Development and application of an electrochemical biosensor based on carbon paste and silica modified with niobium oxide, alumina and DNA (SiO2/Al2O3/Nb2O5/DNA) for amitriptyline determination

• The composite biosensor graphite/SiO2/Al2O3/Nb2O5/DNA was developed for the determination of amitriptyline.
• The proposed biosensor exhibited the best analytical response by differential pulse voltammetry.
• The sensibility of sensor was found to be 0.216 μA μmol−1 L.
• Validation parameters presented results within the acceptable range.
• The proposed biosensor was used to determine amitriptyline in pharmaceutical formulation.

A simple differential pulse voltammetric method based on a composite biosensor graphite/SiO2/Al2O3/Nb2O5/DNA (GRT/SiAlNb/DNA) was developed and validated for the determination of amitriptyline (AMT). The best results were obtained by using differential pulse voltammetry under measurements at pH 7.5 buffered with 0.20 mol L−1 phosphate buffer and DNA immobilization onto SiAlNb surface using 0.6 mg mL−1 concentration. Validation parameters such as: selectivity, linearity, precision, accuracy, and stability presented results within the acceptable range. The sensitivity of sensor was found to be 0.216 μA μmol−1 L, linear range from 10 to 80 μmol L−1 and limit of detection of 0.12 μmol L−1. Therefore, the developed method was successfully applied for the AMT determination in real samples of pharmaceutical formulations and can be used for routine quality control analysis of bulk pharmaceutical and pharmaceutical formulations containing AMT.