All-Solid-State Disposable Polymeric Ion Selective Electrode for Determination of Milnacipran in Pharmaceutical Dosage Form

Screen printing technology offers a simple and cost-effective methodology for large scale production of electrochemical sensors with high reproducibility. Herein, a novel polymeric all-solid-state screen printed ion selective electrode is developed for determination of milnacipran (MLN) in pharmaceutical formulation. The morphology of the electrode was characterized by Scanning Electron Microscopy (SEM). The electrode response was optimized with regard to the membrane composition, type of the plasticizer and the ion exchanger. Optimal potentiometric response was obtained with a membrane containing milnacipran-phosphomolybdate (MLN-PMA) ion associate as ion exchanger and tricresyl phosphate as a plasticizer. The electrode exhibited a Nernstian response of 57.2±1 mV/decade (n = 3) over the concentration range from
$1.0 \times 10^{-5}$
to
$1.0 \times 10^{-2}$
M of MLN (r=0.9998) with a detection limit of
$2.0 \times 10^{-6}$
M. The electrode showed a fast potentiometric response time (
$\le 10\text{s}$
) with a high potential stability (
$\Delta \text{E}/\Delta \text{t}~\le 1.3~\mu \text{V}$
/s over 40 min of continuous monitoring). The electrode response is independent of pH in the range from 2.5 to 7.0. The electrode is selective to MLN over common pharmaceutical excipients, inorganic cations and amino acids. The electrode was used for determination of MLN in pharmaceutical dosage form with high accuracy (average recovery = 99.30%) and precision (RSD≤2%, n = 5).