Patent ID: 11913878
Assignee: CRC CARE PTY LTD
Field: Measurement (Instruments)
Classification: CPC G | IPC G

Claim 0:
1. A method of determining petroleum hydrocarbon fractions (Cn) in a sample, the method including:
inputting the sample into a chamber;
emitting infrared light from an optical light source into the chamber with the sample;
detecting at a detector a detected infrared light from the chamber;
transforming the detected infrared light to a Fourier Transform Infrared (FTIR) spectrum of the sample at a processor, wherein the FTIR spectrum has wavenumbers between 4000 and 400 cm−1;
processing the FTIR spectrum to identify sub-bands each having at least one doublet of sub-band peaks at respective wavenumbers in a second derivative curve of the FTIR spectrum using a second derivation algorithm implemented by the processor;
comparing the at least one doublet of sub-band peaks to data indicative of known doublets of sub-band peaks at known wavenumbers for petroleum hydrocarbon fractions in the FTIR spectrum to classify the petroleum hydrocarbon fractions in the sample; and
determining a dominant petroleum hydrocarbon fraction of the petroleum hydrocarbon fractions in the sample based on a ratio of intensities of the sub-band peaks of the at least one doublet for each of the petroleum hydrocarbon fractions in the sample;
wherein the at least one doublet includes a first doublet of sub-band peaks at wavenumbers between 3000 and 2800 cm−1.