Why choose anhydrous magnesium sulfate as a water remover?
In the d-SPE purification process, the moisture content plays a crucial role in the purification effect of PSA. The lower the moisture content, the better the purification effect of PSA. Experiments show that the water removal effect of MgSO4 is much better than that of NaSO4.
Why introduce GCB (graphitized carbon black) in d-SPE?
The experimental results show that when a large amount of pigment is present in the sample, as the number of injections increases, the pigment will seriously contaminate the liner and the column, which will result in distortion of the later results and increase the frequency of maintenance of the instrument.
GCB is produced by heating carbon black to an inert atmosphere at 2700 °C to 3000 °C. The graphitized carbon black surface is a planar hexagon composed of six carbon atoms. It is mostly used for the removal of pigments in pesticide samples. At the very beginning, activated carbon was widely used for the removal of pigments, but the adsorption of activated carbon was too strong (irreversible adsorption), resulting in a low recovery rate of many pesticides. Thus it has been slowly replaced by graphitized carbon black in recent years.
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