Multi-determination of organic pollutants in water by gas chromatography coupled to triple quadrupole mass spectrometry

A multi-determination method has been developed for the determination and confirmation of 68 organic pollutants in water samples by gas chromatography coupled to triple quadrupole mass spectrometry (GC-MS/MS). The following chemical families were determined in a chromatographic run of less than 26?min: polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), polybrominated diphenylethers (PBDEs), and pesticides (organochlorine, organophosphorus, triazine and others). The sample preparation involved a liquid-liquid extraction (LLE) procedure, obtaining recoveries ranging from 70 to 130% when dichloromethane was used as the extracting solvent. The detection limits of the proposed method were between 0.75 and 19.8?ng?L^?1. Samples from the Maipo River in central Chile were taken from 29 different points. Seven pesticides and two PAHs were detected in field collected samples with concentrations ranging from 10 to 95?ngL^?1. Concentrations of benzo[a]pyrene in environmental samples ranged from 25 to 33?ngL^?1 and were near the maximum levels established by the European Union Directives (50?ng?L^?1).     

Analysis of organic pollutants in water at trace levels using fully automated solid-phase extraction coupled to high-performance liquid chromatography

Summary A method has been developed for the determination of trace levels of 32 pesticides, 19 explosives and 16 polycyclic aromatic hydrocarbons (PAH) in water in three individual steps. Solid-phase enrichment (SPE) is coupled to high-performance liquid chromatography (HPLC) with a fully automated system. The organic pollutants are enriched on reusable cartridges packed with adsorbent materials: pesticides and explosives on a mixed bed of divinylbenzene-ethylvinylbenzene copolymers (LiChrolut EN^?) and perfluorinated polyethylene (PolyF^?), and polycyclic aromatic hydrocarbons on C₁₈-modified silica (Zorbax^? ODS1). Thermally assisted desorption (TAD) has been shown to increase the recovery of analytes significantly. As all enriched analytes are transferred to the detector, only fifty millilitres of sample is needed for each single on-line analysis, compared with at least a litre for conventional methods. The separation of the enriched organic analytes is performed on specialized HPLC columns based on reversed-phase materials. The limits of detection of the system employed were found to be below 100 ng L⁻¹. Use of fluorescence detection for the polycyclic aromatic hydrocarbons resulted in limits of detection in the upper pg L⁻¹ range. Thek values, number of theoretical plates, the recovery rates and the limits of detection of this method for fast screening of organic pollutants from three fifty-millilitre aqueous samples are described. Presented at the 21^st ISC held in Stuttgart, Germany, 15^th–20^th September, 1996     

保留时间两点校正反相高效液相色谱法测定持久性有机污染物的正辛醇-水分配系数

采用改进的反相高效液相色谱法(RP-HPLC)测定了持久性有机污染物(POPs)包括多环芳烃(PAHs)、多氯二苯并二恶英(PCDDs)、多氯二苯并呋喃(PCDFs)和十溴二苯乙烷(DBDPE)等的正辛醇-水分配系数(logKow)。采用保留时间双点校正法(DP-RTC)校正因色谱柱老化等引起的保留时间漂移。以37种有可靠logKow实验值的苯系物、PAHs、PCDD/Fs类似物为模型化合物,建立了logKow和外推至纯水相的保留因子logkw的定量结构-色谱保留关系(QSRR)模型,回归方程为logKow=(1.18±0.02)logkw+(0.36±0.11),其相关系数(R2)为0.985,交叉验证相关系数(R2cv)为0.983,标准偏差(SD)为0.16。进而,用4个已有可靠logKow实验值的验证化合物(联苯、芴、PCDD 1和PCDF 114)对模型进行了外部验证,表明RP-HPLC测得的logKow值与摇瓶法/慢搅法结果有很好的一致性,尤其是对疏水性强的化合物。采用该模型测定了29种特别受关注的POPs的logKow值,这些化合物的logKow实验值均未见报道。所建立的DP-RTC-HPLC是测定强疏水性POPs的logKow值的一种值得推荐的方法。     

