Analysis of Multiclass Antibiotics in Lettuce by Liquid Chromatography-Tandem Mass Spectrometry to Monitor Their Plant Uptake.

The main entry routes of antibiotics in the environment are the application of organic wastes to improve soil quality and the irrigation with recycled water. Once in the environment, antibiotics can be introduced in the food chain through their uptake by crops. This paper describes the development of an analytical method based on ultrasound-assisted extraction for the determination of seven antibiotics in lettuce. The developed method was applied to evaluate antibiotic uptake by lettuce grown in pots fertilized with composted poultry litter doped with a mixture of antibiotics to reach a final concentration of 2.5 µg/g in soil. Lettuce were harvested after 21, 36, and 55 days. Five of the seven studied antibiotics were found in all samples. The highest uptake was found for lincomycin (51 ng/g fresh weight) followed by sulfamethoxazole (44 ng/g fresh weight) and sulfamethazine (21 ng/g fresh weight) in lettuce harvested after 21 days. An important decrease of their levels was observed after 36 days, but these levels remained similar after 55 days. Although levels found in lettuce were low, the presence of antibiotics demonstrates the need for further assessing food safety risks related with the use of soil amendments or irrigation water contaminated with antibiotics.

Analysis of emerging organic contaminants in poultry manure by gas chromatography-tandem mass spectrometry.

A multiresidue method was developed for the determination of 19 emerging organic contaminants (pharmaceutical drugs, personal care products, and bisphenol A) in poultry manure. Lyophilized samples of manure were extracted by ultrasound-assisted matrix solid-phase dispersion and the extracts were analyzed by gas chromatography with tandem mass spectrometry after derivatization. Analysis of spiked poultry manure samples, at levels ranging from 25 to 150 ng/g, gave satisfactory recovery results for all the compounds, with values from 67 to 106%. The developed procedure provided detection limits that ranged from 0.9 to 2.2 ng/g. Finally, the validated method was applied to poultry manure samples collected from 23 poultry farms in Spain. Salicylic acid was found in most of the samples analyzed at levels up to 2501 ng/g, whereas, methyl paraben, orthophenylphenol, ibuprofen, paracetamol, and carbamazepine were detected at levels up to 250 ng/g. Composting of manure showed an important decrease in the levels of the detected contaminants.

Uptake of azoles by lamb's lettuce (Valerianella locusta L.) grown in hydroponic conditions.

An uptake and translocation study of azole compounds was performed in lamb's lettuce (Valerianella locusta L.) grown in nutrient solution fortified with different azoles. Three azoles, (clotrimazole, fluconazole and propiconazole), which have different physico-chemical properties and are ubiquitous in the aquatic environment, were the compounds selected. An analytical method, based on matrix solid phase dispersion (MSPD) followed by LC-MS/MS determination, was developed to quantify these compounds in aqueous solution and in roots and leaves. The physicochemical properties of azoles are the main factors governing the uptake and plant accumulation. These azoles were detected in leaves indicating their transport within lamb's lettuce. Translocation from nutrient solution to the aerial part of lamb's lettuce was found to be highly dependent on the hydrophobicity of the azole. Clotrimazole accumulates in roots causing necrosis in roots and leaves, whereas fluconazole was the azole with the highest concentration in leaves without causing apparent phytotoxicity symptoms. The assessment of the levels of these azoles in leaves indicates that the risk for human health is negligible.

Rapid determination of natural and synthetic hormones in biosolids and poultry manure by isotope dilution GC-MS/MS.

