Desenvolvimento de uma língua optoeletrônica utilizando dispositivos microfluídicos em papel para identificação de bebidas contaminadas com drogas de abuso

Abstract

Scopolamine (SCP) is a natural alkaloid extracted from Solanaceae family and is widely used for several applications, from clinical purposes to criminal activities. For instance, SCP is added to drinks with criminal intent, in a practice popularly known as “Good Night, Cinderella”, causing effects on the individual's central nervous system. Colorimetric tests are considered a very useful tool to identify suspicious substances on site and are based on rapid chemical reactions that result in visual color changes. Colorimetric tests are popular because of their inherent simplicity, low cost, and portability, however, in many cases, the results of such tests may not be conclusive, in part because of interference from similar chemical species. The purpose of this dissertation is the development of an optoelectronic tongue using a paper-based microfluidic device – so-called µOPTO - composed of six reagents instead of a single specific test, capable of discriminating scopolamine from similar alkaloids and different alcoholic beverages. The wax printing method was used to fabricate the device with six circulars spots for accommodation of reagents connected to a centralized spot to allow simultaneous reactions with a single sample injection. The color changes related to each reaction were used to build differential maps with a unique fingerprint for each analyte. Based on this information (RGB values), the chemometric tools PCA (Principal Component Analysis) and HCA (Hierarchical Cluster Analysis) were used to discriminate among the samples and beverages spiked with scopolamine. The results showed that small amounts of the drug (i.e. µg) were identified in different beverages, proving that our device has the potential to be used on site to prevent the ingestion of contaminated samples.