Microfluidic enzymatic biosensor with immobilized tyrosinase for the electrochemical detection of pipemidic acid in pharmaceutical samples

FRANCO A. BERTOLINO; IRMA E. DE VITO; GERMÁN A. MESSINA; HÉCTOR FERNÁNDEZ; JULIO RABA

JOURNAL OF ELECTROANALYTICAL CHEMISTRY

ELSEVIER

Año: 2011 vol. 651 p. 204 - 210

0022-0728

The present article describes the development of a microfluidic-enzymatic sensor with electrochemicaldetection for the quantification of pipemidic acid (PA), which is a synthetic quinolone used as antibacterialagent. This property of the quinolones is associated with their potential to inhibit topoisomerase II(DNA gyrase) of bacteria. PA detection in pharmaceutical samples was based in the use of tyrosinaseenzyme [EC 1.14.18.1] that was immobilized on 3-aminopropyl-modified-controlled-pore glass (APCPG)packet in a central channel (CC) of the microfluidic-enzymatic device. This enzyme catalyzes the oxidationof catechol to o-benzoquinone, whose back electrochemical reduction was detected at gold electrodesurface at 0 V vs. Ag/AgCl. Thus, when PA was added to the solution, this piperazine-containing compoundparticipates in a Michael addition reaction with o-benzoquinone to form the correspondingamino-quinone derivative, as result of this interaction the peak current obtained for o-benzoquinonereduction decreased proportionally to the increase of the PA concentration. The recovery of PA from foursamples ranged from 97.50% to 102.50%. This method could be used to determine the PA concentration inthe range 0.02–70 lM (r = 0.998) with a limit of detection of 18 nM. This method was successfully appliedfor the analysis of PA in pharmaceutical formulations.