Figure 5. Sample depletion due to nonspecific adsorption.
a) A comparison of the linearity in dose response measurements with equimolar injections from stock solutions of differing concentration ([10−10 and 10−9M]). The accuracy and reproducibility of measurement is confirmed by multiple linear responses in either sample but smaller slopes produced by the [10−10M] indicate significant depletion. b) Processing a [10−9M] standard mix by off-line reverse phase HPLC fractionation and reconstitution with eluent “A” increased recovery.