A recent field test conducted by a Middle East customer has demonstrated the outstanding low (ppb)-concentration measurement capability of the AQMS NOx Analyzer (0–500 ppb) ESE-AQMS-100 from ESEGAS.
Real Test Results
The customer performed verification using a gas calibrator under controlled conditions.
Test Result 1 – Zero Point Verification
- Gas calibrator input: 0 ppb NO
- AQMS NOx Analyzer reading: 1.49 ppb
At an input concentration of 0 ppb, the analyzer output remained extremely close to the true value, with only 1.49 ppb residual response. This result demonstrates exceptionally low baseline fluctuation and confirms the analyzer’s capability to detect trace-level NO concentrations with high stability.
Test Result 2 – Low-Level Accuracy Verification
- Gas calibrator input: 100.06 ppb NO
- AQMS NOx Analyzer reading: 98.83 ppb
For a full scale of 500 ppb:
- Indication error specification: ±1% F.S. (±5 ppb)
- Actual observed deviation: 1.23 ppb
The measured performance was significantly tighter than the allowable full-scale tolerance, demonstrating excellent linear response and confirming stable operation in ultra-low concentration monitoring scenarios.
Technology Behind the Measurement
The AQMS NOx Analyzer is based on the Chemiluminescence Detection (CLD) principle and adopts a modular architecture combined with advanced microprocessing technology to provide accurate and reliable PPB–PPM level NOx monitoring.
Measurement Principle
NO concentration is measured through the chemiluminescent reaction:
NO + O₃ → NO₂ + O₂*
The generated excited-state NO₂* releases photons while returning to the ground state:
NO₂ → NO₂ + hv*
A photomultiplier tube (PMT) detects the emitted light intensity and converts it into NO concentration.
For total NOx measurement, NO₂ is first converted into NO through a converter. The NOx analyzer then calculates total NOx by combining NO and converted NO₂ values.
These latest customer validation results further demonstrate that the ESEGAS AQMS NOx Analyzer can provide dependable trace-level NOx monitoring performance for ambient air quality monitoring networks and dilution-based CEMS systems.
If you want to know more details, watch our AQMS NOx Analyzer video or contact with us for your tailored solution.
