痕量壬基酚及相关化合物的样品预处理和测定

对近年来环境样品中痕量内分泌干扰物壬基酚及相关化合物的分离富集方法和测定技术的研究进展进行了综合评述。重点讨论了索氏提取、液液萃取、液膜分离、回流萃取、固相萃取、固相微萃取、超临界流体萃取、超声提取八种样品预处理方法和气相色谱质谱联用、高效液相色谱两种测定方法,而且针对以上方面提出了尚需进一步研究的问题。     

光催化降解水体异味物质2-MIB的机理

以水体异味物质2-甲基异莰醇(2-methylisoborneol,2-MIB)为研究对象,在紫外光(λ<380 nm)照射下,探讨TiO2(P25)对2-MIB的光催化降解特性及光化学作用机理。结果表明,UV/TiO2光催化体系可以有效去除水体异味物质2-MIB,紫外光照射60 min,对2-MIB的降解率达95%。同时研究了光催化降解体系介质pH,共存腐殖酸(HA)和过硫酸钾(K2S2O8)对UV/TiO2光催化体系降解2-MIB的影响,发现低浓度HA([HA]≤0.5 mg/L)可以提高2-MIB降解速率,当HA浓度高于0.5 mg/L,2-MIB降解反应受到抑制;同时当加入电子受体K2S2O8后,降解体系中活性物种羟基自由基(.OH)明显增加,提高了TiO2对2-MIB的降解能力。利用苯甲酸荧光光度法和POD-DPD显色法跟踪测定降解过程中羟基自由基(·OH)和过氧化氢(H2O2)的变化,表明光催化反应涉及·OH机理。     

顶空箭型固相微萃取—气相色谱—串联质谱法测定水中9种藻致异味物质

通过单因素设计实验考查萃取时间、萃取温度和氯化钠加入量对9种藻致异味物质(2-甲基异莰醇、土臭素、2-异丙基-3-甲氧基吡嗪、2-异丁基-3-甲氧基吡嗪、2,4,6-三氯苯甲醚、2,3,6-三氯苯甲醚、2,3,4-三氯苯甲醚、β-紫罗兰酮、β-环柠檬醛)萃取效果的影响,并通过响应面设计进一步优化得到顶空箭型固相微萃取的条件,建立了顶空箭型固相微萃取—气相色谱—串联质谱法高效测定水中9种典型藻致异味物质的方法,并进行方法学验证。结果表明,最佳萃取条件为每5.0 mL水样萃取时间10.0 min、萃取温度40℃、氯化钠加入量1.78 g。利用优化方法分析苏州河实际水样,检出4种藻致异味物质,加标回收率为63.8%～140.0%,精密度为0.67%～15.50%,该方法可有效应用于地表水中藻致异味物质的检测。     

固相萃取分离富集分光光度法测定水环境中的二价铁

提出了应用固相萃取分离富集分光光度法测定水环境中痕量Fe2 的新方法.水样中的Fe2 首先与1,10-邻二氮菲(1,10-phen)络合剂作用生成有色阳离子络合物, 然后通过Sep-Pak C18柱预富集分离,以乙醇和盐酸混合溶液为洗提液,在509 nm测定痕量Fe2 .同时,以人工海水为对象详细讨论了盐含量对分析测定的影响.该方法灵敏度高, 选择性好,方法的最低检测限2.9 μg/L,相对标准偏差0.93%,可用于测定淡水和海水水样中痕量Fe2 , 回收率为92%～102%.     

饮用水中典型致嗅物质吹扫捕集-气相色谱质谱检测方法及优化

采用吹扫捕集/气相色谱-质谱(GC-MS)法对饮用水中致嗅物质2-甲基异茨醇(2-MIB)和土臭素(GSM)进行测定。通过调整吹扫温度、吹扫时间、吹扫时捕集阱的温度、六通阀温度和传输管线温度,分析吹扫捕集条件对吹扫捕集效率的影响,并确定最佳吹扫捕集条件。2-MIB和GSM的方法检出限(MDL)分别为0.729 ng·L~(-1)和1.037 ng·L~(-1),方法定量限(MQL)分别为2.187 ng·L~(-1)和3.112 ng·L~(-1),平均加标回收率分别在92%~108%和88%~104%范围内,相对标准偏差分别小于6.5%和9.0%.在20~300 ng·L~(-1)的范围内,各异嗅化合物浓度与响应值的线性关系均良好,相关系数均大于0.999。该方法具有操作简便、检出限低,相关性良好、灵敏度高、重复性好等优点。     

