4) was used as the running buffer in the subsequent studies. The effect of ionic strength SCH900776 of the running buffer was also investigated for the optimization of the conditions. The effect of ionic strength was studied by adding different concentrations of NaCl to the running buffer for the standard BSA solution of 1.0 × 10−10 M. As shown in Fig. 4(B), the change in the capacitance decreased with the increasing ionic strength of the

medium. Thus, maximum capacitance change was observed in the running buffer which did not contain any salt. After optimization of BSA detection conditions, real-time BSA detection studies from aqueous BSA solutions were carried out with the automated flow-injection capacitive system as described in Section 3.2. The BSA imprinted electrode was placed in the electrochemical flow cell and it was connected to the automated flow injection system. The running buffer was continuously passed through the flow system by the pump at a flow rate of 100 μL/min. Standard solutions of BSA in the concentration range of 1.0 × 10−20–1.0 × 10−8 M were prepared in the same running buffer and sequentially injected into the system. Phosphate buffer (10 mM, pH 7.4) was used as running buffer. Each solution was injected for 3 times through the flow system. After injection and equilibration periods, in total 15 min,

regeneration buffer was injected during 2.5 min before running buffer was used for reconditioning MycoClean Mycoplasma Removal Kit until the baseline signal was achieved. The decrease in capacitance increased with the increasing concentrations of BSA, as expected Everolimus order (Fig. 5(A)). In order to obtain a reliable analytical signal, an average of the last five capacitance readings was calculated. The graph was obtained by plotting the capacitance change (−pF cm−2) versus the logarithm of BSA molar concentration (Fig. 5(B)). An almost linear relationship was obtained between 1.0 × 10−18 and 1.0 × 10−8 M and the limit of detection

(LOD) was determined to be 1.0 × 10−19 M, based on IUPAC guidelines. Due to the results, the capacitance change as a function of log concentration of the analyte in the studied concentration range was linear with the regression equation of y = 52.27x + 1805.2 (R2 = 0.9477). When not in use, the electrodes were stored at 4 °C in a closed Petri dish. In order to test the selectivity of the BSA imprinted electrode, HSA and IgG were selected as competing proteins. For this purpose, the interactions between the aqueous solutions of BSA, HSA and IgG molecules and pre-mixed protein solutions having BSA/HSA, BSA/IgG, BSA/HSA/IgG and the BSA imprinted electrode were also investigated. As seen from Fig. 6(A), the change in capacitance was very low for the standard HSA (1.0 × 10−10 M, 10 mM phosphate buffer, pH 7.4) and IgG solutions (1.0 × 10−10 M, 10 mM phosphate buffer, pH 7.4) compared to that from the standard BSA solution (1.0 × 10−10 M, 10 mM phosphate buffer, pH 7.4).