Capillary electrophoresis with capacitively coupled contactless conductivity detection (CE-C(4)D) was employed for fast determination of meldonium (MEL) in urine samples. Background electrolyte consisting of 2M acetic acid (pH 2.3) was used for separation of MEL from cationic compounds present in urine samples and the overall analysis time was less than 4min per sample. Direct injection of urine samples was possible after 1:9 dilution with deionized water. This simple sample pretreatment was sufficient to eliminate possible matrix effects on CE performance and allowed for precise and sensitive determination of free MEL in urine. Excellent linearity (r(2)≥0.9998) was obtained for two concentration ranges, 0.02-4μgmL(-1) and 2-200μgmL(-1), by simply changing injection time from 10 to 2s without the need for additional dilution of urine samples. Limit of detection was 0.015μgmL(-1) and average recoveries from urine samples spiked at 0.02-123.5μgmL(-1) MEL ranged from 97.6-99.9%. Repeatability of migration times and peak areas was better than 0.35% and 4.2% for intraday and 0.95% and 4.7% for interday measurements, respectively. The above reported data proved good applicability of the CE-C(4)D method to determination of various MEL concentrations in urine samples and good long-term performance of the analytical system. The method might be particularly useful in analyses of large batches of samples for initial testing of MEL-positive vs. MEL-negative urine samples.
- MeSH
- Doping in Sports MeSH
- Electric Conductivity MeSH
- Electrophoresis, Capillary methods MeSH
- Electrolytes MeSH
- Humans MeSH
- Methylhydrazines urine MeSH
- Substance Abuse Detection methods MeSH
- Water MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
Electromembrane extraction (EME) was used as an off-line sample pre-treatment method for the determination of heavy metal cations in aqueous samples using CE with capacitively coupled contactless conductivity detection (CE-C(4) D). A short segment of porous polypropylene hollow fibre was penetrated with 1-octanol and 0.5% v/v bis(2-ethylhexyl)phosphonic acid and constituted a low cost, single use, disposable supported liquid membrane, which selectively transported and pre-concentrated heavy metal cations into the fibre lumen filled with 100 mM acetic acid acceptor solution. Donor solutions were standard solutions and real samples dissolved in deionized water at neutral pH. At optimized EME conditions (penetration time, 5 s; applied voltage, 75 V; and stirring rate, 750 rpm), 15-42% recoveries of heavy metal cations were achieved for a 5 min extraction time. Repeatability of the EME pre-treatment was examined for six independent EME runs and ranged from 6.6 to 11.1%. Limits of detection for the EME-CE-C(4) D method ranged from 25 to 200 nM, resulting into one to two orders of magnitude improvement compared with CE-C(4) D without sample treatment. The developed EME sample pre-treatment procedure was applied to the analysis of heavy metal cations in tap water and powdered milk samples. Zinc in the real samples was identified and quantified in a background electrolyte solution consisting of 20 mM L-histidine and 30 mM acetic acid at pH 4.95 in about 3 min.
- MeSH
- Chemical Fractionation instrumentation methods MeSH
- Equipment Design MeSH
- Electric Conductivity MeSH
- Electrophoresis, Capillary methods MeSH
- Cations analysis isolation & purification MeSH
- Hydrogen-Ion Concentration MeSH
- Milk chemistry MeSH
- Reproducibility of Results MeSH
- Sensitivity and Specificity MeSH
- Metals, Heavy analysis isolation & purification MeSH
- Water chemistry MeSH
- Zinc analysis chemistry isolation & purification MeSH
- Animals MeSH
- Check Tag
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
