Advancing accurate, consistent & drift-free CH2O Measurements

Formaldehyde (CH2O) is a key impurity in fuel cell hydrogen, where it is responsible for the degradation of the proton exchange membrane, adversely affecting performance. Tiger Optics delivers a powerful analytical tool for the measurement of trace CH2O for diverse applications. The low detection limit allows monitoring for compliance with SAE J2719, ISO 14687 or similar purity standards and protects fuel cell electric vehicles (FCEVs) from damage*.

Based on powerful Continuous-Wave Cavity Ring-Down Spectroscopy (CW-CRDS), with a proprietary laser lock cell, the HALO 3 CH2O is free of drift, guaranteeing consistent and reliable trace CH2O detection in nitrogen, hydrogen and other inert gases. Highly specific to the target molecule, CW-CRDS also prevents cross-interferences from distorting your measurement. Plus, there is no need to perform costly and time-consuming zero and span calibrations, saving both time and money with continuous, online service.

The HALO 3 CH2O gives you unsurpassed speed of response and ease of use. In sum, the HALO 3 analyzer serves a range of applications where trace gas measurement is extremely critical, such as sensor validation, gas standard preparation, and fuel cell hydrogen purity analysis.

Designed for formaldehyde analysis in laboratory and process applications:

  • Accuracy traceable to the world’s major national reference labs
  • Industry-proven technology
  • Freedom from the need for span calibrations
  • No periodic sensor replacement/maintenance
  • Low ppb detection limit
  • Wide dynamic range and no drift

*For fuel-cell hydrogen analysis according to ASTM Standard Test Method D7941, the method detection limit (MDL) is 2.5 ppb, as determined via U.S. EPA 40 CFR Part 136 Appendix B (95% Confidence Limit).


  • High-Purity Gases & Systems
  • Hydrogen Fuel Cells
  • Research & Development
  • Syngas & Fuel Gas Production

Learn More


Laboratory & Scientific

Stack, Process & CEMS

Detection Capability

Detection and Matrix Range LDL (3σ) Precision (1σ) @ zero
CH2O in N2 0 – 40 ppm 2.5 ppb 0.9 ppb
CH2O in H2 0 – 40 ppm 3 ppb 1.0 ppb


Operating range See Detection Capability table
Detection limit (LDL, 3σ/24h) See Detection Capability table
Precision (1σ, greater of) ± 0.75% or 1/3 of LDL
Accuracy (greater of) ± 4% or LDL
Speed of response < 3 minutes to 95%
Environmental conditions 10°C to 40°C, 30% to 80% RH (non-condensing)
Storage temperature -10°C to 50°C
Gas Handling System and Conditions
Wetted materials 316L stainless steel, 10 Ra surface finish
Gas connections 1/4″ male VCR inlet and outlet
Leak tested to 1 x 10-9 mbar l / sec
Inlet pressure 10 – 125 psig (1.7 – 9.6 bara)
Flow rate <1 slpm
Sample gases Nitrogen and hydrogen
Gas temperature Up to 60°C
Dimensions, H x W x D
Standard sensor 8.73″ x 8.57″ x 23.6″ (222 mm x 218 mm x 599 mm)
Sensor rack (fits up to two sensors) 8.73″ x 19.0″ x 23.6″ (222 mm x 483 mm x 599 mm)
Standard sensor 34 lbs (15.4 kg)
Alarm indicators 2 user programmable, 1 system fault, Form C relays
Power requirements 90 − 240 VAC, 50/60 Hz
Power consumption 40 Watts max.
Signal output Isolated 4−20 mA per sensor
User interfaces 5.7” LCD touchscreen, 10/100 Base-T Ethernet, RS-232
802.11g Wireless (optional), Modbus TCP (optional)
Certification CE Mark
U.S. Patent #7,277,177

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