优化实验,得到了这两种物质固相微萃取的最佳条件,采用CAR/PDMS纤维头、在水样中加入3.0 g的Na Cl、30℃的孵化温度下顶空萃取30 min。该方法甲硫醚的检出限为5 ng/L,二甲基三硫醚的检出限为2 ng/L,测定结果的相对标准偏差为8.09%~9.55%,加标回收率为78.1%~103.8%。     

HS-SPME-GC-MS/MS测定16种硫醚类嗅味物质

针对可导致饮用水中腥臭味/沼泽味/腐败味的硫醚类物质,基于顶空固相微萃取与气相色谱三重四极杆串联质谱联用,建立了可同时快速分析水中16种硫醚类嗅味物质的方法。对萃取纤维类型、盐浓度、萃取温度、萃取和解吸时间等条件进行了优化,确定的最佳顶空固相微萃取条件为：水样加入20%NaCl,采用DVB/PDMS/Carbon WR萃取纤维于45℃条件下萃取30 min,在250℃条件下解吸180 s。16种硫醚的标准曲线具有较好的线性（R2>0.99）,检出限为0.2～2.9 ng/L,超纯水和原水加标回收率分别为80.4%～105.4%和78.3%～108.2%,相对标准偏差分别为0.7%～13.4%和1.6%～14.1%,可满足饮用水及水源中硫醚类嗅味物质的快速检测。采用该方法对三个水厂的原水进行了分析,有二甲基二硫醚（4.2～45.3 ng/L）、二甲基三硫醚（1.9～6.1 ng/L）和二乙基二硫醚（N.D.～1.5 ng/L）检出,值得关注。     

顶空固相微萃取-气质联用法测定水中7种致嗅物质

采用自动顶空固相微萃取-气相色谱/质谱联用技术,建立了一种快速测定水中7种腥味醛类物质的方法,重点针对纤维萃取头类型、萃取方式、萃取温度、萃取时间以及离子强度等影响因素进行了优化。自动固相微萃取优化后条件为:CAR/PDMS(85μm)纤维头,Na Cl含量25%(W/V),65℃恒温振荡10 min,顶空萃取20 min,250℃下解吸3 min进入气相色谱/质谱进行分析。在优化的前处理和分析条件下,7种物质的回收率为86.30%~113.61%,方法检出限为1.61~17.53 ng/L,远低于各种物质的嗅阈值。     

顶空固相微萃取/气相色谱/质谱法测定水中二溴乙烯

建立了顶空固相微萃取(HS-SPME)与气相色谱-质谱(GC-MS)联用测定水中二溴乙烯的分析方法。对固相微萃取纤维类型、萃取温度、萃取时间等萃取条件进行了优化。结果表明,最佳萃取条件为采用DVB/CAR/PDMS固相微萃取纤维头,萃取温度为60℃,萃取时间为15min。该分析方法在20~500 ng/L范围内线性良好,顺(反)-二溴乙烯方法检出限分别为3.72、2.36 ng/L,相对标准偏差小于10%,回收率范围为85.7%~111%。该方法操作简单、省时,检测结果准确、可靠,适用于生活饮用水及其水源水的分析。     

顶空固相微萃取/气相色谱/质谱法检测饮用水中戊二醛

采用顶空固相微萃取/气相色谱/质谱法(HS/SPME/GC/MS)测定生活饮用水中戊二醛。对顶空固相微萃取的参数进行了优化,确认了最优实验条件,Na Cl加入量为0.6 g/m L、样品p H值为7、萃取时间为20 min、萃取温度为70℃、解吸时间为200 s。在优化实验条件下采用气相色谱/质谱选择性离子扫描方式(SIM)进行定量分析,戊二醛的保留时间为7.76 min,线性范围为0.030～0.60 mg/L,线性关系良好(r为0.998),定量限为0.030 mg/L。对实际水样进行分析,加标回收率为91.0%～99.9%,相对标准偏差为1.7%～5.4%(n=6)。本方法操作简单,环境友好,能够快速、灵敏、准确地测定生活饮用水中戊二醛的含量。     

吹扫捕集-气相色谱/质谱联用法测定饮用水中28种挥发性有机物

建立了吹扫捕集-气相色谱/质谱联用(PT-GC/MS)测定《生活饮用水卫生标准》(GB 5749-2006)中规定的28种挥发性有机物(VOCs)的方法。水样中微量或痕量的有机物经吹扫捕集后,经DB-VRX毛细管色谱柱进行程序升温分离,质谱选择离子监测(SIM)方式,内标法定量。28种VOCs的加标回收率为90. 1%～110%,线性相关系数为0. 9990～0. 9998,检出限(S/N=3)为0. 002～0. 129μg/L,相对标准偏差(RSD)在2. 93%～9. 21%。该方法具有操作简便、灵敏快速的优点,适用于同时测定饮用水中的28种VOCs。     

