Current regulations on exhaust automotive emissions focus on
certain pollutants to control vehicle emissions. Hydrocarbons, the
main components of gasoline, are one of these regulated compounds;
however, the regulation only refers to the sum of total
hydrocarbons (THC) without taking into account the individual
components.
Vehicles also emit a large variety of chemical besides
hydrocarbons that can become much more harmful, depending on their
environmental toxicity and the amounts that are emitted to the
atmosphere. In recent years, due to the emergence of alternative
fuels such as bioethanol and biodiesel, the interest in these not
so well characterized compounds has grown. For example, when
ethanol is used in gasoline blends as a fuel for
internal-combustion engine vehicles, the study of other compounds
such as alcohols, aldehydes and ketones, in addition to
hydrocarbons, acquires more importance.
Based on SOP 101, 102-103 and 104 by California Air Resources
Board (CARB), three chromatographic methods for the analysis of
methanol and ethanol (HRGC-FID), aldehydes and ketones (HLPC-UV),
and individual hydrocarbons (C₂-C₁₂) (thermal adsorption/desorption
system-HRGC/FID-FID) have been developed. All three methods have
been optimized, validated and implemented in automotive exhaust
samples analysis. This has allowed us to determine regulated as
well as non-regulated compounds from emissions among different
ethanol-gasoline fuels (E0, E5-S, E10 and E85), applied to Euro 4
and Flexifuel vehicles.