Patent ID: 8759775

Claim:
A method for the selective detection of total petroleum hydrocarbon (TPH) in an environmental sample containing natural organic matter (NOM) by diffuse reflectance spectroscopy, the method comprising the steps of: (i) providing TPH concentration regression models that have been obtained by performing multivariate regression analysis on data obtained by correlating the TPH concentration of one or more reference samples comprising known amounts of TPH with absorbance values of infrared (IR) signal(s) representative of TPH in the sample(s) centered on a signal at 1380 cm −1 , 2690 cm −1 , 2730 cm −1 , 2830 cm −1 , 2870 cm −1 , 4164 cm −1 , 4256 cm −1 , 4329 cm −1 and/or 4388 cm −1 ; (ii) subjecting the environmental sample to IR radiation, and detecting an IR signal centered on a signal at 1380 cm −1 , 2690 cm −1 , 2730 cm −1 , 2830 cm −1 , 2870 cm −1 , 4164 cm −1 , 4256 cm −1 , 4329 cm −1 and/or 4388 cm −1 to provide predictive TPH data; (iii) analyzing the predictive TPH data using the TPH concentration regression models; and (iv) providing an output TPH concentration of the environmental sample based on the analysis performed at step (iii), wherein said output TPH concentration is substantially independent of the presence of NOM in the environmental sample.