Voltammetric determination of sulfur in biodiesel microemulsion using a silver solid amalgam electrode

Author(s)

Modenes Junior, Marco Antonio ; Beluomini, Maisa Azevedo ; Stradiotto, Nelson Ramos

• Document type: Journal article
• Source: ANALYTICAL METHODS; v. 14, n. 36, p. 9-pg., 2022-08-19.

Abstract

Monitoring sulfur in biodiesel is of fundamental importance because even in low concentrations, it can harm the operation of the engine parts and increase the emission of toxic gases and particulate material. Hence, a simple, quick and sensitive adsorptive stripping voltammetry (AdSV) method based on a silver solid amalgam electrode (AgSAE) was developed to determine sulfur in biodiesel. The novel electrochemical method was evaluated through the linear sweep adsorptive stripping voltammetry (LSAdSV), square wave adsorptive stripping voltammetry (SWAdSV) and differential pulse adsorptive stripping voltammetry (DPAdSV) in a NH3/NH4+ buffer solution (pH 9.0), containing Na2SO3. The method was applied in biodiesel microemulsion samples under optimal conditions. To this end, a ternary phase diagram was constructed, employing three components: biodiesel/propan-1-ol/buffer solution. The microemulsion with the best response was found to be 25% NH3/NH4+ buffer (pH 9.0), 5.0% biodiesel and 70% propan-1-ol. The method reached a detection limit in the order of 10(-7) mol L-1 of sulfur, and recovery values between 80% and 116%. The method was applied in the determination of sulfur in biodiesel, and the amount in the samples was found to be below the value stipulated by the regulatory agencies. The method can be a promising alternative for determining sulfur in the microemulsion of biodiesel, with the ability to provide a fast response regarding the quality of this biofuel. (AU)

• FAPESP's process: 17/22401-8 - Fruit-refinery: obtention processes, characterization methods and generation of products derived from residues of the fruitculture
• Grantee: Nelson Ramos Stradiotto
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 11/05633-6 - Development of a solid amalgam sensor for the determination of sulfur in biodiesel microemulsions
• Grantee: Marco Antonio Modenes Junior
• Support Opportunities: Scholarships in Brazil - Master
• FAPESP's process: 14/50945-4 - INCT 2014: National Institute for Alternative Technologies of Detection, Toxicological Evaluation and Removal of Micropollutants and Radioactivies
• Grantee: Maria Valnice Boldrin
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 18/12131-6 - Wireless electrochemical sensors based screen-printed electrodes modified with metallic nanopores for determination of flavonoids in wastes of the citrus industry
• Grantee: Maísa Azevedo Beluomini
• Support Opportunities: Scholarships in Brazil - Post-Doctoral