Easy determination of benzophenone and its derivatives in sunscreen samples by direct-immersion solid-phase microextraction and gas chromatography-mass spectrometry.

Benzophenones (BPs) absorb different sun radiation wavelengths, making them effective UVA and UVB filters, widely used in industry. In Europe, sunscreen products contain regulated amounts (6 % w/w) of benzophenone-3 (BP-3), usually combined with other filters like octocrylene. BPs are mutagens in UV radiation, and octocrylene may degrade into BPs, making their monitoring crucial. The present manuscript proposed a novel procedure based on liquid-liquid extraction followed by direct-immersion solid-phase microextraction (LLE-DI-SPME) to isolate and determine 10 BPs in sunscreen lotions with potential results. Parameters like extraction solvent, pH, adsorption, desorption time, stirring, sating effect, and presence of organic solvents were optimized and compared with different SPME fibers, being polyacrylate (PA) fiber the most effective. Detection and quantification were performed by gas chromatography-mass-spectrometry. Analytical parameters as limits of detection were 0.05-0.10 µg kg-1, while the linear range was 0.16 up to 2000 µg kg-1. In terms of recovery, the method ranged from 83 % to 103 %; the precision of the method was good in terms of relative standard deviation (RSD) from 3.2 % to 18.7 % and without a remarkable matrix effect (-15.06-8.45 %). Despite the complexity of the samples and the difficulty posed by the DI-SPME technique, the method proved robust. The proposed method successfully detected 10 BPs in 6 different sunscreen lotions. The total presence of BPs in sunscreens ranged from 165 to 931 mg kg-1, with BP-3 detected in all samples from 4.2 to 740 mg kg-1.

Determination of Parabens and Phenolic Compounds in Dairy Products through the Use of a Two-Step Continuous SPE System Including an Enhanced Matrix Removal Sorbent in Combination with UHPLC-MS/MS.

Dairy products can be contaminated by parabens and phenolic compounds from a vast variety of sources, such as packaging and manufacturing processes, or livestock through feed and environmental water. A two-step continuous solid-phase extraction (SPE) and purification methodology was developed here for the determination of both types of compounds. In the first step, a sample extract is passed in sequence through an EMR-lipid sorbent and an Oasis PRiME HBL sorbent to remove fat and preconcentrate the analytes for subsequent detection and quantification by UHPLC-MS/MS. This method enabled the determination of 28 parabens and phenolic contaminant with excellent recovery (91-105%) thanks to the SPE sorbent combination used. The proposed method was validated through the determination of the target compounds, and was found to provide low detection limits (1-20 ng/kg) with only slight matrix effects (0-10%). It was used to analyse 32 different samples of dairy products with different packaging materials. Bisphenol A and bisphenol Z were the two phenolic compounds quantified in the largest number of samples, at concentrations over the range of 24-580 ng/kg, which did not exceed the limit set by European regulations. On the other hand, ethylparaben was the paraben found at the highest levels (33-470 ng/kg).

A Simple, Efficient, Eco-Friendly Sample Preparation Procedure for the Simultaneous Determination of Hormones in Meat and Fish Products by Gas Chromatography-Mass Spectrometry.

Food safety can be severely compromised by the presence of chemical contaminants. This has raised a pressing need to develop efficient analytical methods for their determination at very low levels in complex food matrices. In this manuscript, we developed a simple, sensitive, fast, green analytical method for the determination of thirteen natural and synthetic hormones from different families including progestogens, estrogens and androgens in meat and fish products. The method involves direct extraction with a (9:1) acetonitrile-water mixture and subsequent purification of the extract by semi-automated solid-phase extraction on a sorbent column (hydrophilic-lipophilic copolymer of N-vinylpyrrolidone and divinylbenzene). This treatment enriches samples with the target compounds while removing proteins, lipids and other potential interferences from their matrix for the accurate determination of the analytes by gas chromatography-mass spectrometry, all within 15 min. The proposed method exhibits good linearity (r ≥ 0.996), low limits of detection (0.4-15 ng/kg), acceptable recoveries (90-105%) and relative standard deviations (≤7%); in addition, it is scarcely subject to matrix effects (1-20%). The method was successfully used to determine natural and synthetic hormones in meat and fish products from Spain, Portugal, Italy, Germany, Greece, Norway, Morocco and the USA. The analytes were found at especially high levels (30-1900 ng/kg) in mussels, beef and pork.

