The application of tubular ion-exchange membranes for on-line use with flame atomic absorption (FAA) was investigated. Signal enhancement factors as high as 22 were observed within five minutes for a variety of cations. Enhancements improved with lower pH receiver solutions, increased tubing length, and increased temperature. Optimum receiver flow rates were a compromise between optima for independent Donnan dialysis or FAA experiments. Low anion interferences were observed for phosphate-to-calcium mole ratios up to 80.
