• Paper and wood industry
  • Textile
  • Productions of resins and adhesives
  • Chemical industry


Colorimetric analyzer for the determination of formaldehyde


An excess of MTBH (3-methyl-2-benzothiazoline hydrazone) is added to the sample. The reaction between the compound and formaldehyde leads to the formation of an azine. The subsequent addition of the developing solution oxidizes the excess MTBH, the resulting compound reacts with the azine to form a coniugate system which absorb in the red region of the spectrum. The absorbance is proportional to the formaldehyde concentration and it is measured at 660 nm.


Measured parameter CH2O


(Ø 16 mm) 0 - 2 ppm
Wavelength 660 nm
Demineralized water Not required
Number of reagents 2
Min. analysis time 18 minutes
Default analysis time 30 minutes

Reagent consumption**

** per month, at the default analysis frequency.
(Ø 26 mm) 16 L
(Ø 16 mm) 12 L

Technical Specifications

Model 3S-CL
Sampling Mode Batch, with freely settable frequency.
Sample Pressure: Atmospheric
Temperature: 5 ‐ 45°C (41 ‐ 113°F)
Flow Rate: 80 to 500 mL/min
Connection: 6 mm (¼-in.)
Drain Pressure-free drain
Connection: 12 mm (½-in.)
Input Streams 2
Material Epoxy-coated stainless steel AISI 304
Dimensions (H x W x D) 604 x 380 x 210 mm (23.6 x 14.8 x 8.2 in)
Weight 20 kg (44 lbs)
Power Supply Input Voltage: 115 VAC,230 VAC,24 VDC
Power consumption: max. 80 W
Output signals 2 x 4-20 mA analog outputs
Modbus via RS485,Ethernet
Alarms 2 SPDT programmable voltage-free relays
Digital Input None, Online, Start Extra, Skip Idle, Emergency Stop
Ambient Temperature 5 - 45 °C (41 - 113 °F)
Ambient Humidity 10 - 90 % RH (non-condensing)
Protection Grade IP54 (indoor only, outdoor use possible with external cabinet, not included)