The TOG/TPH oil analyzer is based on the extraction procedures of EPA 413.2 and 418.1 methods, using vinyl chloride and n-hexane or other infrared transmission solvents to determine the concentration of oil/fat. The extract is deposited in a 10mm quartz test tube, retaining the light volatile components for determination.

The TOG/TPH oil analyzer is an infrared spectroscopic method for rapidly determining the concentrations of total oil (TOG) and total petroleum hydrocarbons (TPH) in water and soil samples. Its working principle follows the Lambert Beer law. Illuminate the sample with a beam of characteristic infrared light with an intensity of I0. Due to the absorption of characteristic infrared light by oil, the transmitted light intensity decreases to I. The absorbance of the sample to characteristic infrared light is A=lg I0/I. According to the Lambert Beer law of light absorption, the relationship between absorbance and oil concentration (C) in the sample is A=aBC, where a is the absorbance coefficient and b is the thickness of the sample cell, indicating that the absorbance of the sample is directly proportional to the oil concentration. By preparing a calibration system with known oil concentration, the relationship between absorbance and oil concentration can be obtained. Based on this relationship and the absorbance of the tested sample, the oil concentration in the tested sample can be determined.