Document ID: chunk:federal_register_of_legislation:F2013C00288:reg:13:p5
Version: federal_register_of_legislation:F2013C00288
Segment Type: reg
Provision Reference: reg 13 (pt 5/9)
Character Range: 861421–864344

regression of >0.99
    * At a minimum, run a daily check of the lowest calibration standard and the midpoint calibration standard to confirm stability of the calibration curve. Rerun the calibration curve if the low standard deviates by more than 30% from the curve or if the midpoint calibration standard deviates by more than 20% from the curve.
    * A CVS is run to check the validity of the calibration curve against a characterised hydrocarbon product.

13.2.6.2     Measurement of test sample
After calibration, carry out the determination on the test samples (field or laboratory methanol extracts). Where the analyst has some prior knowledge regarding the relative concentration of analytes in the samples, the run should be arranged in order of increasing concentration. In the absence of such information and if samples with high concentration of analytes occur in the middle of a run, the analyst should examine the analytical run for possible carry-over, and re-analyse affected samples, if required.

    13.2.7     Calculations

13.2.7.1     Integration of peaks
All peaks in a chromatogram should be integrated and included in the calculation of results. The total area contributed by the surrogate and internal standards should be excluded from the calculation of the final result.

13.2.7.2     Calculation of vTRH (C6 – C10) content

Integrate the appropriate chromatogram.

The C6C10 fraction is integrated from the peak start of the nC6 peak to the time corresponding to the end of the nC10 peak.

The vTRH content is calculated according to the following formula:

C = Area of C in sample x  ISTD   x conc. of standard  x VF x  ME x  100

ISAM    Area of standard    MA W (100  % moisture)

where:

C            =   vTRH in soil (mg/kg)
VF           =   Volume of watermethanol extract as analysed by purge and trap (L)
MA           =   Volume of methanol extract transferred into reagent water (L)
ME           =   Volume of methanol added to soil/sediment (L)
W            =   Weight of soil/sediment analysed (kg)
ISTD         =   Peak area or height produced by internal standard in calibration chromatogram
ISAM         =   Peak area or height produced by internal standard in sample chromatogram
% Moisture   =   Moisture content of original soil/sediment expressed as % w/w

The method blank should contain no detectable levels of analytes of interest and results of the method blank should not be subtracted from sample results.

13.3          Method A2: Determination of semi-volatile TRH: TRH >C10 – C40

    13.3.1     Scope and application
The method is applicable to the determination of hydrocarbons eluting between >nC10 and nC40 alkanes. The method extracts target component hydrocarbons such as PAHs. If the presence of PAHs is suspected, target analysis techniques are preferred for risk assessments. Volatile hydrocarbons with lower boiling points than nC10 or heavy petroleum