Single drop microextraction for the analysis of organophosphorous insecticides in water

Summarization: A new method used for the extraction of 10 organophosphorous insecticides from water samples coupling single-drop microextraction with gas chromatography–mass spectrometry is presented here. Parameters, such as organic solvent, exposure time, agitation, organic drop volume and salt concentration were controlled and optimised. Overall, extraction was achieved by suspending a 1.5 μl toluene drop to the tip of a microsyringe immersed in a 5 ml donor aqueous solution containing 2.5% NaCl (w/v) and stirred at 800 rpm. The developed protocol was found to yield a linear calibration curve in the concentration range from 0.5 to 100 μg l−1 for all target analytes. Under selected ion monitoring mode, the limits of detection were found to be in the range between 0.010 and 0.073 μg l−1.Παρουσιάστηκε στο: Analytica chimica act

Occurrence of pharmaceuticals in surface waters: analytical method development and environmental risk assessment

<div><p>The present work illustrates the development of an analytical method, based on offline solid phase extraction (SPE) followed by liquid chromatography–electron spray ionisation–single quadrupole mass spectrometry (LC-ESI-MS) for the simultaneous determination of pharmaceuticals belonging to various therapeutic classes (analgesics/anti-inflammatories, lipid regulators, antibiotics, antiepileptics, antipsychotics, psychomotor stimulants, glucocorticoid steroids, disinfectants, beta-blockers, H2 receptor antagonists and oestrogens) in surface waters. The method developed was applied for the analysis of pharmaceutical residues in surface waters from different sampling points along the aquatic systems of Lake Pamvotis and the River Kalamas, close to the city of Ioannina (Epirus, Greece), while the monitoring programme was carried out during the four seasons of the year. According to the results obtained, the majority of the compounds were detected in discrepant concentrations. The concentrations for all the compounds ranged from levels below quantification limit to 3506 ng/L, with caffeine and salicylic acid being the ubiquitous compounds. The results of the monitoring contributed substantially to the knowledge on the occurrence of pharmaceuticals in Greece and more specifically in surface waters of the region of Epirus. Regarding the environmental risk due to the presence of target compounds in surface waters, this was estimated calculating risk quotients (RQs) for different aquatic organisms (algae, daphnids and fish). The results denoted a possible threat for the aquatic environment, rendering in this way the RQ method as a helpful tool for a first approach. Extensive study is needed for triclosan, salicylic acid, sulfamethoxazole and erythromycin in order to better correlate their occurrence and potential toxic effects in aquatic life and humans.</p></div