Pablo Vázquez-Roig

Determination of pharmaceuticals in soils and sediments by pressurized liquid extraction and liquid chromatography tandem mass spectrometry

The present work describes the development of a sensitive analytical method based on pressurized liquid extraction (PLE) and pre-concentration by solid-phase extraction (SPE), followed by liquid chromatography-electrospray tandem mass spectrometry (LC-ESI-MS/MS) for the determination of seventeen pharmaceuticals in soils and sediments. The method is based on sample homogenisation using Na(2)-EDTA washed sand and extraction with water at 90 degrees C. Special emphasis was placed on the optimization of the extraction procedure to develop a green method that reduces, at a maximum, the use of organic solvents in order to eliminate matrix components during the clean-up. The proposed method was linear in a concentration range from 0.3 to 333ngg(-1), with correlation coefficients higher than 0.993. Method detection (MDLs) and quantification (MQLs) limits ranged from 0.1 to 6.8ngg(-1) and from 0.25 to 23ngg(-1), respectively. Absolute recoveries were analyte dependent, varying between 50% and 105% at the MQL level, except for fenofibrate (40%) and diclofenac (34%). The intra-day and inter-day precision was given by RSD values from 0.7% to 7.9% and from 1.6% to 14.5%, respectively. Acetaminophen, carbamazepine, ciprofloxacin, clofibric acid, codeine, diazepam, fenofibrate, metropolol, ofloxacin and propanolol were detected at concentrations from MDL to 35.62ngg(-1) in soils and sediments from marsh areas. Due to the low recoveries, results for fenofibrate and diclofenac can only be considered as semi-quantitative. The method was fully suitable for the other 15 pharmaceuticals.

Screening of currently used pesticides in water, sediments and biota of the Guadalquivir River Basin (Spain)

The occurrence of 50 currently used pesticides and their transformation products in surface and waste waters, sediment and fish in the Guadalquivir River Basin was determined in 2010 and 2011. After selective sample extraction, pesticides were identified and quantified by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). The contamination profile in water and sediments is marked by the presence of organophosphorus and triazines. Transformation products were even at higher concentrations than parent pesticides. A wider range of pesticides was present in water than in sediments but none of them were detected in fish. The mean concentrations ranged from 0.2 to 13.0 ng/L in water and from 0.1 to 13.2 ng/g d.w. in sediment. The spatial distribution of most pesticides was consistent with the agricultural activities of the area or their urban applications. The waste water treatment plant effluents that impact the river are minor sources for few pesticides but for most of them run-off would be the most important contribution. The temporal distribution showed differences between both sampling campaigns related to the river flow. The low-flow produced a pesticide concentration effect, generating higher levels in water and accumulation in sediments. This forecasts a hazard in future scenarios if the current situation of the climate change and water scarcity evolves to more critical conditions highlighting the need of these monitoring studies.

Risk assessment on the presence of pharmaceuticals in sediments, soils and waters of the Pego–Oliva Marshlands (Valencia, eastern Spain)

This study is focused on the occurrence of 17 pharmaceuticals in waters (34 samples), sediments (16 samples) and soils (23 samples, at two different depths) in a typical Mediterranean coastal wetland (Pego-Oliva marsh, Spain). Soil and sediment samples were extracted by pressurized liquid extraction (PLE). Aqueous extracts from PLE and water samples were concentrated by solid-phase extraction (SPE) and determined by liquid-chromatography tandem mass spectrometry (LC-MS/MS). Pharmaceuticals were detected in concentrations up to 112 ng/L in water samples, up to 15.1 ng/g sediments and up to 8.4 ng/g in soil. In surface waters, ibuprofen and codeine were the compounds more frequently detected (up to 59 ng/L and 63 ng/L, respectively). Ground and tap water samples analyzed were also contaminated with pharmaceuticals. The 94% of sediments and the 80% of agricultural soils were polluted (mostly by carbamazepine and acetaminophen). Diffusion of codeine and fluoroquinolones to deeper soil horizons was observed. Possible relationships between variables were established by Pearson correlations and principal components analysis (PCA). An environmental risk assessment based on the available long-term data was performed. Results showed actual risk for the lowest trophic level, and for fishes, due to the presence of fluoroquinolones and ibuprofen. Nevertheless, the presence of pharmaceuticals in the environment is not limited only to an ecological problem since contamination also affects drinking water, being a potential risk to human health.

