BS EN 15199-1-2006 pdf download.Petroleum products Determination of boiling range distribution by gas chromatography method Part 1: Middle distillates and lubricating base oils.
3.10
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 normal alkanes, covering the sample boiling range. under the same conditions. From these data, the boiling range distribution is obtained.
5 Reagents and materials
Unless otherwise stated, only chemicals of recognized analytical quality shall be used.
5.1 Liquid stationary phase, a methyl silicone stationary phase for the column.
5.2 Carrier gases. helium, nitrogen or hydrogen, 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.
5.3 Hydrogen, grade suitable for flame ionisation detectors
5.4 Compressed air, regulated for flame ionisation detectors.
5.5 Alkanes, normal alkanes of at least 98 % (rn/rn) purity from C5 to C10, C12, C14, C16, C18, C. C24 and
C28 to be used with Polywax (5.6).
NOTE The calibrabon mixture from ISO 3924 [3J is also suitab’e.
5.6 Polywax 655 or 1000
5.7 Carbon disulfide, purity 99,7 % (V/V) minimum.
WARNING — Extremely flammable and toxIc by inhalation.
NOTE To confirm the suitability of the carbon disulfide as a solvent, it is recommended to check elution profiles (see Figure 2).
5.8 Calibration mixture
The mixture shall contain at least one normal alkane with a boiling point lower than the IBP of the sample, and at least one normal alkane with a boiling pornt higher than the FBP of the sample.
Dissolve 0,1 g of Polywax (5.6) in 7 ml carbon disulfide (5.7), warming gently if necessary. Prepare an equal volume mixture of alkanes (5.5) and add 10 p1 to the Polywax solution.
NOTE I Commercially available alkane standards are suitable for column performance checks.
NOTE 2 The calib-ation mix is used to determine the column resolubon, skewness of the C peak, and retention time versus boiling point calibration curve.
5.9 Reference materials (RM)
5.9.1 A reference material has two functions:
External Standard: to determine the recovery of samples by comparing the total sample area (3.8) of the reference material with the total sample area 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 (5.9.2).
5.9.2 Reference Material 5010, a reference sample that has been analyzed by laboratories participating in the test method cooperative study. Consensus values for the boiling range distribution of this sample are given in Table 1.
5.9.3 Cyclohexane. (C6H12)—(99+ % pure) may be used in place of CS2 for the preparation of the calibration mixture.
5.9.4 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 3 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 lonisatlon detector, connected to the column so as 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.
NOTE The capllary 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.
6.1.2 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
Use a metal column with 0,53 mm internal diameter and coated with methyl silicone (5.1). Commercially available columns with film thickness (d1) = 0,09 pm (for analysis up to C1) and (Jr) = 0,17 pm (for analysis up to C1) have been found to be satisfactory.
NOTE I It is recommended that the column resdubon, R, es at least 2 and not more than 4 (see B.2). Use some form of column bleed compensation to obtain a stable baseline.
NOTE 2 This may 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.BS EN 15199-1-2006 pdf download.
BS EN 15199-1-2006 pdf download
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