Trace-Level Determination of Polycyclic Aromatic Hydrocarbons in Dairy Products Available in Spanish Supermarkets by Semi-Automated Solid-Phase Extraction and Gas Chromatography-Mass Spectrometry Detection.

Polycyclic aromatic hydrocarbons (PAHs) have been classified as priority pollutants by the U.S. Environmental Protection Agency (EPA) and the European Commission on the grounds of their carcinogenic, mutagenic and teratogenic properties. Because of their ubiquity in industrial processes and the environment, PAHs can reach milk and dairy products and, eventually, humans. In this work, a new method was developed to detect and quantify sixteen of the EPA's priority PAHs in commercial milk and dairy products. The method involves liquid−liquid extraction (LLE) followed by semi-automated solid-phase extraction (SPE) to clean up and preconcentrate the analytes prior their detection and quantification by gas chromatography−mass spectrometry (GC−MS). The proposed method provided high precision (relative standard deviation < 11.5%), recoveries of 80−107% and low detection limits (1−200 ng/kg). The method was applied to analyze 30 dairy products, the majority of which contained some PAH at concentrations from 7.1 to 1900 ng/kg. The most-detected analytes were the lighter PAHs (naphthalene, acenaphthylene, fluorene and phenanthrene). None of the samples, however, contained more than four PAHs.

A sensitive, robust method for determining natural and synthetic hormones in surface and wastewaters by continuous solid-phase extraction-gas chromatography-mass spectrometry.

Over recent decades, steroidal estrogens have become an emerging and very serious issue as they pose a serious threat to living organisms, soil, plants, and water resources in general. Estrogens have therefore been the subject of considerable scientific attention in order to develop new methodologies for its determination, being able of detecting them at very low concentrations. Those procedures minimize or eliminate the consumption of organic solvents and reagents that may be incompatible with the environment. In this respect, we developed a sensitive, selective method for the simultaneous determination of thirteen natural and synthetic hormones present at the nanogram-per-liter level in various types of water by using continuous solid-phase extraction in combination with gas chromatography and mass spectrometry (GC-MS). The target analytes were preferentially sorbed on an Oasis HLB sorbent column (80 mg) and eluted with acetone (600 µL) for derivatization with a mixture of 70 µL of N,O-bis(trimethylsilyl) trifluoroacetamide and trimethylchlorosilane and 35 µL of petroleum ether in a household microwave oven at 200 W for 4 min. Under optimum conditions, the ensuing method exhibited good linearity (r ≥ 0.998), good precision (RSD ≤ 7%), high recoveries (92-103%), and low detection limits (0.01-0.3 ng L-1). The method outperforms existing alternatives in robustness, sensitivity, throughput, flexibility-it allows both estrogens, progestogens, and androgens to be determined simultaneously-and compliance with the principles of Green Chemistry. It was successfully used to analyze various types of water samples (mineral, tap, well, pond, swimming pool, river, and waste) that were found to contain four estrogens (estrone, 17ß-estradiol, 17α-ethinylestradiol, and hexestrol), two progestogens (testosterone, dihydrotestosterone), and one progestogen (progesterone) at concentrations ranging from 3.0 to 110 ng L-1.

Occurrence and distribution of endocrine disrupting chemicals and pharmaceuticals in the river Bouregreg (Rabat, Morocco).

In this work, Moroccan surface waters were analysed for 27 endocrine disrupting chemicals and pharmaceutically active compounds. The study area was selected on the grounds of the scarcity of information about the contamination status of rivers in the Rabat region, which receive micropollutants from municipal and industrial wastewater, and runoff from agricultural fields. In fact, animal feed residues, urban water runoff and untreated waste discharges into old landfills reach river water in an area with a population of ca. 3 752 800 where more than 99% of all drinking water is obtained from surface water. Samples were collected at five different sites upstream and downstream the river Bouregreg and the target compounds determined by using a continuous solid-phase extraction system and gas chromatography-mass spectrometry. Unlike the pharmaceuticals, most of the EDCs (specifically, 4-tert-octylphenol, nonylphenol, 4-phenylphenol, 2-phenylphenol, estrone, 17ß-estradiol, triclosan and bisphenol A) were present in all samples with detection frequencies above 68%, the highest concentrations (142-368 ng/L) being those at the river mouth. The pharmaceuticals found encompassed five therapeutic classes and their concentrations ranged from 2.5 to 351 ng/L. Overall, the most abundant class were the anti-inflammatory/analgesic drugs with high detection frequencies (80%), followed by antibiotics and anti-epileptics (64%), lipid regulators (56%) and ß-blockers (12%). Based on the principal component analysis, the distribution of the emerging contaminants studied among sampling sites was consistent with the physico-chemical properties of the water, the most heavily contaminated sites being those close to the mouth of the river.

