engleski

Sediment sample preparation for chromatographic determination of veterinary pharmaceuticals

Pharmaceuticals used in human and animal medicine are very heterogeneous class of emerging organic pollutants and they have been determined in several matrices such as sewage, ground water or sediments. Sediments act as a potential receiver for many hazardous chemicals, including the pharmaceuticals, which have been emitted to surface waters. Due to their physico-chemical properties, many of these pharmaceuticals sorbed to sediment. These sediments may become a secondary source of pollution when they are eroded and transported further downstream. From these reasons it is necessary to monitor the pharmaceuticals in sediment with adequate analytical techniques, in most cases that are chromatographic methods. Chromatographic methods demand good and delicate sample preparation procedure because of complex sediment matrix. So, the purpose of this research is optimization and comparison of different extraction methods [extraction by agitation (EA), microwave assisted extraction (MAE), ultrasound solvent extraction (USE), pressurized liquid extraction (PLE) and matrix solid-phase dispersion (MSPD)] of target analytes from sediment. Investigated chemicals are veterinary pharmaceuticals: antihelmintics (albendazole, febantel and levamisole), local anesthetics (lidocaine and procaine), macrolide antibiotic tylosin, and glucocorticosteroids (dexamethasone and hydrocortisone). Actually, the main aim of this work was to extract mentioned pharmaceuticals from sediment samples with high efficiency and less matrix effect. The extraction of listed compounds from sediments has been traditionally performed using solvent extraction (Soxhlet) or steam distillation techniques. Traditional methods of extraction are labour-intensive, time consuming and require large volumes of solvents. So, alternative methods like EA, MAE, USE, PLE and MSPD offers quick and simple extraction, but also require less volumes of solvents. All extraction methods are optimized. The goal of optimization process was to find the optimal composition of elution solvent, solvent volume, suitable sorbent (for MSPD), extraction duration, speed and revolutions per minute (for EA), temperature, pressure for MAE and PLE). Finally results showed that EA was the least effective than other methods, highest matrix effect was observed for EA and USE, the most effective methods were PLE and MAE, and the least matrix effect was observed for MSPD on C18 sorbent for investigated pharmaceuticals. Extraction efficiency was determined by high performance liquid chromatography with diode array detector (HPLC-DAD) on the column InterSustain™ 250x4.6 mm, 5 μm ; GL Sciences, Japan at 30 oC and injection volume was 30 μL. The analysis was conducted using eluent A (0.01 % formic acid in MilliQ water) and eluent B (0.01 % formic acid in acetonitrile) in gradient elution mode. The flow rate was 0.5 mL/min.

sediment; sample preparation; veterinary pharmaceuticals

This work has been supported by Bilateral project HR-SLO: Determination of toxicity and physico-chemical properties of pharmaceuticals.