A method for measuring the concentration of a solution

Abstract

When a linearly polarized light beam enters a surface-plasmon-resonanse (SPR) apparatus and is incident on the boundary surface with tested solution at the resonant angle, the phase difference between s- and p- polarizations is changed with the concentration of the solution. And the phase difference can be measured accurately by the heterodyne interferometry. Based on these effects, a method for measuring the concentration of a solution is presented.