A Green Analytical Methodology for Detecting Adulteration in Automotive Urea-SCR Products Using Microfluidic-Paper Analytical Devices

Danielle da Silva Souza, Gabriel Martins Fernandes, Barbara Cristina Dias, José Roberto Stefanelli Junior, Rodrigo Sequinel and João Flávio da Silveira Petruci
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Danielle da Silva Souza: Institute of Chemistry, Federal University of Uberlândia (UFU), Av. João Naves de Ávila 2121, Uberlândia 38408-902, MG, Brazil
Gabriel Martins Fernandes: Institute of Chemistry, Federal University of Uberlândia (UFU), Av. João Naves de Ávila 2121, Uberlândia 38408-902, MG, Brazil
Barbara Cristina Dias: Institute of Chemistry, Federal University of Uberlândia (UFU), Av. João Naves de Ávila 2121, Uberlândia 38408-902, MG, Brazil
José Roberto Stefanelli Junior: Perícia Oficial e Identificação Técnica (POLITEC), Pontes e Lacerda 78250-000, MT, Brazil
Rodrigo Sequinel: Department of Exact Sciences and Engineering, Federal University of Paraná (UFPR), Palotina 85950-000, PR, Brazil
João Flávio da Silveira Petruci: Institute of Chemistry, Federal University of Uberlândia (UFU), Av. João Naves de Ávila 2121, Uberlândia 38408-902, MG, Brazil

Sustainability, 2022, vol. 14, issue 6, 1-8

Abstract: The application of urea-based selective catalytic reduction products (i.e., Urea-SCR) provides a reduction of NO x and, therefore, minimizes pollution emissions from vehicles fueled by diesel. Such products can be easily found in the market; however, they are often susceptible to adulteration, mainly in terms of the urea content and dilution with non-mineralized water. In this study, we propose a simple, low-cost, disposable, and straightforward paper-based microfluidic device for the quality-control of Urea-SCR products for the first time by quantifying urea and water hardness simultaneously via colorimetric reactions using a small volume of sample. 4-(dimethylamino)benzaldehyde and Eriochrome T were used as colorimetric indicators for urea and water hardness determination, respectively. Each reagent (1.5 µL) was combined with 6 µL of sample for analysis, contributing to an expressive reduction of waste generation. Digital images of the µPAD were obtained, and linear relations between color intensity and urea and Ca 2+ and Mg 2+ concentrations in the range of 0.2 to 1.0% and 0.1 to 3.5 mmol L −1 were obtained with a correlation coefficient higher than 0.99. Recovery experiments were employed to evaluate the accuracy of the methodology, revealing suitable values between 91.5 and 115%. Brazilian Urea-SCR samples were acquired from different distributors and submitted to the proposed procedure to evaluate its applicability. The application of microfluidic paper-based devices with colorimetric reactions enables the quality control of Urea-SCR products with high accuracy, portability, low consumption of reagents, and no generation of toxic residues; thereby contributing to the green analytical chemistry field.

Keywords: paper-based microfluidic device; Urea-SCR; green analytical methods; colorimetry; digital image treatment (search for similar items in EconPapers)
JEL-codes: O13 Q Q0 Q2 Q3 Q5 Q56 (search for similar items in EconPapers)
Date: 2022
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