Abstract
A sensitive micellar electrokinetic chromatographic method to analyze salbutamol, guaifenesin, and dyphylline employing 20 µm inner diameter capillaries was developed. Sensitive analysis of the drugs at a concentration range of about 0.5 to 60 µg/mL was demonstrated using large volume sample stacking with 75% acetonitrile as the sample diluent. Using dyphylline as the internal standard, detection limits were 0.07 µg/mL and 0.21 µg/mL for salbutamol and guaifenesin, respectively. Using the standard addition method, accurate determination of salbutamol and guaifenesin in syrup and capsule preparations was achieved. Recovery values were satisfactory (95 to 100%), but matrix interferences affected the reproducibility.
Notes
a n = 3, constructed in terms of corrected peak area with 7 concentrations 1–70 µg/mL; Other conditions used were the same as in Figure a; corrected peak area = (peak area/migration time)Analyte/(peak area/migration time)Internal Standard.
a Values are the mean values ± standard deviation; Concentration of control samples = 20 µg/mL.
b Relative standard deviation.
c Accuracy = (Mean measured value/Nominal value) × 100.
a n = 4, concentration range of standard salbutamol added = 0–4 µg/mL.
b n = 4, concentration range of standard guaifenesin added = 0–20 µg/mL.
c versus calibration curve equation by external standard method y = 0.0463x +0.0394 from Table 1.
d versus calibration curve equation by external standard method y = 0.0480x + 0.3098 from Table 1.
a Average value, n = 3.
b Values in parentheses are the accuracy of the measurement expressed in %.
a Calculated from Table 4.
b Average value ± standard deviation, n = 3.