固相萃取与气相色谱-质谱联用测定水中痕量多环芳烃

采用固相萃取与气相色谱-质谱联用测定水中痕量多环芳烃(PAHs)。通过正交试验,得到最佳固相萃取条件为:上样流速为5mL/min、采用二氯甲烷洗脱、洗脱剂用量为3mL、洗脱流速为2mL/min。测定结果显示,固相萃取与气相色谱—质谱联用技术对萘、菲、荧蒽3种PAHs的检出限为0.03～0.07μg/L,加标回收率为70%～100%,相对标准偏差为3.90%～9.58%。该方法精密度高、准确度好,能满足实际水样中痕量PAHs的测定要求。     

分散固相萃取法萃取再生水中DBP与DEHP

为定量分析再生水中邻苯二甲酸二丁酯(DBP)和邻苯二甲酸二(2-乙基己基)酯(DEHP)痕量环境激素,考察了分散固相萃取(DSPE)预处理方法的萃取条件,并用于实际再生水样的预处理分析。结果表明,当萃取剂(HC-C18)用量为0.20 g、洗脱剂为6 m L乙酸乙酯、萃取时间为20 min、摇床振荡速度为200 r·min~(-1)、萃取温度为50℃时,DBP与DEHP回收率分别为96.91%和101.82%。2种物质在0.50~50.00μg·L~(-1)范围内线性良好,相关系数(R2)分别为0.998 6和0.998 8,检出限分别是0.05和0.008μg·L~(-1),加标回收率平均为96.58%和97.23%,相对标准偏差分别为3.37%~8.29%和4.91%~5.74%。该方法无需过滤水样,能够减少目标物在过滤过程中的损失,预处理时间短,且不会造成萃取小柱堵塞,适用于水质变化大、悬浮物含量高的再生水分析。采用DSPE-GC-MS方法对再生水中DBP、DEHP检测分析,方法的准确度和精密度满足痕量物质分析要求。     

聚丙烯基改性纤维固相萃取水中的苯酚

通过高能电子束辐照的方法,在聚丙烯（PP）纤维基体上分别接枝长链丙烯酸十八酯（SA）和亲水性丙烯酸-β-羟乙酯（HEA）2种单体,并将该纤维作为固相萃取填料,用于固相萃取（SPE）水中的痕量苯酚。研究了SPE过程中上样速度、洗脱溶剂、洗脱体积以及洗脱速度等因素对纤维萃取效果的影响。结果表明,改性纤维对痕量苯酚的富集倍数达95~145倍,回收率达到90%~98%,甲醇对纤维有良好的再生效果,纤维重复使用6次以内时,吸附性能无明显变化。     

有机改性剂对水中有机氯农药提取效率的影响研究

通过有机改性剂在液液萃取和固相萃取条件下水中有机氯农药的提取效率比对分析,首次探讨了有机改性剂对水中有机氯农药提取效率的影响。结果表明,(1)液液萃取前处理水样中不加有机改性剂、固相萃取前处理水样中添加一定量有机改性剂时,水中有机氯农药的提取效率较高;(2)采用正交实验优化水中有机氯农药固相萃取的提取效率实验表明,有机改性剂添加量对其影响大于有机改性剂种类对其影响;最佳优化方案为水样中添加1%甲醇时,提取效率最高。     

固相萃取-气相色谱/质谱法测定水中多环芳烃

建立了固相萃取-气相色谱／质谱联用测定水中多环芳烃(PAHs)的分析方法．优化了固相萃取条件。结果表明,固相萃取效率高、萃取时间短,采用MS的选择离子检测方式对实际水样中PAHs进行定性定量分析,平均回收率在80．4％～115％之间,相对标准偏差为7．03％～18．5％,方法的检出限在0．010～0．020μg／L之间。通过实际样品中PAHs的分析表明,该法快速,溶剂用量少,能满足痕量分析的要求。     

Multiresidue analysis of organophosphate and pyrethroid pesticides in duplicate-diet solid food by pressurized liquid extraction

