اندازه‌گیری مقدار باقیمانده مایع بر اساس استاندارد EN 15470

Method

Gas chromatograph:
Chromatec-Crystal 5000/9000

Detector:
FID

Column:
HT-5 type capillary column, 12 m × 0.53 mm × 0.1 µm, #054657

Injection system:
Programmable evaporator 7.3
DAZh-2M or DAZh-2M 3D autosampler
Column oven cooling system

Additional equipment:
Hydrogen generator
Air compressor
Gas fittings kit 4.078.000

Method Description

The EN 15470 method (STB EN 15470) is used to determine the liquid residue content in liquefied hydrocarbon gases in the concentration range from 40 mg/kg to 100 mg/kg.

Higher residue levels can also be determined by selecting an appropriate sample mass.

Liquid residue is defined as the amount of organic compounds determined by gas chromatography after evaporation of the sample at room temperature and subsequent evaporation in a drying oven at 105°C, excluding solids and polymers.

The advantage of this method is that only a small amount of liquefied hydrocarbon gas is required for testing (from 50 g to 75 g), while the qualitative characteristics can help identify the origin of the residue, such as liquefied hydrocarbon gas, lubricants, plasticizers, etc.

Principle of the Method

A 50–75 g sample of liquefied hydrocarbon gas is taken.

Sampling is performed using a flask cooled with a mixture of isopropyl alcohol and dry ice.

After sampling, the sample is allowed to evaporate at room temperature.

The resulting residue is then heated in a drying oven for 1 hour at 105°C.

After that, it is diluted with a solvent (CS2) and an internal standard (octane) is added.

The resulting mixture is analyzed by gas chromatography, and quantitative calculation is performed using the internal standard method.

Additional Notes

This method requires high temperatures in the column oven, so it can rarely be combined in the same instrument with other analytical applications.