The release of hormones into the environment due to land application of biosolids and manure is a cause of concern for their potential impacts. This paper presents the development of a rapid and sensitive method, based on extraction, for the analysis of 13 hormones in biosolids and poultry manure. A simultaneous derivatization of hydroxyl and ketone groups was carried out for the determination of hormones by GC­MS/MS. The method was validated in three matrices (sewage sludge, manure, and broiler litter). Recoveries from spiked samples at three concentration levels (50, 25, and 10 ng/g) ranged from 76 to 124% with relative SDs ≤ 16%. Method detection limits for the three matrices were in the range of 0.5­3.0 ng/g dry weight. The optimized method was applied to biosolid and poultry manure samples collected in Spain. Only seven of the 13 studied hormones were detected in the different samples. trans-Androsterone was detected at high levels (up to 3.1 µg/g in biosolid samples). Estrone and estradiol were the two hormones detected at higher levels in layer manure, whereas estrone and 4-androstene-3,17-dione presented the highest levels in broiler litter.

Multiresidue analysis of insecticides and other selected environmental contaminants in poultry manure by gas chromatography/mass spectrometry.

An analytical method was developed for the simultaneous determination in poultry manure of 41 organic contaminants belonging to different chemical classes: pesticides, polycyclic aromatic hydrocarbons, polychlorinated biphenyls, and polybrominated diphenyl ethers. Poultry manure was extracted with a modified QuEChERS method, and the extracts were analyzed by isotope dilution GC/MS. Recovery of these contaminants from samples spiked at levels ranging from 25 to 100 ng/g was satisfactory for all the compounds. The developed procedure provided LODs from 0.8 to 9.6 ng/g. The analysis of poultry manure samples collected on different farms confirmed the presence of some of the studied contaminants. Pyrethroids and polycyclic aromatic hydrocarbons were the main contaminants detected. DDT and its metabolite DDE were also found but at relatively low concentrations.

Fast ultrasound-assisted extraction combined with LC-MS/MS of perfluorinated compounds in manure.

A fast analytical method for the determination of perfluorinated compounds in poultry manure by LC-MS/MS was developed. The extraction was carried out by ultrasound-assisted extraction of 1 g of sample, during 2 × 15 min using low volume (5.5 mL) of a mixture of methanol and acetonitrile. An efficient extraction of perfluoroalkyl carboxylates, perfluoroalkyl sulfonates, and perfluoroalkyl sulfonamides from poultry manure was obtained with recoveries higher than 81%. The cleanup of extracts was carried out by dispersive SPE. The validation of the proposed method showed the suitability of this procedure to determine perfluorinated compounds in poultry manure with detection limits in the range of 0.44-2.12 ng/g, depending on the target compound. In comparison with previously published methods, the miniaturization of the sample preparation method with ultrasound-assisted extraction together with the use of a core-shell column permit a lower consumption of organic solvents and a fast analysis of perfluorinated compounds. Manure samples obtained from Spanish commercial farms were analyzed and low perfluorinated compounds levels were found, which may be originated by dietary or environmental exposure. The highest concentrations measured corresponded to the perfluoroalkyl sulfonates, which varied from 8.2 to 35.9 ng/g.

Review of sample preparation techniques for the analysis of pesticide residues in soil.

This paper reviews the sample preparation techniques used for the analysis of pesticides in soil. The present status and recent advances made during the last 5 years in these methods are discussed. The analysis of pesticide residues in soil requires the extraction of analytes from this matrix, followed by a cleanup procedure, when necessary, prior to their instrumental determination. The optimization of sample preparation is a very important part of the method development that can reduce the analysis time, the amount of solvent, and the size of samples. This review considers all aspects of sample preparation, including extraction and cleanup. Classical extraction techniques, such as shaking, Soxhlet, and ultrasonic-assisted extraction, and modern techniques like pressurized liquid extraction, microwave-assisted extraction, solid-phase microextraction and QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) are reviewed. The different cleanup strategies applied for the purification of soil extracts are also discussed. In addition, the application of these techniques to environmental studies is considered.

Determination of azoles in sewage sludge from Spanish wastewater treatment plants by liquid chromatography-tandem mass spectrometry.

