Determination of phthalates in crude extracts of sewage sludges by high-resolution capillary gas chromatography with mass spectrometric detection

A simple solvent extraction by ethyl acetate without subsequent cleanup was used to determine 16 phthalic acid esters (PAEs), including bis(2-ethylhexyl) phthalate (DEHP), in sewage sludge samples from different catchment areas. The compounds were separated on a gas chromatographic capillary column with a nonpolar HT-8 stationary phase. For most of the PAEs, internal standard quantification with deuterated dibutyl phthalate (DBP) and deuterated DEHP was best achieved by using electron ionization mass spectrometry in the selected-ion monitoring mode. Because of its high concentrations in the sludges, DEHP was quantified in the full-scan acquisition mode. Molecular weight and ester-type information for the PAEs was obtained in the positive chemical ionization mode with methane as the reagent gas. Finally, selected sewage sludges containing different amounts of industrial wastewater were analyzed by the proposed method. DEHP was the most abundant compound found at 21-114 mg/kg x dm, followed by the lower-molecular weight PAEs diethyl phthalate, diisobutyl phthalate, and DBP and the higher-molecular weight compounds butylbenzyl phthalate, dicyclohexyl phthalate, di-n-octyl phthalate, and dinonyl phthalate, which were present mostly at <1 mg/kg x dm.     

Multivariate optimization of a solid-phase microextraction method for the analysis of phthalate esters in environmental waters

A solid-phase microextraction method (SPME) coupled to gas chromatography-mass spectrometry (GC-MS) has been developed for the determination of the six phthalate esters included in the US Environmental Protection Agency (EPA) Priority Pollutants list in water samples. These compounds are dimethyl phthalate (DMP), diethyl phthalate (DEP), di-n-butyl phthalate (DBP), butylbenzyl phthalate (BBP), di-2-ethylhexyl phthalate (DEHP) and di-n-octyl phthalate (DOP). Detailed discussion of the different parameters, which could affect the extraction process, is presented. Main factors have been studied and optimized by means of a multifactor categorical design. Different commercial fibers, polydimethylsiloxane (PDMS), polydimethylsiloxane-divinylbenzene (PDMS-DVB), polyacrylate (PA), Carboxen-polydimethylsiloxane (CAR-PDMS) and Carbowax-divinylbenzene (CW-DVB), have been investigated, as well as the extraction mode, exposing the fiber directly into the sample (DSPME) or into the headspace over the sample (HS-SPME), and different extraction temperatures. The use of this experimental design allowed for the evaluation of interactions between factors. Extraction kinetics has also been studied. The optimized microextraction method showed linear response and good precision for all target analytes. Detection limits were estimated considering the contamination problems associated to phthalate analysis. They were in the low pg mL(-1), excluding DEHP (100 pg mL(-1)). The applicability of the developed SPME method was demonstrated for several real water samples including mineral, river, industrial port and sewage water samples. All the target analytes were found in real samples. Levels of DEP and DEHP were over 1 ng mL(-1) in some of the samples.     

Preparation of polypyrrole-coated magnetic particles for micro solid-phase extraction of phthalates in water by gas chromatography-mass spectrometry analysis

In this work, polypyrrole (PPy)-coated Fe(3)O(4) magnetic microsphere were successfully synthesized, and applied as a magnetic sorbent to extract and concentrate phthalates from water samples. The PPy-coated Fe(3)O(4) magnetic microspheres had the advantages of large surface area, convenient and fast separation ability. The PPy coating of magnetic microspheres contributed to preconcentration of phthalates from water sample, due to the π-π bonding between PPy coating and the analytes. Also, the coating could prevent aggregation of the microspheres, and improve their dispersibility. In this study, seven kinds of phthalates were selected as model analytes, including dimethyl phthalate (DMP), diethyl phthalate (DEP), di-iso-butyl phthalate (DIBP), di-n-butyl phthalate (DBP), benzylbutyl phthalate (BBP), di-(2-ethylhexyl) phthalate (DEHP) and di-n-octyl phthalate (DNOP), and gas chromatography-mass spectrometry (GC-MS) was introduced to detect the phthalates after sample pretreatment. Important parameters of the extraction procedure were investigated, and optimized including eluting solvent, the amount of Fe(3)O(4)@PPy particles, and extraction time. After optimization, the procedure took only 15 min to extract and concentrate analytes with high efficiency. Validation experiments showed that the optimized method had good linearity (0.985-0.998), precision (3.4-11.7%), high recovery (91.1-113.4%), and the limits of detection were from 0.006 to 0.068 μg/L. The results indicated that the novel method had advantages of convenience, good sensitivity, high efficiency, and it could also be applied successfully to analyze phthalates in real water sample.     

