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.     

Quantitative determination of endocrine- disrupting polychlorinated biphenyls and organochlorinated pesticides in human serum using gas chromatography with electron-capture detection and tandem mass spectrometry

A sensitive, selective and reliable procedure was developed and validated to determine organochlorinated compounds, which have endocrine-disrupting effects, in human serum. Target compounds were selected between polychlorinated biphenyls and organochlorinated pesticides. Sample workup consisted of (1) extraction of serum with organic solvents, (2) clean-up of the organic extract using acid treatment with H(2)SO(4), (3) elution of the cleaned-up extract through a liquid column chromatographic system and (4) analysis of the fraction eluted by gas chromatography with electron capture detection (ECD) and tandem mass spectrometry (MS/MS) detection. Performance characteristics, such as linearity, sensitivity, precision, accuracy and recovery, of both chromatographic methods were studied. The proposed analytical methodology was applied to determine the target compounds in serum samples from women living in agricultural areas of Almería (Spain). The results show the advantage of MS/MS over ECD in the analysis of real human serum samples where matrix interferences can be confused with target pesticides.     

Preparation of magnetic core mesoporous shell microspheres with C18-modified interior pore-walls for fast extraction and analysis of phthalates in water samples

In this study, core-shell magnetic mesoporous microspheres with C18-functionalized interior pore-walls were synthesized through coating Fe(3)O(4) microspheres with a mesoporous inorganic-organic hybrid layer with a n-octadecyltriethoxysilane (C18TES) and tetraethyl orthosilicate (TEOS) as the silica source and cetyltrimethylammonia bromide (CTAB) as a template. The obtained C18-functionalized Fe(3)O(4)@mSiO(2) microspheres possess numerous C18 groups anchored in the interior pore-walls, large surface area (274.7 m(2)/g, high magnetization (40.8 emu/g) and superparamagnetism, uniform mesopores (4.1 nm), which makes them ideal absorbents for simple, fast, and efficient extraction and enrichment of hydrophobic organic compounds in water samples. Several kinds of phthalates were used as the model hydrophobic organic compounds to systematically evaluate the performance of the C18-functionalized Fe(3)O(4)@mSiO(2) microspheres in extracting hydrophobic molecules by using a gas chromatography-mass spectrometry. Various parameters, including eluting solvent, the amounts of absorbents, extraction time and elution time were optimized. Hydrophobic extraction was performed in the interior pore of magnetic mesoporous microspheres, and the materials had the anti-interference ability to macromolecular proteins, which was also investigated in the work. Under the optimized conditions, C18-functionalized Fe(3)O(4)@mSiO(2) microspheres were successfully used to analyze the real water samples. The results indicated that this novel method was fast, convenient and efficient for the target compounds and could avoid being interfered by macromolecules.     

Monitoring organochlorine pesticides from landfill leachates by gas chromatography-electron-capture detection after solid-phase microextraction

Landfill leachates contain significant amounts of organic carbon, nitrogen and heavy metals as well as other specific trace organic compounds like organochlorine pesticides. In this study a simple and reliable methodology was improved to detect organochlorine pesticides in leachate samples by using a previous solid-phase microextraction procedure [with a 100 microm poly(dimethylsiloxane) fiber] and chromatographic analysis by GC-electron-capture detection. The extraction time, temperature, ionic strength of the solution and sampling of the headspace were the parameters studied. Reproducibility achieved values below 20% RSD, and standard addition was used for pesticides confirmation.     

Analysis of Organic Compounds in Antarctic Snow and Their Origin

Abstract

Organic compounds extractable with n-hexane were identified and quantitatively determined in pack, surface and deep snow samples taken at different depths and collected at several altitudes above sea level from Antarctica during the 1993/94 Italian expedition. The comparison between the composition of organic compounds in snow and the ones in pack and sea-water samples pointed out that the three matrices substantially contain the same biogenic and anthropogenic organic compounds. The contribution of marine aerosol to organic content in the snow is confirmed by the enrichment ratios calculated for the more representative classes of identified compounds (n-alkanes, phthalates and low molecular weight alkylbenzenes). The changes in the composition of organic compounds in snow as the altitude increases seem to depend on the dimensional spectrum of the aerosol. Thus, smallest particles, richest in surfactant material, reach the highest altitudes.     

