Methods for the simultaneous analysis of hydrogen sulfide and sulfur dioxide.

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This post was last edited by liaifeng on 2018-8-15 at 18:40 regarding methods for the simultaneous analysis of hydrogen sulfide H2S and sulfur dioxide SO2. Our method: A gas chromatograph with a TCD detector and a GDX-303 packing column (diameter 3 mm, length 2 m) is used; the volume of the quantitation tube can be determined as needed. Desiccant CaCl2 particles. Once, I met someone in a factory who was doing analysis and said that chromatography manufacturers do not allow H2S and SO2 to be injected simultaneously; I was surprised by this, as we have always injected them together without any problems so far. After a detailed analysis, the following possible issues were identified: 1. Ordinary factories may use capillary chromatography columns with a small inner diameter, which are prone to clogging ； 2. Chromatography manufacturers warn that a reaction may occur, but in reality, sulfur element is produced only when H2S, SO2, and water are present together ； 3. Before sampling, the analyst did not dry the gas, or the degree of gas drying was insufficient. Advantages of our method: 1. It uses a packed column with a large inner diameter, making it less prone to clogging ； 2. The gas is thoroughly dried, and neutral desiccants are used that do not react with H2S or SO2 ； 3. The temperature control in the column box is relatively low (50–80°C); even if a reaction occurs, its rate is low, resulting in an extremely small amount of elemental S being produced ； 4. Even if clogging does occur, it is sufficient to raise the column temperature by 30–50°C above the dew point of elemental S (by aging the chromatography column separately); the treatment method is very simple. Note: Since both H2S and SO2 analyzed in the factory are at constant levels (several thousand ppmV to percentage levels), a packed column along with a TCD detector is more than sufficient for the analysis requirements; domestic instruments are fully adequate for this purpose. I’d like to share some experience; I hope it will be helpful to everyone!