How to overcome the interference of chloride ions when analyzing sulfur content using the microcoulometry method
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Dear experts, our factory uses microcoulometers to analyze the sulfur content in organic substances at the ppm level. This method works very well for analyzing acetic acid/acetic anhydride, but it does not function properly when analyzing chloroacetic acid. It is believed that chloride ions cause significant interference. Could anyone suggest a way to overcome this interference? Thank you
The presence of chlorine mainly causes interference as the chlorine atoms in the sample are converted into chlorine gas and hypochlorous acid; most of the chlorine is transformed into hydrochloric acid, which does not interfere with the measurement. Adding sodium azide to the electrolyte can effectively prevent interference from chlorine and nitrogen (excerpt from the Laboratory Technician’s Handbook). If this still does not resolve the issue, a gas chromatograph equipped with a FPD-specific detector for sulfur and phosphorus can be purchased