Validation and Use of an Accurate, Sensitive Method for Sample Preparation and Gas Chromatography-Mass Spectrometry Determination of Different Endocrine-Disrupting Chemicals in Dairy Products.

Endocrine disrupting chemicals (EDCs) are exogenous substances capable of altering the human hormone system and causing various diseases such as infertility and cancer as a result. In this work, a method for determining twenty-three different EDCs including parabens, alkylphenols, phenylphenols, organophosphorus pesticides, bisphenol A and triclosan in dairy products was developed. Samples are conditioned by addition of acetonitrile containing 1% formic acid, centrifugation and clean-up of the extract by continuous solid-phase extraction. EDCs in the extract are derivatised by heating in a microwave oven and quantified by gas chromatography-mass spectrometry. The proposed method features good limits of detection (6-40 ng/kg) and precision (relative standard deviation < 7.6%); also, it is scarcely subject to matrix effects (1-20%). EDC recoveries from spiked samples ranged from 80 to 108%. The method was used to analyse a total of 33 samples of dairy products including cow, sheep and goat milk, yoghourt, milkshakes, cheese, cream, butter and custard. Bisphenol A was the individual contaminant detected in the greatest number of samples, at concentrations from 180 to 4800 ng/kg. 2-Phenylphenol and ethylparaben were found in more than one-half, at concentrations over the range 130-3500 and 89-4300 ng/kg, respectively. In contrast, alkylphenols, organophosphorus pesticides and triclosan were detected in none.

Determination of atropine and scopolamine in spinach-based products contaminated with genus Datura by UHPLC-MS/MS.

Datura species are well known because of their high concentration of tropane alkaloids, which has led to poisoning episodes when Datura is accidentally mixed with edible crops. Therefore, the European Union has set a maximum level in cereal-based infant food products of 1 µg kg-1 for atropine and scopolamine. However, the occurrence of these compounds in other commodities has become a global concern. Spinach and derived products can be contaminated with Datura innoxia leaves. In this study, we tested frozen spinachs and spinach-based infant food products. The determination was carried out by UHPLC-MS/MS after applying the QuEChERS method as sample treatment. The LOQs were below 0.016 µg kg-1, achieving satisfactory results in terms of precision, accuracy, and matrix effects. The obtained results (ranging between 0.02 and 8.19 µg kg-1) were close to the maximum level set by the European Union for 24% of the samples tested.

A multi-residue method for determining twenty-four endocrine disrupting chemicals in vegetables and fruits using ultrasound-assisted solid-liquid extraction and continuous solid-phase extraction.

In this work, we developed an analytical approach using an ultrasound-assisted extraction (UAE) followed by continuous solid-phase extraction (SPE) and gas chromatography-mass spectrometry (GC-MS) detection in order to determine simultaneously 24 endocrine disrupting chemicals such as alkylphenols, organophosphorus pesticides, parabens, phenylphenols, triclosan and bisphenol A in vegetable and fruit samples. Different variables influencing UAE and SPE performance were optimized in order to maximize removal of the sample matrix and preconcentration of the analytes. The optimized extraction and GC-MS quantitation conditions provided acceptable sensitivity, selectivity, accuracy and precision. Limits of detection spanned the range 0.6-25 ng kg-1, recoveries were near-quantitative and relative standard deviations ranged from 4.5 to 7.6%. The proposed method was used to analyse 11 vegetable samples and 7 fruit samples purchased at various Spanish and Moroccan supermarkets. Most samples contained more than three of the analytes, at levels between 5.8 and 580 ng kg-1.

Determination of alkylphenols, phenylphenols, bisphenol A, parabens, organophosphorus pesticides and triclosan in different cereal-based foodstuffs by gas chromatography-mass spectrometry.

