A new length detection-micro fluidic device using an autocatalytic reaction

摘要

A new length detection-micro fluidic device was developed using a sodium sulfite/hydrogen peroxide autocatalytic reaction system as a model reaction, and sub-ppm levels of horse radish peroxidase were determined with this device. Sodium sulfite solution containing bromo thymol blue as an indicator and hydrogen peroxide solution were pumped into a T-shaped mixer with the help of a microliter syringe pump and then mixed. The blue solution had changed to yellow beyond the midpoint of the fine pathway (micro channel). Furthermore, when horse radish peroxidase (PO_x) was pumped, a part of the blue solution in the micro channel (blue band) was shortened. Therefore, it was possible to determine the PO_x concentration by via the length of the blue band. The relationship between the blue band length (y, mm) and the common logarithm of the PO_x concentration (x, M) gave a straight line in the concentration range of 0.05–1 ppm. The equation for the straight line was as follows: y = −3.78 log(x) + 16.4. The correlation coefficient was γ = 0.995, the relative standard deviation was 5.7% (n = 10), and the detection limits of the PO_x concentration was 0.029 ppm.