气相动态顶空进样同时分析饮用水源水中17种有机物

建立了对饮用水源水中乙醛、丙烯醛、丙烯腈、环氧氯丙烷、硝基苯、硝基氯苯、氯苯、二氯苯、三氯苯和四氯苯进行同时分析的气相动态顶空进样-气相色谱-质谱法(D-HS-GCMS),目标物均为集中式生活饮用水地表水源地特定项目。经过对比试验,确定了优化后的气相动态顶空进样法主要参数:样品盐度为35%、平衡温度为50℃、平衡时间为10 min、吹脱捕集气流速为60 mL/min、吹脱捕集时间为15 min。利用优化后的方法参数对乙醛等17种有机物进行分析,环氧氯丙烷和丙烯腈的方法检出限分别为7和19μg/L,乙醛、丙烯醛、硝基苯和硝基氯苯的方法检出限介于0.7~1.5μg/L,氯苯类化合物的检出限则为0.003~0.015μg/L。使用气相动态顶空进样法对饮用水源水实际样品进行监测,加标回收率均值介于78.7%~128%,对应的RSD为2.8%~23.0%(n=5)。     

固相萃取/气相色谱/质谱法测定饮用水中毒死蜱

建立了检测饮用水中毒死蜱的固相萃取/气相色谱/质谱法,该方法对毒死蜱的测定下限可达0.000 6 mg/L,远低于国标法的0.002 mg/L。线性范围为0.5～5.0 mg/L,样品平均加标回收率在74.86%～86.14%之间,测定结果的相对标准偏差<5.4%。该方法简单、灵敏度高、准确、重现性好,可用于饮用水中痕量毒死蜱的测定。     

饮用水水源中锑、砷、铊的综合去除方法研究

采用混合预氧化和强化混凝方法处理Sb、As和Ti质量浓度分别为20,25和20μg/L的模拟水源水。经过分析得到最佳的综合处理条件为:高锰酸钾投加量0.50~1.00 mg/L,次氯酸钠投加量1.00~1.50 mg/L,聚合硫酸铁投加量30 mg/L,pH值6.0。将该方法应用到受污染的饮用水水源(Sb≤20μg/L、As≤25μg/L、Ti≤0.20μg/L)常规处理工艺中,Sb、As和Ti的质量浓度分别由原来的16.2,8.1和0.15μg/L降至3.9,2.8和0.06μg/L,去除率分别为75.9%,84.5%和60.0%,该方法可为应对饮用水水源污染突发事件采取经济可行的应急措施提供参考。     

Impact of source waters,disinfectants, seasons and treatment approaches on trihalomethanes in drinking water: a comparison based on the size of municipal systems

This study compares concentrations of trihalomethanes (THMs) in municipal water for 2001–2007 from the small and large systems in two provinces in Canada (Newfoundland and Quebec) based on source waters, disinfectants, seasons and treatment approaches. Approximately 71 and 94%, respectively, of the municipal systems in Quebec and Newfoundland are small systems (serving fewer than 3000 people). The small systems serve approximately 8.6% (0.57 million) and 44.1% (0.18 million) of the populations in Quebec and Newfoundland, respectively. Concentrations of THMs and its variability are much higher in the small systems (Quebec: 0–941 μg/L; Newfoundland: 0–875 μg/L) than in the systems with populations 10 000 or more (Quebec: 0–364 μg/L; Newfoundland: 2.3–205 μg/L). The study reveals that the differences in THMs between the small and medium/large systems are because of different types of source waters, treatments, disinfection strategies and seasons. The results emphasize that regulatory agencies must focus more on the occurrence of DBPs in small systems and identify strategies to reduce their levels in drinking water.     

