A Single Platinum Microelectrode for Identifying Soft Drink Samples

Abstract

Cyclic voltammograms recorded with a single platinum microelectrode were used along with a non-supervised pattern recognition, namely, Principal Component Analysis, to conduct a qualitative analysis of sixteen different brands of carbonated soft drinks (Kuat, Soda Antarctica, H2OH!, Sprite 2.0, Guarana Antarctica, Guarana Antarctica Zero, Coca-Cola, Coca-Cola Zero, Coca-Cola Plus, Pepsi, Pepsi Light, Pepsi Twist, Pepsi Twist Light, Pepsi Twist 3, Schin Cola, and Classic Dillar’s). In this analysis, soft drink samples were not subjected to pre-treatment. Good differentiation among all the analysed soft drinks was achieved using the voltammetric data. An analysis of the loading plots shows that the potentials of −0.65 V, −0.4 V, 0.4 V, and 0.750 V facilitated the discrimination process. The electrochemical processes related to this potential are the reduction of hydrogen ions and inhibition of the platinum oxidation by the caffeine adsorption on the electrode surface. Additionally, the single platinum microelectrode was useful for the quality control of the soft drink samples, as it helped to identify the time at which the beverage was opened.

MIP-based electrochemical protein profiling

“…Three-dimensional PCA scores of the binding data described by Takeuchi et al revealed that a clear protein distinction was possible and that protein-imprinted polymer arrays can be applied to protein profiling by pattern analysis of binding activity for each polymer [19][20][21]. PCA has also been used in conjunction with electrochemical methods such as cyclic voltammetry [16,17,[22][23][24][25]. An attractive approach for the development of biochemical sensors would be the integration of smart materials (e.g., MIPs) with said electrochemical techniques This paper demonstrates the use of pattern recognition techniques to uniquely identify fingerprint profiles for four different proteins by coupling electrochemical sensor strategies with hydrogel-based MIPs.…”

Voltammetric Electronic Tongue for Discrimination of Milk Adulterated with Urea, Formaldehyde and Melamine

“…As an alternative approach, electrochemical techniques are relatively easy to operate, allow the use of low-cost materials for the fabrication of sensors, and enable quantification and discrimination between samples in a short time, without the necessity to circumvent the problems reported for optical and colorimetric techniques. The use of electrochemical sensors has been previously reported for food and beverage analysis [30][31][32][33]. We now demonstrate the fabrication of an array of electrochemical sensors that, with the aid of chemometric tools (electronic tongue) [34], are able to distinguish between unadulterated milk samples and those containing urea, formaldehyde or melamine contaminants.…”