Simultaneous screening and determination eight phthalates in plastic products for food use by sonication-assisted extraction/GC-MS methods

Studies on determination of eight kinds of phthalates, e.g. di-ethyl phthalate (DEP), di-propyl phthalate (DPP), di-isobutyl phthalate (DIBP), di-butyl phthalate (DBP), benzyl butyl phthalate (BBP), di-cyclohexyl phthalate (DCHP), di-(2-ethylhexyl) phthalate (DEHP), di-octyl phthalate (DOP), in 25 kinds of plastic products for food use, including packaging bags, packaging film, containers, boxes for microwave oven use, sucking tubes, spoons, cups, plates, etc. by gas chromatography in combination with mass spectrometry detector (GC-MS) in electronic ionisation mode (EI) with selected-ion monitoring (SIM) acquisition method (GC-MS (EI-SIM)) have been carried out. Methods have been developed for both qualitative and quantitative analysis of phthalates. Extraction, clean-up and analysis procedure have been optimized. Determination of samples were performed after frozen in liquid nitrogen and sonication-assisted extraction with hexane, clean-up with LC-C18 SPE and analyzed by GC-MS methods. The base peak (m/z = 149) of all the phthalates was selected for the screening studies. The characteristic ions, 121, 177, 222 for DEP; 191, 209 for DPP; 57, 223 for DIBP; 104 for DBP; 91, 132, 206 for BBP; 55, 167 for DCHP; 113, 167, 279 for DEHP; 279 for DOP were chosen for quantitative studies. These techniques are possible to detect phthalates at the level of 10.0 μg/kg. Overall recoveries were 82-106% with R.S.D. values at 3.8-10.2%. Only one of the 25 examined samples was free from phthalates. The rest 24 samples were found to contain at least three or more of these phthalates. The predominant phthalate detected in the studied samples was DEHP.     

Simultaneous determination of phthalates and adipates in human serum using gas chromatography–mass spectrometry with solid‐phase extraction

A gas chromatography–mass spectrometry assay was developed and validated for the simultaneous determination of phthalates and adipates in human serum. The phthalates and adipates studied were dimethyl phthalate, diethyl phthalate, dibutyl phthalate, benzylbutyl phthalate, di‐2‐ethylhexyl phthalate, di‐n‐octyl phthalate, diethyl adipate, dibutyl adipate, diisobutyl adipate, bis(2‐butoxyethyl) adipate and di‐2‐ethylhexyl adipate, with diisooctyl phthalate as internal standard. The extraction and cleaning up procedure was carried out with solid‐phase extraction cartridges containing dimethyl butylamine groups, which showed extraction efficiencies over 88% for each analyte and the internal standard. The calibration curves obtained were linear with correlation coefficients greater than 0.98. For all analytes, the assay gave CV% values for intra‐day precision from 4.9 to 13.3% and mean accuracy values from 91.4 to 108.4%, while inter‐day precision was 5.2–13.4% and mean accuracy 91.0–110.2%. The limits of detection for the assay of phthalates and adipates were in the range 0.7–4.5 ng/mL. The method is simple, sensitive and accurate, and allows for simultaneous determination of nanogram levels of phthalates and adipates in human serum. It was successfully applied to an investigation on the level of phthalates and adipates in a non‐occupationally exposed population.     

