Quantitative Analysis of Total Petroleum Hydrocarbons in Soils: Comparison between Reflectance Spectroscopy and Solvent Extraction by 3 Certified Laboratories

Table 5

Accuracy of TPH determination by reflectance spectroscopy and three commercial laboratories.

Lab	Spectroscopy				A				B				C
TPH level (calculated)	AVG; delta	AVG deviation	Max; delta	Max deviation	AVG; delta	AVG deviation	Max; delta	Max deviation	AVG; delta	AVG deviation	Max; delta	Max deviation	AVG; delta	AVG deviation	Max delta	Max deviation
Low (400–600)	325	68%	747	143%	349	68%	500	93%	192	42%	356	84%	283	57%	508	97%
Medium (2500–6000)	2055	47%	4360	74%	1956	51%	2795	92%	1010	30%	2532	78%	2590	60%	4781	97%
High; (9000–12000)	6187	61%	11494	83%	4392	49%	6150	81%	1827	26%	4210	73%	4413	50%	5859	95%