Ion-transfer voltammetric determination of the [beta]-blocker propranolol in a physiological matrix at silicon membrane-based liquid/liquid microinterface arrays

In this work, the ion-transfer voltammetric detection of the protonated [beta]-blocker propranolol in artificial saliva is presented. Cyclic voltammetry, differential pulse voltammetry, and differential pulse stripping voltammetry (DPSV) were employed in the detection of the cationic drug based on ion-transfer voltammetry across arrays of microinterfaces between artificial saliva and an organogel phase. It was found that the artificial saliva matrix decreased the available potential window for ion-transfer voltammetry at this liquid/liquid interface but transfer of protonated propranolol was still achieved. The DPSV method employed a preconditioning step as well as a preconcentration step followed by analytical signal generation based on the back-transfer of the drug across the array of microinterfaces. The DPSV peak current response was linear with drug concentration in the artificial saliva matrix over the concentration range of 0.05-1 [micro]M ([i.sub.p] = -8.13 (nA [micro][M.sup.-1])(concentration) + 0.07 (nA), R = 0.9929, n = 7), and the calculated detection limit (3[S.sub.b]) was 0.02 [micro]M. These results demonstrate that DPSV at arrays of liquid|liquid microinterfaces is a viable analytical approach for pharmaceutical determinations in biomimetic matrixes.