Evaluation of the mixed aggregate method as an alternative to the bismuth active substances and cobalt thiocyanate active substances procedures for the determination of nonionic surfactants in raw and treated sewage

The mixed aggregate (MA) method was evaluated for the routine determination of total ethoxylated nonionic surfactants in municipal raw and treated sewage. Nonionics in wastewater samples were enriched with a C8 solid-phase extraction cartridge, eluted with ethyl acetate-methanol, and separated from interferences with stacked strong anionic (quaternary ammonium form) and cationic (benzenesulfonic acid form) exchange columns. Sample extracts were evaporated to dryness and redissolved in distilled water. The total amount of ethoxylates, on a weight basis, was determined by measuring the critical micelle concentration of a mixed micelle made up of ethoxylates and the anionic surfactant sodium dodecyl sulfate, used as the reagent. The dye Coomassie Brilliant Blue G was used as a photometric probe. The minimum amount of ethoxylate required for a single determination was 1 microg. For raw sewage samples, mean recoveries and standard deviations were 98 +/- 6 and 98 +/- 4% at fortification levels of 0.3 and 0.6 microg/mL, respectively. For treated sewage samples, mean recoveries and standard deviations were 95 +/- 2 and 100 +/- 2% at fortification levels of 0.03 and 0.06 microg/mL, respectively. The MA method and the classical bismuth active substances and cobalt thiocyanate active substances procedures were compared. The former offers some significant advantages over the classical procedures in terms of sensitivity, selectivity, precision, simplicity, and rapidity; the type of response is independent of both the molecular weight and the chain length of the surfactant.     

LC-MS determination of linear alkylbenzene sulfonates and their carboxylic degradation products in influent and effluent water samples and sludges from sewage-treatment plants

Linear alkylbenzene sulfonates (LAS) have been determined in samples of the influent and the effluent, and in the sludge, from sewage-treatment plants (STP). LAS and sulfophenyl carboxylate compounds (SPC) were isolated by solid-phase extraction (SPE) with the polymeric phase Isolute ENV, then determined by liquid chromatography-electrospray mass spectrometry (LC-ESI-MS). The method enabled unequivocal identification of C10-C13 LAS by monitoring the ion at m/z 183 and the base peak corresponding to the [M-H]- ion. Average recoveries varied from 77-93% and the linear range of the method varied from 0.2 to 10 microg L(-1), with a limit of detection ranging from 10 ng L(-1) to 1.5 microg L(-1) when 200 mL waste water were preconcentrated. For sewage sludge, recoveries varied from 58 to 90% and the linear range was between 0.2 and 100 microg L(-1), with a detection limit ranging from 0.4 to 120 microg kg(-1) when 2.5 g sewage sludge was extracted. Unequivocal identification and determination of some metabolites of the LAS, the sulfophenyl carboxylate compounds (SPC), was achieved by monitoring [M-H]- ions.     

Simultaneous determination of the endocrine disrupting compounds nonylphenol, nonylphenol ethoxylates, triclosan and bisphenol A in wastewater and sewage sludge by gas chromatography-mass spectrometry

An integrated analytical method for the simultaneous determination of 4-n-nonylphenol (4-n-NP), nonylphenol monoethoxylate (NP1EO), nonylphenol diethoxylate (NP2EO), bisphenol A (BPA) and triclosan (TCS) in wastewater (dissolved and particulate phase) and sewage sludge was developed based on gas chromatography-mass spectrometry. Chromatographic analysis was achieved after derivatization with bis(trimethylsilyl)trifluoroacetamide (BSTFA). Extraction from water samples was performed by solid-phase extraction (SPE). The optimization of SPE procedure included the type of sorbent and the type of the organic solvent used for the elution. Referred to solid samples, the target compounds were extracted by sonication. In this case the optimization of the extraction procedure included the variation of the amount of the extracted biomass, the duration and the temperature of sonication and the type of the extraction organic solvent. The developed extraction procedures resulted in good repeatability and reproducibility with relative standard deviations (RSDs) less than 13% for all the tested compounds for both types of samples. Satisfactory recoveries were obtained (>60%) for all the compounds in both liquid and solid samples, except for 4-n-NP, which gave recoveries up to 35% in wastewater samples and up to 63% in sludge samples. The limits of detection (LODs) of the target compounds varied from 0.03 (4-n-NP) to 0.41 microg l(-1) (NP2EO) and from 0.04 (4-n-NP) to 0.96 microg kg(-1) (NP2EO) for liquid and solid samples, respectively. The developed methods were successfully applied to the analysis of the target compounds in real samples.     