Determination of phthalates in milk and milk products by liquid chromatography/tandem mass spectrometry

A liquid chromatographic/tandem mass spectrometric method using pneumatically assisted electrospray ionisation (LC/ESI-MS/MS) was developed for determination of dibutyl phthalate (DBP), benzyl butyl phthalate (BBP), di-2-ethylhexyl phthalate (DEHP), di-'isononyl' phthalate (DINP) and di-'isodecyl' phthalate (DIDP) in milk and milk products including infant formulas. The phthalates were extracted by a mixture of tert-butyl methyl ether and hexane from liquid samples. DBP, BBP and DEHP were removed from fats by liquid/liquid extraction into acetonitrile while DINP and DIDP were cleaned up on deactivated silica. The phthalates were detected in positive ion mode after separation on a reversed-phase C5 analytical column. Two transition products were monitored for each compound. The detection limits related to the transition products of lowest abundance were in the range 5-9 microg/kg.     

Identification of plasticizers in medical products by a combined direct thermodesorption--cooled injection system and gas chromatography--mass spectrometry.

The combination of a new thermodesorption module with a cooled injection system now provides a powerful system for direct analysis of volatile trace compounds in gaseous, liquid and solid samples by gas chromatography-mass spectrometry (GC-MS). As a cooled injection system is used for the cryofocusing of the desorbed volatiles the GC-MC system still can be used for the regular analysis of liquid samples. Although plasticizers usually are analyzed by GC-MS after solvent extraction, contaminated solvents and glassware are very well known problems. Analysis of plasticizers in plastic materials by direct thermodesorption instead saves time and avoids cross contaminations. Many medical products are made of plasticized polyvinyl chloride. Extraction of the common plasticizer di(2-ethylhexyl) phthalate (DEHP) into blood will occur, and harmful effects of DEHP in the human body have been suggested. We therefore analyzed 21 different plastic devices which are used for various invasive techniques in medicine by direct thermodesorption GC-MS. In some of the plastics up to 30 different components were identified. By far the most common plasticizer found was DEHP, followed by diethyl and dibutyl phthalates.     

固相萃取-气相色谱/质谱法同时测定化妆品中的邻苯二甲酸酯和对羟基苯甲酸酯

采用超声协助甲醇提取、固相萃取净化、气相色谱/选择离子质谱联用法,同时测定化妆品中8种邻苯二甲酸酯和4种对羟基苯甲酸酯。该方法线性范围广、重现性好、快速简便、干扰小。样品的加标回收率为80%～100%;含量检测的相对标准偏差小于10%;方法的检出限为0.1~5.0 μg/kg。用该方法对15种实际样品中的12种残留物进行定量检测,结果表明除了一种样品中不含待测物外,其余样品均检测到3~7种待测物。其中以对羟基苯甲酸甲酯、对羟基苯甲酸丙酯、邻苯二甲酸丙酯、邻苯二甲酸环己酯和邻苯二甲酸乙基庚基酯为主。     

Headspace solid-phase microextraction of phthalic acid esters from vegetable oil employing solvent based matrix modification

A new solvent-free analytical procedure based on headspace solid-phase microextraction (SPME) coupled to gas chromatography employing an electron capture detector (GC/ECD) or alternatively a mass spectrometric detector (GC/MSD) has been developed for the determination of phthalic acid esters (dimethyl-[DMP], diethyl-[DEP], di-n-butyl-[DnBP], butylbenzyl-[BBP], di-2-ethylhexyl-[DEHP] and di-n-octyl [DnOP] phthalate) in vegetable oils. Four different fiber coatings were evaluated, among them polydimethylsiloxane with a thickness of 100 μm appeared to be the best choice for allowing extraction of the whole group of analytes. Various solvents were tested as sample matrix modification agents with the aim to facilitate the transfer of esters with low vapour pressure (DEHP and DnOP) from oil matrix into the headspace. The addition of methanol resulted in optimal set-up applicable for all phthalate esters. Temperature control and the way of sample stirring were recognized as critical points of the whole procedure. Primarily, because shaking rather than stirring of the sample is carried out using a CombiPal multipurpose sampler, the automation of the SPME method employing this instrument was found to be not fully suitable for efficient stripping of phthalates from the oil matrix into the sample headspace. Nevertheless, the optimized manual SPME method, encompassing GC/ECD or GC/MSD for the separation and detection of target analytes, offers a unique solution and showed acceptable performance characteristics: linear response in the range of 0.5-2 mg kg⁻¹ and repeatability expressed as R.S.D. between 14 and 23% at the spiking level of 2 mg kg⁻¹.     

