CON 765

NOY Gold Converter


  • Ambient air quality control
  • Atmospheric research
  • Tropospheric research
  • Continuous trace gas analysis


  • Compact design
  • High conversion efficiency
  • Low interferences against HCN, NH3 and amines
  • Remotely controllable in combination with a ECO PHYSICS nCLD

Converter volume

24 ccm

Converter temperature


Converter efficiency

> 90%


NOY Gold Converter

The CON 765 NOY converter was developed for combination with a highly sensitive ECO PHYSICS CLD analyzer and allows the measurement of the total reactive nitrogen oxides (NOY) in the range of parts per trillion.

The Role of Oxides of Nitrogen
The oxides of nitrogen play an important role in atmospheric chemistry. In the troposphere, nitric oxide (NO) and nitrogen dioxide (NO2) first function as catalysts in photochemical reaction cycles, that either produce or destroy ozone (O3), second, they are precursors of nitric acid (HNO3), which is an important constituent of acid precipitation. Compounds such as peroxyacetyl nitrate (PAN) are an important source of NOX (NO + NO2) in areas far off from anthropogenic sources. In the lower stratosphere, NOY and ClONO2 are the principal reactive nitrogen species involved in ozone depletion. Accurate measurement techniques for the above mentioned compounds are important to be able to understand their chemistry and verify model calculations.

The Measurement Technique
The CON 765 utilizes the reduction of the higher oxides of NO in reaction with CO on a metal catalyst NOY + CO > NO + CO2 + X and the subsequent detection of NO by a ECO PHYSICS chemiluminescence NO analyzer.

Continuous Monitoring
The CON 765 NOY gold converter enables the continuous and automatic monitoring of nitrogen oxides at remote clean air areas. Many features have been integrated to assure robust, accurate and safe operation. The conversion efficiency exceeds 90% and is linear over the complete range. The presence of water vapor in the sample reduces the interference of NH3 and HCN to a negligible level.

The Ideal Combination
The CON 765 is designed to be operated together with an ECO PHYSICS NO analyzer. The CON 765 is in use at several remote research and monitoring locations in Europe.

What is NOY?:

NOY = NOz + NOx
NOx = NO + NO2
NOZ = HNO3 + HONO + 2N2O5 + HO2NO2 + PAN + NO3 + Organic Nitrates – but not NH3


Sample flow rate



depending on CLD:

nCLD 899 and Cranox II: 0.7l/min

nCLD 88 p: 0.3 l/min

CLD 780 TR: 3l/min

Converter volume

24 ccm

Converter temperature

300°C (regulated)

Converter efficiency

> 90%

Converter material   


Humidity tolerance


5 – 95% rel. h

(non-condensing, ambient air and sample gas)

Input pressure

ambient (600–1’100 mbar abs.)

Flow settings

selectable sample intake:

– direct into converter tube or

– through valve, allowing fully automatic calibration

– switching mode: NO&NOY

Supply Gas             

CO 99.999: 30 ml/min; outlet press. CO bottle: 1.5bar

Power required

320 VA

Supply voltage

240 V/50 Hz, 115 V/60 Hz


digital, fits with ECO PHYSICS nCLD’s


height: 120 mm

width: 290 mm

length: 650 mm


12 kg

Delivery includes

converter incl. gold tube, power cable, interface cable


*Depending on filter setting.

Connectivity properties are country-specific.

ECO PHYSICS reserves the right to change these specifications without notice.

Further information can be found in the Product Brochure

Download Brochure


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