Determination of Vanadium Levels in Seafood Using Dispersive Liquid-Liquid Microextraction and Optical Sensors
2015
Santos, Analu Pires | Lemos, Valfredo Azevedo
In this study, we developed a new method for the preconcentration and spectrophotometric determination of vanadium (V) using dispersive liquid-liquid microextraction (DLLME) and optical sensors using 4-(5-bromo-2-pyridylazo)-5-(diethylamino)-phenol (Br-PADAP) as a complexing reagent. The preconcentration is based on the extraction of vanadium ions (V) in trichloroethylene in the form of a complex with Br-PADAP, using ethanol as a dispersion solvent. After injecting the solvent into a solution containing vanadium, a homogeneous mixture is obtained. The mixture is centrifuged to deposit the desired phase onto a triacetylcellulose membrane. Then, the supernatant is discarded, and the membrane is exposed to the radiation beam of a spectrophotometer without the use of a microcuvette. Under optimal conditions, the detection limit was determined to be 0.57 μg L⁻¹, and the quantification limit was 1.91 μg L⁻¹. The accuracy of the method was verified by analyzing a certified reference material, BCR®414, plankton. The procedure was applied to the determination of vanadium levels in shellfish samples, specifically shrimp and oyster.
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