Novel Method for the Fast Determination of Ultra Trace Amount of Nortriptyline in its Pharmaceutical Formulations by Fast Fourier Transform Continuous Cyclic Voltammetric Technique at Au Microelectrode in Flowing Solutions

In this work a novel method for the determination of nortriptyline in flow-injection systems has been developed. The proposed method was used for the fast determination of nortriptyline in its pharmaceutical formulations. The developed technique is very simple, precise, accurate, time saving, and economical, compared to all of the previously reported methods. The effects of various parameters on the sensitivity of the method were investigated. The best performance obtained at pH value of 2, scan rate value of 30 V/s, accumulation potential of 400 mV, and accumulation time of 0.5 s. The proposed method has some advantages over other reported methods such as, no need for the removal of oxygen from the test solution, a subnanomolar detection limit, and finally the method is sufficiently fast for the determination of any such compound, in a wide variety of chromatographic methods. The potential waveform, consisting of the potential steps for cleaning, accumulation and potential ramp of analyte, was continuously applied on an Au disk microelectrode (12.5 µm in radius). The detection limit of the method was 2.0 × 10−11 M. The relative standard deviation of the method at 1.2 × 10−8 M was 2.1% for eight runs.