Adding ethers, alcohols, and other oxygen-containing compounds to gasoline can increase octane rating and reduce carbon monoxide emissions in gasoline. However, excessive addition of certain oxygen-containing compounds can also cause environmental pollution. For example, if the content of MTBE exceeds 7%, the nitrogen oxides in car emissions will increase. Aromatic hydrocarbons in gasoline can increase its octane rating, but these aromatic hydrocarbons, such as benzene, are carcinogens.

The national standard sets clear limit requirements for the content of oxygen-containing compounds, benzene, and aromatic hydrocarbons in unleaded gasoline for vehicles.

Reference standard for gasoline analysis gas chromatograph:

GB17930-2013 Automotive Gasoline

GB 18351-2013 Ethanol Gasoline for Vehicles

SH/T0663 Determination of Certain Alcohols and Ether Oxygenates in Gasoline

SH/T0720-2002 Determination of Oxygen Compounds in Gasoline

SH/T0693 Determination of Aromatic Hydrocarbons in Gasoline

Operation steps of gasoline analysis gas chromatograph:

1、 Power on preparation

Environmental inspection: The instrument should be placed in a well ventilated laboratory, and high-end instruments are best used in a constant temperature environment of 20-25 ℃.

Gas path connection: Ensure good gas tightness of the carrier gas (such as nitrogen), gas (hydrogen), and auxiliary gas (air), and the circuit system should also be adapted.

2、 Power on and heating up

Connect the carrier gas: First, open the carrier gas and adjust the pressure regulator valve and flow regulator valve to the required flow rate.

Power on: Turn on the main power of the host, start the temperature control systems of the gasification chamber, column constant temperature box, and detector chamber in sequence, and set the temperature.

Stable heating: After each component reaches the set temperature, start the detector (if FID needs to be ignited), adjust the bridge flow, balance, and zero adjustment knobs until the baseline is stable.

3、 Injection and Separation

Injection operation: Use a syringe or automatic sampler to inject the sample. The sample volume is generally around 1 microliter, and the injection should be stable, accurate, and firm to avoid puncturing too shallow or too deep.

Separation control: The temperature of the chromatographic column should be appropriate, and the flow rate of the carrier gas should also be adjusted according to the column specifications. If it is too fast or too slow, it will affect the separation effect.

4、 Detection and Data Analysis

Detector startup: The FID detector needs to be ignited, while the TCD detector needs to be heated and started directly, taking care not to exceed the set value.

Baseline adjustment: Adjusting parameters to make the baseline stable is essential for reliable results.

Data viewing: Check if the peak shape is sharp, and the peak position and area represent the type and content of the substance, respectively. Remember to save the data.

5、 Shutdown and maintenance

Shutdown sequence: First turn off the gas and auxiliary gas, then turn off the detector power and temperature control power, and finally turn off the main power. Wait for the instrument to cool down before turning off the carrier gas.

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