The high toxicity of endocrine disrupting chemicals (EDCs) has promoted the development of effective techniques for their separation and detection in various types of matrices. In this work, we developed a method for the rapid, reliable determination of 24 EDCs from six different families of organic compounds (viz. alkylphenols, phenylphenols, bisphenol A, parabens, organophosphorus pesticides and triclosan) in cereal-based foodstuffs. The target compounds were subjected to ultrasound-assisted extraction with methanol, cleaned up and preconcentrated by automated solid-phase extraction, and derivatized for their determination by gas chromatography-mass spectrometry (GC-MS). The method features low limits of detection (0.4-23 ng/kg), good precision (3.8-7.2%) and recoveries from 82% to 105%. The proposed method was used to analyse 12 samples of products purchased in Andalusia (Spain). A total of 14 analytes were detected in most of the samples. In any case, their concentrations (3.8-620 ng/kg) were all lower than the applicable maximum residue limits.

A multi-residue method for GC-MS determination of selected endocrine disrupting chemicals in fish and seafood from European and North African markets.

An integrated study was conducted to determine the presence of six types of endocrine disrupting chemicals (bisphenol A, triclosan, two alkylphenols, two phenylphenols, eleven organophosphorus pesticides and seven parabens) in the fish and seafood samples from Europe and North Africa. The proposed method involves ultrasound-assisted extraction followed by continuous solid-phase extraction prior to GC-MS analysis. Analytical quality parameters such as linearity, accuracy, precision, sensitivity and selectivity were all good. Limits of detections ranged from 0.5 to 20.0 ng/kg. The relative standard deviation was lower than 7.5% and recoveries ranged from 84 to 105%. The method was successfully used to determine the target analytes in 20 fish and seafood samples from different fish shops and supermarkets in Europe and North Africa. Analyte contents spanned the range 4.6-730 ng/kg and were all below the maximum legally allowed limits. EDCs most frequently found in the samples analysed were dichlorvos, 2-phenylphenol and nonylphenol.

Use of semi-automated continuous solid-phase extraction and gas chromatography-mass spectrometry for the determination of polycyclic aromatic hydrocarbons in alcoholic and non-alcoholic drinks from Andalucía (Spain).

BACKGROUND: Polycyclic aromatic hydrocarbons (PAHs) are a large group of contaminants that can reach drinks in various ways. Their assessment in terms of food safety is needed as a priority. The present study developed a methodology to estimate their presence in several types of drinks. RESULTS: In this work, a method was developed for detecting and quantifying PAHs in drinks using a semi-automated, solid-phase extraction closed system for clean up and isolation, and gas chromatography-mass spectrometry (GC-MS) for determination. The proposed method is accurate, precise, and sensitive, with low limits of detection (0.02-0.6 ng L-1 ), low relative standard deviations (< 6.5%), and high recoveries (90-103%). Its high flexibility allows application to a variety of drinks from (Spain) including distillates, beer, wine, cider, soft drinks, fruit juice, tea, and coffee. CONCLUSION: This methodology allows the detection of this family of compounds at trace levels using low quantities of sample and solvents. Most of the samples studied contained two or more of the Environmental Protection Agency's (EPA's) 16 PAH priority pollutants, albeit at levels below the legally allowed limit. © 2018 Society of Chemical Industry.

Determination of free and conjugated forms of endocrine-disrupting chemicals in human biological fluids by GC-MS.

BACKGROUND: Humans are exposed to hazardous substances including endocrine-disrupting chemicals (EDCs). These compounds have been associated with some diseases such as cancer and ascribed adverse effects on life-essential organs. RESULTS: The method, which allows the determination of both free and conjugated forms of EDCs, involves the liquid-liquid extraction from the sample with ethyl acetate, followed by its preconcentration and clean-up by SPE in a continuous system for the subsequent determination by GC-MS. The proposed method affords very low LODs and RSD. CONCLUSION: This allowed its successful application to the determination of EDCs in human urine, blood and breast milk. The most frequently founded were methylparaben, ethylparaben, bisphenol A and triclosan.

Determination of 13 endocrine disrupting chemicals in environmental solid samples using microwave-assisted solvent extraction and continuous solid-phase extraction followed by gas chromatography-mass spectrometry.

Soil can contain large numbers of endocrine disrupting chemicals (EDCs). The varied physicochemical properties of EDCs constitute a great challenge to their determination in this type of environmental matrix. In this work, an analytical method was developed for the simultaneous determination of various classes of EDCs, including parabens, alkylphenols, phenylphenols, bisphenol A, and triclosan, in soils, sediments, and sewage sludge. The method uses microwave-assisted extraction (MAE) in combination with continuous solid-phase extraction for determination by gas chromatography-mass spectrometry. A systematic comparison of the MAE results with those of ultrasound-assisted and Soxhlet extraction showed MAE to provide the highest extraction efficiency (close to 100%) in the shortest extraction time (3 min). The proposed method provides a linear response over the range 2.0 - 5000 ng kg(-1) and features limits of detection from 0.5 to 4.5 ng kg(-1) depending on the properties of the EDC. The method was successfully applied to the determination of target compounds in agricultural soils, pond and river sediments, and sewage sludge. The sewage sludge samples were found to contain all target compounds except benzylparaben at concentration levels from 36 to 164 ng kg(-1). By contrast, the other types of samples contained fewer EDCs and at lower concentrations (5.6 - 84 ng kg(-1)).