Phthalates determination in pharmaceutical formulae used in parenteral nutrition by LC-ES-MS: importance in public health

A method for determining a group of phthalate esters in pharmaceutical formulae used in parenteral nutrition samples (with and without vitamins) has been developed. The phthalic acid esters (PAEs) studied were dimethyl phthalate, diethyl phthalate, butyl benzyl phthalate, dibutyl phthalate, di-(2-ethylhexyl) phthalate, and dioctyl phthalate. This group of phthalates was determined by high performance liquid chromatography (HPLC)–electrospray ionization–mass spectrometry, working in positive ion mode. The phthalates analyzed were extracted from the sample using hexane and sodium hydroxide. The hexane was then evaporated, and the compounds were redissolved in acetonitrile. The compounds were separated by HPLC working in gradient mode with acetonitrile-ultrapure water starting from 5% to 75% acetonitrile in 5 min, followed by isocratic elution for 27 min. Standard calibration curves were linear for all the analytes over the concentration range 10–250 μg L⁻¹. The method was precise (with RSD from 3.3% to 12.9%) and sensitive. The proposed analytical method has been applied to the analysis of these compounds in different pharmaceutical formulae (with different compositions) for parenteral nutrition samples in order to check the presence of phthalates and determine their concentration.     

Recent advances in the mass spectrometric analysis related to endocrine disrupting compounds in aquatic environmental samples

An overview of mass spectrometric methods used for the determination of endocrine disrupting compounds (EDCs) in environmental samples is presented. Among the EDCs we have selected five groups of compounds that are of priority within European Union and US research activities: alkylphenols, polychlorinated compounds (dioxins, furans and biphenyls), polybrominated diphenyl ethers, phthalates and steroid sex hormones. Various aspects of current LC-MS and GC-MS methodology, including sample preparation, are discussed.     

In-tube solid-phase microextraction coupled by in valve mode to capillary LC-DAD: Improving detectability to multiresidue organic pollutants analysis in several whole waters

A simple and fast capillary chromatographic method has been developed to identify and quantify organic pollutants at sub-ppb levels in real water samples. The major groups of pesticides (organic halogens, organic phosphorous, and organic nitrogen compounds), some hydrocarbons (polycyclic aromatic hydrocarbons), phthalates and some phenols such as phenol and bisphenol A (endocrine disruptors) were included in this study. The procedure was based on coupling, in-tube solid-phase microextraction (IT-SPME) by using a conventional GC capillary column (95% methyl–5% phenyl substituted backbone, 80 cm × 0.32 mm i.d., 3 μm film thickness) in the injection valve to capillary liquid chromatography with diode array detection. A comparative study between the IT-SPME manifold and a column-switching device using a C₁₈ column (35 mm × 0.5 mm i.d., 5 μm particle size) has been performed. The IT-SPME procedure was optimal, it allows reaching limits of detection (LODs) between 0.008 and 0.2 μg/L. No matrix effect was found and recoveries between 70 and 116% were obtained. The precision of the method was good, and the achieved intra- and inter-day variation coefficients were between 2 and 30%. This procedure has been applied to the screening analysis of 28 compounds in whole waters from several points of the Mediterranean coast (Valencia Community, Spain).     

Expanding the number of phthalates monitored in house dust

Phthalates have been used as plasticisers for several decades in various industry and consumer products. A method was developed for the determination of 13 not commonly monitored phthalates in household dust. The method was based on solvent extraction using sonication, sample clean-up by solid phase extraction (SPE), and analysis using isotope dilution gas chromatography-tandem mass spectrometry (GC/MS/MS). The method was applied to the analysis of dust samples collected using two vacuum sampling techniques from 38 urban Canadian homes: a sample of fresh or ‘active’ dust (FD) collected by technicians and a composite sample taken from the household vacuum cleaner (HD). Spearman rank correlations between HD and FD samples were significant for six phthalates with median concentrations above their method detection limits (MDLs), suggesting that the HD samples provide comparable results with FD samples. Seven phthalates were detected and quantified in a Canada-wide set of 126 household dust samples, among which six phthalates were detected at frequencies higher than 87%, with median (range) concentrations of 1.9 (<0.42–240) (μg/g) for diisohexyl phthalate (DIHxP), 3.8 (<0.16–260) (μg/g) for di-n-heptyl phthalate (DHepP), 6.6 (<1.1–1170) (μg/g) for diisooctyl phthalate (DIOP), 1.1 (<0.12–390) (μg/g) for di-n-octyl phthalate (DOP), 6.3 (<0.16–430) (μg/g) for dinonyl phthalate (DNP), and 1.8 (<0.18–850) (μg/g) for di-n-decyl phthalate (DDP). High detection frequencies and widely scattered concentration levels of these phthalates in this preliminary set of 126 samples suggested a high variability in potential exposure to phthalates in Canadian homes. NIST SRM 2585 (organic contaminants in house dust) was also analysed; eight phthalates were detected, with concentrations ranging from 6.0 μg/g for DOP to 79 μg/g for DIHxP. The results from SRM 2585 may contribute to the certification of phthalate concentration values in this SRM.     