Pitfalls and Solutions for the Trace Determination of Phthalates in Water Samples

A method based on liquid-liquid extraction (LLE) and automated large volume injection (LVI)-GC-MS analysis was developed for the trace determination of phthalate di-esters in water samples at sub-g L^–1 (ppb) levels. Strategies applied to reduce contamination include (i) careful selection of tools, glassware and solvents, (ii) systematic blank checks of the chromatographic system, glassware and solvents and (iii) frequent verifications of blanks during sequences. Background levels could be reduced to those present in the extraction solvent. For phthalates not present in the extraction solvent the limits of quantitation (LOQ) are 6 ng L^–1 for di-methyl phthalate (DMP), 3 ng L^–1 for benzylbutyl phthalate (BzBP) and 45 ng L^–1 for the isomeric phthalate mixtures di-isononyl phthalate (DiNP) and di-isodecyl phthalate (DiDP). For the other phthalates, the LOQ was set at twice the blank (extraction solvent) level and are 20 ng L^–1 for di-ethyl phthalate (DEP), 60 ng L^–1 for di-isobutyl phthalate (DiBP), 80 ng L^–1 for di-n-butyl phthalate (DBP) and 30 ng L^–1 for bis-(2-ethylhexyl) phthalate (DEHP).Dedicated to Professor K. Jinno on the occasion of his 60^th birthday     

Differential Contribution of Albumin and Lipids to the Hydrophobic Extraction of Bis-(2-ethylhexyl) Phthalate from Hemodialysis Tubing by Human Serum: Analysis by Gas Chromatography - Stable Isotope Dilution Mass Spectrometry

Abstract

A method is presented which allows quantitative assignment of hydrophobic human serum components to the extraction of bis-(2-ethylhexyl) phthalate (DEHP) from medical tubing. Under optimized conditions (sample pH 5.5; fluid-fluid extraction with ethyl acetate + tert-butyl methyl ether 1 + 1 v/v; DEHP-ring-D4 as internal standard with ratios of endogenous (m/z = 149) and added deuterated DEHP (m/z = 153) adjusted to around 1.0; equilibration of added internal standard with the hydrophobic sample for 24 hours), a high precision can be achieved with an intra-assay coefficient of variation of 1.5% (n = 7) for sample DEHP quantification. Phthalate migration from hemodialysis tubing was quantified by use of a peristaltic pump and recirculation (200 minutes) of serum with different degrces of hypertriglyceridemia (range from 2.26 to 14.5 g/L) or solutions of human albumin (10 to 50 g/L). Only DEHP, but no other phthalates are detected in the extracts. There exist linear relations between DEHP extraction and triglyceride content (increase by 1.01 μg DEHP/g tubing material per g triglyceride/L serum) as well as between DEHP extraction and albumin content (0.59 μg DEHP/g tubing material per g albumin/L). Under physiological conditions, the total amount of albumin extracts 17.7-fold more DEHP than the total triglyceride amount in human serum. The suitability of the proposed method as a candidate reference method as well as consequences for dyslipidemic and hypalbuminemic patients on hemodialysis schemes are discussed.     

