Analytical method for the determination of carbon monoxide
Translation of DGUV Information 213-584
CAS Number: 630-08-0
Method 02 – FTIR
Method for the determination of carbon monoxide in workplace air using a Fourier‐transform infrared spectrometer (FTIR spectrometer)
The sampling is performed stationary. In the measurement procedure the concentration of carbon monoxide is measured continuously and recorded directly.
A portable spectrometer with a measurement gas pump and an external computer (PC or PDA) is used. The FTIR spectrometer has the capacity to simultaneously quantify the concentration of up to 50 other IR‐active gases, such as carbon dioxide, nitrogen monoxide, nitrogen dioxide, ammonia, sulphur dioxide, hydrogen chloride, hydrogen fluoride, formaldehyde, methane as well as organic gases present in the vaporous state, such as alkanes, alkenes, aromatic substances, alcohols, ethers, ketones, acids, esters, amines and compounds containing halogens.
Principle
The air sample is transferred to the measurement cell by means of an internal sampling pump. Infrared‐active gases, such as carbon monoxide, absorb IR radiation at specific wavelengths. The signal patterns in the IR spectrum are compared, and the concentrations of carbon monoxide and other gases in the air sample are determined. Signal overlaps are taken into consideration in the calculations.
Limit of quantification (LOQ)
The limit of quantification is 0.29 ppm of CO for a measuring period of one Minute.
Issue
March 2017
The complete measuring method is available in the Wiley Online Library: Method for the determination of carbon monoxide in workplace air using a Fourier‐transform infrared spectrometer (FTIR spectrometer) (Air Monitoring Methods, 2019).
Method 01 – NDIR
Method for the determination of carbon monoxide in workplace air using a non‐dispersive infrared gas measurement device (NDIR)
The NDIR method measures the concentration of carbon monoxide at the workplace using direct‐reading, continuously monitoring instruments with high temporal resolution.
Only portable, electrically‐powered gas measurement devices with integrated air sampling by means of a measurement gas booster pump, an intake tube and a particle filter connected upstream are used in the breathing zone at the workplace. The devices can emit warning signals in the cases where previously set alarm thresholds are exceeded and measurement results over a long period of time.
Principle
The air sample is transferred to the measurement cell by means of an internal sampling pump. Infrared‐active gases, such as carbon monoxide, absorb electromagnetic radiation in a wavelength range specific for the gas in question. The signal is measured at a wavelength of 4700 nm in the IR spectrum and the concentration of carbon monoxide is determined.
Limit of quantification (LOQ)
The limit of quantification for carbon monoxide is 1.6 ppm in the measurement range of 0 to 100 ppm.
Issue
March 2017
The complete measuring method is available in the Wiley Online Library: Method for the determination of carbon monoxide in workplace air using a non‐dispersive infrared gas measurement device (NDIR) (Air Monitoring Methods, 2019).
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