Microextraction techniques coupled to liquid chromatography with mass spectrometry for the determination of organic micropollutants in environmental water samples

[EN]Until recently, sample preparation was carried out using traditional techniques, such as liquid–liquid extraction (LLE), that use large volumes of organic solvents. Solid-phase extraction (SPE) uses much less solvent than LLE, although the volume can still be significant. These preparation methods are expensive, time-consuming and environmentally unfriendly. Recently, a great effort has been made to develop new analytical methodologies able to perform direct analyses using miniaturised equipment, thereby achieving high enrichment factors, minimising solvent consumption and reducing waste. These microextraction techniques improve the performance during sample preparation, particularly in complex water environmental samples, such as wastewaters, surface and ground waters, tap waters, sea and river waters. Liquid chromatography coupled to tandem mass spectrometry (LC/MS/MS) and time-of-flight mass spectrometric (TOF/MS) techniques can be used when analysing a broad range of organic micropollutants. Before separating and detecting these compounds in environmental samples, the target analytes must be extracted and pre-concentrated to make them detectable. In this work, we review the most recent applications of microextraction preparation techniques in different water environmental matrices to determine organic micropollutants: solid-phase microextraction SPME, in-tube solid-phase microextraction (IT-SPME), stir bar sorptive extraction (SBSE) and liquid-phase microextraction (LPME). Several groups of compounds are considered organic micropollutants because these are being released continuously into the environment. Many of these compounds are considered emerging contaminants. These analytes are generally compounds that are not covered by the existing regulations and are now detected more frequently in different environmental compartments. Pharmaceuticals, surfactants, personal care products and other chemicals are considered micropollutants. These compounds must be monitored because, although they are detected in low concentrations, they might be harmful toward ecosystems.

Phenolic Constituents, Antioxidant and Preliminary Antimycoplasmic Activities of Leaf Skin and Flowers of Aloe vera (L.) Burm. f. (syn. A. barbadensis Mill.) from the Canary Islands (Spain)

[EN]The methanol extracts of leaf skins and flowers of Aloe vera from the Canary Islands were analyzed for their phenolic profiles and screened for their antioxidant and antimycoplasmic activities. The use of reversed phase high performance liquid chromatography (RP-HPLC) allowed the identification of 18 phenolic constituents. Leaf skin extracts were characterized by the abundance of catechin, sinapic acid and quercitrin. Gentisic acid, epicatechin and quercitrin were the most prominent phenolic compounds of the flowers. The in vitro antioxidant activities determined by using the 1,1-diphenyl-2- picrylhydrazyl (DPPH) and ferric antioxidant reducing power (FRAP) assays revealed that both extracts exhibited antioxidant activity, being the leaf skin extract the most active fraction. The leaf skin extract was also found to be active against the microbial strains tested. Therefore, A. vera extracts from leaf skin and flowers can be considered as good natural antioxidant sources.

An assessment of the concentrations of pharmaceutical compounds in wastewater treatment plants on the island of Gran Canaria(Spain)

[EN] An assessment of the concentrations of thirteen different therapeutic pharmaceutical compounds was conducted on water samples obtained from different wastewater treatment plants (WWTPs) using solid phase extraction and high- and ultra-high-performance liquid chromatography with mass spectrometry detection (HPLC-MS/MS and UHPLC-MS/MS), was carried out. The target compounds included ketoprofen and naproxen (anti-inflammatories), bezafibrate (lipid-regulating), carbamazepine (anticonvulsant), metamizole (analgesic), atenolol (?-blocker), paraxanthine (stimulant), fluoxetine (antidepressant), and levofloxacin, norfloxacin, ciprofloxacin, enrofloxacin and sarafloxacin (fluoroquinolone antibiotics). The relative standard deviations obtained in method were below 11%, while the detection and quantification limits were in the range of 0.3 ? 97.4 ng·L-1 and 1.1 ? 324.7 ng·L-1, respectively. The water samples were collected from two different WWTPs located on the island of Gran Canaria in Spain over a period of one year. The first WWTP (denoted as WWTP1) used conventional activated sludge for the treatment of wastewater, while the other plant (WWTP2) employed a membrane bioreactor system for wastewater treatment. Most of the pharmaceutical compounds detected in this study during the sampling periods were found to have concentrations ranging between 0.02 and 34.81 ?g·L-1.

Optimización de un método basado en SPE-LC-MS/MS para la determinación de multiresiduos de compuestos farmacéuticos en aguas depuradas

Universidad de Las Palmas de Gran Canaria, Facultad de Ciencias del Mar, Doctorado en Gestión Costera.

Assessment of the presence of pharmaceutical compounds in seawater samples from coastal area of Gran Canaria Island (Spain)

[EN]This study presents the evaluation of seven pharmaceutical compounds belonging to different commonly used therapeutic classes in seawater samples from coastal areas of Gran Canaria Island. The target compounds include atenolol (antihypertensive), acetaminophen (analgesic), norfloxacin and ciprofloxacin (antibiotics), carbamazepine (antiepileptic) and ketoprofen and diclofenac (anti-inflammatory). Solid phase extraction (SPE) was used for the extraction and preconcentration of the samples, and liquid chromatography tandem mass spectrometry (LC-MS/MS) was used for the determination of the compounds. Under optimal conditions, the recoveries obtained were in the range of 78.3% to 98.2%, and the relative standard deviations were less than 11.8%. The detection and quantification limits of the method were in the ranges of 0.1–2.8 and 0.3–9.3 ng·L−1, respectively. The developed method was applied to evaluate the presence of these pharmaceutical compounds in seawater from four outfalls in Gran Canaria Island (Spain) during one year. Ciprofloxacin and norfloxacin were found in a large number of samples in a concentration range of 9.0–3551.7 ng·L−1. Low levels of diclofenac, acetaminophen and ketoprofen were found sporadically.

Evaluación de la presencia de compuestos farmacéuticos en aguas residuales procedentes de estaciones de depuración de aguas residuales (EDARS) de la isla de Gran Canaria

[ES]En este trabajo se ha realizado la evaluación de la concentración de compuestos farmacéuticos de uso común de diferentes grupos terapéuticos tales como, antibióticos, antiinflamatorios, analgésicos, reguladores lipídicos, betabloqueantes, antidepresivos, estimulantes y antiepilépticos, en aguas procedentes de Estaciones de Depuración de Aguas Residuales de la isla de Gran Canaria, con el fin de poner en conocimiento la situación del problema, siendo ésta un paso previo para su posible regulación y remediación. Debido a las bajas concentraciones en que estos compuestos se encuentran en las aguas residuales, para llevar a cabo el estudio, se utilizaron procesos analíticos basados en un retratamiento de la muestra utilizando la extracción en fase sólida y su posterior determinación por técnicas instrumentales de altas prestaciones

Determinación de hormonas esteroideas en aguas depuradas de la isla de Gran Canaria

[ES]La comunidad científica internacional ha mostrado su preocupación en las últimas décadas sobre la presencia de hormonas esteroideas en el medio ambiente, las cuales han sido catalogadas como “compuestos disruptores endocrinos” (EDCs). Las hormonas pueden llegar al medio a través de diferentes vías, siendo la fuente principal la descarga al medio de los efluentes de las estaciones depuradoras de aguas residuales (EDARs), debido a la eliminación incompleta de estos compuestos que se produce en ellas. Las concentraciones de hormonas presentes en el medio acuático suelen ser del orden de ng·L-1, por lo que se necesitan metodologías analíticas sensibles y selectivas para su determinación