EN 15199-1-2020 pdf download.Petroleum products – Determination of boiling range distribution by gas chromatography method – Part 1:Middle distillates and lubricating base oils.
3.8
recovery
ratio of the cumulative area count of the sample to that of the reference material (external standard) corrected for dilution and material weights combined with the percentage of light ends, if applicable
4 Principle
A test portion is introduced into a gas chromatographic column, which separates hydrocarbons in the order of increasing boiling point. The column temperature is raised at a linear reproducible rate and the area under the chromatogram is recorded throughout the analysis. Boiling points are assigned to the time-axis from a calibration curve obtained by running a mixture of known n-alkanes, covering the sample boiling range, under the same conditions. From these data, the boiling range distribution is obtained.
Several SIMDIS methods are standardized test methods and each one is dedicated to a certain boiling point range or product.
EN ISO 3924 [1] is limited to products having an initial boiling point greater than 55 °C, a final boiling point lower than 538 °C and having a vapour pressure sufficiently low to permit sampling at ambient temperature.
EN 15199-2 is applicable to materials with initial boiling points (IBP) above 100°C and final boiling points (FBP) above 750 °C, for example, heavy distillate fuels and residuals. The method is not applicable to bituminous samples.
EN 15 199-3 is applicable to crude oils. The boiling range distribution and recovery (3.8) up to C100 or Co can be determined.
5 Reagents and materials
Unless otherwise stated, only chemicals of recognized analytical quality shall be used.
5.1 Carrier gas, helium, of at least 99,999 % (V/V) purity. Any oxygen present is removed by a chemical resin filter.
WARNING — Follow the safety instructions from the filter supplier.
5.2 Hydrogen, grade suitable for flame ionization detectors.
5.3 Compressed air, suitable for flame ionization detectors.
5.4 Alkanes, n-alkanes of at least 98 % (rn/rn) purity from C5 to C10, C12, C14, C16, C18, C20, C24 and C28.
Cyclohexane (C6H12)—(>99 % pure) can be used in place of CS2 for the preparation of the calibration mixture. However, the precision of this method Is based on calibration mixtures, reference material and samples prepared with CS2 only.
5.7 Calibration mixture
Dissolve 0,1 g of Polywax (5.5) in 7 ml CS2 (5.6), warming gently if necessary. Prepare an equal volume mixture of alkanes (5.4) and add 10 p1 to the Polywax solution.
NOTE 1 Commercially available alkane standards are suitable for column performance checks.
NOTE 2 The calibration mix is used to determine the column resolution, skewness of the C20 peak. and retention Lime versus boiling point calibration curve.
5.8 Reference materials
5.8.1 A reference material has two functions:
— External Standard: to determine the recovery of samples by comparing the total sample area (3.6) of the reference material with the total sample area (3.5) of the unknown sample;
— Boiling Point Distribution Standard: to check the proper functioning of the system by comparing the results with a known boiling point distribution on a routine basis. A typical example is given in
(5.8.2).
5.8.2 Reference Material 5010, a reference sample that has been analysed by laboratories participating in the test method cooperative study. Consensus values for the boiling range distribution of this sample are given in Table 1.
5.8.3 Binary gravimetric blend, a binary distillate mixture with boiling points ranges that gives a baseline at the start, a baseline between the two peaks and an end time that is as close to the end of the chromatogram as possible (see Figure 2 and B.3). This mixture is used to check the relative response of the two distillates and to check the baselines at the start, middle and end of the chromatogram.
6 Apparatus
6.1 Gas chromatograph, with the following performance characteristics.
6.1.1 Flame ionization detector, connected to the column to avoid any cold spots. The detector shall be capable of operating at a temperature at least equivalent to the maximum column temperature employed in the method.
6.1.2 Column temperature programmer, capable of linear programmed temperature operation over a range of 10°C above ambient to 450 °C.
6.1.3 Sample inlet system, consisting of a programmable temperature vaporizer (PTV) or cold on- column (COC) injection port. The maximum temperature of the injection device shall be equal to, or higher than, the final oven temperature. The minimum temperature shall be low enough to prevent sample or solvent flashback, but high enough to allow sample focusing at the front of the column. Table 2 contains the typical operating conditions.
6.2 Column
6.2.1 The capillary column should sit just below the flame tip and it is recommended that the orifice of
the jet should be 0,6 mm minimum to prevent frequent blocking with silicones.
6.2.2 Use a metal column, 0.53 pm internal diameter coated with methyl silicone. Commercially available columns with film thickness (df) = 0,09 pm (for analysis up to C120) and (df) = 0,17 pm (for analysis up to C100) have been found to be satisfactory.
It is recommended that the column resolution, R, is at least 2 and not more than 4 (see B.2).
6.2.3 Use some form of column bleed compensation to obtain a stable baseline. This can be carried out by subtraction of a column bleed profile previously obtained using exactly the same conditions as used for the sample analysis, by injecting the same volume, using solvent for the blank run and sample dilution from one batch taken at the same time, to avoid differences due to contamination.EN 15199-1-2020 pdf download.