Fermentation Characteristics of <Emphasis Type="Italic">Mortierella alpina</Emphasis> in Response to Different Nitrogen Sources

The fermentation characteristics of Mortierella alpina were investigated in response to various nitrogen sources. Influences on nitrogen source and glucose uptake rate, mycelial morphology of M. alpina, and pH of medium in relation to different nitrogen sources were discussed. Effects of different nitrogen sources on cell growth, fatty acid composition, arachidonic acid (ARA), and total lipid concentration were also evaluated. It revealed that the maximum nitrogen source uptake ratio was obtained when corn steep liquor was used as nitrogen source. When yeast extract was used as the sole nitrogen source, glucose was completely exhausted at the end of fermentation. The maximum dry cell weight obtained from medium with yeast extract as nitrogen source had the highest total lipid concentration. Sodium nitrate was the favorable nitrogen source for ARA accumulation, and the highest ARA percentage in total fatty acids was obtained, 35.9%. Urea was identified as the favorable nitrogen source for ARA production, the highest ARA concentration obtained from urea was 5.8 g/l. Compared with inorganic nitrogen sources, organic nitrogen compounds are favorable for both cell growth and total lipids accumulation.     

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).     

宝明页岩柴油碱性氮化物的梯度富集及GC-MS分析

利用溶剂萃取和柱色谱等技术浓缩分离新疆宝明页岩油柴油馏分中的碱性氮化物。以宝明页岩柴油为原料,经糠醛溶剂精制,初步得到富集碱性氮化物的抽出油。以抽出油为深度富集碱性氮化物的原料,采用柱色谱等分离方法,从抽出油中分离得到碱性氮化物。利用傅立叶变换红外光谱仪(FT-IR)和气相色谱-质谱联用仪(GC-MS)分别对富集的碱性氮化物进行官能团检测和定性、定量分析。结果表明:新疆宝明页岩油柴油馏分中的碱性氮化物经溶剂精制和柱色谱等分离方法梯度富集后,碱性氮化物的质量分数由抽出油的12.08%提高到最终产物的69.48%,并在富集分离的产物中鉴定出60种碱性氮化物,其中主要为苯胺类、喹啉类和吡啶类化合物,各占25.85%,23.56%和16.52%。     

桂花精油化学成分研究

用水蒸汽蒸馏法对江苏产桂花精油进行了提取, 并用GC-MS联用仪对其有效成分进行了测定. 结果表明: 江苏产桂花精油的香味成分主要是萜烯、醇类、氧化芳樟醇类、 5-己基二氢呋喃-2-酮、紫罗兰酮类、邻苯二甲酸酯类, 其中邻苯二甲酸酯类含量最大. 对水蒸汽蒸馏后的桂花水溶液进行萃取和GC-MS测试, 进一步证实了邻苯二甲酸酯的存在. 与其它产地的桂花精油化学成分比较, 其主要的香味成分基本相同, 但邻苯二甲酸酯含量不同, 这一研究结果表明: 研究不同产地的香料香味成分时需要将多种提取方法结合;对现有应用于化妆品和食用香精的桂花精油是否含有邻苯二甲酸酯需作进一步的研究.     

Microwave assisted extraction of polycyclic aromatic hydrocarbons from atmospheric particulate samples

For several years, microwave assisted extraction (MAE) was applied to extract organic compounds such as polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls, etc., from soils, sediments and standard reference materials. Very few authors applied this methodology for the extraction of PAHs from atmospheric particulate matter. In the present study, MAE of polycyclic aromatic hydrocarbons with hexane/acetone (1:1) from real atmospheric particulate samples was investigated and the effect of microwave energy and irradiation time studied. The yields of extracted compounds obtained by microwave irradiation were compared with those obtained using traditional Soxhlet extraction. MAE was evaluated using spiked real atmospheric particulate samples and two standard reference materials. Analytical determinations of PAHs were carried out by high performance liquid chromatography (HPLC) with ultraviolet and fluorescence detection. The best recoveries were achieved with a microwave energy of 400 W and an irradiation time of 20 min.     

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.     