A simple and rapid analytical method for the determination of 16 azoles in sewage sludge has been developed and validated. The method was based on ultrasound-assisted extraction followed by dispersive solid-phase extraction cleanup and liquid chromatography-electrospray tandem mass spectrometric detection. The azoles were selected by their intensive usage as biocides (tebuconazole, propiconazole, cyproconazole and thiabendazole), antimycotic pharmaceuticals (ketoconazole, econazole, fluconazole and clotrimazole) or fungicides in agriculture (difenoconazole, flusilazole, hexaconazole, prochloraz, bromuconazole, epoxiconazole and triticonazole). The recoveries of these compounds through the method were between 71.9 and 115.8%, with relative standard deviations lower than 20%. Detection limits were in the range of 0.5-5.0 ng/g. The developed method was applied to the analysis of azoles in sewage sludge samples collected from 19 Spanish wastewater treatment plants. Although azoles used as biocides or agriculture fungicides were present in a few sludge samples, the pharmaceuticals ketoconazole, econazole and clotrimazole were present in all of the analyzed sludge samples, being ketoconazole the one found at the highest level, representing the 68.6% of the total azole content found in the 19 sludge samples studied.

Determination of triclosan and methyl triclosan in environmental solid samples by matrix solid-phase dispersion and gas chromatography-mass spectrometry.

In this study, a method for the determination of triclosan (TCS) and methyl triclosan (MTCS) in soil and sewage sludge samples from municipal wastewater treatment plants was developed based on the extraction by matrix solid-phase dispersion. After extraction, the analytes were derivatized with N-(tert-butyldimethylsilyl)-N-methyl-trifluoroacetamide for their determination by isotope dilution GC with electron impact MS detection in the SIM mode, using (13)C(12)-labeled compounds as internal standards. Recoveries of MTCS and TCS from laboratory spiked sludge samples were in the range from 95.7 to 101.0% and 97.4 to 101.3%, respectively. In the case of soil samples, the recoveries of MTCS and TCS ranged from 98.4 to 101.0% and 98.7 to 99.0%, respectively. The limits of detection (S/N=3) varied from 0.10 to 0.12 ng/g for sewage sludge samples and from 0.05 to 0.08 ng/g for soil samples. The validated method was used to assess the levels of TCS and MTCS in sewage sludge collected from 19 wastewater treatment plants located in Madrid (Spain) and in soil samples collected from agricultural fields in Madrid. Both compounds were detected in all the sludge samples at concentrations ranging from 54 to 2987 ng/g dry weight for TCS and from 4 to 311 ng/g dry weight for MTCS. The levels encountered in soil were much lower, 0.8 to 4.7 ng/g dry weight for TCS and 0.3 to 3.8 ng/g dry weight for MTCS.

Determination of pesticide residues in sewage sludge: a review.

Pesticides are widely applied to protect plants from diseases, weeds, and insect damage, and they usually come into contact with soil where they may undergo a variety of transformations and provide a complex pattern of metabolites. Spreading sewage sludge on agricultural lands has been actively promoted by national authorities as an economic way of recycling. However, as a byproduct of wastewater treatment, sewage sludge may contain pesticides and other toxic substances that could be incorporated into agricultural products or be distributed in the environment. This article reviews the determination of pesticides in sewage sludge samples. Sample preparation including pretreatment, extraction, and cleanup, as well as the subsequent instrumental determination of pesticide residues, are discussed. Extraction techniques such as Soxhlet extraction, ultrasound-assisted extraction, pressurized liquid extraction, supercritical fluid extraction, and matrix solid-phase dispersion and their most recent applications to the determination of pesticides in sewage sludge samples are reviewed. Determination of pesticides, generally carried out by GC and HPLC coupled with different detectors, especially MS for the identification and quantification of residues, is summarized and discussed.

Analysis of polybrominated diphenyl ethers in sewage sludge by matrix solid-phase dispersion and isotope dilution GC-MS.

