Continuous Solid-phase Extraction Research Articles

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).

Simultaneous determination of phenolic pollutants in dairy products held in various types of packaging by gas chromatography−mass spectrometry

The U.S. Environmental Protection Agency (EPA) has deemed phenolic compounds priority organic pollutants. These compounds can reach milk and dairy products at different production stages from farm to packaging. In this work, we developed a procedure involving ultrasound-assisted extraction from milk and dairy products, and subsequent clean-up of the extract and preconcentration of the analytes by continuous solid-phase extraction (SPE) for their quantification by gas chromatography−mass spectrometry. The proposed method was used to detect and quantify a total of 21 phenolics including phenols, alkylphenols, bisphenols and chlorophenols in milk and dairy products. The method was validated in terms of recovery (85–108%), linearity, matrix effects (slight, <20%), precision (relative standard deviation < 11%), and limits of detection (6–63 ng/kg). Then, it was used to analyze nineteen milk samples and as many dairy product samples. The most detected analytes were bisphenol Z, bisphenol A and 4-t-butylphenol, which were found in the samples at concentrations spanning the ranges 96–1100, 30–1400 and 310–2100 ng/kg, respectively. The contaminants were present mainly in milk and dairy products packed in polystyrene terephthalate (PET), multilayer packaging (carboard/polyethylene/‌aluminum) or polystyrene (PS) packaging. By contrast, the samples packed in glass containers contained very low levels of the phenolics.

Pollution, source and risk assessment of PAHs in Chinese tea

In this study, multi-walled carbon nanotubes continuous solid-phase extraction (MWCNTs-CSPE) combined with high-performance liquid chromatography in series with ultraviolet and fluorescence dual detectors (HPLC-DAD-FLD) approach were employed to investigate the concentration, source, and risk of 22 PAHs from Chinese tea products, classified and analyzed seven major categories and 28 varieties of 119 tea samples. The results found that the pollution degree of different varieties of tea is different, and the total concentration range of Σ22 PAHs is 136.99–462.51 μg/kg, in which ΣPAH4 (BaA, CHR, BbF, BaP) ranges from 37.64 to 106.90 μg/kg, ∑16 EPA PAHs is 136.99–440.82 μg/kg. PAHs are mainly composed of 2–4 rings. PAHs characteristic parameter analysis shows that PAHs in Chinese tea products are mainly from fuel oil, wood burning, coal and oil combustion. Benzo[a]pyrene always plays an important role in the carcinogenicity of samples. Lifetime cancer risk assessment showed that black tea had a higher cancer risk level which was 3.75 × 10−7–2.31 × 10−6. The cancer risk of ILCR increases with age, older adults have a higher lifetime cancer risk than younger children, and females have a higher lifetime cancer risk than males, but it can be ignored.

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, 17β-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, 17β-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 β-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.

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.

Facile preparation of Ce enhanced vinyl-functionalized silica aerogel-like monoliths for selective separation of radioactive thorium from monazite

Thorium (Th) is an associated ore of rare earth metals that is radioactive and harmful to the environment, but it is also a potential nuclear fuel replacement for uranium. The separation of Th from rare earth elements (REEs) is of great importance in environmental governance and clean-energy development. In this work, a monolithic cerium (Ce) doped silica aerogel-like with flexibility was synthesized using a low consumption and rapid technique, and it was used in a continuous solid-phase extraction as an adsorbent for the selective separation of Th/REEs. The batch adsorption experiments showed that the adsorption efficiency of Th(IV) can be up to 96% when abnormally high levels of metal ions (20 ppm) exist. Under the same conditions, the adsorption efficiency of REEs is at a near-zero level, which demonstrates the great selective separation of Th/REEs for the aerogel-like. The results also indicated that Th(IV) could desorb from the adsorbent in weak acidic media, which is friendly to the environment. Therefore, the material has application prospects for the separation of Th/REEs and removal of radioactive contamination from the environment.

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.

Assessing polycyclic aromatic hydrocarbons in cereal-based foodstuffs by using a continuous solid-phase extraction system and gas chromatography–mass spectrometry

Polycyclic aromatic hydrocarbons (PAHs) are a family of sixteen compounds of which are deemed priority pollutants by the European Commission and the US Environmental Protection Agency for their carcinogenic and mutagenic properties. A method for their determination in a variety of cereal-based foodstuffs including bread, cookies, flours and cereals is reported here. The method uses solid–liquid extraction with a semi-automated solid-phase extraction system to clean up sample extracts, and gas chromatography–mass spectrometry to determine and quantify the target analytes. The analytical figures of merit of the proposed method, which include high precision, sensitivity and selectivity for all 16 PAHs, testify to its robustness. Thus, the limits of detection for 1 g of sample span the range from 2 to 60 ng kg−1, relative standard deviations are all lower than 7.5% and recoveries range from 88 to 103%. The method was successfully applied to several cereal-based foodstuffs samples. The European Commission has set a tolerated limit of 1 μg kg−1 for PAH4 [a combination of benzo(a)pyrene, benzo(a)anthracene, benzo(b)fluoranthene and chrysene] in cereal products for infants that was exceeded by three breakfast cereal foodstuffs (3.1–7.5 μg kg−1). Also, home toasting bread was found to raise the concentrations of some PAHs above the allowable levels.

