Abstract
In this contribution, nonaqueous capillary electrophoresis with end-column amperometric detection using a platinum ultra-microelectrode is presented along with several extraction procedures, both liquid-liquid extraction (LLE) and solid-phase extraction (SPE), for extracting trimetazidine from urine. Trimetazidine is an anti-ischemic drug, which changes hearth metabolism pathways and is being abused as a doping.
Electrochemical detection in a nonaqueous environment provided a stable response with a relative standard deviation of only 3.6% (n = 10) in repeatability measurement at concentration of 50 µg cm(-3). LOD and LOQ of the proposed method were determined as 0.054 µg cm(-3) and 0.180 µg cm(-3), respectively.
From the point of view of LLE, the most efficient procedure was the double extraction with ethyl acetate as an extraction agent in combination with prior alkalinization of the sample by Na2CO3. Nevertheless, the extraction efficiency was only around 68%.
The most efficient SPE procedure was based on the combination of HLB cartridge and elution with background electrolyte containing 20% of methanol. Its recovery reached up to 92% and 101% in case of 50 µg cm(-3) and 5.0 µg cm(-3) of trimetazidine in urine, respectively.