Single-run capillary electrophoresis method for the fast simultaneous determination of amoxicillin, clavulanate, and potassium.

We report a new fast method for the simultaneous determination of amoxicillin, clavulanate, and potassium by capillary electrophoresis with capacitively coupled contactless conductivity detection. Samples containing potassium as the cation, and both amoxicillin and clavulanate as anions were determined simultaneously in a single run (in less than 45 s) using 10 mmol/L of both 2-amino-2-hydroxymethyl-propane-1,3-diol and 3-{[2-hydroxy-1,1-bis(hydroxymethyl)ethyl]amino}-1-propanesulfonic acid (pH 8.4) as the background electrolyte. Limits of detection were 25.0, 5.0, and 4.0 μmol/L for amoxicillin, clavulanate, and potassium, respectively. The proposed method is inexpensive, simple, fast (75 injections h-1 ), environment friendly (minimal waste generation), and accurate (recovery values between 98 and 103%). The results obtained with the proposed method were statistically similar (95% confidence level) to those obtained by using high-performance liquid chromatography (amoxicillin and clavulanate) and flame photometry (potassium).