Download
1 / 29
290 likes | 458 Vues
Pete the penguin says…. “Before the show begins, don’t forget to visit the snack bar”. MDEQ DRO/ORO Analysis. 8015 – GC/FID. EPA 8015 and Wisconsin 8015. These methods define Diesel Range Organics, DRO, as anything eluting between C 10 and C 28 No other carbon ranges included.
E N D
Pete the penguin says… • “Before the show begins, don’t forget to visit the snack bar”
MDEQ DRO/ORO Analysis 8015 – GC/FID
EPA 8015 and Wisconsin 8015 • These methods define Diesel Range Organics, DRO, as anything eluting between C10 and C28 • No other carbon ranges included
Why change? • This chromatogram looks OK, doesn’t it?
2000 ppm 10W30 Oil “old” method • Much of this material is included in the C10-C28 range
Why change? • Maybe this chromatogram doesn’t look so good, a lot of oil is being defined as Diesel Range Organics.
Why change? (What are the current problems?) • There’s still space left on the run • The diesel is gone before C28 • The motor oil is half included in the diesel range
Why change? (What are some solutions?) • Define DRO as C10-C20 • Add Oil Range Organics as C20-C34
1000 ppm Diesel Fuel “new” method • Most of the diesel (>90%) is contained within the range
2000 ppm 10W30 Oil “new” method • Much of this material would be included in the C10-C28 range, but now has a place of its own
Why change? (What are some outcomes) • Better description of contaminant • There are no regulatory criteria, so its all about aesthetics
Technical DetailsOverview • This analysis has some specific differences from normal chromatographic analyses • Have an open mind • The quantitative results are going to be used for guidance, not necessarily for regulatory compliance
Technical DetailsIntegration/Calibration • Baseline is drawn horizontally • All material under the signal is included • Do not integrate valley to valley • 8015 allows for baseline subtraction to account for column bleed but… • Calibration by linear regression accounts for bleed without need for subtraction
Technical DetailsSurrogate: n-Eicosane (C20) • Why C20? • C20 is the dividing point between the two analyte fractions • C20 is in a good range to determine accurate extraction recovery • Easier to use area summing feature on software (pragmatic, not lazy)
Technical Details Surrogate Recovery • Surrogate recoveries for high concentration samples, or samples containing unknown or degraded hydrocarbons should be considered estimated.
Technical Details Surrogate Recovery • A known amount of surrogate, n-eicosane, is added by the laboratory before extraction. N-Eicosane is also present in many petroleum products. If the product is a known material, the presence and quantity of n-eicosane can be accounted for. Our method includes calculations to make corrections for surrogate recovery based on concentrations of diesel fuel and motor oil in samples. In samples containing unknown or degraded materials the concentration on n-eicosane cannot be accounted for, therefore the calculation of surrogate recovery is and estimate.
Technical Details Surrogate Recovery • A known amount of surrogate, n-eicosane, is added by the laboratory before extraction.
Technical Details Surrogate Recovery • N-Eicosane is also present in many petroleum products. • If the product is a known material, the presence and quantity of n-eicosane can be accounted for. • Diesel fuel in our method has a 1.0% contribution from C20. • 10W30 Motor Oil has a 0.22% contribution from C20. • Our method has calculations to make corrections for surrogate recovery based on concentrations of diesel fuel and motor oil in samples.
Technical Details Surrogate Recovery • In samples containing unknown or degraded materials the concentration on n-eicosane cannot be accounted for, therefore the calculation of surrogate recovery is and estimate.
Technical Details Surrogate Recovery • A known amount of surrogate, n-eicosane, is added by the laboratory before extraction. N-Eicosane is also present in many petroleum products. If the product is a known material, the presence and quantity of n-eicosane can be accounted for. Our method includes calculations to make corrections for surrogate recovery based on concentrations of diesel fuel and motor oil in samples. In samples containing unknown or degraded materials the concentration on n-eicosane cannot be accounted for, therefore the calculation of surrogate recovery is and estimate.
If the surrogate recovery is so estimated, why bother to use it? Surrogate works OK if sample contains diesel or 10W30 and even better as the analyte levels decrease. If you have no analyte, the surrogate will give you a good measure of extraction recovery. Technical Details Surrogate Recovery
Why can’t we use GC/MS? You can! Just make sure to scan to a high enough mass to get signal from all the high molecular weight compounds. Technical Details FID vs MSD
Technical Details Disclaimer • This method defines only the carbon range of analytes. For example, a positive result for DRO does not indicate diesel fuel, only the presence of hydrocarbons in a boiling point range similar to, or encompassed by, diesel fuel.
