GB/T 38395-2019Coal tar—Determination of sulfur and nitrogen content (English PDF)

3.1 Determination of sulfur content by ultraviolet fluorescence method

The sample to be tested is directly injected or diluted and injected into a lysis tube or a sample boat.The sample is sent by the sampler to a high-temperature combustion tube.

Under the conditions, organic sulfur is oxidized to sulfur dioxide (SO2); the gas generated by the combustion of the sample is irradiated with ultraviolet light after removing water, and sulfur dioxide (SO2)

The energy of absorbing ultraviolet light is converted into sulfur dioxide (SO2 *) in the excited state. When the sulfur dioxide (SO2 *) in the excited state returns to the stable state, the

Sulfur oxide (SO2) emits fluorescence and is detected by a photomultiplier tube.The measured signal value is compared with the signal value of the standard sample to calculate the sample to be tested.

Sulfur content.

3.2 Determination of nitrogen content by chemiluminescence

The sample to be tested is directly injected or diluted and injected into a lysis tube or a sample boat.The sample is sent by the sampler to a high-temperature combustion tube.

Under these conditions, organic nitrogen is oxidized to nitric oxide (NO), which is converted into excited state nitrogen dioxide (NO2 *) by contact with ozone.

The emitted light when the nitrogen dioxide (NO2 *) returns to the ground state is detected by the photomultiplier tube, and the obtained signal value is compared with the signal value of the standard sample.

Calculate the nitrogen content in the test sample.

4.1 Elemental Analyzer

Includes combustion furnace, cracking tube, flow control device, drying tube, micro syringe, boat sampling system, UV fluorescence detection

And chemiluminescence detectors.

4.2 Analytical balance

Sensitivity 0.0001g.

4.3 Volumetric flask

Several 25mL volumetric flasks.