Contributions of Flow Analysis for Quality Control of Automotive Fuels: A Review

Abstract

Automotive fuels require strict quality control to assure best energy use with minimal environmental pollution. Fuels can be modified before consumption by inadequate transport, storage, and handling, as well as illegal adulteration. Continuous monitoring is of paramount importance to reduce such irregularities, thus requiring reliable analytical methods, which should be simple, fast, and minimize both reagent consumption and waste generation. The potential for in-situ monitoring is also highly desirable. Flow analysis plays an important role in this sense, by means of automated sample processing in closed systems, under highly reproducible conditions. In spite of this potential, application for routine fuel analysis is yet limited and wide dissemination is desirable. This review focuses on analytical approaches for in-line sample pretreatment and determination of organic and inorganic contaminants in automotive fuels by flow analysis. Applications in gasoline, diesel oil, biodiesel, and ethanol fuels are critically discussed.

Keywords:

• Biodiesel
• Biofuels
• Diesel
• Ethanol
• Flow analysis
• Fuels
• Gasoline

Acknowledgments

This article is part of a Special Issue on Automated Flow Injection Techniques organized by Dr. Paraskevas Tzanavaras of Aristotelian University of Thessaloniki, Greece.

The authors are grateful to Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), Fundação de Amparo à Pesquisa do Estado da Bahia (FAPESB) and Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP). This is a conjunct contribution of the National Institute of Energy and Environment (INCT-E&A) and the National Institute of Advanced Analytical Science and Technology (INCTAA).

Notes

SR: Sampling rate; CV: coefficient of variation; LOD: limit of detection; LR: linear response range; ^a SR without considering the sample preparation step; ^b analyte concentration in gasoline (g L⁻¹); ^c FIA system without dilution; ^d FIA system with on-line dilution; ^e SIA system; ^f analyte concentration in gasoline (mg kg⁻¹); ^g analyte concentration in gasoline (ppm, v/v); *analyte concentration in gasoline (%, v/v).

SR: Sampling rate; CV: coefficient of variation; LOD: limit of detection; LR: linear response range; ^a analyte concentration in ethanol (mg CH₃COOH/100 mL); ^b external calibration with aqueous solutions; ^c analyte concentration in ethanol (mol/L).

SR: Sampling rate; CV: coefficient of variation; LOD: limit of detection; LR: linear response range; ^a SR did not consider the sample preparation; ^b analyte concentration in biodiesel (mg/kg); ^c analyte concentrations in biodiesel (µg/kg); ^d analyte concentration in biodiesel (mg/L).