Rapid Separation and Determination of Aminoglycoside Antibiotics by Capillary Electrophoresis with Contactless Conductivity Detection

Capillary electrophoresis with contactless conductivity detection was applied to rapid separation and determination of 3 aminoglycoside antibiotics, i.e., gentamicin (GE), kanamycin (KA) and streptomycin (ST), which behaved with lack of strong UV absorption chromophore or fluorescence emmision grouping. Various influential factors of CE analysis were studied and the following optimum parameters were found: ① electrophoretic medium: buffer system of 35 mmol·L-1 2-(N-morpholinyl)-ethane sulfonic acid solution and 15 mmol·L-1 histidine solution; ② separation voltage: 17 kV; ③ excitation voltage: 60 V; ④excitation frequency: 600 kHz; and ⑤ time of sample introduction: 5 s. Under the optimum conditions, satisfactory separation of the 3 antibiotics was attained within 10 min. Linear relationships between values of peak area and mass concentration of the 3 antibiotics in definite ranges were kept, with detection limits (3S/N) of 0.2 mg·L-1 (for GE), 0.4 mg·L-1 (for KA) and 0.2 mg·L-1 (for ST).