高效液相色谱-串联质谱法同时测定水中13种有机污染物

以地表水环境质量标准严格控制的特定项目为依据,建立了直接进样-高效液相色谱-串联质谱同时测定水中13种化学性质差异较大的有机污染物的分析方法,这13种有机污染物为乐果、敌敌畏、敌百虫、对硫磷、甲基对硫磷、马拉硫磷、内吸磷、丙烯酰胺、苯胺、联苯胺、甲萘威、微囊藻毒素-LR、阿特拉津。水样经0.22 μm尼龙66滤膜过滤后,采用Kromasil 100-5 C18柱(150 mm×2.1 mm, 5 μm)分离,以甲醇-0.01%甲酸水溶液为流动相进行梯度洗脱,流速0.5 mL/min,柱温40 ℃,电喷雾正离子模式(ESI⁺)电离,多反应监测模式(MRM)进行检测,外标法定量。13种化合物的浓度与其峰面积在一定浓度范围内均呈现良好的线性关系(r≥0.9995),方法检出限为0.02~0.1 μg/L。测定低、中、高浓度的加标样品,13种化合物的相对标准偏差为0.5%~5.0%(n=6),实际样品加标平均回收率为81.2%~112%。此方法灵敏度高、干扰小、分析速度快,可适用于地表水、地下水中这13种有机污染物的同时分析。     

Using gas chromatography with atomic emission detection for determining organic pollutants in water

The efficiency of gas chromatography with atomic emission detection (AED) for determining the composition of complex mixtures of organic water pollutants was studied by the example of 13 compounds of different classes. It was found that the correlation between the ratio of AED signals for single element atoms of the compound in the sample and their predetermined ratio in individual solutions additionally supports the identification of impurities in water at a trace level. The determination of a compound by the concentration of one or two elements in its molecule allows the evaluation of the effect of interfering impurities on the results of analysis.     

Isolation of organic water pollutants by xad resins and carbon

The recovery efficiencies of XAD resins −2, −4, −7, and −8 and of resin mixtures were measured using distilled water samples containing 13 organic pollutants. An equal-weight mixture of XAD-4 and XAD-8 was most efficient. XAD-2 and XAD-4/8 were further terted and found effective using tapwater. Carbon was tested as a sorbent for materials not well retained by the resins. In-column solvent washing before sample sorption was found to be as effective as Soxhlet extraction for removing background impurities. Some compounds can be desorbed from carbon by in-column solvent elution; others require Soxhlet extraction. An XAD-4/8 column in series with a carbon column was used to sample 1000 1 of tapwater. Halomethanes, n-hydrocarbons, polynuclear aromatic compounds and dibenzofuran in the order of ng/l were identified using a gas chromatograph-mass spectrometer-computer system.     

Fractionation of chlorinated and brominated persistent organic pollutants in several food samples by pyrenyl-silica liquid chromatography prior to GC-MS determination

A high-performance liquid chromatography (HPLC) method using a column of 2-(1-pyrenyl) ethyldimethylsilylated silica was developed in this work in order to achieve satisfactory and reproducible fractionation of polychlorinated biphenyls (PCBs) from brominated flame retardants (BFRs) (polybrominated diphenylethers, PBDEs; and polybrominated biphenyls, PBBs). After the study of different chromatographic parameters (mobile phase composition and separation temperature were the most important) an isocratic elution with isooctane:toluene (98:2, v/v) at a flow-rate of 1 mL/min, a temperature of 45 °C, and UV-detection at 225 nm was selected for fractionation of PCBs (time region, 4.0-5.8 min) from PBDEs (5.8-9.0 min) and from PBBs (5.8-11.0 min). The applicability of this method to food samples was demonstrated by fractionating PCBs from PBDEs in three food samples (cheese, milk, and fish). Interferences from PCBs (present in real samples at much higher concentrations than PBDEs) were removed in this way. In addition, by analysing these samples by gas chromatography-mass spectrometry (GC-MS) with and without previous fractionation we were able to observe an improvement in detection sensitivity for PBDEs after HPLC fractionation.     

A novel evaluation method for extrapolated retention factor in determination of n-octanol/water partition coefficient of halogenated organic pollutants by reversed-phase high performance liquid chromatography

The retention factor corresponding to pure water in reversed-phase high performance liquid chromatography (RP-HPLC), k_w, was commonly obtained by extrapolation of retention factor (k) in a mixture of organic modifier and water as mobile phase in tedious experiments. In this paper, a relationship between log k_w and log k for directly determining k_w has been proposed for the first time. With a satisfactory validation, the approach was confirmed to enable easy and accurate evaluation of k_w for compounds in question with similar structure to model compounds. Eight PCB congeners with different degree of chlorination were selected as a training set for modeling the log k_w ? log k correlation on both silica-based C₈ and C₁₈ stationary phases to evaluate log k_w of sample compounds including seven PCB, six PBB and eight PBDE congeners. These eight model PCBs were subsequently combined with seven structure-similar benzene derivatives possessing reliable experimental K_ow values as a whole training set for log K_ow ? log k_w regressions on the two stationary phases. Consequently, the evaluated log k_w values of sample compounds were used to determine their log K_ow by the derived log K_ow ? log k_w models. The log K_ow values obtained by these evaluated log k_w were well comparable with those obtained by experimental-extrapolated log k_w, demonstrating that the proposed method for log k_w evaluation in this present study could be an effective means in lipophilicity study of environmental contaminants with numerous congeners. As a result, log K_ow data of many PCBs, PBBs and PBDEs could be offered. These contaminants are considered to widely exist in the environment, but there have been no reliable experimental K_ow data available yet.     

