EN 15199-3-2020 pdf donwload.Petroleum products – Determination of boiling range distribution by gas chromatography method – Part 3:Crude oil.
B.1.2 Set up an array that contains slices obtained from the Reference Material 5010 chromatogram.
Calculate the average of the first five area slices. Subtract the average slice area from each slice in the
Reference Material 5010 chromatogram. Set negative numbers to zero.
B.1.3 Zero the blank baseline chromatogram by carrying out an analogous calculation as in B.1.2.
B.1.4 Subtract the blank baseline froni the Reference Material 5010 chromatogram. Subtract each zeroed blank baseline slice from the corresponding zeroed Reference Material 5010 slice. Ii there are negative slices, set the slice values to zero.
B.1.5 Determine the end of elution time of Reference Material 5010.
Since it Is a requirement that the sample chosen to obtain a response factor shall fully elute prior to the Final Elution time, FEE, the end of sample elution for this chromatogram should be determined as described in EN 15199-1 [11, using the algorithm to determine the time the signal of the completely eluted sample returns to baseline.
B.1.6 Determine the area of the chromatogram for Reference Material 5010. Determine the end time of solvent elution. Sum all of the slices from the end of solvent elution to the end of sample elution. This is the area of the standard, ASTD.
B.1.7 Calculate the boiling point distribution of Reference Material 5010. The resulting corrected slices obtained for Reference Material 5010 are submitted to a calculation for boiling point distribution as in EN 15199-1 [1J. A comparison of the values obtained with the consensus values listed in Table us made and all the boiling point values should fall within the specified windows. If this requirement is not met, correct any chromatographic problems prior to proceeding with sample analysis.
Typical problems found in this step are: contaminated solvent; problems in sample preparation; sample residue in the inlet or column, or both; quality of the baseline used, a partially blocked detector jet, or a combination thereof.
B.2 Zeroing of sample chromatograms
B.2.1 In the case of crude oil analysis or samples in which the solvent peak is not resolved from the sample components, ensure, by visual inspection of the chromatogram in the data system, that the first 5 slices contain neither sample nor solvent elution. If there is sample elution, decrease the number of slices for the averaging to 3.
B.2.2 Set the sample chromatograni to zero. Proceed in a manner analogous to that described in B.1.2.
B.2.3 Set the blank baseline chromatogram to zero. Carry out an analogous calculation as in 13.1.3.
B.3 Blank baseline subtraction from the sample chromatogram
Carry out an analogous calculation as in B.1.4.
B.4 Quenching correction
8.4.1 For crude oil samples, a quenching factor is used to correct for the diminished FID response when the CS2 co-elutes with sample components. This factor is applied to the time segment corresponding to the elution of CS2. In the interlaboratory study, the factor of 1.930 was applied. This value is determined from experiments made by dissolving butane, pentane, and hexane in toluene.
The solution is analysed by injecting it under conditions identical to sample analysis. The areas for the components are compared to the areas obtained by gradually adding weighed aliquots of CS2 to the original solution. Samples that do not have components that co-elute with solvent, for example, residues or the Reference Material 5010, do not require the quenching correction.
8.4.2 Determine the quenching Interval. Select the time that the solvent peak starts to elute. Determine when the solvent peak has eluted. Note the times of this interval in minutes.
B.4.3 Locate the slices of the quenching interval. For samples in which the solvent component co-elutes with the sample chromatogram (that is, crude oils), determine the quenching interval, QI, as described in 13.4.2. Find the closest slice corresponding to the beginning of elution of the solvent peak as well as the final slice corresponding to the end of elution of the solvent peak.
8.4.4 Correct the diminished response of the interval by multiplying each slice of this interval by the quenching factor, QF. Use the value as discussed in B.4.1.
B.5 Determination of the sample final elution time (FEe)
Determine the time at which the oven reaches the isothermal portion of the temperature program. This is usually recognized as an inflection point in the baseline. This point is called the final elution time (FEJ. The conversion of this slice to temperature will yield the final elution temperature, FET. This conversion is carried out in B.9.4.EN 15199-3-2020 pdf donwload.
EN 15199-3-2020 pdf donwload
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