A method for the determination of 14 polybrominated diphenyl ethers (PBDEs) in sludge from wastewater treatment plants is presented. PBDEs were extracted by matrix solid-phase dispersion assisted by sonication and determined by isotope dilution gas chromatography with electron impact mass spectrometric detection in the selected ion monitoring mode, using labelled( 13)C-PBDEs as internal standards. The limits of detection and quantification for the tri- to hepta-BDEs were in the range of 0.05 to 0.5 ng/g dry weight and 0.15 to 1.8 ng/g dry weight, respectively, and 1.6 ng/g dry weight and 5.6 ng/g dry weight for deca-BDE-209. The proposed analytical method was applied to determine PBDE levels in sewage sludge samples collected from 19 water treatment plants located in the province of Madrid (Spain). In all of the examined samples, BDE-100 and BDE-154 were the main compounds found with a mean concentration of 3.9 and 2.0 ng/g, respectively. PBDEs were detected in all of the samples, and their total concentrations not considering BDE-209 were between 3.9 and 23.0 ng/g dry weight. The dominant PBDE congener in sewage sludge was BDE-209, which constituted 38.7 to 97.3% of the total, and showed concentration levels ranging from 8.1 to 717.2 ng/g dry weight.

Determination of nonylphenol and nonylphenol ethoxylates in wastewater using MEKC.

Nonylphenol ethoxylates (NPEO(x)) are surfactants which are used worldwide and can be transformed in the environment by microorganisms to form nonylphenol (NP). Analysis of these compounds was carried out with micellar electrokinetic capillary chromatography (MEKC). Different parameters such as background electrolyte (BGE) solution, pH, type of surfactant, and sample stacking were optimized. The use of CHES (20 mM, pH 9.1) in combination with 50 mM sodium cholate as a surfactant as BGE solution, together with sample stacking using 50 mM NaCl in the sample and an injection time of 20 s, provided the best separation of the compounds studied. The method was applied to the determination of target analytes in two types of sludge water coming from two steps of a wastewater treatment plant. Liquid-liquid extraction was carried out using toluene as solvent, resulting in recoveries around 100% for all studied analytes. The presence of NPEO(x) was observed in the first step of the sludge water treatment, based on migration time and UV spectra. Identification was confirmed using tandem MS. LOQs of the studied compounds were in the range of 12.7 to 30.8 ng/mL, which is satisfactory for the analysis of real wastewater samples.

Molecularly imprinted polymer for selective extraction of endocrine disrupters nonylphenol and its ethoxylated derivates from environmental solids.

Nonylphenol isomers (NP), linear nonylphenol (4-n-NP) and NP short chain ethoxylated derivates (NPEO1 and NPEO2) are degradation products of nonylphenol polyethoxylates, a worldwide used group of surfactants. All of them are considered endocrine disrupters due to their ability to mimic natural estrogens. In this paper, the preparation and evaluation of several 4-n-NP molecularly imprinted polymers (MIPs) for the selective extraction and clean-up of 4-n-NP, NP, NPEO1 and NPEO2 from complex environmental solid samples is described. Among the different combinations tested, a methacrylic acid-based imprinted polymer prepared in toluene provided the better performance for molecularly imprinted SPE (MISPE). Under optimum MISPE conditions, the polymer was able to selectively retain not only linear NP but also the endocrine disruptors NPEO1, NPEO2 and NP with recoveries ranging from 60 to 100%, depending upon the analyte. The developed MISPE procedure was successfully used for the determination of 4-n-NP, NP, NPEO1 and NPEO2 in sediments and sludge samples at concentration levels according to data reported in the literature for incurred samples. Finally, various sludge samples collected at five different sewage treatment plants from Madrid and commercial sludge for agriculture purposes were analysed. The measured concentrations of the different compounds varied from 3.7 to 107.5 mg/kg depending upon the analyte and the sample.

Analysis of 27 polycyclic aromatic hydrocarbons by matrix solid-phase dispersion and isotope dilution gas chromatography-mass spectrometry in sewage sludge from the Spanish area of Madrid.

