Electrochemical Determination of Chlorogenic Acid in Nutraceuticals Using Voltammetric Sensors Based on Screen-Printed Carbon Electrode Modified with Graphene and Gold Nanoparticles

Abstract

The present study describes the electrochemical properties of three screen-printed electrodes (SPEs), the first electrode being carbon-based (C), the second graphene-based (GPH), and the third based on GPH modified with gold nanoparticles (GNP). These electrodes were used for the study of the electrochemical behavior of chlorogenic acid in different aqueous solutions, at pH = 7. In chlorogenic acid solution, a redox process was noticed in the case of all three electrodes; GPH and GNP significantly improved the sensor response regarding sensitivity and reversibility, a fact demonstrated by characterizing the sensor by cyclic voltammetry in potassium ferrocyanide, which corresponds to the exchange of two electrons and two protons. Moreover, the calibration curves for each sensor were developed, subsequently calculating the detection limits (LOD) and the quantification limits (LOQ). Low LOD and LOQ were obtained, the best—of the order of 10−7 M (LOD = 0.62 × 10−7 M; LOQ = 1.97 × 10−7 M)—being obtained in the case of GPH-GNP-SPE, which demonstrates that the method may be applied for determining chlorogenic acid in real samples. Thus, the sensors were successfully used for the quantitative determination of chlorogenic acid in three nutraceutical products. The validation of the results was done using the FTIR method. The results obtained by cyclic voltammetry were in accordance with those obtained by the spectrometric method, without significant differences from a statistical point of view.

A Review on Electrochemical Sensors and Biosensors Used in Chlorogenic Acid Electroanalysis

“…Two methods were used: CV for determination and FTIR (spectrometric method) for validation of the voltammetric method’s accuracy. The results obtained were very close to those obtained through the standard analysis method, and the confidence level was 99% [ 58 ].…”

“…During reverse scanning, the quinone formed is reduced to CGA. This oxidation mechanism is presented in Figure 4 [ 58 ].…”

“… CVs of: ( a ) C-SPEs, ( b ) GPH-SPE and ( c ) GPH-GNP-SPE immersed in 10 −3 M CGA solution (support electrolyte 10 −1 M PBS solution). Scan rate 0.1 V·s −1 [ 58 ]. …”

Gold Nanomaterials-Based Electrochemical Sensors and Biosensors for Phenolic Antioxidants Detection: Recent Advances

“…Several examples introduced screen-printed carbon electrodes, modified with different gold nanomaterials [ 75 , 84 , 85 , 88 , 89 , 93 , 109 , 114 , 115 , 147 , 148 , 161 , 172 , 173 , 186 ].…”

“…Concerning CGA detection, Apetrei et al compared the performances of different commercial SPCEs such as bare SPCEs, SPCEs modified with graphene, and finally, SPCEs modified with a graphene/AuNPs nanocomposite [ 109 ].…”