Determination of phthalates and adipate in bottled water by headspace solid-phase microextraction and gas chromatography/mass spectrometry

The performance of three fibres for the headspace solid-phase microextraction (SPME) of di-2-ethylhexyl adipate (DEHA) and eight phthalates in water was investigated systematically under different extraction conditions. Good responses on the 65 microm polydimethylsiloxane/divinylbenzene (PDMS/DVB) SPME fibre were observed for DEHA and all phthalates. The polydimethylsiloxane (PDMS) SPME fibre had very poor responses for the lighter and slightly polar phthalates, dimethyl phthalate (DMP) and diethyl phthalate (DEP), while the divinylbenzene/carboxen/polydimethylsiloxane (DVB/CAR/PDMS) SPME fibre had very poor responses for the heavier and non-polar adipate and phthalates. The salt (NaCl) was found to increase the partitioning of DMP, DEP, diisobutyl phthalate (DiBP), di-n-butyl phthalate, and benzyl butyl phthalate (BBP) from water into the headspace, while partitioning of heavier adipate and phthalates from water into headspace was suppressed when the concentration of NaCl was above 10%. The automated headspace SPME methods were developed and validated under two different salting conditions (30% NaCl for DMP, DEP and BBP, and 10% for DEHA, DiBP, DBP, di-n-hexyl phthalate (DHP), di-2-ethylhexyl phthalate (DEHP), and di-n-octyl phthalate (DOP)). Linearity with R(2) values better than 0.9949 was observed for DEHA and eight phthalates over the range from 0.1 to 20 microg L(-1). Method detection limits ranged from 0.003 microg L(-1) for DOP to 0.085 microg L(-1) for BBP. Good repeatability was observed for DEHA and most phthalates with relative standard deviation (RSD) values less than 10%. The methods were used to analyse bottled water samples for DEHA and eight phthalates. DMP, DHP, BBP, DEHA and DOP were not detected in any samples. Concentrations of the other phthalates were low (around sub-ppb) except for DBP in the water from a polycarbonate bottle at 1.72 microg L(-1).     

薄层色谱扫描法测定塑料食品袋中酞酸酯的含量

建立了采用薄层色谱扫描测定塑料食品袋中4种酞酸酯(酞酸二甲酯(DMP)、酞酸二乙酯(DEP)、酞酸二丁酯(DBP)和酞酸二(2-乙基己基)酯(DEHP))的方法。经粉碎的样品先用乙醇浸泡24 h,然后超声提取,经0.45 μm滤膜过滤。点样在以丙酮处理过的硅胶G板上,以乙酸乙酯-无水乙醚-异辛烷(体积比为1∶4∶15)为展开剂展开,以双波长反射吸收飞点扫描测定(λS=275 nm,λR=340 nm),外标法定量。该法的线性关系较好,DMP、DEP、DBP和DEHP的检出限分别为2.1,2.4,3.4和4.0 ng,混合标准品在同一薄层板上的峰面积的相对标准偏差（RSD）为2.8%～3.5%,4种酞酸酯的样品加标回收率为78.58%～111.04%。该方法样品用量少,前处理简单,分离效果好,可用于塑料袋中4种酞酸酯的同时测定。经与气相色谱法的分析结果比较,两种方法对实际样品的分析结果接近。     

An investigation into possible sources of phthalate contamination in the environmental analytical laboratory

A study of common laboratory equipment and components was performed in order to identify sources of contamination of phthalates prior to testing environmental samples for such compounds. A screening study revealed significant leaching from laboratory consumables, such as plastic syringes, pipette tips released maximum leachings of 0.36?µg?cm^?2 diethylhexyl phthalate (DEHP) and 0.86?µg?cm^?2 diisononyl phthalate (DINP), plastic filter holders produced maximum leachings of 2.49?µg?cm^?2 dibutyl phthalate (DBP) from polytetrafluoroethylene (PTFE); specifically 0.61?µg?cm^?2 DBP from regenerated cellulose and 5.85?µg?cm^?2 dimethyl phthalate (DMP) from cellulose acetate and Parafilm® leached levels up to 0.50?µg?cm^?2 DEHP. In addition, a high-temperature bake-out process was found necessary to eliminate quite high levels of two phthalates present in a commercial bulking agent for pressurized liquid extraction.     

