Piezoectric Crystal Detection of Hydrogen Chloride Via Sulfur Dioide/Mercury Displacement

Abstract

Magnesium thiosulfate converts hydrogen chloride to sulfur dioxide, which then reduces mercurous ion to free mercury. This is detected as a mercurygold amalgam using a piezoelectric crystal detector. the reaction sequence has a response time of 2 minutes, is fully reversible, and is made specific for the analyte by the use of appropriate scrubber reagents placed before and after the magnesium thiosulfate. the detector has a linear response with a sensitivity of 8.3 Hz per ppm in the 0.5–92 ppm range, a relative standard deviation less than 5 percent, and an estimated limit of detection of approximately 20 ppb HCI.

Key Words:

• Hydrogen chloride
• Piezoelectric crystal
• Sulfur dioxide
• Mercury displacement