Method
Gas chromatograph:
Kristall 2000M or Chromatec-Crystal 5000/9000
Detector:
FID or TCD
Packed or capillary columns:
Packed Column M, 6 m × 3 mm, composite DBF (2 m) + Vaseline oil (4 m) on TZK
Packed Column M, 6 m × 3 mm, 15% Vaseline oil on aluminum oxide
Packed Column M, 2 m × 2 mm, HayeSep Q 60/80 (with methanol analysis capability)
HP-PLOT Al2O3/S column, 30 m × 0.53 mm × 15 µm
HP-PLOT Al2O3/KCl column, 30 m × 0.53 mm × 15 µm
Other columns may also be used in accordance with the applicable operating standard
Injection system:
Liquefied gas sampling valve with an injection volume from 0.05 to 1 µL
Chromatographic data processing software:
Chromatec Liquefied Gas
Additional equipment:
Hydrogen generator (when using FID)
Air compressor (when using FID)
Gas fittings kit 4.078.000
Sampling cylinders:
PGO and PU sampling cylinders according to GOST 14921
PP-150 constant-pressure sampling cylinders (recommended)
Gas fittings kit 4.078.008 for filling piston sampling cylinders
Filters for gas sampling and sample injection (filter 5.884.057, filter 5.884.083, filter 5.884.056)
Method Description
Injection of liquefied hydrocarbon gas (LPG) samples is generally carried out using special liquefied gas sampling valves.
Chromatec supplies valves both of its own manufacture and from Valco, with injection volumes ranging from 0.05 to 1 µL.
The valves can be equipped with an optional Peltier cooling system.
The valve volume is selected depending on the type of column used and the detector applied.
When analysis of samples with a high content of light components (methane and ethane) is required, it is recommended to use an FID detector and piston-type sampling cylinders, such as the PP-150.
It should be noted that capillary columns provide the best separation and the optimum analysis time.
For analysis of wide fractions of light hydrocarbons (NGL) and gases with a high content of heavy components, capillary columns are also the preferred choice.
At the same time, for routine applications such as quality control of technical propane, technical propane-butane, technical butane, and similar products, packed columns and a TCD detector are still widely used.
In general, for liquefied gas analysis, the FID detector is recommended because it provides better reproducibility of analytical results compared with the TCD detector.
The specific selection of columns, sample cylinder type, sampling valve type, and injection valve volume is discussed in detail in the article:
Gas chromatographic analysis of liquefied hydrocarbon gas composition according to the new national standard GOST R 54484-2011. // Analitika. - 5/2012 (6).
Calculation of the component composition, density, and saturated vapor pressure of liquefied gas is performed using the Chromatec Liquefied Gas software.