Analysis of insecticides in honey by liquid chromatography-ion trap-mass spectrometry: comparison of different extraction procedures.

The feasibility of different extraction procedures was tested and compared for the determination of 12 organophosphorus and carbamates insecticides in honey samples. In this sense, once the samples were pre-treated - essentially dissolved in hot water by stirring - and before they could be analyzed by liquid chromatography-ion trap-second stage mass spectrometry (LC-MS(2)), four different approaches were studied for the extraction step: QuEChERS, solid-phase extraction (SPE), pressurized liquid extraction (PLE) and solid-phase microextraction (SPME). The main aim of this work was to maximise the sensitivity of pesticides and to minimise the presence of interfering compounds in the extract. All pesticides were linear in the range from CC(β) to 1000× CC(β) for the four extraction methods (three orders of magnitude). Detection capabilities (CC(β)) were 0.024-1.155 mg kg(-1) with QuEChERS, 0.010-0.646 mg kg(-1) with SPE, 0.007-0.595 mg kg(-1) with PLE, and 0.001-0.060 mg kg(-1) with SPME. All the target compounds could be recovered by any of the methods, at a CC(β) fortification level ranged from 28 to 90% for the SPME. In comparison, the PLE method was the most efficient extraction method with recoveries from 82 to 104%. It was followed by the QuEChERS method with recoveries between 78 and 101% and the SPE method with recoveries between 72 and 100%. The repeatability expressed as relative standard deviation (RSDs) was below 20% for all the pesticides by any of the tested extraction methods. Results obtained applying the four extraction techniques to real honey samples are analogous.

Presence of pharmaceuticals and heavy metals in the waters of a Mediterranean coastal wetland: Potential interactions and the influence of the environment

The occurrence of 17 relevant pharmaceuticals and 7 heavy metals in the waters of the Pego-Oliva Marsh Natural Park (Valencia Community, Spain) were monitored. Thirty four zones (including the lagoon and the most important irrigation channels), covering the main land uses and water sources, were selected for sampling. Thirty three of them were contaminated with at least one pharmaceutical. Ibuprofen and codeine were the pharmaceuticals more frequently detected, in concentrations between 4.8 and 1.2 ng/L and a maximum of 59 ng/L and 63 ng/L, respectively. Regarding metals, Zn showed values under the detection limit in all the samples, while Cd, Co, Cr, Cu, Ni and Pb were detected at concentrations lower than the WHO and EU maximum levels for drinking waters. Ni showed significant direct correlations with diazepam, norfloxacin, ofloxacin and fenofibrate, and inverse relationships with ibuprofen, at 99 and 95% of significance. Cu, Co and Cr also showed significant correlations with some of the pharmaceuticals. These interactions could favor the synergistic/antagonistic interactions among pharmaceuticals and metals in the marsh, which can affect its aquatic fauna and flora or even human health. The influences of the water sources, land uses and spatial distribution of both types of contaminants were also studied.

Stereoisomeric profiling of drugs of abuse and pharmaceuticals in wastewaters of Valencia (Spain)

The enantiomeric and diastereomeric profiling of chiral pharmaceuticals (ephedrine, norephedrine, atenolol and venlafaxine) and illicit drugs (amphetamine, methamphetamine, 3,4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxy-N-methylamphetamine (MDMA) and 3,4-methylenedioxy-N-ethylamphetamine (MDEA)) was undertaken over a period of fourteen consecutive days in three wastewater treatment plants (WWTPs) in the city of Valencia, Spain. Degradation efficiency of WWTPs was found to be compound and enantiomer dependent. Selective enantiomer enrichment was observed for several target analytes. Amphetamine and MDMA were enriched with R(-)-enantiomers. 1S,2S(+)-pseudoephedrine was found to be more readily degradable during activated sludge treatment than its diastereomer 1R,2S(-)-ephedrine. Atenolol underwent enrichment with either S(-)- or R(+)-enantiomer in different WWTPs. This unexpected enantiomeric variation in the stereoselective degradation of atenolol could be attributed to different processes utilized during activated sludge treatment. The application of (enantiomeric) profiling of wastewater revealed usage patterns of chiral drugs in the Valencia region.