Semicontinuous monitoring of truly dissolved forms of trace elements in streams using dialysis In Situ—I. Principle and conditions

Abstract

A new method of semicontinuous monitoring is described which consists of immersing a dialysis cell filled with pure water into the stream to be monitored. Dissolved species diffuse through a dialysis membrane into the cell, where they are removed from the solution, for instance by adsorption. If the concentration of a dissolved species in the solution inside the cell is maintained at a very low value as compared with the concentration outside the cell, the diffusion flow is directly proportional to the concentration of the dissolved species in the stream water and the mean stream concentration for the monitoring period can be determined from the total amount of the monitored species accumulated in the cell. Basic conditions and limitations of the method are discussed.