On-column amperometric detection of ofloxacin and pasiniazid in urine by capillary electrophoresis with an improved fractured joint and small detection cell

An improved high-voltage electric field isolating joint and small detection cell have been carefully designed and fabricated. The joint possesses shor t steady time, high electric conductance efficiency and high performance. T he cell is convenient to install and remove the capillaries with and withou t the joint, as well as to fix, adjust and insert the microelectrode into t he detection capillary. Using the joint and the cell, an analytical method for determination of ofloxacin (Oflx) and pasiniazid (Ipa) in urine by capi llary electrophoresis with on-column amperometric detection was developed. The calibration lines were linear in the range of 10-100 mg 1(-1) of Oflx a nd 1.0-50 mg 1(-1) of Ipa, respectively. The detection limits were 8.5 mg 1 (-1) of Oflx and 0.80 mg 1(-1) of Ipa. Their recovery ranged from 101 to 10 4%. The accuracy and intra-day and inter-day reproducibility of Oflx and Ip a were determined with satisfactory results. This method was successfully u sed for determining Oflx and Ipa in human urine.