Multi-residue method for trace level determination of pharmaceuticals in solid samples using pressurized liquid extraction followed by liquid chromatography/quadrupole-linear ion trap mass spectrometry
ABSTRACT A simple and sensitive method for simultaneous analysis of 43 pharmaceutical compounds in sewage sludge and sediment samples was developed and validated. The target compounds were extracted using pressurized liquid extraction (PLE) and then purified and pre-concentrated by solid phase extraction (SPE) using a hydrophilic-lipophilic balanced polymer. PLE extraction was performed on temperature of 100 degrees C, with methanol/water mixture (1/2, v/v) as extraction solvent. The quantitative analysis was performed by liquid chromatography tandem mass spectrometry using a hybrid triple quadrupole-linear ion trap mass spectrometer (LC-QqLIT-MS). Data acquisition was carried out in selected reaction monitoring (SRM) mode, monitoring two SRM transitions to ensure an accurate identification of target compounds in the samples. Additional identification and confirmation of target compounds were performed using the Information Dependent Acquisition (IDA) function. The method was validated through the estimation of the linearity, sensitivity, repeatability, reproducibility and matrix effects. The internal standard approach was used for quantification because it efficiently corrected matrix effects. Despite the strong matrix interferences, the recoveries were generally higher of 50% in both matrixes and the detection and quantification limits were very low. Beside the very good sensitivity provided by LC-QqLIT-MS, an important characteristic of the method is that all the target compounds can be simultaneously extracted, treated and analysed. Hence, it can be used for routine analysis of pharmaceuticals providing large amount of data. The method was applied for the analysis of pharmaceuticals in river sediment and wastewater sludge from three treatment plants with different treatment properties (i.e. capacity, secondary treatment, quality of influent waters). The analysis showed a widespread occurrence of pharmaceuticals in the sludge matrices.
SourceAvailable from: Rubén Moreno-González[Show abstract] [Hide abstract]
ABSTRACT: The seasonal variations in the occurrence and distribution of pharmaceuticals were evaluated in seawater and sediment of Mar Menor lagoon from spring 2010 to winter 2011. A total of 20 pharmaceuticals in seawater and 14 in sediments were found at concentrations from low ngL(-)(1) up to 168ngL(-)(1) (azithromycin) in seawater and from low ngg(-1) up to 50.3ngg(-1) (xylazine) in sediments. Azithromycin, xylazine and metoprolol were the most ubiquitous compounds in seawater since they were found in all seawater samples collected. Seven compounds were quantified in both matrices: clarithromycin, erythromycin, hydrochlorothiazide, irbesartan, losartan, salicylic acid and valsartan. Seasonal distribution profiles revealed different sources of pollutants associated to both, El Albujón watercourse (which receives the input of a WWTP) and other non-controlled discharges, into the lagoon. In summer the highest concentrations in seawater for most of the pharmaceuticals were detected close to main touristic nuclei, probably as consequence of sources such as the excretion from bathers and/or other non-controlled discharges, these being significantly higher than in autumn and winter for antibiotics. On the contrary, the mean concentration of lorazepam was significantly higher in colder seasons than in warmer ones. Sulfamethoxazole, erythromycin and especially clarithromycin showed hazard quotients higher than 1 in seawater at some areas of this lagoon indicating a potential risk to aquatic organisms in such specific areas. Copyright © 2015 Elsevier Inc. All rights reserved.Environmental Research 03/2015; 138. DOI:10.1016/j.envres.2015.02.016 · 3.95 Impact Factor
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ABSTRACT: Due to improvements in the instrumental analysis, research studies have allowed to determine the presence of a multitude of organic pollutants in environmental and food samples. Since the invention of atmospheric pressure ionization sources, liquid chromatography coupled to low resolution tandem mass spectrometry instrumentation is the workhorse for quantitative analysis of organic contaminants in the majority of laboratories. However, with the recent access to high resolution mass spectrometry instruments by an increasing number of laboratories this technique is rapidly gaining popularity. With this in mind, this book chapter reviews recent developments in quantitative methods for the determination of the presence of small organic compounds in environmental and food samples using liquid chromatography coupled to low resolution and high resolution mass spectrometry.Fast Liquid Chromatography– Mass Spectrometry Methods in Food and Environmental Analysis, Edited by Oscar Núñez, Héctor Gallart-Ayala, Claudia P B Martins, Paolo Lucci, 01/2014: chapter 9: pages 347-378; Imperial College Press., ISBN: 978-1-78326-494-0
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ABSTRACT: This paper deals with the photolytic and the photocatalytic degradation of sulfonamide antibiotic sulfamethazine (SMT) dissolved in Milli-Q water and in synthetic wastewater. Besides the direct photolysis, oxidation processes including UV/H2O2, UV/TiO2, and UV/TiO2/H2O2 using UV-A and UV-C radiation were investigated. Pseudo-first-order kinetics was observed for the degradation of SMT in all investigated processes. Additions of an electron acceptor (H2O2) and a catalyst (TiO2 film) accelerated the photolytic degradation of SMT for both the UV-A- and the UV-C-based processes. The most efficient process was UV-C/TiO2/H2O2 with complete degradation of SMT obtained in 10 min. The UV-A-based processes have been less efficient in terms of irradiation time required to totally degrade SMT than the UV-C-based processes. It was also confirmed that different wastewater components can significantly reduce the degradation rate of SMT. An almost ninefold reduction in the rate constant of SMT was observed for the specific synthetic wastewater. Although UV-A radiation experiments need more time and energy (2.7 times more electrical energy was consumed per gram of demineralized SMT) than UV-C experiments, they have a potential for practical use since natural UV-A solar radiation could be used here, which lowers the overall cost of the treatment. Five degradation products were detected during the degradation processes, and their structural formulae are presented. The structural formulae were elucidated based on mass spectra fragmentation pattern obtained using the tandem mass spectrometry (MS/MS) and NMR analysis.Environmental Science and Pollution Research 03/2015; DOI:10.1007/s11356-015-4338-5 · 2.76 Impact Factor