An analytical method was developed for determining organophosphate pesticides (OPP) and pyrethroid pesticides (PYR) in duplicate-diet solid food. The method consisted of pressurized liquid extraction (PLE) with dichloromethane followed by cleanup with gel permeation and solid phase extraction columns and gas chromatography/mass spectrometry (GC/MS) analysis. Quantitative recoveries (73–117 %) of the target pesticides were obtained for spiked duplicate-diet food samples. The percent standard deviation (% RSD) of replicate food samples was within ± 20 %. Another method was developed for determining a common OPP metabolite, 3, 5, 6-trichloro-2-pyridinol (TCP) in duplicate-diet food. The method consisted of a PLE with methanol followed by liquid-liquid partitioning, derivatization, and GC/MS analysis. Recoveries of TCP ranged from 83 to 101 % for spiked duplicate-diet food samples. The % RSD of replicate food samples was within ± 15 %. The results confirmed that these methods are reliable and robust, and that they can be used in routine analysis. In addition, a storage stability study for a common OPP, chlorpyrifos (CPF), in solid food samples was performed. The fortified ¹⁵N-¹³C-labeled CPF was stable over 16 mo storage at ?20° C in the dark. The developed analytical methods were successfully applied to 278 duplicate-diet food samples from preschool children, demonstrating that these methods are robust and suitable for routine analysis in future exposure monitoring studies.     

Multiresidue analysis of organophosphate and pyrethroid pesticides in duplicate-diet solid food by pressurized liquid extraction

An analytical method was developed for determining organophosphate pesticides (OPP) and pyrethroid pesticides (PYR) in duplicate-diet solid food. The method consisted of pressurized liquid extraction (PLE) with dichloromethane followed by cleanup with gel permeation and solid phase extraction columns and gas chromatography/mass spectrometry (GC/MS) analysis. Quantitative recoveries (73-117 %) of the target pesticides were obtained for spiked duplicate-diet food samples. The percent standard deviation (% RSD) of replicate food samples was within ± 20 %. Another method was developed for determining a common OPP metabolite, 3, 5, 6-trichloro-2-pyridinol (TCP) in duplicate-diet food. The method consisted of a PLE with methanol followed by liquid-liquid partitioning, derivatization, and GC/MS analysis. Recoveries of TCP ranged from 83 to 101 % for spiked duplicate-diet food samples. The % RSD of replicate food samples was within ± 15 %. The results confirmed that these methods are reliable and robust, and that they can be used in routine analysis. In addition, a storage stability study for a common OPP, chlorpyrifos (CPF), in solid food samples was performed. The fortified (15)N-(13)C-labeled CPF was stable over 16 mo storage at -20° C in the dark. The developed analytical methods were successfully applied to 278 duplicate-diet food samples from preschool children, demonstrating that these methods are robust and suitable for routine analysis in future exposure monitoring studies.     

Influence of rate-limited sorption on the cleanup of layered soils by vapor extraction

The conditions under which rate-limited sorption is important for cleanup of layered soils by vapor extraction are investigated. The investigation includes two steps: (a) the cleanup time is estimated for a number of scenario cases by means of a numerical model and (b) the numerical results are approximated using analytical solutions derived for simplified models. In this way, equations are derived, which give insight into the influence of different parameters characterizing the properties of the soil, the geometry of the formation, the mass transfer mechanisms in it, and the distribution of the contaminant mass in the different phases (gas phase, water phase and solid phase). The numerical model used is based on the advection-dispersion differential equations for Darcian isothermal airflow, local equilibrium contaminant mass transfer between gas phase and soil water and first-order kinetics for mass transfer between soil water and solid phase. The numerical results are approximated combining an analytical solution to estimate cleanup time in layered formations for local equilibrium sorption, which has been presented in a previous work (J. Contam. Hydrol., 36 (1999) 105). with an analytical solution based on the well-mixed reservoir model under consideration of rate-limited sorption. The analytical approximation of the cleanup time is in reasonable agreement with the numerical results and allows its estimation with small computational effort.     

Determination of phenolic and steroid endocrine disrupting compounds in environmental matrices

