Analysis of potential adulteration in herbal medicines and dietary supplements for the weight control by capillary electrophoresis

CIANCHINO, VALERIA; ACOSTA, GIMENA; ORTEGA, CLAUDIA; MARTINEZ, LUIS DANTE; GOMEZ, MARÍA ROXANA

FOOD CHEMISTRY

Elsevier

Año: 2008 vol. 108 p. 1075 - 1081

0308-8146

Four different phytopharmaceutical dosage forms for use in weight control programs were analyzed. Two different ground herbal blends and their correspondent infusions, a capsule and a tincture were investigated for the presence of compounds used as adulterants in these products. A Capillary Electrophoresis (CE) method was developed and validated. The optimized experimental conditions were: BGE, sodium tetraborate buffer 20 mM, pH 9.2, voltage applied 30 kV, capillary temperature 25 °C, injection sample at 0.5 Psi during 5 seconds. Ephedrine, norephedrine, caffeine and furosemide were baseline separated in less than 7 minutes; the migration times were found to be 2.65, 2.90, 3.75 and 6.58 min, respectively. The analysis showed in sample 3 concentrations of 0.45±0.03 mg g-1 (ephedrine), 0.33±0.02 mg g-1 (norephedrine), 1.09±0.41 mg g-1 (caffeine) and 0.80±0.17 mg g-1 (furosemide). Caffeine content in samples 1, 2 and 4 was 0.61±0.06 mg g-1, 15.66±1.05 mg g-1 and 2.27±0.13 mg ml-1, respectively. Linearity was obtained in the concentration range of 1 - 1000 µg ml-1. Limits of detection (LOD) and quantification (LOQ) were determined as 0.42 µg ml-1 and 1.40 µg ml-1 (ephedrine), 0.47 µg ml-1 and 1.40 µg ml-1 (norephedrine), 0.12 µg ml-1 and 0.48 µg ml-1 (caffeine), 0.22 µg ml-1 and 0.73 µg ml-1 (furosemide). The common constituents of the samples did not interfere with the potential adulterants. Repeatability was better than 0.24 % R.S.D. for the retention time and 1.43 % for the peak area. Intermediate precision was tested by changing the capillary, the day of operation and the operator, in all the cases the %RSD was better than 3.06.