气相色谱法同时测定水中多种有机氯农药和多氯联苯

建立了一种同时测定水中16种有机氯农药(OCPs)和8种多氯联苯(PCBs)的气相色谱/电子捕获分析方法。样品经正己烷液液萃取、氮吹浓缩后,以自动不分流进样方式用气相色谱/电子捕获器检测,并对色谱条件进行优化,采用外标法定量。在较佳的试验条件下,16种OCPs和8种PCBs标准曲线的线性相关系数为0.999 0～0.999 9,方法检出限为0.001～0.002μg/L,OCPs和PCBs的平均加标回收率分别在(88.1%～107.0%)、(91.8%～104.2%)之间,相对标准偏差(RSD,n=5)分别为(2.87%～10.42%)、(3.96%～9.02%)。该方法灵敏、准确、稳定,分析时间短,适用于大批量水样中痕量有机氯农药和多氯联苯的测定。     

超高效液相色谱-高分辨质谱法测定水体中青霉素残留

采用超高效液相色谱-高分辨质谱法(UPLC-HRMS)同时测定水体中7种青霉素残留。水样经Oasis HLB固相萃取小柱富集和净化后,用反向C18色谱柱分离,以0.1%的甲酸水溶液和乙腈溶液为流动相进行梯度洗脱,采用电喷雾离子源正离子模式进行检测。7种青霉素类化合物在1.0~20.0μg/L的线性范围内,相关系数r均大于0.99,检出限为1~10 ng/L。实际水样加标回收率为91.15%~106.36%,相对标准偏差为2.30%~8.47%,均小于10%。该方法具有简单快速、准确度高等特点,可以实现水体中7种目标青霉素残留的测定。     

Occurrence of nine nitrosamines and secondary amines in source water and drinking water: Potential of secondary amines as nitrosamine precursors

Due to their high carcinogenicity, the control of nitrosamines, a group of disinfection by-products (DBPs), is an important issue for drinking water supplies. In this study, a method using ultra-performance liquid chromatography-electrospray ionization tandem mass spectrometry was improved for simultaneously analyzing nine nitrosamines in source water and finished water samples of twelve drinking water treatment plants (DWTPs) in China. The method detection limits of the nine target analytes were 0.2-0.9 ng/L for the source water samples and 0.1-0.7 ng/L for the finished water samples. Of the nine nitrosamines, six (N-nitrosodimethylamine (NDMA), nitrosodiethylamine (NDEA), N-nitrosomorpholine (NMor), N-nitrosodi-n-butylamine (NDBA), N-nitrosomethylethylamine (NMEA), and N-nitrosodiphenylamine (NDPhA)) were detected. The total nitrosamine concentrations in source water and finished water samples were no detection-42.4 ng/L and no detection-26.3 ng/L, respectively, and NDMA (no detection-13.9 ng/L and no detection-20.5 ng/L, respectively) and NDEA (no detection-16.3 ng/L and no detection-14.0 ng/L, respectively) were the most abundant. Meanwhile, the occurrence of nine secondary amines corresponding to the nine nitrosamines was also investigated. All of them except for di-n-propylamine were detected in some source water and finished water samples, and dimethylamine (no detection-3.9 μg/L and no detection-4.0 μg/L, respectively) and diethylamine (no detection-2.4 μg/L and no detection-1.8 μg/L, respectively) were the most abundant ones. Controlled experiments involving chloramination of four secondary amines confirmed that dimethylamine, diethylamine, morpholine and di-n-butylamine in water can form the corresponding nitrosamines, with diethylamine and morpholine showing significantly higher yields than dimethylamine which has already been identified as a precursor of NDMA. This study proved that diethylamine, morpholine and di-n-butylamine detected in raw water would be one of the important the precursors of NDEA, NMOR and NDBA, respectively, in drinking water.     

A survey of organic contaminants in household and bottled drinking waters in Kuwait

Chemical analysis of volatile organic compounds (VOCs) and semivolatiles (SVs), including pesticides, was performed on 623 and 568 samples, respectively, of household drinking water, as well as on 113 samples from 71 brands of bottled water available in Kuwaiti markets. The analysis was performed according to United States Environmental Protection Agency (US-EPA) Methods 524.2 and 525.2. Nine VOCs and eight SVs were found in household water. Furthermore, between one and seven of 12 VOCs were detected in 93% of the bottled water brands. All bottled waters were found to be completely free of SVs. Styrene was the main pollutant found in all brands packaged in polystyrene containers of sizes 200-mL and 250-mL, with levels generally higher than the WHO guideline value of 20 µg/L. The levels of styrene, toluene, ethyl benzene and xylenes were found to increase with storage time, which indicates that these VOCs were migrating from the container material. No effect was detected due to changes in the storage temperature. All detected VOCs and SVs in household and bottled waters, except styrene, were found at concentrations much lower than those established as safe by WHO guidelines and US-EPA maximum contaminant levels (MCLs), respectively.     

