Analytical tools employed to determine pharmaceutical compounds in wastewaters after application of advanced oxidation processes.

Today, the presence of contaminants in the environment is a topic of interest for society in general and for the scientific community in particular. A very large amount of different chemical substances reaches the environment after passing through wastewater treatment plants without being eliminated. This is due to the inefficiency of conventional removal processes and the lack of government regulations. The list of compounds entering treatment plants is gradually becoming longer and more varied because most of these compounds come from pharmaceuticals, hormones or personal care products, which are increasingly used by modern society. As a result of this increase in compound variety, to address these emerging pollutants, the development of new and more efficient removal technologies is needed. Different advanced oxidation processes (AOPs), especially photochemical AOPs, have been proposed as supplements to traditional treatments for the elimination of pollutants, showing significant advantages over the use of conventional methods alone. This work aims to review the analytical methodologies employed for the analysis of pharmaceutical compounds from wastewater in studies in which advanced oxidation processes are applied. Due to the low concentrations of these substances in wastewater, mass spectrometry detectors are usually chosen to meet the low detection limits and identification power required. Specifically, time-of-flight detectors are required to analyse the by-products.

Application of microwave-assisted extraction and ultra-high performance liquid chromatography-tandem mass spectrometry for the analysis of sex hormones and corticosteroids in sewage sludge samples.

Hormonal compounds are a concern to the international community because they can affect the aquatic biota and are therefore considered to be endocrine-disrupting compounds. These compounds have lipophilic properties, so they tend to accumulate in solid matrices, such as sewage sludge. This work presents the optimization of a microwave-assisted extraction process combined with ultra-high performance liquid chromatography-tandem mass spectrometry for the determination of 15 hormonal compounds in sludge samples. The proposed method has relative standard deviations below 23 %, good recoveries (over 71 %) for all compounds, detection limits that ranged from 1.1 to 7.9 ng g(-1) and quantification limits which ranged from 3.7 to 26.3 ng g(-1). The method was used to analyse sludge samples from four different wastewater treatment plants of Gran Canaria (Spain) with different wastewater treatments. 17ß-estradiol, 17α-ethynylestradiol, norgestrel and cortisone were detected in sludge samples at concentrations that ranged from 17.3 to 1.44 × 10(3) ng g(-1). The developed method permits the use of small quantities of sample and organic solvents, presents short extractions times and is the first one based on microwave-assisted extraction for the analysis of both sex hormones and corticosteroids.

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

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.

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

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 (ß-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 µg·L(-1).

Assessment of the Presence of Pharmaceutical Compounds in Seawater Samples from Coastal Area of Gran Canaria Island (Spain).

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.

Analysis of anti-inflammatory, analgesic, stimulant and antidepressant drugs in purified water from wastewater treatment plants using SPE-LC tandem mass spectrometry.

This work presents an effective sample preparation method for the evaluation of seven pharmaceutical compounds belonging to different therapeutic classes in purified water from wastewater treatment plants (WWTPs). The target compounds include caffeine (stimulant), nicotine (stimulant), atenolol (beta blocker), metamizole (anti-inflammatory and analgesic), fluoxetine (antidepressant), paraxanthine (stimulant) and clofibric acid (lipid regulator). Solid-phase extraction (SPE) and liquid chromatography-mass spectrometry (LC-MS) were selected as extraction and detection techniques, respectively. A detailed study of the experimental conditions of extraction was performed. Under optimal conditions, recoveries obtained were in the range of 21% to 100%, and the relative standard deviations were below 12%. The detection and quantification limits of the method were in the range 2.2-97.4 and 21.1-324.7 ng L(-1), respectively. The developed method was successfully applied to evaluate the presence of these pharmaceutical compounds in wastewaters samples from wastewater treatment plants located on the Gran Canaria Island (Spain). Most of the compounds were detected at concentrations up to 12.31 µg L(-1) in the WWTP influents that were studied.