Determination of gasoline range,diesel range,and mineral oil range organics in soils and water by flame lonization gas chromatography

This article describes a method for the determination of gasoline range, diesel range, and mineral oil range organics in soils and water. It represents the culmination of a series of efforts to go beyond typical GRO and DRO methodology currently available in the literature to include a quantitative determination of mineral oil organics having a boiling range up to C₄₄. It also is the result of an attempt to develop a cost‐effective method that enables the analyst to quantify three different types of hydrocarbon components in one GC run under conditions without a concentration step. Method performance is comparable to that of current protocols for GRO and DRO determinations and validated further by comparisons to certified standards and in‐house standards. Accuracy as percentage recovery for GRO in water is 82 to 84 and 91 to 92% for soils. Accuracy as percentage recovery for MRO in water is 84 to 102 and 75 to 80% for soils. Accuracy as percentage recovery for DRO in water is 78 to 100 and 71 to 90% for soils. Results from the analysis of in‐house standards and certified standards for DRO and MRO gave higher recoveries than was demonstrated in the MDL studies. The MDL for DRO in water is 31 mg/l and 14 mg/kg for soils. The MDL for GRO in water is 8 mg/l and 4 mg/kg for soils. For MRO in water, the MDL is 7 mg/l and for soils 10 mg/kg. Future proposed improvements to this method will involve updated software that will allow automatic blank subtraction, automatic calculation of surrogate recoveries and the automatic incorporation of dry weight factors in the final calculations for soils. In addition, a GRO method with a run time of only 24 min will be used routinely when only GRO analyses have to be performed.