Extended Gate Field Effect Transistor Based Sensor for Detection of Trace Amounts of Anti-Depressant Drug

Citalopram hydrobromide (CP) is a selective serotonin reuptake inhibitor for the treatment of the depressive disorder. In this work, a novel label-free recognition method based on an extended gate field-effect transistor (EGFET) for selective determination of CP is investigated. A Pt electrode covered by a modified PVC membrane, as the sensing part, is connected to the gate of a MOSFET transducer. Two types of PVC membranes containing ion-pairs, CP ion and tetraphenylborate or phosphotungstate ions (with different percentages), are used in this study. The obtained results indicate that the PVC membrane containing 7 % CP-tetraphenylborate has the highest sensitivity, with a detection limit of 10(-12) M. The sensor exhibits two linear response ranges, in the ranges of 10(-11) - 10(-7) M and 10(-6) - 10(-2) M, characterized by different sensitivities. The proposed method shows clear advantages in terms of increased accuracy, sensitivity, precision, and selectivity. The sensor is successfully applied to assay citalopram in tablets. The features of simplicity in preparation, fast response, capability for the miniaturization, and easy operatory, make the sensor a promising candidate for future integrated lab-on-chip devices for pharmaceutical quality control measurements.