A method for the determination of 27 polycyclic aromatic hydrocarbons (PAHs) in sludge from wastewater treatment plants (WWTPs) located in urban, industrial or rural zones is presented. PAHs were extracted by matrix solid-phase dispersion (MSPD) assisted by sonication. Purification of extracts was carried out by solid-phase extraction with C(18) and PAHs were eluted with acetonitrile. PAHs were determined by isotope dilution gas chromatography with electron impact mass spectrometric detection in the selected ion-monitoring mode (GC-MS-SIM), using deuterated PAHs as internal standards. The limits of detection ranged from 0.03 ng/g for acenaphthylene to 0.45 ng/g for benzo[b]naphtho[2,1-d]thyophene. After optimization, the method was validated with a certified reference sludge. The proposed analytical method was applied to determine PAH levels in sewage sludge samples collected from 19 water treatment plants located in the province of Madrid (Spain). In most of the examined samples, phenanthrene was the main compound with a mean concentration of 1062 ng/g. PAHs were detected in all of the samples, with total concentrations between 390 and 6390 ng/g dry weight for the 27 PAHs analyzed and from 310 to 5120 ng/g dry weight for the sum of the 10 PAHs considered in the draft European Union directive.

Evaluation of laboratory assays for the assessment of leaching of copper and chromium from ground-contact wood.

Laboratory studies were conducted to assess the leaching of Cu and Cr from wood, treated with a Cu-Cr-B preservative, when placed in contact with soil. Two laboratory assays were performed: Wood in contact with soil solutions over 30 d, and wood in direct contact with soil over 30 weeks. The influence of several factors, such as soil type and fertilizer use, was studied in both assays. In addition, the effect of soil moisture content and temperature was evaluated when wood was in contact with soil. A discrepancy in the results of the laboratory assays was observed. Leaching of Cu and Cr increased when soil in contact with wood was fertilized, but only an increase of Cu leaching was observed when soil solutions from fertilized soils were used. Moreover, soil solutions from a sandy clay loam soil produced a higher Cu leaching than those from a loamy sand soil, whereas the contrary occurred when treated wood was in direct contact with these soils. In the assay of treated wood in ground contact, the highest metal losses were produced in fertilized soils maintained at constant temperature and high soil moisture content, the latter being the most important factor. These losses were in the range of 5.34 to 15.6% for Cu and 1.85 to 2.35% for Cr in the soils studied. The proposed laboratory assay, using treated wood in direct contact with soil at a moisture content near field capacity during a period of 30 weeks, produced total metal losses that were in accordance with those reported by other authors under field conditions, expressed on a per-year basis.

Application of matrix solid-phase dispersion followed by GC-MS/MS to the analysis of emerging contaminants in vegetables.

A multiresidue method for the determination of 17 emerging contaminants in vegetables was developed based on ultrasound-assisted matrix solid-phase dispersion (MSPD). The analysis was performed using isotope dilution gas chromatography tandem mass spectrometry. In the development of the MSPD procedure, different parameters such as sonication and the type of sorbent or extraction solvent were assayed. Manual and in situ derivatization was assayed and the chromatographic response was higher when the reaction takes place in the injection port. The limits of detection obtained for the studied compounds were in the range of 0.1-0.4ngg(-1) for the different vegetables analyzed. The developed method was applied to vegetables obtained from several local markets. At least one of the organophosphates was detected in the analyzed samples at levels ranging from 0.6 to 4.6ngg(-1) and bisphenol A was detected in all the samples at concentration up to 16ngg(-1).

Simultaneous determination of multiclass emerging contaminants in aquatic plants by ultrasound-assisted matrix solid-phase dispersion and GC-MS.

A multiresidue method was developed for the simultaneous determination of 31 emerging contaminants (pharmaceutical compounds, hormones, personal care products, biocides, and flame retardants) in aquatic plants. Analytes were extracted by ultrasound-assisted matrix solid-phase dispersion (UA-MSPD) and determined by gas chromatography-mass spectrometry after sylilation, The method was validated for different aquatic plants (Typha angustifolia, Arundo donax, and Lemna minor) and a semiaquatic cultivated plant (Oryza sativa) with good recoveries at concentrations of 100 and 25 ng g-1 wet weight, ranging from 70 to 120 %, and low method detection limits (0.3 to 2.2 ng g-1 wet weight). A significant difference of the chromatographic response was observed for some compounds in neat solvent versus matrix extracts, and therefore, quantification was carried out using matrix-matched standards in order to overcome this matrix effect. Aquatic plants taken from rivers located at three Spanish regions were analyzed, and the compounds detected were parabens, bisphenol A, benzophenone-3, cyfluthrin, and cypermethrin. The levels found ranged from 6 to 25 ng g-1 wet weight except for cypermethrin that was detected at 235 ng g-1 wet weight in O. sativa samples.

Leaching of copper, chromium, and boron from treated timber during aboveground exposure.

Field studies were conducted to evaluate leaching of Cu, Cr, and B from timber treated with a Cr, Cu, and B wood preservative and exposed aboveground in Spanish weathering conditions during one year with a total rainfall of approximately 500 mm. The effect of timber orientation (horizontal for decks and vertical for fences) on metal leaching was assessed. Leaching of metals after one year was higher for decks than for fences, with total amounts of metals leached being 226.6 and 87.8 mg/m2 for Cu, 199.5 and 42.4 mg/m2 for Cr, and 110.1 and 32.6 mg/m2 for B from decks and fences, respectively. Leaching rates did not drop constantly with time, because an increase in metal leaching, except for B, was observed at the end of the year after a long dry period. The order of metal emission varied with cumulative rainfall: Leaching of B was higher than Cr initially, but the opposite occurred at the end of the assay. Total emissions of Cu and Cr obtained in a laboratory assay were lower than those for decks and fences under field conditions when expressed per unit surface area (mg/m2), but they were similar to the values obtained for fences when expressed as a percentage of the initial amount. However, the percentage of B leached from wood was higher in laboratory than in field assays for both orientations, with the amount of B leached per unit surface area under laboratory conditions being higher than that leached from fences but lower than that leached from decks. Emission rates extrapolated to one year from laboratory data underestimated metal leaching from decks and overestimated emissions from fences.

Determination of pesticide residues by GC-MS using analyte protectants to counteract the matrix effect.

An analytical method was developed to determine pesticides of various chemical classes in soil, juice and honey using analyte protectants to counteract the enhancement of the chromatographic response produced by the presence of matrix components (matrix effect). This effect was more pronounced for soil and honey samples than for juice samples; regarding the pesticide chemical class, organochlorine pesticides were less affected by the presence of matrix components than triazines and organophosphorus pesticides. Several analyte protectants (2,3-butanediol, L-gulonic acid gamma-lactone, corn oil and olive oil) were tested for counteracting the observed matrix effect. L-Gulonic acid gamma-lactone was an effective protecting agent for most of the pesticides studied in soil and honey samples, whereas olive oil was very effective for juice samples. The combination of these two protectants was found to be an effective analyte protectant for all compounds in soil and honey samples.

Influence of organic fertilizer application on pendimethalin volatilization and persistence in soil.

Laboratory studies were undertaken to evaluate the influence of fertilizers on pendimethalin volatilization and persistence in soil. Various organic fertilizers such as liquid humic substances and urea were used at doses of 100 L/ha or 170 kg of N/ha, respectively. Herbicide residues were determined in air, soil solution, and soil samples by GC-ECD; the recovery of pendimethalin from spiked fertilized or control samples was found to be 81-103%. Liquid humic fertilizers increased pendimethalin dissipation during the first part of the assay, although 4 months after application, herbicide levels were similar to those observed in unfertilized soil. Fertilization of soil with urea decreased, in general, pendimethalin volatilization but increased herbicide levels in soil solution and persistence in soil, with a pendimethalin half-life approximately 70% higher than that found in unfertilized soil.