Low electroosmotic flow measurement by tilting microchip.

A novel method for low electroosmotic flow (EOF) rates measurement by tilting microchip which based upon the hydrostatic pressure conception and sampling zone method is described. Sampling zone could be detected in the tilting microchip but not in non-tilting one due to the hydrostatic pressure driven. The method is fulfilled to calculate low EOF rates by detecting the liquid flow velocity driven by hydrostatic pressure, and difference between the apparent mobility of the migrating analyte in two modes is caused by the effect of hydrostatic pressure. And then the EOF rates in unknown low EOF microchip can be calculated. Different microchannels modified with bovine serum albumin (BSA), myoglobin (MB) and polyvinyl alcohol (PVA) were used to verify the method, the EOF rate value was 1.73+/-0.03, 1.21+/-0.05, 0.34+/-0.04 x 10(-4)cm(2) V(-1)s(-1), respectively. The results obtained by the proposed method were agreed well with conventional methods.