Determination of polycyclic aromatic hydrocarbons in environmental waters from southern Spain by using a continuous solid-phase extraction system and gas chromatography-mass spectrometry

Environmental contextPolycyclic aromatic hydrocarbons are widespread carcinogenic compounds resulting from incomplete combustion of fossil fuels. We report a robust analytical method suitable for detecting these compounds at trace levels in various types of environmental waters. The method allows for accurate monitoring of the levels and behaviour of these priority environmental pollutants. AbstractHuman exposure to polycyclic aromatic hydrocarbons (PAHs) is a major challenge for the scientific community. The European Commission and the European Food Safety Agency have declared PAHs as priority pollutants, and sanctioned their quantification and monitoring in water and foods, owing to their carcinogenic, teratogenic, and mutagenic properties. We report a method for determining sixteen PAHs in various types of environmental water samples collected from various sources and places in the south of Spain. The target compounds were preconcentrated to a reduced volume (350 µL) with an automatic solid-phase extraction system and determined by gas chromatography–mass spectrometry. Optimising the operational variables, such as the type and nature of sorbent, and analytical variables resulted in a very low limit of detection (0.01–0.3 ng L−1), high accuracy and precision (RSD &lt; 7.5 %), and recoveries of 86–102 % from 200 mL of sample. The method was applied to a variety of environmental water samples, many of which were found to contain PAHs at different levels, depending on the nature and origin the sample. In any case, such levels were lower than the maximum tolerated limits except for sea and waste water. In the case of waste water, a comparison between influent and effluent from the waste water treatment plant was performed to assess the effect over the environment after their treatment, where a reduction of the presence of PAHs in the samples was observed.

Isolation and determination of ivermectin in post-mortem and in vivo tissues of dung beetles using a continuous solid phase extraction method followed by LC-ESI+-MS/MS.

A new analytical method based on solvent extraction, followed by continuous solid-phase extraction (SPE) clean-up using a polymeric sorbent, was demonstrated to be applicable for the detection of ivermectin in complex biological matrices of dung beetles (hemolymph, excreta or dry tissues) using liquid chromatography combined with positive electrospray ionization tandem mass spectrometry (LC/ESI+–MS/MS). Using a signal-to-noise ratio of 3:1, the limit of detection (LOD) in the insect matrices at trace levels was 0.01 ng g–1 and the limit of quantification (LOQ) was 0.1 ng g–1. The proposed method was successfully used to quantitatively determine the levels of ivermectin in the analysis of small samples in in vivo and post mortem samples, demonstrating the usefulness for quantitative analyses that are focused on future pharmacokinetic and bioavailability studies in insects and the establishment of a new protocol to study the impact of ivermectin on non-target arthropods such as dung beetles and other insects that are related with the “dung community”. Because satisfactory precision and accuracy values were obtained in both in vivo matrices, we suggest that the method can be consistently used for quantitative determinations that are focused on future pharmacokinetic and bioavailability studies in insects. Furthermore, this new analytical method was successfully applied to biological samples of dead dung beetles from the field suggesting that the method can be used to establish a new routine analysis of ivermectin residues in insect carcasses that is applied to complement typical mortality tests.

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 (r2>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.

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)).

HPLC-spectrophotometric detection of trace heavy metals via ‘cascade’ separation and concentration

A cascade pre-concentration and separation system involving continuous solid-phase extraction and one-drop solvent concentration was developed to enable high-performance liquid chromatography (HPLC) determination of trace levels of Ni(II), Co(II), Cu(II), Se(IV) and Cr(VI) ions in aqueous solution via complexation with sodium diethyldithiocarbamate. The metal complexes were almost completely adsorbed on the solid phase (octadecylsilyl packed column). Ethyl acetate (eluent) containing the metal complexes was then placed in a centrifuge tube, to which a microvolume of dimethyl sulfoxide (DMSO) was added. Successful pre-concentration of the metal complexes into the DMSO phase was accomplished by removing the ethyl acetate using a compact evaporator in a water bath (40°C); 1000-fold concentration was achieved within 45 min. A portion of the residual DMSO phase was then subjected to HPLC analysis. The proposed method has high reproducibility and high sensitivity with detection limits (3σ) for Ni(II), Co(II), Cu(II), Se(IV) and Cr(VI) ions of 0.08, 0.11, 0.12, 0.44 and 0.20 µg/L, respectively. Relative standard deviations (RSDs) (n = 5) at Ni(II) 5.87 µg/L, Co(II) 5.89 µg/L, Cu(II) 6.35 µg/L, Se(IV) 7.90 µg/L and Cr(VI) 5.20 µg/L (1.0 × 10−7 mol/L each) were 4.0%, 4.6%, 4.6%, 7.2% and 3.4%, respectively.

