A novel microfluidic chip system with simplified amperometric detector was manufactured and used to determine nicotinamide in commercially available nicotinamide tablets.The integrated two electrode in the simplified amperometric detector was comprised of a carbon-nanotubes electrode and a titanium tube.The carbon-nanotubes electrode in the middle of the electrode was used as the working electrode,and the titanium tube was used not only as a counter electrode of amperometric detection but also as the ground electrode of power source in separation.The structure of microfluidic chip system was more simplified and miniaturized.The experimental conditions,such as type and concentration of buffer solution,separation voltage and injection time etc,were optimized.The results showed that nicotinamide was separated and detected within 2 min in the buffer of 10 mmol?L-1 phosphate solution(pH 7.8) at a separation voltage of 2.0 kV and an injection time of 10 s.The calibration curve of nicotinamide was linear in the range of 10-600 μmol?L-1.The limit of detection(LOD,S/N=3) reached to 5 μmol?L-1 and the relative standard deviation(RSD) was 3.0% for nicotinamide.The average spiked recovery was 99.1%.This device has realized miniaturization and integration with high sensitivity,good selectivity and low cost,and could be used for the quality control of medicines.