E. M. G. Santos, C. M. C. M. Couto, M. C. B. S. Monte-negro, M. G. P. M. S. Neves, S. L. H. Rebelo, J. A. S. Cavaleiro and B. F. Reis, “Ion-Selective Electrodes Based on Metalloporphyrins for Gibberellic Acid Determination in Agricultural Products,” Analytical and Bioanalytical Chemistry, Vol. 375, No. 4, 2003, pp. 511-516.

has been cited by the following article:

• TITLE: Sequential Injection Analysis of Ampicillin in Pharmaceuticals by Using Potentiometric Detectors Based on PVC and Sol-Gel Membranes

  AUTHORS: Nestor Zárate, Alberto N. Araujo, M. Conceiçao B. S. M. Montenegro, Ricardo Pérez-Olmos

  KEYWORDS: Ampicillin, SIA, Potentiometric Detection, Pharmaceutical Formulations

  JOURNAL NAME: American Journal of Analytical Chemistry, Vol.2 No.4, August 31, 2011

  ABSTRACT: This work describes the construction and the evaluation of the general performance of new ampicilli-nate-selective electrodes based on manganese (III) tetraphenylporphyrin [Mn(III) TPP-Cl] as ionophore, incorporated in both PVC and sol-gel membranes and directly applied onto a conductive graphite/epoxy resin support. The units were constructed without inner reference solution adopting conventional configuration and in the case of PVC membrane the tubular configuration was also adopted. The good working characteristics of these electrodes, made possible its application to the determination of ampicillin in pharmaceuticals formulations, both in conventional batch analysis and in flow conditions, when the electrodes were coupled to a SIA system. In the last case the potentiometric sensors presented linear response towards ampicillin concentration between 5.0 × 10–4 and 5.0 × 10–2 mol?l–1 with slopes of –57.4 and –63.5 mV?dec–1 for the PVC and sol-gel membranes, respectively. The developed procedures enable mean relative standard deviations better than 3% for all the samples analysed. The obtained results do not statistically differ from those furnished by applying the HPLC reference method.