HORIBA ONE Series Introduces New N-Compounds Analyzer

The MEXA-ONE-QL-NX is an analyzer for the direct, simultaneous real-time measurement of the four relevant nitrogen-containing exhaust gas components NO, NO2, N2O and NH3.
The analyzer combines a light source based on the new quantum cascade technology (efficient lasers in the mid-infrared spectral region) with a precisely adjusted dual path cell to measure low concentrations with maximum sensitivity. The detection limit complies with current European legal requirements.
Furthermore, the MEXA-ONE-QL-NX offers wide measuring ranges of up to 5000 ppm (for NO). By using extremely narrowband light sources and measuring under reduced pressure the cross-sensitivity to other exhaust gas components can be drastically minimized.
The complete measuring system - including filtration - is specifically developed for the measurement of NH3 and thus guarantees a very fast NH3 rise time (T10-T90) of less than 5 seconds. 
The MEXA-ONE-QL-NX can be operated as a stand-alone analyzer or integrated into the MEXA-ONE software interface for user-friendly and simplified system operation.

For R&D of advanced NOx after-treatment systems

  • Simultaneous real-time measurement of four nitrogen compounds (NO, NO2, N2O and NH3)
  • Wide dynamic ranges for all components (e.g. NH3: 0.6 ppm to 2000 ppm)
  • Fast response times (T10-T90):
    NO, NO2, N2O: <2 s 
    NH3: <5 s



  • Development of new NOx after-treatment systems, such as urea-SCR, CRTs and LNTs
  • Certification of NH3 emissions according to the latest European legislation for light duty vehicles (WLTP/ GTR 15)
  • As an R&D tool for worldwide regulations - certification or reporting of greenhouse gas emissions (EPA) or ammonis (Euro VI)


All advantages at a glance

  • Compliant with WLTP / GTR 15 for NH3 measurement
  • Suitable for the measurement of very low concentrations
  • Wide dynamic ranges (up to 5000 ppm)
  • Very low cross-sensitivity for other exhaust gas components
  • No operating gases other than compressed air
  • Direct NO2 measurement
  • Easy handling (no liquid nitrogen cooling necessary)
  • Operation within HORIBA ONE PLATFORM





Measuring principle

Quantum Cascade Laser Infrared (QCL-IR) Spectroscopy

Measuring components


Measuring range

NO: (low) 0-100 ppm (high) 0-5000 ppm
NO2:(low) 0- 50 ppm (high) 0-2000 ppm
N2O:(low) 0-100 ppm (high) 0-2000 ppm
NH3:(low) 0- 50 ppm (high) 0-2000 ppm

Zero noise(2σ)
(σ:standard deviation)

NO :(low) < 0.4 ppm (high) < 20 ppm
NO2:(low) < 0.2 ppm (high) < 8 ppm 
N2O:(low) < 0.4 ppm (high) < 20 ppm
NH3 (low) < 0.2 ppm (high) < 8 ppm

Sample line temperature

113 ± 6℃

Response time( t10-90)

NO, NO2, N2O: < 2 s
NH3: < 5 s*

Dimensions/ mass

Main unit:440×660×877 (mm)
Approx.: 120 kg (excluding protruding objects)

Sampling rate

10 Hz

Flow rate

8 L/min ± 1 L/min )

Inlet pressure

standard: - 5 kPa to +30 kPa (relative)
optional: -5 kPa to + 200 kPa (relative)

Span noise

< 2% full scale (FS)

Zero/ span drift

< 1% FS/ 8 h

Warm-up time

2 h

* determined with NH3 (50 ppm) supplied to the sample inlet at a flow rate of 8 L/min via a 0.3 m sample probe, a heated filter and a 6 m heated line.