Diffraction detection of sucrose by electrophoresis in a microfluidic chip

Based on the change of diffraction pattern, a microfluidic chip electrophoresis detection system is developed. Using tris(hydroxymethyl)aminomethane (Tris) of 10 mmol/l as buffer and sucrose solutions (with concentration of 0.054, 0.1725, 0.24775 and 0.2975 g/ml respectively) as samples, quantity as tiny as 55 pl (pico-liter) of sucrose solution in the microfluidic chip (with a channel diameter of 60 μm) is detected successfully with an unfocused He-Ne laser beam (633 nm, 1 mW). The experiment is simple and the detection result is obvious. PACS  42.25.Fx; 82.45.h; 42.66.Lc