Determination of endocrine-disrupting compounds in cereals by pressurized liquid extraction and liquid chromatography-mass spectrometry. Study of background contamination

A sensitive method based on pressurized liquid extraction (PLE) and liquid chromatography-electrospray ionization mass spectrometry (LC-ESI-MS) has been developed for the determination in cereal samples of seven endocrine-disrupting compounds: bisphenol A (BPA), 4-tert-butylbenzoic acid (BBA), 4-nonylphenol (NP), 4-tert-butylphenol (t-BP), 2,4-dichlorophenol (DCP), 2,4,5-trichlorophenol (TCP) and pentachlorophenol (PCP). For the PLE procedure, methanol was selected as the extraction solvent. An experimental design approach was applied to optimize other PLE parameters. The recoveries achieved for the all seven compounds were in the 81-104% range, with relative standard deviations of 4-9%. An additional preconcentration step, based on solid-phase extraction (SPE), after the PLE step proved to be a successful way for obtaining a more sensitive method. The detection limits achieved in corn breakfast cereals were in the 0.003-0.013 microg g(-1) range, except for BPA, with a detection limit of 0.043 microg g(-1), for a sample size of 2.5 g. These values are similar to or even lower than currently legislated limits for pesticides in cereals and cereal-based foodstuffs. We also investigated possible contamination during the experimental process by the target compounds released from purified water, plastics, syringes, peristaltic pump tubes, glassware and other laboratory materials in contact with the samples along the analytical process.     

Multiresidue analysis of fungicides in soil by sonication-assisted extraction in small columns and gas chromatography

A rapid multiresidue method for the simultaneous determination of 14 fungicides in soil was developed. Fungicides were exacted from soil, placed in small columns, by sonication-assisted extraction with ethyl acetate. The effect of residue residence time and soil moisture content on the fungicide recovery was studied. Residue levels in soil were determined by gas chromatography with electron-capture and nitrogen-phosphorus detection. Residue identities were confirmed by gas chromatography coupled with mass spectrometry, in the selected ion monitoring mode. Recovery studies were carried out at 0.5, 0.1 and 0.05 microg/g fortification levels for each fungicide, and average recoveries obtained for these compounds ranged from 80 to 104% with relative standard deviations between 1 and 8%. The method is linear over the range assayed, 0.5-0.05 microg/g, and the detection limit for the fungicides studied varied from 2 to 10 microg/kg.     

Determination of pharmaceuticals from various therapeutic classes in dewatered sludge by pressurized liquid extraction and high performance liquid chromatography and tandem mass spectrometry (HPLC-MS/MS)

Pharmaceuticals are released to the environment after human and animal consumption, which partly comes from accumulation in sewage sludge during wastewater treatment. This paper developed a method for the determination of N,N-diethyl-meta-toluamide (DEET) and 14 pharmaceuticals belonging to multiple therapeutic classes such as antibiotic, anti-inflammatory, antilipidemic, anti-hypertensive, and anticonvulsant in dewatered sludge. Pressurized liquid extraction using methanol/McIlvaine buffer (volume ratio, 1?:?1), associated with HPLC-MS/MS was proven to be effective for extraction and quantification of pharmaceuticals and DEET in dewatered sludge. Optimization procedures, including extraction method, extraction solvents and clean-up treatment, were carried out by simulating naturally aged samples to provide a more realistic extraction than previous methods, which were often done by spiking the standard solution before extraction without any aging procedures. The internal standard quantification method using six isotopically labelled compounds was applied to improve the poor absolute recoveries induced by severe matrix effects to obtain better relative recoveries (70–120%). Good relative standard deviations (lower than 19.0% for 7 repeats) and the limit of quantification (0.6–19.4?µg/kg) indicated that the developed method was reliable and sensitive to extract and quantify the studied pharmaceuticals in dewatered sludge. For samples collected from eight sewage treatment plants in Beijing, China, it was found that trimethoprim, caffeine, ketoprofen and ibuprofen were the most prominent contaminants, with the median concentrations reaching 97.6, 179.4, 268.0 and 153.0?µg/kg, respectively. The level of ketoprofen, ibuprofen, mefenamic acid, cabamazepine and diclofenac were similar to results reported from Spain, whilst the levels of other compounds were similar to those found in Germany, Canada and the US.     

