Desenvolvimento e aplicação de metodologia analítica associado ao uso de μPAD para determinação colorimétrica de Cr(VI) e Hg (II)

Abstract

In the last years, paper-based microfluidic devices (μPADs), manufactured by applying hydrophilic materials on hydrophobic paper, have emerged as a promising platform for pointof-care diagnostics in developing countries, where the availability of resources is limited. These devices have attractive features such as low cost, ease of use, low consumption of reagents and sample, portability, and disposability. This paper describes alternative methods for manufacturing and using μPADs using low cost materials such as paraffin, PDMS (polydimethylsiloxane) and wax. The μPADs were evaluated in the colorimetric determination by the 1,5-diphenylcarbazide reacting with Cr(VI) and with Hg(II), respectively, in the range of 5 to 100 μmol / L concentration. In this study, the best results were obtained with assays made with hydrophobic barriers of PDMS in the μPADs, allowing for Cr(VI) LD equal to 0.01 μM and LQ equal to 0.03 μM. For Hg(II) LD of 0.004 μM and LQ of 0.015 μM. For this, analytical curves were constructed with concentrations ranging from 5 to 100 μM Cr (VI) and Hg (II), obtaining a better correlation coefficient (R) for Cr(VI) of 0.969 and for Hg(II) R = 0.900.