Environmentally friendly analysis of emerging contaminants by pressurized hot water extraction–stir bar sorptive extraction–derivatization and gas chromatography–mass spectrometry

This work describes the development, optimization, and validation of a new method for the simultaneous determination of a wide range of pharmaceuticals (beta-blockers, lipid regulators…) and personal care products (fragrances, UV filters, phthalates…) in both aqueous and solid environmental matrices. Target compounds were extracted from sediments using pressurized hot water extraction followed by stir bar sorptive extraction. The first stage was performed at 1,500 psi during three static extraction cycles of 5 min each after optimizing the extraction temperature (50–150 °C) and addition of organic modifiers (% methanol) to water, the extraction solvent. Next, aqueous extracts and water samples were processed using polydimethylsiloxane bars. Several parameters were optimized for this technique, including extraction and desorption time, ionic strength, presence of organic modifiers, and pH. Finally, analytes were extracted from the bars by ultrasonic irradiation using a reduced amount of solvent (0.2 mL) prior to derivatization and gas chromatography–mass spectrometry analysis. The optimized protocol uses minimal amounts of organic solvents (<10 mL/sample) and time (≈8 h/sample) compared to previous existing methodologies. Low standard deviation (usually below 10 %) and limits of detection (sub-ppb) vouch for the applicability of the methodology for the analysis of target compounds at trace levels. Once developed, the method was applied to determine concentrations of these compounds in several types of sample (wastewater, seawater, pore water, and sediment) from Cadiz Bay (SW Spain). To our knowledge, these findings represent the first information available on the presence of some of the target compounds in the marine environment.     

固相萃取法分析水生生物体中17种酞酸酯类环境激素

水生生物样品去壳、搅碎、匀浆;干货样品则首先烘干、研磨和过筛。以丙酮作为提取剂超声波辅助提取3次,提取液经无水硫酸钠脱水后进行氮吹浓缩;浓缩液经处理过的Florisil硅藻土吸附柱净化和乙酸乙酯/己烷(1/5,V/V)洗脱剂洗脱与浓缩后,采用气相色谱-电子轰击电离源/质谱法进行定性分析与内标法定量分析。实验优化与选择了提取剂的种类、吸附剂的种类及其活化条件、洗脱剂的种类等样品前处理过程,并讨论了分析空白值的控制问题。分析方法的线性相关系数均大于0.99987,方法检出限均小于3.67μg/L,平均加标回收率为64.1%~124%,方法的相对标准偏差均小于16.4%。此分析方法成功地应用于3种鱼类(刀鱼、黑鱼、草鱼)、2种贝类(沙螺、牡蛎)、1种甲壳类(明虾)、1种头足类(章鱼)、2种植物(海带、海藻)和2种干货(干海带、丁香鱼干)样品中17种酞酸酯类环境激素含量的同时分析,所分析的样品都检测到邻苯二甲酸二甲酯、邻苯二甲酸二异丁基酯和邻苯二甲酸二丁酯,在大部分样品中还检测出邻苯二甲酸二乙酯和邻苯二甲酸二乙基己基酯,说明此5种酞酸酯已造成了一定程度的水体污染。     

土壤中64种痕量半挥发性有机污染物的分析方法研究

利用超声提取技术将土壤中的半挥发性有机污染物(SVOC)提取出来, 经旋转蒸发浓缩至一定体积后, 用ODSC18柱净化, 再用氮吹浓缩后, 取1.0 μL注入气相色谱中, 用DB-5 ms柱分离, 用气相色谱质谱仪(GC-MS)进行定性定量分析. 本方法研究土壤中64种半挥发性有机污染物, 其中包括苯系物、苯酚类、苯胺类、硝基芳香烃类、氯代芳烃类、多环芳烃类和酞酸酯类等物质的提取、净化方法以及回收率、精密度和检测限的测定. 该方法回收率为52.5%～105%.     

Horizontal and vertical distributions of Biogenic and Anthropogenic Organic compounds in the Ross Sea (Antarctica)

Horizontal and vertical distributions of organic compounds extractable with n-hexane were investigated at five sampling stations (Ross Sea) during the Italian Antarctic Expedition 1997/98. Samples were collected from seven depths under pack ice and from two or three depths at the other stations located at different distances from the coast. The lowest concentrations of biogenic and anthropogenic compounds were found at station Y3, the furthest from the coast, while the highest concentrations were observed under pack ice (B2-2 station) or in the Polynya zone (Y1 station). The levels of organic compounds in the particulate phase were higher than those in the dissolved phase for all the investigated samples. Concentrations of biogenic organic compounds (long-chain aldehydes and alcohols, fatty acid esters and n-alkanes) were well related to fluorescence intensity, which is usually reported as a biological activity index. The odd-to-even carbon-number ratio for n-alkanes was lower than 1 at stations B2-2, Y1, Y5 and Y6 (located less than 150?km far from the coast) with the predominance of n-C16, n-C24 and n-C28, indicative of autochthonous pelagic species. An odd-to-even ratio higher than unity and a different n-alkane profile were observed at station Y3 (about 300?km from the Ross Ice Shelf and 600?km from Terra Nova Bay). Low levels of pollutants (i.e. phthalates) were found, mainly in the particulate phase up to a depth of 50?m, confirming a local source of the phthalates found at significant concentrations during previous expeditions.     

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.