Screen-Printed Electrode Modified With Silver Hexacy Anoferrate-Nafion® for Ascorbic Acid Determination

Abstract

A flow injection system using a new and/or re-used graphite screen-printed electrode modified with silver hexacyanoferrate and a Nafion ® polymer layer (AgHCF/GSPE) was employed for the determination of ascorbic acid in orange juice and drugs samples. Both modified electrodes showed an initial sensitivity of 0.015 A.cm . The response of the electrodes was stable, with no variation of base line after 6-8 hours of continuous operation. With this system it is possible to measure 65-70 samples (20µL) per hour. By using 1.06 mg of AgNO 3 , 4.12 mg of K 3 Fe(CN) 6 , 50.5 mg of KNO 3 and 800µL of HNO 3 , it is possible to obtain between 25 and 30 modified electrodes. The proposed system showed to be inexpensive, versatile, robust and suitable for industrial application. The surface morphology of the bare and/or modified graphite screen-printed electrode was characterized by scanning electron microscopy.

Simultaneous Electrochemical Detection of Dopamine, Ascorbic Acid and Uric Acid Using Copper-Phthalocyanine Functionalized MWCNTS

“…As a result, the accuracy of its determination is remarkably low in real samples 10 . However, DA, AA and UA are of great biomedical interest and play an important role in human metabolism 11,12 , so it is impossible to avoid their presence in real samples. The basal DA concentration is very low (0.01-1 µM), while the concentration of AA and UA is generally much higher than that of DA (from 100 to 1000 times higher), thus, it is extremely important to develop sensitive and selective methods for the determination of DA in routine analysis [13][14][15] without the problem of interferents.…”