Comparison of two extraction methods for the analysis of per- and polyfluorinated chemicals in digested sewage sludge

A rapid and reliable analytical method, based on ion-pair extraction, clean-up on Envicarb cartridge and detection by liquid chromatography–tandem mass spectrometry (LC–MS/MS), was developed for determination of 17 per- and polyfluorinated chemicals (PFCs) in digested sewage sludge. Envicarb cartridge and six labeled internal standards were selected for the elimination/reduction and correction of matrix effects, respectively. As a result, the matrix effect for perfluorooctane sulfonamides (FOSAs) and perfluorocarboxylic acids (PFCAs) with carbon chain length from C6 to C14 was lowered to a range of −14% to +28%. However, the matrix effect for other analytes was still great mainly due to the absence of appropriate internal standard. Mean recoveries of the target analytes based on matrix spikes, at different spike levels (10–300 ng/g), ranged from 70% to 169%. Relative standard deviations (RSDs) were in the range of 2–20% at different spike levels. The limit of quantification (LOQ) ranged between 0.6 and 30 ng/g. The method was successfully applied to several sewage sludge samples from wastewater treatment plants nearby Zürich, Switzerland. In addition, by comparing the accuracy and precision of ion-pair extraction method and methanol extraction method, we further demonstrated that the ion-pair extraction method can be used for the analysis of PFCs in sludge samples. To our knowledge, this is the first study to extract the PFCs in sewage sludge with ion-pair method and to find unsaturated fluorotelomer carboxylic acids (FTUCAs) in sewage sludge.     

Selective extraction of sulfonamides, macrolides and other pharmaceuticals from sewage sludge by pressurized liquid extraction

A method for the quantitative determination of three macrolides, five sulfonamides, ranitidine, omeprazole and trimethoprim in sewage sludge samples was developed by using pressurized liquid extraction and high-performance liquid chromatography-electrospray ionization mass spectrometry. The extraction solvent and such operational parameters as temperature, pressure, extraction time and purge time were optimized in pressurized liquid extraction. The experimental conditions were: an extraction solvent of water (pH 3):methanol (1:1, v/v), a temperature of 80 degrees C, a pressure of 1500 psi, a sample weight of 5 g, an extraction time of 5 min, one cycle, a flush volume of 60% and a purge time of 120 s. All recoveries were over 74%, except those for ranitidine whose value was 54%. The repeatability and reproducibility between days expressed as relative standard deviation (n = 3) were lower than 11% and 15%, respectively. The limit of detection values ranged from 2 to 11 microg/kg dry weight (d.w.). The method was applied to determine the pharmaceuticals in sewage sludge from two domestic sewage treatment plants. Roxithromycin and tylosin were determined in the samples and tylosin showed the highest value (4.0 mg/kg d.w.).     

Determination of azoles in sewage sludge from Spanish wastewater treatment plants by liquid chromatography-tandem mass spectrometry

A simple and rapid analytical method for the determination of 16 azoles in sewage sludge has been developed and validated. The method was based on ultrasound-assisted extraction followed by dispersive solid-phase extraction cleanup and liquid chromatography-electrospray tandem mass spectrometric detection. The azoles were selected by their intensive usage as biocides (tebuconazole, propiconazole, cyproconazole and thiabendazole), antimycotic pharmaceuticals (ketoconazole, econazole, fluconazole and clotrimazole) or fungicides in agriculture (difenoconazole, flusilazole, hexaconazole, prochloraz, bromuconazole, epoxiconazole and triticonazole). The recoveries of these compounds through the method were between 71.9 and 115.8%, with relative standard deviations lower than 20%. Detection limits were in the range of 0.5-5.0 ng/g. The developed method was applied to the analysis of azoles in sewage sludge samples collected from 19 Spanish wastewater treatment plants. Although azoles used as biocides or agriculture fungicides were present in a few sludge samples, the pharmaceuticals ketoconazole, econazole and clotrimazole were present in all of the analyzed sludge samples, being ketoconazole the one found at the highest level, representing the 68.6% of the total azole content found in the 19 sludge samples studied.     