Microwave‐assisted extraction combined with on‐line solid phase extraction followed by ultra‐high‐performance liquid chromatography with tandem mass spectrometric determination of benzotriazole UV stabilizers in marine sediments and sewage sludges

Benzotriazole ultra‐violet stabilisers are compounds widely used in personal care products, which can reach the environment after passing through wastewater treatment plants. In this work, we develop a novel method to evaluate the presence of seven compounds in marine sediments and sewage sludges using microwave‐assisted extraction followed by a clean‐up step based in on‐line solid phase extraction coupled to ultra‐high‐performance liquid chromatography with MS/MS detection. This method allows for fast and efficient extraction from the solid matrix, subsequent automatic on‐line purification and preconcentration, and analysis. For the optimised method, LOD were from 53.3 to 146 ng/kg and LOQ were in the range of 176–486 ng/kg. The method was validated for different environmental solid samples with satisfactory recoveries and relative standard deviations, between 46.1 and 83.9 and 7.8 and 15.5% (sludges) and 50.1 and 87.1% and 8.83 and 16.3% (sediments), respectively. Finally, the studied analytes were quantified in concentrations between 0.18 and 24.0 ng/g in real samples of marine sediments and sewage sludges from Gran Canaria Island (Spain).     

Challenges encountered in the analysis of phthalate esters in foodstuffs and other biological matrices

Phthalate esters are ubiquitous environmental pollutants and are recognized as environmental endocrine disruptors because of their potential to elicit reproductive and developmental toxicity. Several phthalate esters have been listed by the US Environmental Protection Agency (EPA) as chemicals of concern. Determination of concentrations of phthalate esters in foodstuffs, typically present at sub to low nanogram-per-gram concentrations (between 0.1 and 100?ng?g^?1), is essential for assessment of human dietary exposure. However, phthalate esters are commonly present as contaminants in several laboratory products, including organic solvents, that are used in sample preparation and analysis. Therefore, accurate analysis of phthalates in food samples is a challenging task. In this review, we summarize the methods available for the determination of phthalate esters in foodstuffs and report on concentrations of phthalates in foodstuffs and potential sources of contamination by phthalates in the analysis of foodstuffs. We offer suggestions to eliminate and/or reduce background levels of contamination by phthalates in the analysis of food and other biological samples. We also introduce methods that are suitable for trace analysis of phthalates in a variety of liquid and solid food samples, in particular, a liquid–liquid extraction method for removal of lipids from food samples, because these can substantially reduce background levels of phthalates in the analytical procedure.     

毛细管气相色谱法测定化妆品中的酞酸酯

建立了用毛细管气相色谱配氢火焰离子化检测器测定化妆品中6种酞酸酯(邻苯二甲酸二甲酯(DMP)、邻苯二甲酸二乙酯(DEP)、邻苯二甲酸二丁酯(DBP)、邻苯二甲酸丁基苄基酯(BBP)、邻苯二甲酸二(2-乙基己)酯(DEHP)和邻苯二甲酸二正辛酯(DOP))的方法。样品用甲醇超声提取,经高速冷冻离心,清液经干燥脱水过0.5 μm滤膜过滤,直接注入气相色谱仪进行分析。然后,经过气相色谱-电子电离-质谱检测分析,确证气相色谱-氢火焰检测的阳性检出结果。用保留时间定性,外标法定量。6种酞酸酯的回收率为82.90%～     

基于杯［6］芳烃萃取头的固相微萃取-气相色谱法测定啤酒中痕量的酞酸酯类化合物

选用自制杯［6］芳烃溶胶-凝胶固相微萃取(SPME)萃取头,建立了顶空SPME与气相色谱联用检测啤酒中8种酞酸酯(PAEs)的方法。采用L25(56)正交设计对萃取条件进行了优化,所得方法检出限为0.003～3.429 μg/L,相对标准偏差不超过13.5%,加标回收率为86.3%～109.3%。采用标准加入法对3种瓶装啤酒中PAEs进行了检测,结果表明邻苯二甲酸二(2-乙基己)酯(DEHP)是啤酒中最主要的酞酸酯类污染物,含量最高达5.24 μg/L。迁移试验表明,瓶装啤酒所用塑料垫圈中高含量的DEHP可能成为酒体中PAEs的一种来源,且延长贮存时间、提高贮存温度和振荡都能加快垫圈中DEHP的迁移。     

