Method for determination of methanol content in vehicle fuel methanol (2)

A.

Start the gas chromatograph, debug the instrument according to the chromatographic operating conditions listed in Table A.

Use a sampler for sample analysis, and use a chromatographic data processor or integrator to process the calculation results

A.

Internal standard method

A.

A.

The mass fraction w _{i of} methanol impurity components of vehicle fuel , the value is expressed in %, calculated according to formula (A.

Where:

A _i —the peak area of ​​the measured impurity component;

f _i — the relative correction factor of the measured impurity component;

m _s —the mass of the internal standard, in grams (g);

A _s —the peak area of ​​the internal standard;

m—The mass of the sample, in grams (g)

A.

The mass fraction w _i of the impurity components in the vehicle fuel methanol, expressed in %, is calculated according to formula (A.

Where:

w _{is —the} mass fraction of component i in the standard sample expressed in %;

A _i —the peak area of ​​component i in the sample;

As—the peak area of ​​component i in the standard sample

A.

The mass fraction w of vehicle fuel methanol, expressed in %, is calculated according to formula (A.

w=100-∑ _wi -w _water .

Where:

∑ _{wi —the} sum of the mass fractions of impurity components in methanol as vehicle fuel;

w _Water —The mass fraction of water in methanol measured in accordance with 4.

A.
7.
4 Allowable difference

Take the arithmetic average of two parallel determinations as the report result
.
The absolute difference between the two parallel determination results, the impurity content is not more than 20% of the two arithmetic average; the main content is not more than 0.
2%
.