Determination of chlorobenzenes in water by drop-based liquid-phase microextraction and gas chromatography-electron capture detection

A drop-based liquid phase microextraction and gas chromatographic-electron capture detection (GC-ECD) method was described for the determination of chlorobenzenes including chlorobenzene, 1,2-dichlorobenzene, 1,3-dichlorobenzene, 1,4-dichlorobenzene and 1,2,3-trichlorobenzene in 5 ml of water. The method used 2 microl of n-hexane as extraction solvent, 5 min extraction time, a stirring rate of 600 rpm and sample ionic strength of 3 M maintained with sodium chloride at 25 degrees C (ambient temperature). The limits of detection (LODs) ranged from 0.004 microg l(-1) (for 1,3-dichlorobenzene) to 0.008 microg l(-1) (for monochlorobenzene). The dynamic linear range for all investigated chlorobenzenes was 1-50 microg l(-1). Recoveries of chlorobenzenes from fortified distilled water are over 90% for three different fortification levels (5, 15 and 45 microg l(-1)) and relative standard deviations of the recoveries are below 6%. Analysis of fortified (5 microg l(-1)) real water samples revealed that matrices had no adverse effect on extraction efficiency of proposed method. The recovery of fortified real water samples was from 90 to 94% with relative standard deviations below 6%.     

三相中空纤维膜液相微萃取-高效液相色谱法测定水中痕量双酚A

建立了三相中空纤维膜液相微萃取-高效液相色谱(HF-LPME-HPLC)方法,用于分析测定水中痕量双酚A的含量.设计了三相中空纤维膜液相微萃取系统,优化的HP-LPME最佳萃取条件为:萃取剂为正辛醇,接受相NaOH浓度为0.09 mol/L,样品溶液pH=4.0,NaC1加入量为30 g/L,搅拌速度为900 r/min,萃取时间为60 min.萃取后取20 μL接受相进行色谱分析.在最佳萃取条件下,方法的线性范围为0.5～200 μg/L(r＞ 0.999),检出限(信噪比为3)为0.2 μg/L;富集因子为241;方法RSD＜3.2％ (n=3).在实际环境水样中添加5,20和50μg/L的双酚A标准物质,加标平均回收率为92.8％～101.9％.表明本方法可用于水中痕量双酚A的快速准确测定.     

Determination of bisphenol A in water by isotope dilution headspace solid-phase microextraction and gas chromatography/mass spectrometry without derivatization

The original solid-phase microextraction (SPME) fibers use an epoxy resin adhesive that releases bisphenol A (BPA) during thermal desorption of the fiber. This adversely affects the method detection limit and accuracy when these products are used for the determination of BPA. In this work, 5 new metal alloy SPME fibers that do not use epoxy resins were compared for the extraction of BPA in water. The performance of the optimum SPME fiber with 60 microm carbowax-polyethylene glycol coating for the headspace SPME of BPA in water was investigated systematically under different extraction conditions. Salt was found to increase the partitioning of BPA from water into the headspace until saturation was reached. Partitioning of BPA from water into the headspace also increased at higher extraction temperatures, as did longer extraction times. However, extraction of BPA from water onto the SPME fiber was not improved for solutions adjusted to pH 2 compared to the unadjusted neutral solutions. The new BPA method showed good linearity over the concentration range of 2.5 to 40 microg/L [correlation coefficient (r2) = 0.995] .The method detection limit for BPA was 0.5 microg/L, while the instrument detection limit was as low as 0.05 microg/L. Good repeatability was observed for BPA at levels of 5 and 20 microg/L with relative standard deviation values < 10%. The automated headspace SPME method developed in this work was used to investigate migration of BPA from polycarbonate bottles into water, and levels of BPA in water ranged from 1.7 to 4.1 microg/L.     