BACKGROUND, AIM AND SCOPE: Many pollutants have received significant attention due to their potential estrogenic effect and are classified as endocrine disrupting compounds (EDCs). EDCs comprise many classes of organic compounds. The development or optimization of analytical protocols for the simultaneous determination of EDCs in environmental samples is an analytical challenge because these compounds exhibit different physicochemical characteristics, they occur in the aquatic environment in relatively low concentrations and, furthermore, environmental samples are considered as complex matrices. The aim of this study is the development of analytical methods for the simultaneous determination of phenolic and steroid EDCs in aqueous and solid samples. The target compounds are 4-nonylphenol, 4-octylphenol, their ethoxylate oligomers (mono- and di-ethoxylates of nonylphenol and octylphenol), bisphenol A, the estrogens (estriol, estrone, 17beta-estradiol, 17alpha-estradiol) and the synthetic steroids (mestranol and 17alpha-ethynylestradiol). MATERIALS AND METHODS: Solid phase extraction employing Oasis HLB cartridges and different elution solvents was used for the recovery studies of the target compounds from various types of water samples (ultrapure water, artificial seawater, river water and seawater). Ultrasonic assisted extraction was applied for the recovery of the target EDCs from the solid samples. The recoveries were assessed using various solvents for the extraction and the elution of EDCs from different SPE cartridges used for clean up. Gas chromatography-mass spectrometry after derivatization with N,O-bis(trimethylsilyl)-trifluoroacetamide was employed for the determination of these compounds. RESULTS AND DISCUSSION: The recovery rates of three elution solvents (methanol, acetone and ethylacetate) for the extraction of target EDCs from artificial seawater were assessed after preconcentration on SPE cartridges. Acetone showed better recoveries and was further tested for its extraction efficiency in different water types (river water, seawater). Ultrasonic assisted extraction was used for the recovery of target EDCs from solid matrices. Acetone, methanol, mixture of acetone-methanol (1:1) and ethylacetate were used as extraction solvents. Ethylacetate and the mixture of acetone-methanol (1:1) exhibited better extraction efficiencies. An additional clean up step was necessary for sediment samples. Different SPE cartridges were employed for clean up of the extracts (Oasis HLB, C18, Florisil, silica, combination of silica and alumina). Florisil cartridges were finally used. The proposed methods were further validated on the determination of target EDCs in field collected samples (river water, seawater, wastewater, total suspended solids and sediments) from the major area of Thessaloniki, Greece. CONCLUSIONS: Efficient and accurate integrated methods for the simultaneous determination of alkylphenols (nonylphenol, octylphenol), their ethoxylate oligomers (mono- and di-ethoxylate of nonylphenol and octylphenol), bisphenol A and steroids (estriol, estrone, 17beta-estradiol, 17alpha-estradiol, mestranol and 17alpha-ethynylestradiol) in aqueous and solid samples were developed. The proposed methods were applied for the determination of the target compounds in representative environmental samples in the area of Thessaloniki, Northern Greece. RECOMMENDATIONS AND PERSPECTIVES: This study confirms the occurrence of selected EDCs in inland and marine waters in the area of Thessaloniki, Northern Greece. Since there is no previous data on the occurrence of the target EDCs in the major area, an extended survey is in progress to evaluate the occurrence and fate of these compounds.     

Rapid resolution liquid chromatography-tandem mass spectrometry method for the determination of endocrine disrupting chemicals (EDCs), pharmaceuticals and personal care products (PPCPs) in wastewater irrigated soils

A multiresidue analytical method was developed for the determination of 9 endocrine disrupting chemicals (EDCs) and 19 pharmaceuticals and personal care products (PPCPs) including acidic and neutral pharmaceuticals in water and soil samples using rapid resolution liquid chromatography-tandem mass spectrometry (RRLC-MS/MS). Solid phase extraction (SPE), and ultrasonic extraction combined with silica gel purification were applied as pretreatment methods for water and soil samples, respectively. The extracts of the EDCs and PPCPs in water and soil samples were then analyzed by RRLC-MS/MS in electrospray ionization (ESI) mode in three independent runs. The chromatographic mobile phases consisted of Milli-Q water and acetonitrile for EDCs and neutral pharmaceuticals, and Milli-Q water containing 0.01 % acetic acid (v/v) and acetonitrile: methanol (1:1, v/v) for acidic pharmaceuticals at a flow rate of 0.3 mL/min. Most of the target compounds exhibited signal suppression due to matrix effects. Measures taken to reduce matrix effects included use of isotope-labeled internal standards, and application of matrix-match calibration curves in the RRLC-MS/MS analyses. The limits of quantitation ranged between 0.15 and 14.08 ng/L for water samples and between 0.06 and 10.64 ng/g for solid samples. The recoveries for the target analytes ranged from 62 to 208 % in water samples and 43 to 177 % in solid samples, with majority of the target compounds having recoveries ranging between 70–120 %. Precision, expressed as the relative standard deviation (RSD), was obtained less than 7.6 and 20.5 % for repeatability and reproducibility, respectively. The established method was successfully applied to the water and soil samples from four irrigated plots in Guangzhou. Six compounds namely bisphenol-A, 4-nonylphenol, triclosan, triclocarban, salicylic acid and clofibric acid were detected in the soils.     