Trihalomethanes in the drinking water of Concepción and Talcahuano,Chile

Formation of trihalomethanes (THMs) during water disinfection has been related to several health problems, although the magnitude of these effects is under discussion. This paper quantifies the THMs in drinking water from the Bío‐Bío Region of central Chile, the first since the modification of the national reference value (Nch 409/05) to include maximal values for THMs. THMs were quantified using a solid phase micro‐extraction (SPME) method and GC‐MS. The concentration ranges were 9.7–111.6, 0.1–1.0 and 0.9–25.5 μg/L for chloroform (CHCl₃), and dibromochloromethane (CHClBr₂) and bromodichloromethane (CHCl₂Br), respectively. Bromoform was not detected in any sample. There were good correlations (R²=0.91–0.98, P<0.001) between the THMs and the residence time of the water, the distance from the treatment plant and an inverse correlation to free chlorine in the water. The Additive Toxicity Index Value (0.07–1.00) showed that all samples were within the Chilean reference value for THMs in drinking water. However, several values were close to exceeding the maximum permitted concentration (200, 100, 100 and 60 μg/L for CHCl₃, CHBr₃, CHClBr₂ and CHCl₂Br, respectively), which may occur when the water demand is low and thus residence times are longer.     

Determining estrogenic steroids in Taipei waters and removal in drinking water treatment using high-flow solid-phase extraction and liquid chromatography/tandem mass spectrometry

River water and wastewater treatment plant (WWTP) effluents from metropolitan Taipei, Taiwan were tested for the presence of the pollutants estrone (E1), estriol (E3), 17beta-estradiol (E2), and 17alpha-ethinylestradiol (EE2) using a new methodology that involves high-flow solid-phase extraction and liquid chromatography/tandem mass spectrometry. The method was also used to investigate the removal of the analytes by conventional drinking water treatment processes. Without adjusting the pH, we extracted 1-L samples with PolarPlus C18 Speedisks under a flow rate exceeding 100 mL/min, in which six samples could be done simultaneously using an extraction station. The adsorbent was washed with 40% methanol/60% water and then eluted by 50% methanol/50% dichloromethane. The eluate was concentrated until almost dry and was reconstituted by 20 microL of methanol. Quantitation was done by LC-MS/MS-negative electrospray ionization in the selected reaction monitoring mode with isotope-dilution techniques. The mobile phase was 10 mM N-methylmorpholine aqueous solution/acetonitrile with gradient elution. Mean recoveries of spiked Milli-Q water were 65-79% and precisions were within 2-20% of the tested concentrations (5.0-200 ng/L). The method was validated with spiked upstream river water; precisions were most within 10% of the tested concentrations (10-100 ng/L) with most RSDs<10%. LODs of the environmental matrixes were 0.78-7.65 ng/L. A pre-filtration step before solid-phase extraction may significantly influence the measurement of E1 and EE2 concentrations; disk overloading by water matrix may also impact analyte recoveries along with ion suppression. In the Taipei water study, the four steroid estrogens were detected in river samples (ca. 15 ng/L for E2 and EE2 and 35-45 ng/L for E1 and E3). Average levels of 19-26 ng/L for E1, E2, and EE2 were detected in most wastewater effluents, while only a single effluent sample contained E3. The higher level in the river was likely caused by the discharge of untreated human and farming waste into the water. In the drinking water treatment simulations, coagulation removed 20-50% of the estrogens. An increased dose of aluminum sulfate did not improve the performance. Despite the reactive phenolic moiety in the analytes, the steroids were decreased only 20-44% of the initial concentrations in pre- or post-chlorination. Rapid filtration, with crushed anthracite playing a major role, took out more than 84% of the estrogens. Except for E3, the whole procedure successfully removed most of the estrogens even if the initial concentration reached levels as high as 500 ng/L.     

Effect of medium-pressure UV irradiation on bromate concentrations in drinking water, a pilot-scale study

This study investigated the potential for bromate removal from drinking water on irradiation with medium-pressure UV lamps-a technique gaining considerable interest for drinking water disinfection. Waters from two different sources were spiked with 20microg/L of bromate and irradiated with UV fluences up to 718mJ/cm(2) utilizing a pilot-scale reactor (Calgon Carbon Corp.) at a flow of 76L/min (20 gallon/min). Essentially no removal was observed in one of the source waters. Limited bromate removal, up to 19%, was observed in the second source water at high UV fluences (696mJ/cm(2)) and a fluence-response relationship was clearly evident. All removals would be negligible at UV fluences anticipated for drinking water disinfection (< or =40mJ/cm(2)). Different water characteristics, in particular competitive absorption by nitrate and possibly DOC, were most likely responsible for the differences in bromate removal in the waters tested. The source water that did not show any removal had a higher nitrate concentration (4 vs. 0.1mg N/L) and also a higher DOC concentration (4.1 vs. 3.1mg C/L) than the other source water which showed 19% bromate removal.