Simultaneous determination of parabens, alkylphenols, phenylphenols, bisphenol A and triclosan in human urine, blood and breast milk by continuous solid-phase extraction and gas chromatography-mass spectrometry.

A highly sensitive gas chromatography-mass spectrometry (GC-MS) method for the determination of endocrine disrupting chemicals (EDCs) including parabens, alkylphenols, phenylphenols, bisphenol A and triclosan in human breast milk, blood and urine samples is proposed. Blood and milk require a pretreatment to remove proteins and other substances potentially interfering with the continuous solid-phase extraction (SPE) system used; on the other hand, urine samples can be directly introduced into the system after filtering. Analytes are retained on a LiChrolut EN column and derivatized by silylation following elution with acetonitrile. The resulting trimethylsilyl derivatives are determined by GC-MS. The proposed method exhibited good linearity (r(2)>0.995) for all target EDCs over the concentration range 0.7-10,000ng/l in urine, and 3.3-50,000ng/l in blood and milk. Also, it provided low limits of detection (0.2-1.8ng/l in urine, and 1.0-9.0ng/l in blood and milk), good precision (relative standard deviations less than 7%) and recoveries from 86 to 104%. A total of 24 human fluid samples were analyzed and most found to contain some target EDC at concentrations from 0.10 to 14µg/l.

Multiresidue method for the determination of pharmacologically active substances in egg and honey using a continuous solid-phase extraction system and gas chromatography-mass spectrometry.

A sensitive, selective, efficient gas chromatography-mass spectrometry method for the simultaneous determination of 22 pharmacologically active substances (antibacterials, nonsteroidal antiinflammatories, antiseptics, antiepileptics, lipid regulators, ß-blockers and hormones) in eggs and honey was developed. The sample pretreatment includes precipitation of proteins and lipids with acetonitrile:water (3:2, v/v), centrifugation and continuous solid-phase extraction for cleanup and preconcentration. The proposed method was validated with quite good analytical results including limits of detection of 0.4-3.3 ng/kg for 2g of sample and good linearity (r(2)>0.995) throughout the studied concentration ranges. The recoveries of analytes from real honey and egg samples spiked at concentrations of 15-2,000 ng/kg fell in the range 87-102%, with relative standard deviations from 2.6% to 7.0%. The method was successfully used to determine the target compounds in various types of eggs (hen, quail and duck) and honey samples (flower, forest, acacia, sunflower, clover and pine tree). Two samples of hen eggs bought at supermarkets and one of quail eggs were found to contain florfenicol, pyrimethamine, estrone and 17ß-estradiol at levels from 0.095 to 2.7 µg/kg.

Trace analysis of endocrine disrupting compounds in environmental water samples by use of solid-phase extraction and gas chromatography with mass spectrometry detection.

A novel analytical method using a continuous solid-phase extraction system in combination with gas chromatography-mass spectrometry for the simultaneous separation and determination of endocrine disrupting compounds (EDCs) is reported. The method was applied to major EDCs of various types including parabens, alkylphenols, phenylphenols, bisphenol A and triclosan in water. Samples were preconcentrated by using an automatic solid-phase extraction module containing a sorbent column, and retained analytes eluted with acetonitrile for derivatization with a mixture of N,O-bis(trimethylsilyl)trifluoroacetamide and trimethylchlorosilane. A number of variables potentially influencing recovery of the target compounds such as the type of SPE sorbent (Silica gel, Florisil, RP-C18, Amberlite XAD-2 and XAD-4, Oasis HLB and LiChrolut EN), eluent and properties of the water including pH and ionic strength, were examined. LiChrolut EN was found to be the most efficient sorbent for retaining the analytes, with ∼100% efficiency. The ensuing method was validated with good analytical results including low limits of detection (0.01-0.08ng/L for 100mL of sample) and good linearity (r(2)>0.997) throughout the studied concentration ranges. The method exhibited good accuracy (recoveries of 90-101%) and precision (relative standard deviations less than 7%) in the determination of EDCs in drinking, river, pond, well, swimming pool and waste water. Waste water samples were found to contain the largest number and highest concentrations of analytes (3.2-390ng/L).