Pesticide residues in thermal mineral water in Greece

Eight different hot springs (SPA) in Greece were monitored over a one-year survey for priority pesticide residues. A specific and effective procedure including solid phase extraction in combination with HPLC and GC analytical methods were applied. Samples that were sensitive to nitrogen-phosphorus (NPD) and/or electron capture (ECD) detectors were analysed by capillary gas chromatography. From the twenty-six water samples, pesticide residues were detected in fourteen of them (54%) but no one exceeding the European Union Maximum Acceptable Concentration (MAC). Lindane (gamma-BHC) was the most frequently detected pesticide. It was found in nine samples (35%) in concentrations from < 0.005 to 0.01 microg/L. Other pesticides detected were phorate (in five samples), propachlor (in two samples) and chlorpyriphos ethyl (in three samples) but in concentrations far below the permissible levels.     

PESTICIDE RESIDUES IN THERMAL MINERAL WATER IN GREECE

Eight different hot springs (SPA) in Greece were monitored over a one-year survey for priority pesticide residues. A specific and effective procedure including solid phase extraction in combination with HPLC and GC analytical methods were applied. Samples that were sensitive to nitrogen-phosphorus (NPD) and/or electron capture (ECD) detectors were analysed by capillary gas chromatography.

From the twenty-six water samples, pesticide residues were detected in fourteen of them (54%) but no one exceeding the European Union Maximum Acceptable Concentration (MAC).

Lindane (γ-BHC) was the most frequently detected pesticide. It was found in nine samples (35%) in concentrations from <0.005 to 0.01 μg/L. Other pesticides detected were phorate (in five samples), propachlor (in two samples) and chlorpyriphos ethyl (in three samples) but in concentrations far below the permissible levels.     

Simultaneous quantification of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and pharmaceuticals and personal care products (PPCPs) in Mississippi river water, in New Orleans, Louisiana, USA

An effective analytical method for simultaneously determining 16 polycyclic aromatic hydrocarbons (PAHs), 28 polychlorinated biphenyl (PCBs), and 12 pharmaceuticals and personal care products (PPCPs) has been developed to measure their concentrations in the Mississippi river waters in New Orleans, Louisiana, USA. The method involves the simultaneous extraction of the selected PAHs, PCBs, and PPCPs, from the aqueous phase by solid phase extraction using two-layer disks consisting of C(18) and SDB-XC, and collection of suspended solid in water samples by 0.2-0.6 microm filter in a single step. Target compounds adsorbed on the extraction disks were eluted with methanol, acetone, and dichloromethane. The suspended particles retained by the filter were sonically extracted using the same solvents. GC/MS was used for quantification of PAHs and PCBs directly and of PPCPs after derivatization. The analytical method was used in a 6-month field study of the Mississippi river water for contamination by PAHs, PCBs, and PPCPs and the following concentrations (ng/l) have been obtained: clofibric acid (3.2-26.7), ibuprofen (0-34.0), acetaminophen (24.7-65.2), caffeine (0-38.0), naproxen (0-135.2), triclosan (8.8-26.3), bisphenol A (0-147.2), carbamazepine (42.9-113.7), estrone (0-4.7), 17beta-estradiol (0-4.5), total PAHs (62.9-144.7), and total PCBs (22.2-163.4).     

Overview of passive Chemcatcher sampling with SPE pretreatment suitable for the analysis of NPEOs and NPs

The European Union Water Framework Directive (WFD; 2000/60/EC) is an important piece of environmental legislation that protects rivers, lakes, coastal waters and groundwaters (EC 2000). The implementation of the WFD requires the establishment and use of novel and low-cost monitoring programmes, and several methods, e.g. passive sampling, have been developed to make the sampling process more representative compared to spot sampling. This review considers passive sampling methods focusing mainly on a passive sampler named Chemcatcher®, which has been used for monitoring several harmful compounds in aquatic environments. Also, the sample treatment and analysis of nonylphenol ethoxylates (NPEOs) and nonylphenol (NPs) from water using solid phase extraction (SPE) is briefly summarized. The procedure of Chemcatcher passive sampling is quite similar to that of the SPE extraction since it concentrates the studied compounds from water as well. After sampling, the accumulated substances are extracted from the receiving phase of the sampler. The concentrations of NPEOs and NPs are currently monitored by taking conventional spot samples; SPE can be successfully used as a pretreatment procedure. Chemcatcher® passive sampling technique is a simple and useful monitoring tool and can be applied to new chemicals, such as NPEOs and NPs in aquatic environments.