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, β-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 0.4–3.3ng/kg for 2g of sample and good linearity (r2>0.995) throughout the studied concentration ranges. The recoveries of analytes from real honey and egg samples spiked at concentrations of 15–2000ng/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 17β-estradiol at levels from 0.095 to 2.7μg/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 (r2>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)

Comparison of microwave assisted, ultrasonic assisted and Soxhlet extractions of N-nitrosamines and aromatic amines in sewage sludge, soils and sediments

This paper describes a cost-effective and sensitive method for the gas chromatographic determination of 10 aliphatic and aromatic N-nitrosamines and 14 aromatic amines (including aniline, several chloroanilines and 2-nitroaniline) in various soil matrices, after microwave-assisted extraction (MAE) combined with continuous solid-phase extraction. A systematic comparison of MAE with ultrasonic assisted and Soxhlet extraction alternatives showed that MAE provided the highest extraction efficiency (94–96%) with the shortest extraction time (3min). The method developed provides a linear response throughout the concentration range 0.1–150ngg−1 and features low limits of detection (0.03–0.35ngg−1) and good precision. The method was successfully applied to study the occurrence of the analytes in sewage sludge, agricultural soils, and river and pond sediments. Aniline and chloroanilines were the amines most frequently detected (0.4–5.4ngg−1), whereas N-nitrosodimethylamine, N-nitrosodiethylamine and N-nitrosomorpholine were only found in two of the urban sewage sludge samples analyzed (0.4−1.6ngg−1).

Gas chromatography–mass spectrometry determination of pharmacologically active substances in urine and blood samples by use of a continuous solid-phase extraction system and microwave-assisted derivatization

A sensitive method based on gas chromatography–mass spectrometry was used to determine 22 pharmacologically active substances (frequently used in the treatment of human and animal's diseases) including analgesics, antibacterials, anti-epileptics, antiseptics, β-blockers, hormones, lipid regulators and non-steroidal anti-inflammatories in blood and urine samples. Samples were subjected to continuous solid-phase extraction in a sorbent column (Oasis HLB), and then the target analytes were eluted with ethyl acetate and derivatized in a household microwave oven at 350W for 3min. Finally, these products were determined in a gas chromatograph–mass spectrometer equipped with a DB-5 fused silica capillary column. The analyte detection limits thus obtained ranged from 0.2 to 1.3ngL−1 for urine samples and 0.8–5.6ngL−1 for blood samples. Recoveries from both blood and urine ranged from 85 to 102%, and within-day and between-day relative standard deviations were all less than 7.5%. The proposed method offers advantages in reduction of the exposure danger to toxic solvents used in conventional sample pretreatment, simplicity of the extraction processes, rapidity, and sensitivity enhancement. The method was successfully used to quantify pharmacologically active substances in human and animal (lamb, veal and pig) blood and urine. The hormones estrone and 17β-estradiol were detected in virtually all samples, and so were other analytes such as acetylsalicylic acid, ibuprofen, ketoprofen and triclosan in human samples, and florfenicol, pyrimethamine and phenylbutazone in animal samples.

Combined microwave-assisted extraction and continuous solid-phase extraction prior to gas chromatography–mass spectrometry determination of pharmaceuticals, personal care products and hormones in soils, sediments and sludge

This paper reports a sensitive analytical method based on microwave-assisted extraction and continuous solid-phase extraction (SPE), followed by gas chromatography–mass spectrometry (GC−MS), for the simultaneous determination of residues of 18 pharmaceuticals (analgesics, antibacterials, anti-epileptics, β-blockers, lipid regulators and non-steroidal anti-inflammatories), one personal care product and 3 hormones in soils, sediments and sludge. The analytes are extracted with 3:2 methanol/water under the action of microwave energy and the resulting extract is passed through a SPE column to clean up the sample matrix and preconcentrate the analytes. Then, the analytes, trapped on Oasis-HLB sorbent, are eluted with ethyl acetate, silylated and determined by GC–MS. The proposed method provides a linear response over the concentration range 2.5–20000ng/kg with correlation coefficients higher than 0.994 in all cases. Also, it features low limits of detection (0.8–5.1ng/kg), good precision (within- and between-day relative standard deviation less than 7%) and recoveries ranging from 91 to 101%. The method was successfully applied to agricultural soils, river and pond sediments, and sewage sludge. All samples contained some target analyte and sludge contained most —some at considerably high concentrations.