Detectação de ferro em amostras de biodiesel por imagem digital

Abstract

In this work, a simple, low-cost microanalytical procedure was developed for the determination of biodiesel iron using reversed-phase dispersive liquid-liquid microextraction (RP-DLLME), and digital imaging detection. The following operational parameters of the (RP-DLLME) technique were optimized and optimized: nature of the dispersing solvent (propanol and n-propanol), nature and concentration (pH0 of the solvent as extracting solvent (HNO3 and HCL + HNO3) and the pH (1, 2 and 3, proportion/extractor of the disperser solvent solution (40/60%/50% and 70/30% (v/v)), volume of solvent/extractor/solution for 1 g of decompactor Image, (1, 0; 1.5 and 2.0 mL) and centrifugation time. Nato sample for colorimetric determination of iron (digital detection) was the concentration of the complexing reagent Thiocia-) in the Study between (0.6; 0.8 and 1, 0 mol L-1). For the digital image of the colored complex [FeSCN] a manifold was used, produced by 3D printing, 15 cm x 15 cm box, which contains a mini USB camera coupling for image capture, a white LED to maintain luminosity and control, a set of wells for colorimetric reaction that support volumes of up to 30 uL. Video processing obtained in digital images is was performed using the SisGAR program. After the optimization response of the operational parameters, the procedure presented as the following figures of merit: Linearity of total iron g-1 to 10 µg g-1, Limit of detection and quantification of biodiesel in 0.007 µg g-1 0.022 µg g- 1, respectively. The accuracy and precision of the procedure was performed by testing a biodiesel sample at two test levels in the RSD3 package and 10 recoveries between 98 to 107%, with around 6%.