Concentration and determination of trace organic pollutants in water

Organic pollutants in water are isolated on a mini-sampler tube containing a macroporous resin. The sorbed pollutants are next thermally transferred to a second sorption tube and then to an analytical column where they are separated and determined by temperature-programmed gas chromatography. Excellent recoveries were obtained for tests in which model organic compounds of various classes were added to water. The water sample is much smaller than that required with previous analytical methods.     

Detection by ion-pairing probes in reversed-phase liquid chromatography

Summary Compounds without own detector response can be detected and quantified by a UV-absorbing or fluorescent, ion-pairing probe in reversed-phase liquid-solid systems. Charged as well as uncharged samples give response by affecting the distribution of the probe between the phases. The probe is usually a hydrophobic organic ion. It is included in the mobile phase, which also contains a counter ion and an ion of the same charge as the probe, both fairly hydrophilic. The choice of properties and concentrations of the hydrophilic ions is essential for the response since too low and too high distribution of the mobile phase ions to the adsorbent will make the system insensitive. It is with UV-absorbing probes possible to get a response corresponding to a molar absorptivity of more than 3000 for ionic samples. Fluorescent probes have given 3–5 times higher sensitivity. Uncharged compounds give as a rule lower response. A combination of two UV-absorbing probes with different charge gives a considerable improvement of the response for samples with low retention. A simplified theoretical model for the detector response is suggested on the basis of detailed studies of the concentration changes in the eluted mobile phase.     

水环境介质中有机污染物微观分布的理论模型——污染物·水复合体·水簇模型

以水簇模拟水环境介质, 水体中有机污染物的分子状态用水-有机污染物分子复合体模拟,得出有机污染物在水环境介质中微观分布的数学表达式, 经过微观动力学方法处理, 得到了相应的数学解析式.用 ab initio 方法 STO-3G 基组计算了4个多环芳烃在水中的微观分布情况, 计算结果与辛醇-水分配系数的实验值相吻合.     

水环境介质中有机污染物微观分布的理论模型：污染物.水复合体 …

以水簇模拟水环境介质,水体中有机污染物的分子状态用水－有机污染物分子复合体模拟,得出有机污染物在水环境介质中微观分布的数学表达式,经过微观动力学方法处理,得到了相应的数学解析式。用ａｂ ｉｎｉｔｉｏ方法ＳＴＯ－３Ｇ基组计算了４个多环芳烃在水中的微观分布情况,计算结果与辛醇－水分配系数的实验值相吻合。     

Determination of bromine in organic compounds by high-performance liquid chromatography

A method is proposed for the determination of bromine in organic compounds (which may also contain chlorine and iodine) by oxygen-flask combustion of the compound followed by pre-column reaction of bromide with acetanilide and 2-iodosobenzoic acid to form 4-bromoacetanilide which is then chromatographed on an ODS column with a mobile phase of methanol: water, 65:35 v/v, detection at 240 nm, and 4-N-acetylaminotoluene as internal standard. The method is rapid and precise (RSD 相似文献   

Detection of volatile organic sulfur compounds in water by headspace gas chromatography and membrane inlet mass spectrometry

Two gas chromatographic methods, GC-FID (flame ionization detection) and GC-ELCD (electrolytic conductivity detector) are compared in tlie analysis of volatile organic sulfur compounds (VOSCs) in water samples with a membrane inlet mass spectrometry (MIMS) technique. Carbon disulfide, ethanethiol, dimethyl sulfide, ethyl-methyl sulfide, thiophene, and dimethyl disulfide were used as test compounds. Linear dynamic ranges were found to be two decades with the GC-ELCD method and four decades with the GC-FID and MIMS methods. Detection limits were at low (μg/1 levels with the two gas chromatographic methods and clearly below μg/1 level with the MIMS method. Analysis of one sample takes 40 min with the gas chromatographic methods and five minutes with the MIMS method. The selectivity was good, especially with the GC-ELCD and the MIMS method. In addition, quantitative results obtained with spiked water samples by the three methods are compared.     