Simultaneous determination of selected endocrine disrupters (pesticides,phenols and phthalates) in water by in-field solid-phase extraction (SPE) using the prototype PROFEXS followed by on-line SPE (PROSPEKT) and analysis by liquid chromatography-atmospheric pressure chemical ionisation-mass spectrometry

In this study, a new procedure, based on on-line solid-phase extraction (SPE) and analysis by liquid-chromatography-atmospheric pressure chemical ionization-mass spectrometry (LC-APCI-MS), has been developed for the simultaneous, multianalyte determination of 21 selected pesticides, phenols and phthalates in water. SPE was carried out on polymeric PLRP-s cartridges by percolating 20 mL-samples. For sample preconcentration, the performance of a prototype programmable field extraction system (PROFEXS) was evaluated against the commercial laboratory bench Prospekt system used for method development. The Profexs is designed for the automated on-site sampling, SPE preconcentration, and storage of up to 16 samples in SPE cartridges. These cartridges are further eluted and on-line analyzed with the Prospekt coupled to the chromatographic system. In the optimized method, where completely on-line SPE-LC-MS analysis of the samples is carried out with the Prospekt in the laboratory, detection limits lower than 100 ng/L, and satisfactory precision (relative standard deviations <25%) and accuracies (recovery percentages >75%) were obtained for most investigated compounds from the analysis of spiked Milli-Q water. The extraction efficiency achieved with the Profexs was comparable to that of the Prospekt for most compounds and somewhat lower for the most apolar analytes, probably due to adsorption on the pump filters. The completely on-line optimized method was applied to the analysis of surface water, ground water and drinking water from a waterworks in Barcelona. Some pesticides and phenols were found in both surface water and groundwater at ng/L or µg/L levels, but not in the final drinking water. Di(2-ethylhexyl)phthalate (DEHP) was present in all samples investigated, including blanks. To the author's knowledge, this is the first work describing the application of a fully automated on-line SPE-LC-MS method for the simultaneous analysis of pesticides, phenols, and phthalates in water, and the second one that examines the possibilities of the prototype Profexs for automated on-site SPE preconcentration of organic pollutants from water samples.     

Separation of phthalates by cyclodextrin modified micellar electrokinetic chromatography: Quantitation in perfumes

A new CE method has been developed for the simultaneous separation of a group of parent phthalates. Due to the neutral character of these compounds, the addition of several bile salts as surfactants (sodium cholate (SC), sodium deoxycholate (SDC), sodium taurodeoxycholate (STDC), sodium taurocholate (STC)) to the separation buffer was explored showing the high potential of SDC as pseudostationary phase. However, the resolution of all the phthalates was not achieved when employing only this bile salt as additive, being necessary the addition of neutral cyclodextrins (CD) and organic modifiers to the separation media. The optimized cyclodextrin modified micellar electrokinetic chromatography (CD-MEKC) method consisted of the employ of a background electrolyte (BGE) containing 25 mM β-CD-100 mM SDC in a 100 mM borate buffer (pH 8.5) with a 10% (v/v) of acetonitrile, employing a voltage of 30 kV and a temperature of 25 °C. This separation medium enabled the total resolution of eight compounds and the partial resolution of two of the analytes, di-n-octyl phthalate (DNOP) and diethyl hexyl phthalate (DEHP) (Rs ~ 0.8), in only 12 min. The analytical characteristics of the developed method were studied showing their suitability for the determination of these compounds in commercial perfumes. In all the analyzed perfumes the most common phthalate was diethyl phthalate (DEP) that appeared in ten of the fifteen analyzed products. Also dimethyl phthalate (DMP), diallyl phthalate (DAP), dicyclohexyl phthalate (DCP), and di-n-pentyl phthalate (DNPP) were found in some of the analyzed samples.