双酚A分子印迹聚合物为萃取介质搅拌饼固相萃取的制备及其萃取性能研究

以双酚A为模板,4-乙烯基吡啶为单体,利用整体材料"原位"聚合技术制备分子印迹聚合物为基质的萃取饼,并与利用一次性注射器空管加工而成的萃取器相结合,建立了分子印迹搅拌饼固相萃取(MIP-SCSE)技术。考察了制备条件对MIP-SCSE选择吸附性能的影响。在此基础上,与高效液相色谱-二极管阵列检测器联用,探讨MIP-SCSE对环境水样中双酚A及其它酚类物质的选择萃取性能,考察萃取过程中基底离子强度、pH值以及吸附与解吸时间等萃取条件对萃取性能的影响。结果表明;在最佳萃取条件下,MIP-SCSE对模板分子及其它酚类物质具有一定选择性能和较高的富集能力,对双酚A的线性范围为1.0～200μg/L;检出限LOD(S/N=3)为0.67μg/L;定量限LOQ(S/N=10)为2.24μg/L。在实际水样分析中,模板分子加标回收率为86.2%～112.2%。在MIP-SCSE使用过程中,萃取饼不与容器壁接触,因此具有优良的使用寿命,至少可连续使用600 h。     

Determination of Chlorophenols in Sewage Sludge and Soil by High-Performance Liquid Chromatography–Tandem Mass Spectrometry with Ultrasonic-Assisted and Solid-Phase Extraction

Chlorophenols are a category of toxic pollutants that are ubiquitously present in the environment. This paper presents a reliable and feasible method for the determination of five chlorophenols in sewage sludge and soil using liquid chromatography–tandem mass spectrometry (LC-MS/MS). The pretreatment involved ultrasonic-assisted extraction and solid-phase extraction purification with hydrophilic–lipophilic balance cartridges. LC-MS/MS equipped with an electrospray ionization source operated in negative mode was used for detection, and multitude reaction monitoring mode was applied for data acquisition. The pretreatment and working conditions of LC-MS/MS were optimized to achieve satisfactory results. The intra-batch accuracies were 100.5–113.4% with relative standard deviations?≤?15.6% for the chlorophenols in sewage sludge and 71.3–102.7% with relative standard deviations?≤?14.0% for those in soil. The inter-batch accuracies were 86.1–100.5% (relative standard deviations?≤?33.6%) for sewage sludge samples and 70.5–112.5% (relative standard deviations?≤?28.2%) for soil samples, respectively. This method has been applied to the determination of chlorophenols in sewage sludge of wastewater treatment plants and soil collected from Guangzhou, China. Parachlorophenol, 2,4,6-trichlorophenol, 2,3,4,6-tetrachlorophenol, and pentachlorophenol were detected in some sewage sludge samples, with concentrations from 0.51 to 13.20?ng/g. In addition, parachlorophenol, 2,3,4,6-tetrachlorophenol, and pentachlorophenol were found in all the soil samples with concentrations from 0.33 to 5.21?ng/g. The chromatographic behavior, on-filter adsorption behavior, and the relationship between optimal collision energies and degree of chlorination of the chlorophenols was investigated. This method will be conducive to environmental research focusing on pollution investigation of chlorophenols in the environment.     

人体血清中的多溴联苯醚、邻苯二甲酸酯和双酚A的连续在线分离及气相色谱-质谱测定

建立了人体血清中多种环境雌激素:多溴联苯醚、邻苯二甲酸酯和双酚A的快速可靠的连续在线分离及在气相色谱-质谱上的分析方法.血清样品经过浓盐酸使蛋白质变性,用乙醚萃取,经硅胶柱分离出多个族组分:多溴联苯醚(Polybrominated diphenyl ethers,PBDEs)、邻苯二甲酸酯(Phthalate estcrs,PAEs)和双酚A(Bisphenol A,BPA),最后由气相色谱-质谱的选择离子检测测定.PBDEs,PAEs和BPA标准曲线回归方程拟合度R2均大于0.99,表明在测试的浓度范围内线性关系良好.PBDEs目标化合物的检出限为0.005～0.048μg/L,PAEs目标化合物的检出限为0.103～0.833μg/L,BPA的检出限是0.035 μg/L.标准样品重复样中,PBDEs的RSD(relative standard deviation)值分别为2.8％～10.9％;PAEs的RSD值为5.6％～9.9％;BPA的RSD值为3.0％.实际血清样品中,PBDEs的加标回收物PCB209(Polychloride diphenyl ether 209)的回收率范围是74.8％～88.5％;PAEs中的加标回收物DBP-D4(Dibutyl phthalateDeutorium 4)的回收率范围为78.7％～97.0％;BPA中的加标回收物BPA-D16( Bisphenol A-Deutorium 16)的回收率范围是76.3％～93.1％.本方法检测血液中多种环境雌激素灵敏度高、重现性和回收率均良好.     

Determination of organic compounds in water using dispersive liquid-liquid microextraction

A new microextraction technique termed dispersive liquid-liquid microextraction (DLLME) was developed. DLLME is a very simple and rapid method for extraction and preconcentration of organic compounds from water samples. In this method, the appropriate mixture of extraction solvent (8.0 microL C2Cl4) and disperser solvent (1.00 mL acetone) are injected into the aqueous sample (5.00 mL) by syringe, rapidly. Therefore, cloudy solution is formed. In fact, it is consisted of fine particles of extraction solvent which is dispersed entirely into aqueous phase. After centrifuging, the fine particles of extraction solvent are sedimented in the bottom of the conical test tube (5.0 +/- 0.2 microL). The performance of DLLME is illustrated with the determination of polycyclic aromatic hydrocarbons (PAHs) in water samples by using gas chromatography-flame ionization detection (GC-FID). Some important parameters, such as kind of extraction and disperser solvent and volume of them, and extraction time were investigated. Under the optimum conditions the enrichment factor ranged from 603 to 1113 and the recovery ranged from 60.3 to 111.3%. The linear range was 0.02-200 microg/L (four orders of magnitude) and limit of detection was 0.007-0.030 microg/L for most of analytes. The relative standard deviations (RSDs) for 2 microg/L of PAHs in water by using internal standard were in the range 1.4-10.2% (n = 5). The recoveries of PAHs from surface water at spiking level of 5.0 microg/L were 82.0-111.0%. The ability of DLLME technique in the extraction of other organic compounds such as organochlorine pesticides, organophosphorus pesticides and substituted benzene compounds (benzene, toluene, ethyl benzene, and xylenes) from water samples were studied. The advantages of DLLME method are simplicity of operation, rapidity, low cost, high recovery, and enrichment factor.     

An analytical method for the simultaneous trace determination of acidic pharmaceuticals and phenolic endocrine disrupting chemicals in wastewater and sewage sludge by gas chromatography-mass spectrometry

This article presents an analytical method based on solid-phase extraction (SPE) and gas chromatography coupled with mass spectrometry for the simultaneous determination of the most frequently used acidic pharmaceutical residues, ibuprofen, diclofenac, naproxen and ketoprofen (KFN), and phenolic endocrine disruptors, bisphenol (BPA), triclosan (TCS), nonylphenol, nonylphenol monoethoxylate and nonylphenol diethoxylate, in wastewater and sewage sludge samples. In the first phase of the study, each compound has been characterized individually and afterwards in mixture as a trimethylsilyl derivative in order to identify the characteristic ions (m/z ratio) constituting the mass spectrum and to choose the ions for quantification and confirmation. Subsequently, derivatization was evaluated by testing different variables such as the volume of the derivatization solvent bis(trimethylsilyl)trifluoroacetamide and the effect of each catalyst, pyridine and 1% trimethyl chlorosilane, in the derivatized solution. For the analysis of wastewater samples, two commercial SPE cartridges, C18 and Oasis HLB, were compared for their extraction efficiency of the target compounds. The key parameter of extraction procedure included the effect of pH (2.5, 5.3 and 7) of the loading solution. For solid samples, parameters such as the extracted biomass, the volume of the extraction organic solvent and the effect of matrix interferences in chromatographic analysis were evaluated. By using C18 cartridges as purification procedure and ultrasound sonication, satisfactory mean relative recoveries with BPA-d16 and meclofenamic acid as surrogates were obtained ranging from 91% to 117% for wastewater and 84% to 107% for sewage sludge samples. Nine-point calibration of the standard mixture was performed by linear regression analysis with a correlation coefficient >0.99 for all the tested compounds. Limits of detection for the developed methods were established between 0.3 (KFN) and 14.8 (BPA) ng L⁻¹, and 15.0 (TCS) and 32.9 (BPA) ng g⁻¹ for wastewater and sewage sludge, respectively. Application to real samples of the wastewater treatment plant in Athens, the capital of Greece, demonstrated the presence of all tested compounds in most of the samples.     