Heterogeneous degradation of toxic organic pollutants by hydrophobic copper Schiff-base complex under visible irradiation

A hydrophobic complex of Cu2+[bis-salicylic aldehyde-o-phenylenediamine],Cu-SPA,was prepared and used as a heterogeneous photocatalyst to degrade organic pollutants in water under visible irradiation(420 nm)at neutral pH.The structure of complex was characterized by using nuclear magnetic resonance(NMR),elemental analysis,IR and UV-vis spectrometries.Degradation of Rhodamine B(RhB),Sulforhodamine B(SRB)and Benzoic acid(BA)in water were used as model reactions to evaluate the photocatalytic activities of Cu-SPA.The results indicated that RhB and SRB were easily adsorbed on the hydrophobic surface of Cu-SPA from aqueous solution(the maximum adsorption amount:Qmax=11.09 and 8.05μmol/g,respectively).Under visible irradiation,RhB and SRB were decolorized completely after 210 and 240 min,respectively,and BA was removed completely after 5 h.The efficiency of H2O2was>95%,in contrast to that of the reaction without catalyst or light(<20%).In water soluble medium,the hydrophobic Cu-SPA can be used more than 6 cycles.ESR results and the behavior of cyclic voltammetry showed that,in the reaction process,Cu2+-SPA was reduced to intermediate state Cu+-SPA firstly,which was extremely unstable and reacted rapidly with H2O2,leading to high reactive oxygen species(·OH radical)to degrade the substrate.     

Detection of sialuria by cation-exchange high-performance liquid chromatography

A simple and selective method for the detection of sialuria by high-performance liquid chromatography is described. The urine sample (2 ml) is purified using a C18 cartridge or ion-exchange chromatography, and free N-acetylneuraminic acid is separated on an Aminex HPX-87 cation-exchange column using 3 mM sulphuric acid as the mobile phase. The retention time of N-acetylneuraminic acid is ca. 8 min and the detection limit ca. 1 mumol/l. The within-day coefficient of variation is less than 4.9% and the day-to-day coefficient of variation is less than 5.6%. The method was tested on twenty normal individuals and four sialuria patients.     

Improved screening analysis of organic pollutants in river water samples by gas chromatography with atomic emission detection (GC-MIP-AED)

 The potential of gas chromatography with a microwave-induced plasma atomic emission detector (GC-MIP-AED) for the screening analysis of trace organic components in river water samples is presented. The application of a commercially available GC-MIP-AED system to the screening of organic trace compounds has been greatly enhanced by the optimisation of the operating parameters to achieve the highest sensitivity for the simultaneous determination of C, H, Cl, Br, S and N. An improved evaluation of the chromatographic data has been carried out using several new self-developed macros, which allow the calculation of elemental response ratio factors (RRFs) and empirical formulas for the analysed compounds at different concentration levels. A significant dependence of the RRFs on the concentration level was found for hydrogen and sulphur, whereas the dependence of the RRFs on the type of compound is not significant, considering the analytical objective. Limits of detection in the pg-range can be obtained for the elements investigated. The calculation of empirical formulas and its precision is shown for several analytes over a wide range of concentration. At a concentration level close to the limit of detection the error of the formula calculation increases significantly. The performance characteristics of the GC-MIP-AED system in the presence of matrix interferences are assessed by measuring spiked river water samples. Received: 29 July 1996 / Revised: 12 October 1996 / Accepted: 24 October 1996     

共价有机框架材料磁固相萃取-高效液相色谱法分析环境水体中对羟基苯甲酸酯

建立了一种基于共价有机框架材料的磁固相萃取-高效液相色谱方法,用于环境水样中对羟基苯甲酸酯的快速灵敏分析。首先以Fe₃O₄纳米粒子为磁核,通过1,3,5-苯三甲醛(Tb)和联苯胺(Bd)在室温下的席夫碱反应合成了磁性共价有机框架材料——Fe₃O₄@TbBd,通过扫描电镜、热重分析、X射线衍射和振动样品磁强计等表征手段证明了该磁性共价有机框架材料具有良好的热稳定性和化学稳定性,且磁响应强度较大,是用于磁固相萃取的理想材料。随后系统研究了影响萃取效率的因素,包括吸附剂用量、萃取时间、pH、解吸溶剂、解吸时间和解吸次数,建立了基于Fe₃O₄@TbBd的磁固相萃取-高效液相色谱测定环境水样中4种对羟基苯甲酸酯的方法。方法的线性范围良好,4种目标物的检出限和定量限范围分别为0.2~0.4 μg/L和0.7~1.4 μg/L,加标回收率为86.1%~110.8%,日内和日间精密度的相对标准偏差(RSD)分别低于5.5%和4.9%。最后将该方法应用于东湖水、长江水和生活废水中对羟基苯甲酸酯的测定,不同加标水平下对羟基苯甲酸酯的回收率在80.7%~117.5%之间,RSD在0.2%~8.8%之间。该方法操作简单,萃取时间短,灵敏度较高且对环境友好,在环境水样中对羟基苯甲酸酯的检测方面有良好的应用潜力。