Formaldehyde Detection Tubes (8 to 6400 ppm)

Formaldehyde Detection Tubes (8 to 6400 ppm)

Gastec Detection Tube No. 91M measures Formaldehyde with a Range of 8 to 6400 ppm.

• Measuring Range:
  • 8 to 20 ppm
  • 20 to 2000 ppm
  • 2000 to 6400
• Pump Strokes: 2, 1, 1/2
• Correction Factor: 0.4, 1, 3.2
• Sampling time: 1 minute per pump stroke
• Detecting Limit: 4 ppm (2 pump strokes)
• Changes from Yellow to Red
• Corrections for temperature & humidity: Temperature correction is necessary
• Reaction Principle:
  • 3HCHO + (NH₂OH)₃H₃PO₄ → H₃PO₄
  • H₃PO₄ + Base → Phosphate
• Relative Standard Deviation: 10% (for 20 to 500 ppm), 5% (for 500 to 2000 ppm)
• 2 Year Shelf Life (in the refrigerator)
• Store the tubes in the refrigerator to keep at 10ºC (50ºF) or below.

Possible coexisting substances and their interferences: