José Benito Quintana

Comparing illicit drug use in 19 European cities through sewage analysis.

The analysis of sewage for urinary biomarkers of illicit drugs is a promising and complementary approach for estimating the use of these substances in the general population. For the first time, this approach was simultaneously applied in 19 European cities, making it possible to directly compare illicit drug loads in Europe over a 1-week period. An inter-laboratory comparison study was performed to evaluate the analytical performance of the participating laboratories. Raw 24-hour composite sewage samples were collected from 19 European cities during a single week in March 2011 and analyzed for the urinary biomarkers of cocaine, amphetamine, ecstasy, methamphetamine and cannabis using in-house optimized and validated analytical methods. The load of each substance used in each city was back-calculated from the measured concentrations. The data show distinct temporal and spatial patterns in drug use across Europe. Cocaine use was higher in Western and Central Europe and lower in Northern and Eastern Europe. The extrapolated total daily use of cocaine in Europe during the study period was equivalent to 356 kg/day. High per capita ecstasy loads were observed in Dutch cities, as well as in Antwerp and London. In general, cocaine and ecstasy loads were significantly elevated during the weekend compared to weekdays. Per-capita loads of methamphetamine were highest in Helsinki and Turku, Oslo and Budweis, while the per capita loads of cannabis were similar throughout Europe. This study shows that a standardized analysis for illicit drug urinary biomarkers in sewage can be applied to estimate and compare the use of these substances at local and international scales. This approach has the potential to deliver important information on drug markets (supply indicator).

Multi-residue analytical method for the determination of emerging pollutants in water by solid-phase extraction and liquid chromatography–tandem mass spectrometry

This paper describes the development and validation of a method for the simultaneous determination of 53 multi-class emerging organic pollutants in water samples using solid-phase extraction (SPE) followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS), using electrospray ionisation (ESI) in both positive and negative modes. Target compounds include acidic herbicides, UV filters, insect repellents, organophosphorous flame retardants, a bactericide, pharmaceuticals and metabolites. A single SPE consisting on the loading of 200-500 mL of sample adjusted to pH 7 on Oasis HLB 200mg cartridges and elution with methanol, permitted obtaining good recoveries: higher than 60% for tap, surface and wastewater in most cases. The 7 isotopically labelled internal standards effectively compensated losses during sample preparation and matrix effects at LC-MS/MS determination. The precision of the method, calculated as relative standard deviation (RSD) was below 15% for all compounds and all tested matrices. Detection limits (LODs) based on the confirmation, less intense, MRM (multiple reaction monitoring) transition and considering blanks varied between 0.3 and 30 ngL(-1). Finally, the developed method was applied to the determination of target analytes in various samples, including tap, surface and waste water. Among the tested emerging pollutants, 31 were found in wastewater in concentrations reaching up to 10 microgL(-1) in the case of ibuprofen. Also, 13 species were detected in tap water with concentrations up to 0.13 microgL(-1) for tri(chloropropyl) phosphate (TCPP).

Emerging pollutants in sewage, surface and drinking water in Galicia (NW Spain)

A monitoring programme was carried out on wastewater, surface and drinking water on the NW area of Spain during the four seasons of a year period (November 2007-September 2008). This study covered a series of emerging pollutants of different classes, including pharmaceuticals, neutral and acidic organophosphorus flame retardant/plasticizers (OPs), triclosan, phenoxy-herbicides, insect repellents and UV filters. From the total set of 53 compounds, 19 were found in raw wastewater with median concentrations higher than 0.1 μg L(-1). Among them, salicylic acid, ibuprofen and the UV filter benzophenone-4 (BP-4) were the most concentrated, exceeding the 1 μg L(-1) median value. Subsequently, 11 of these contaminants are not efficiently enough removed in the small WWTPs tested and their median concentrations in effluents still surpassed the 0.1 μg L(-1), so that they can spread through surface water. These chemicals are the pharmaceuticals naproxen, diclofenac and atenolol; the OPs tri(2-chloroethyl) phosphate (TCEP), tri(chloropropyl) phosphate (TCPP), tri-n-butyl phosphate (TnBP), diphenyl phosphate (DPhP) and diethylhexyl phosphate (DEHP); and the sulphonate UV filters BP-4 and 2-phenylbenzimidazole-5-sulphonic acid (PBSA). These OPs were then the dominant emerging pollutants occurring in surface and drinking water, where they are detected in the 20-200 ng L(-1) range. Pharmaceuticals and UV filters are typically below the 10 ng L(-1) level. Finally, herbicides were only detected in the last sampling campaign under the 100 ng L(-1) drinking water European Union limit.

Determination of acidic drugs in sewage water by gas chromatography–mass spectrometry as tert.-butyldimethylsilyl derivatives

A procedure is described for the determination of five acidic non-steroidal anti-inflammatory pharmaceuticals (ibuprofen, naproxen, ketoprofen, tolfenamic acid and diclofenac) in sewage water. The analytical method involves the concentration of water samples using a solid-phase extraction polymeric sorbent, functionalized with N-vinylpyrrolidone. Analytes were eluted with ethyl acetate. derivatized using N-methyl-N-(tert.-butyldimethylsilyl)trifluoroacetamide (MTBSTFA) and analyzed by GC-MS. Influence of time, temperature and volume of MTBSTFA in the yield of the derivatization step were studied in detail using a factorial central composite design. Quantification limits of the analytical procedure for 500 ml of sewage water ranged from 20 to 50 ng/l. Recoveries from 90 to 115% were found for sewage water samples spiked with the studied compounds at the low ng/ml level. Results obtained for real samples show the presence of ibuprofen and naproxen in both influent and effluent of a sewage water treatment plant.

Multiclass Determination of Sunscreen Chemicals in Water Samples by Liquid Chromatography−Tandem Mass Spectrometry

A novel analytical method based on solid-phase extraction (SPE) and liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) for the determination of UV sunscreen agents in the water environment is presented. After a thorough investigation of SPE and LC-MS/MS conditions, it permits the enrichment and determination of nine of these compounds in a single methodology, including three very polar sulfonates (e.g., 2-phenylbenzimidazole-5-sulfonic acid, PBSA) and six other less polar compounds (e.g., benzophenone-3, BP-3; octocrylene, OC,...). Other important matters of concern in the determination of UV filters at trace levels in water, i.e., adsorption on glassware and blank contamination problems, have also been discussed and minimized. This methodology affords detection limits between 7 and 46 ng L-1 and SPE recoveries in the range 63-102% from different real water matrixes, except for butylmethoxydibenzoylmethane (BM-DBM), which was not determinable in wastewater samples due to adsorption problems. The application of the method allowed reporting the levels of benzophenone-4 (BP-4) in environmental water samples for the first time, where it was identified as one of the most important in concentration among the UV filters studied, particularly in wastewater (237-1481 ng L-1).

Simultaneous determination of parabens, triclosan and triclocarban in water by liquid chromatography/electrospray ionisation tandem mass spectrometry.

A method for the determination of several household biocides in water by liquid chromatography/electrospray ionisation tandem mass spectrometry (LC/ESI-MS/MS) is presented. It permits the simultaneous determination of triclosan (TCS), triclocarban (TCC) and seven parabens, including the distinction between branched and linear isomers of propyl (i-PrP and n-PrP) and butyl parabens (i-BuP and n-BuP). Prior to LC/MS/MS, analytes are preconcentrated by solid-phase extraction (SPE) on Oasis HLB (60 mg) cartridges at natural sample pH and subsequently eluted with 4 mL of methanol. This simple SPE procedure provides extraction recoveries above 85% except for raw wastewater, where it falls to 65% for TCC. The performance of the method was tested with two triple-quadrupole LC/MS instruments from a low/mid and mid/high market range: a Varian 1200L and an API-4000. The latter system provided between 3 and 80 times lower limits of quantification (LOQs) than the first one, in the 0.08-0.44 ng/L range for surface water. Moreover, a comparison of matrix effects on both instruments showed a very different behaviour, particularly in the case of parabens. For these compounds signal suppression was observed in the 1200L instrument and signal enhancement with the 4000 instrument. As a result, different calibration approaches were chosen for them and this pointed to the need of matrix effect re-evaluation in method transfer between different LC/MS systems. The application of the method to real samples showed the ubiquity of methyl paraben (MeP) and n-PrP (at the 1-6 microg/L in raw wastewater) and the coexistence of i-BuP and n-BuP at similar levels (ca. 100-200 ng/L in raw wastewater).

Evaluation of the occurrence and biodegradation of parabens and halogenated by-products in wastewater by accurate-mass liquid chromatography-quadrupole-time-of-flight-mass spectrometry (LC-QTOF-MS).

An assessment of the sewage occurrence and biodegradability of seven parabens and three halogenated derivatives of methyl paraben (MeP) is presented. Several wastewater samples were collected at three different wastewater treatment plants (WWTPs) during April and May 2010, concentrated by solid-phase extraction (SPE) and analysed by liquid chromatography-electrospray-quadrupole-time-of-flight mass spectrometry (LC-QTOF-MS). The performance of the QTOF system proved to be comparable to triple-quadrupole instruments in terms of quantitative capabilities, with good linearity (R(2) > 0.99 in the 5-500 ng mL(-1) range), repeatability (RSD < 5.6%) and LODs (0.3-4.0 ng L(-1) after SPE). MeP and n-propyl paraben (n-PrP) were the most frequently detected and the most abundant analytes in raw wastewater (0.3-10 μg L(-1)), in accordance with the data displayed in the bibliography and reflecting their wider use in cosmetic formulations. Samples were also evaluated in search for potential halogenated by-products of parabens, formed as a result of their reaction with residual chlorine contained in tap water. Monochloro- and dichloro-methyl paraben (ClMeP and Cl(2)MeP) were found and quantified in raw wastewater at levels between 0.01 and 0.1 μg L(-1). Halogenated derivatives of n-PrP could not be quantified due to the lack of standards; nevertheless, the monochlorinated species (ClPrP) was identified in several samples from its accurate precursor and product ions mass/charge ratios (m/z). Removal efficiencies of parabens and MeP chlorinated by-products in WWTPs exceeded 90%, with the lowest percentages corresponding to the latter species. This trend was confirmed by an activated sludge biodegradation batch test, where non-halogenated parabens had half-lives lower than 4 days, whereas halogenated derivatives of MeP turned out to be more persistent, with up to 10 days of half-life in the case of dihalogenated derivatives. A further stability test performed with raw wastewater also showed that parabens degrade rapidly in real sewage, with half-lives lower than 10 h for n-butyl-paraben, while dihalogenated species again turned out to be more stable, with half-lives longer than a week.

Determination of drugs of abuse in water by solid-phase extraction, derivatisation and gas chromatography–ion trap-tandem mass spectrometry

An alternative method for the sensitive determination of several drugs of abuse and some of their metabolites in surface and sewage water samples is proposed. Analytes are concentrated using a solid-phase extraction (SPE) sorbent, converted into the corresponding trimethylsilyl derivatives and selectively determined by gas chromatography (GC) with tandem mass spectrometry (MS/MS) detection. Parameters affecting the performance of extraction, derivatisation and determination steps are systematically investigated. Moreover, the stability of target analytes in sewage water samples is discussed. Under final working conditions, water samples were adjusted at pH 8.5 and concentrated using a 200mg OASIS HLB SPE cartridge. Analytes were sequentially eluted with ethyl acetate followed by acetone and silylated using N-methyl-N-(trimethylsilyl)trifluoroacetamide (MSTFA). The reaction was completed in 60 min at 80 degrees C and the mixture injected directly in the GC-MS/MS system without further purification. In most cases, analytes presented a poor stability in sewage water samples; however, once they are submitted to the SPE process, cartridges can be stored at -20 degrees C for at least 3 months without significant degradation and/or inter-conversion reactions of illicit drugs. The proposed method provided recoveries over 74% and LODs between 0.8 and 15 ng/L for river and treated wastewater samples. In the case of raw wastewater slightly worse recoveries, between 63 and 137%, and similar LODs were attained. Analysis of a limited number of waste and surface water samples confirmed the presence of several illicit drugs in the aquatic environment, with the highest levels and frequency corresponding to benzoylecgonine, the main metabolite of cocaine.