Determination of sixteen polycyclic aromatic hydrocarbons in aqueous and solid samples from an Italian wastewater treatment plant

A robust procedure for the determination of 16 US EPA PAHs in both aqueous (e.g. wastewaters, industrial discharges, treated effluents) and solid samples (e.g. suspended solids and sludge) from a wastewater treatment plant (WWTP) is presented. Recovery experiments using different percentages of organic modifier, sorbents and eluting solvent mixtures were carried out in Milli-Q water (1000 mL) spiked with a mixture of the PAH analytes (100 ng/L of each analyte). The solid phase extraction (SPE) procedures applied to spiked waste water samples (1000 mL; 100 ng/L spiking level) permitted simultaneous recovery of all the 16PAHs with yields >70% (6-13% RSD). SPE clean up procedures applied to sewage and stabilized sludge extracts, showed percent recoveries in the range 73-92% (7-13% RSD) and 71-89% (7-12% RSD), respectively. The methods were used for the determination of PAHs in aqueous and solid samples from the WWTP of Fusina (Venice, Italy). Mean concentrations, as the sum of the 16PAHs in aqueous and suspended solid samples, were found to be approx. in the 1.12-4.62 microg/L range. Sewage and stabilized sludge samples contained mean PAH concentrations, as sum of 16 compounds, in the concentration range of 1.44-1.26 mg/kg, respectively. Extraction and clean up procedures for sludge samples were validated using EPA certified reference material IRM-104 (CRM No. 912). Instrumental analyses were performed by coupling HPLC with UV-diode array detection (UV-DAD) and fluorescence detection (FLD).     

高效液相色谱-质谱联用法同步测定城市污水处理厂活性污泥中的多类抗生素残留

采用超声萃取、固相萃取及高效液相色谱-质谱联用技术(LC-MS),建立了活性污泥中3类共9种抗生素(包括5种磺胺类、3种四环素类及1种大环内酯类)的同时分析方法.样品经甲醇-Na2,EDTA/Mcllvaine缓冲液(1∶1,体积比)超声萃取,HLB固相萃取柱净化富集后,以Symmetry C18反相柱为分析柱,0.2...     

Combination of microwave-assisted micellar extraction with liquid chromatography tandem mass spectrometry for the determination of fluoroquinolone antibiotics in coastal marine sediments and sewage sludges samples

In this work, a method for the analysis of fluoroquinolone antibiotics using microwave-assisted micellar extraction combined with liquid chromatography-mass spectrometry detection has been developed. Different surfactants were tested for use as extractants in the isolation of the analytes from solid samples, and several experimental designs were evaluated for the determination and optimization of the variables that affect recovery from the matrix. Under optimal conditions, we obtained recoveries greater than 73% with relative standard deviations below 8%. Compounds were detected by liquid chromatography-electrospray ionization tandem mass spectrometry with detection limits between 0.15 and 0.55 ng g(-1) and quantification limits between 0.49 and 1.85 ng g(-1) . Finally, the optimized method was applied in the determination of antibiotics in real solid samples. Four fluoroquinolones (levofloxacin, norfloxacin, ciprofloxacin and enrofloxacin) were found in coastal marine sediments taken close to a marine outfall and in sewage sludge samples from a wastewater treatment plant. Concentrations ranged between 0.81 and 34.3 ng g(-1) in the sediments and 3.43 and 206.1 ng g(-1) in the sludge.