Setup Of Miniaturized Total Analytical System With Conductivity Detection

Miniaturized total analytical system was becoming the hot-point in the researching fields of analytical chemistry. It was really difficult for miniaturization of Laser Induced Fluorescence (LIF), which was of high sensitivity. On the other hand, it was practical to realize true concept ——Lab-on-a-chip with integration of electro-detector on microchip, because of its inherent miniaturization, remarkable sensitivity, compatibility with advanced microfabrication, and minimal cost of electrochemical devices. Amperometric method and conductivity method were the most popular ones in μ-TAS.Fluidic characters in microchannel were discussed, and effects of miniaturization of pipeline on mixing, separation, and detection were discussed based on parameters' downscale of μ-TAS. Feasibility and some superiority of miniaturization were proved. Design theory of microchip with conductivity detection was proposed. PMMA microchip fabrication with integrated conductivity electrode was studied in details. The fabricating process and conditions for chip prepared in normal lab were optimized. The liquid flowing status in microconduit was observed with microscope. Influence factors of μTAS with conductivity detection were discussed. Standard potassium chloride solution was detected with μTAS set-up in this work. Normal conductivity detecting method was also applied for comparing. Conductivity detection on microchip with pressure driving was demonstrated. The mixture of potassium chloride and sodium chloride solution was separated in PMMA microchip with conductivity detection. The feasibility of conductivity detection for separation process on PMMA microchip was proved.The iron in soil was detected with pressure driven μTAS set-up in this work by means of integrated conductivity detector. Atomic Emission Spectroscopy and normal conductivity method were applied for co-existing interference analysis in the soil sample detection. Many factors that affected detection of iron ion (II) were analyzed. The results of iron in soil with μTAS detection were matched well with the results of Atomic Absorption Spectroscopy. At the same time, aspirin was determined with the same μTAS setup. The veracity of detecting results of aspirin with μTAS was compared with the detecting results of codex method and normal conductivity method.The detecting results of practical samples, such as: iron in soil and aspirin in medicine, proved that the μTAS with integrated conductivity detection was practical. The research is helpful for the truly integration of μTAS and μTAS application forin-situ and in-fields in the coming future.