Renal function is generally determined by serum creatinine levels in blood serum. Clinical determination of creatinine in blood is based on the Jaffe reaction, in which creatinine in the serum reacts with sodium picrate to produce a colored product that can be spectrophotometrically quantified. Previous work has introduced an electrophoretically mediated initiation of this reaction utilizing nanoliter volumes in a capillary column, followed by electrophoretic separation of the reactions product from excess reactant(s).

This work involves a fundamental and quantitative investigation of the factors influencing the reaction yield and the transient isotachophoretic stacking of the Jaffe product. The effect of the background electrolyte on the reaction was principally investigated, with borate, glycine, AMPSO, and CAPSO buffers used in the experimentation. The background electrolytes seem to primarily affect the flow rate within the capillary, but they also have a minimal effect on the Jaffe reaction product. Additionally, the timing of the applied voltage used to overlap the reactant zones was studied. Addition of chloride to the creatinine zone is found to yield a significant improvement in stacking behavior, presumably due to minimized electrodispersion of the product.