Parallel Detection Of Uric Acid And Ascorbic Acid Based On Microfluidic Technique

Uric acid and ascorbic acid are the most important antioxidants in the body. And ascorbic acid known as vitamin C is an important position of the collagen synthesis. Ascorbic acid and uric acid exist in many animals. Ascorbic acid and uric acid have electroactive, so they can be determined by using electrochemical detection. As antioxidants are often easy to denaturate, the detection of antioxidants must be finished in short time. Comparing to the optical absorbance, electrochemical detection needs smaller sample volume and shorter time. In this paper, electrochemical detection was studied for detection of uric acid and ascorbic acid, and the microfluidic chip in polydimethylsiloxane(PDMS) was made. The major contents are as follows:By using the method of molding and micro-assembly, an electrochemical detection system with three electrodes was achieved based on the microfluidic technique.The influence of pH and temperature on the peak current of uric acid and ascorbic ascorbic acid was investigated experimentally. With the carbon nanotube electrodes, the decreasing of pH caused the increasing of peak current potential of uric acid, while the peak current of ascorbic acid did not change obviously, In the buffer solution of pH3, both ascorbic acid and uric acid can be recognized out.By using cyclic voltammetry and differential pulse voltammetry, the detections with&without microfluidic chip was compared. From the result, in the microfluidic chips, detecting current decreased about1order of magnitude, but the detection process was more stable. In the two detection methods of microfluidic platform, the peak current was proportional to the concentration for both the uric acid and the ascorbic acid.The effect of the continuous pumping on the parallel detection was experimentally analyzed too. In the pumping condition, with the increase of concentration, the peak current and potential ascorbic acid gradually disappeared, while the peak current of uric acid remained in the distinguishable level, which may be related to two kinds of acid chemical reaction rate constant difference.