Analytical method for biomonitoring of perfluoroalkyl acids in human urine.

Perfluoroalkyl acids are an important class of synthetic compounds widely used in commercial and residential settings, which may have potential adverse health effects. The objective of this study was to monitor 6 perfluorocarboxylic acids and perfluorooctane sulphonate in human urine to obtain a way to asses exposure. The target analytes were extracted from urine by using a semi automated solid-phase extraction module and derivatised with isobutyl chloroformate by catalysis with 3% N,N-dicyclohexylcarbodiimide in pyridine. Determination and quantisation were achieved by gas chromatography with a mass spectrometer detector operating in the selected-ion monitoring mode. The developed approach is fast and provided low limits of detection (0.2-1.0 ng L(-1)) with good precision (relative standard deviation lower than 7.5%, within-day and between day). Recoveries from urine samples, which were spiked with the studied compounds at levels of 10 and 50 ng L(-1) ranged from 93% to 96%. Perfluorohexanoic (≤ 70 ng L(-1)) and perfluoroheptanoic acids (<2 ng L(-1)) were found in the urine samples from exposed researchers taken after handling these compounds. From the calculation of the excretion kinetics it was found that the dosage absorbed was eliminated within 15 h after exposure.

Occurrence of carboxylic acids in different steps of two drinking-water treatment plants using different disinfectants.

The occurrence of 35 aliphatic and aromatic carboxylic acids within two full scale drinking-water treatment plants was evaluated for the first time in this research. At the intake of each plant (raw water), the occurrence of carboxylic acids varied according to the quality of the water source although in both cases 13 acids were detected at average concentrations of 6.9 and 4.7 µg/L (in winter). In the following steps in each treatment plant, the concentration patterns of these compounds differed depending on the type of disinfectant applied. Thus, after disinfection by chloramination, the levels of the acids remained almost constant (average concentration, 6.3 µg/L) and four new acids were formed (butyric, 2-methylbutyric, 3-hydroxybenzoic and 2-nitrobenzoic) at low levels (1.1-5 µg/L). When ozonation/chlorination was used, the total concentration of the carboxylic acids in the raw water sample (4.7 µg/L) increased up to 6 times (average concentration, 26.3 µg/L) after disinfection and 6 new acids (mainly aromatic) were produced at high levels (3.5-100 µg/L). Seasonal variations of the carboxylic acids under study showed that in both plants, maximum levels of all the analytes were reached in the coldest months (autumn and winter), aromatic acids only being found in those seasons.

Semiautomated solid-phase extraction followed by derivatisation and gas chromatography­mass spectrometry for determination of perfluoroalkyl acids in water.

This paper describes a sensitive approach for the determination of 6 perfluoroalkyl carboxylic acids and perfluorooctane sulfonic acid in water. Samples were preconcentrated using an automatic solid-phase extraction module and then manually derivatised and determined by gas chromatography­mass spectrometry. The analytes were derivatised with a isobutyl chloroformate/isobutanol mixture, using 3% N,N-dicyclohexylcarbodiimide in pyridine as the catalyst. From a systematic comparison of several reversed-phase and anion-exchange sorbent materials for the retention of perfluoroalkyl acids, the high-est retention efficiencies (∼100%) were achieved with LiChrolut EN and Discovery DSC-SAX columns.LiChrolut EN was the sorbent selected due to several advantages (sample pH ∼1; sample flow rate,5.5 mL/min; breakthrough volume, 300 mL) over Discovery DSC-SAX (sample pH ∼6; sample flow rate,3.0 mL/min; breakthrough volume, 45 mL), for the retention of the studied compounds. Detection and quantification limits within the range of 0.1­0.5 ng/L and 0.4­1.7 ng/L, respectively, were obtained for a sorbent column of 70 mg of LiChrolut EN and 250 mL of sample, the relative standard deviation being lower than 7%. The method was applied both to the analysis of water collected at the intake (raw) and atthe exit (treated) of two drinking water treatment plants, as well as to various types of water. Few samples were positive for perfluoroalkyl acids and only one acid (perfluoroheptanoic or perfluorooctanoic) was found in each treatment plant. The highest number and concentration of analytes (perfluoroheptanoic,perfluorooctanoic and perfluorodecanoic acid) were found in one wastewater.