A method of detecting one or more markers in a petroleum fuel using a photoacoustic detector

A system, comprising:

• a chamber having a marked petroleum fuel comprising a fuel additive, a mixture of a fluid petroleum fuel and a marker, wherein the marker is selected from the group consisting of organic IR absorbing compounds and mixtures thereof;
• a modulated light source for emitting a modulated light beam to the marked petroleum fuel to generate an acoustic signal due to the presence of the marker;
• a sensor disposed proximate the chamber, for detecting the acoustic signal;
• and
• a processor based module communicatively coupled to the sensor and configured to receive the acoustic signal from the sensor and determine the marker and a concentration of the marker in the marked petroleum fuel based on the acoustic signal.

A method of detecting a counterfeit or adulterated petroleum fuel, comprising:

• a) emitting a modulated light beam from a modulated light source to a marked petroleum fuel in a chamber, wherein the marked petroleum fuel comprising a fuel additive, a mixture of a fluid petroleum fuel and a marker, wherein the marker is selected from the group consisting of organic IR absorbing compounds and mixtures thereof;
• b) producing an acoustic signal from the marker in the chamber, in response to the emitted modulated light beam;
• c) detecting the acoustic signal via a sensor disposed in the chamber;
• d) transmitting the acoustic signal from the sensor to a processor based module;
• and
• determining the marker and a concentration of the marker in the marked petroleum fuel via the processor based module, from the acoustic signal.