Screening and selective quantification of illicit drugs in wastewater by mixed-mode solid-phase extraction and quadrupole-time-of-flight liquid chromatography-mass spectrometry.

For the first time, a mixed-mode solid-phase extraction with fractionation of basic analytes from neutral and acidic species during cartridge elution and liquid chromatography-quadrupole-time-of-flight mass spectrometry (LC-QTOF-MS) was combined for the quantitative determination of 24 illicit drugs and metabolites in urban sewage samples. The effects of several sample preparation and instrumental parameters in the sensitivity and selectivity of the quantitative method are thoroughly discussed. Under final working conditions, recoveries above 63% and 82% were attained for all species in raw and treated sewage, respectively; whereas, the limits of quantification of the method, defined for a signal-to-noise of 10 (S/N = 10), ranged from 2 to 50 ng L(-1). Sequential elution of mixed-mode cartridges allowed a significant reduction of matrix effects observed during electrospray ionization of basic drugs versus those measured for hydrophilic balance reversed-phase sorbents and the same mixed-mode polymer without fractionated elution. Analysis of raw wastewater samples confirmed the ubiquity of cocaine (COC), benzoylecgonine (BE), and 11-nor-9-carboxy-Δ(9)-tetrahydrocannabinol (THCCOOH) in this matrix. The capability of the above methodology to identify new illicit drugs and/or metabolites in sewage samples is also discussed. With this aim, a two step strategy is proposed. First, high-resolution MS chromatograms, acquired throughout each chromatographic run, are automatically searched against an in-house built database, a reduced list of candidate drugs is generated, and the corresponding extracted ion chromatograms are obtained. In a further LC run, the tandem mass spectrometry (MS/MS) spectra of unknown peaks are acquired using different collision energies and compared with those existing in public libraries, or interpreted, to assign the unknown peak to one of the previously selected candidates.

Investigating the chlorination of acidic pharmaceuticals and by-product formation aided by an experimental design methodology.

The degradation of seven acidic drugs and two metabolites during chlorination was investigated by liquid chromatography-mass spectrometry (LC-MS). A triple-quadrupole (QqQ) system was used to follow the time course of the pharmaceuticals and by-products, while a quadrupole time-of-flight (Q-TOF) system was also used for the identification of the by-products. Under strong chlorination conditions (10mg/L Cl(2), 24h), only four of the target compounds were significantly degraded: salicylic acid, naproxen, diclofenac and indomethacine. The degradation kinetics of these four compounds were investigated at different concentrations of chlorine, bromide and pH by means of a Box-Behnken experimental design. Depending on these factors, measured pseudo-first order half-lives were in the ranges: 23-573h for salicylic acid, 13-446min for naproxen, 5-328min for diclofenac and 0.4-13.4min for indomethacine. Also, it was observed that chlorine concentration was the overall most significant factor, followed by the bromide concentration (except for indomethacine), resulting in increased degradation kinetics as they are increased. The degradation path of salicylic acid, naproxen and diclofenac consisted of aromatic substitution of one or two hydrogens by chlorine and/or bromide. Moreover, for diclofenac, two other by-products corresponding to a decarboxylation/hydroxylation pathway from the monohalogenated products were also identified. On the other hand, indomethacine degradation did not lead to halogenation products but to oxidation ones. The investigation of these by-products in real samples by LC-MS/MS (QqQ) showed that the halogenated derivates of salicylic acid occurred in all the drinking water and wastewater samples analysed.