This article introduces a fast GC-FID method for the analysis of mineral oil in environmental samples using a low thermal mass system. The fast oven temperature programming achieved by the low thermal mass system dramatically reduced the analysis cycle time and increased the sensitivity. The regulated method requirements are met for the environmental analysis of the C10-C40 hydrocarbon fraction in soil and water extracts using splitless injection with an analysis time less than three minutes. Cool-down time is less than two minutes, resulting in an injection-injection cycle time of five minutes. Method performance criteria, including repeatability, linearity and solute discrimination, are presented.
This document details a method for analyzing hydrocarbon oil index (HOI) in environmental samples using Gas Chromatography with Flame Ionization Detection (GC-FID). The method utilizes an Agilent 7890A GC system equipped with a Low Thermal Mass (LTM) oven module to significantly reduce analysis time compared to standard procedures.
| Analysis time (LTM) | less than three minutes |
|---|---|
| Cool-down time | less than two minutes |
| Injection-injection cycle time | five minutes |
| Column dimensions | 10 m x 0.32 mm, 0.1 pm |
| Linearity (r²) | > 0.999 |
| Limit of Detection (LOD) | < 25 mg/L |
The total injection-injection cycle time is five minutes.
The analysis is performed on an Agilent 7890A GC System equipped with an LTM column module.
The ratio of the peak areas of the C40-C20 fraction versus the C19-C49 fraction should be between 1.25 and 1.40.