Gases and Detection Limits
List of several gases and groups of molecules accessible with our detectors and the performed sensitivity.
|
Gas
|
Detection limit
|
Detector
|
|---|---|---|
| Acetaldehyde CH3CHO | 0.03 ppbv | PTR-MS |
| Acetone C3H6O | 0.03 ppbv | PTR-MS |
| Acetonitrile CH3CN | 0.03 ppbv | PTR-MS |
| Ammonia NH3 | 0.1 ppbv | CO2-laser / OPO |
| Benzene C6H6 | 0.06 ppbv | PTR-MS |
| Dimethyl sulphide (CH3)2S | 1 ppbv | PTR-MS |
| Ethane C2H6 | 0.01 ppbv | OPO |
| Ethanol CH3CH2OH | 3 ppbv | PTR-MS |
| Ethylene C2H4 | 0.006 ppbv | CO2-laser |
| Isoprene C5H8 | 0.1 ppbv | PTR-MS |
| Methane CH4 | 0.1 ppbv | OPO |
| Methanol CH3OH | 0.8 ppbv | PTR-MS |
| Methyl Ethyl Ketone C4H8O | 0.03 ppbv | PTR-MS |
| Nitric oxide NO | 1 ppbv | QCL |
| Ozone | 0.03 ppbv | CO2-laser |
| Pentane C5H12 | 0.2 ppbv | OPO |
| a-Pinene C10H16 | 0.8 ppbv | PTR-MS |
| Sulfurhexafluoride SF6 | 0.003 ppbv | CO2-laser |
| Toluene C7H8 | 0.6 ppbv | PTR-MS |
| O-,M-Xylene C8H10 | 0.8 ppbv | PTR-MS |
The above table shows a selection of gases that we can measure with these systems. Especially using PTR-MS, more compounds can be measured such as alcohols, aldehydes, ketones, monoterpenes, esters and aromatic compounds.
Optical Parametric Oscillator: example of several strong molecular absorption bands in the 3-5 µm wavelength region
|
Molecular end-group or bond type
|
Spectral position (nm)
|
Molecular end-group or bond type
|
Spectral range (nm)
|
|---|---|---|---|
| -S-H | 3846-3922 | CºCH | 3000-3040 |
| P-H | 4167-4255 | COOH | 3330-4000 |
| -N=C=O | 4396-4444 | O=CH3 | 3380-3420 |
| -N3 | 4629-4717 | CH2 or CH3 | 3390-3510 |
| -N=C=N- | 4640-4695 | CHO | 3450-3700 |
| >C=C=O | ~4650 | O-CH3 | 3500-3560 |
| R-S-CºN | 4670-4600 | POOH | 3700-3900 |
| -N=C=S | 4673-5025 | SH | 3850-3920 |
PTR-MS : Proton-Transfer Reaction Mass Spectrometry
PTR-MS can detect various organic compounds such as aldehydes (e.g. acetaldehyde, propanal, formaldehyde), ketones (e.g. acetone, methyl ethyl ketone, methyl vinyl ketone), aromatic compounds (e.g. benzene, toluene, xylene), alcohols (e.g. methanol, ethanol, propanol, iso propanol), sulphur compounds (e.g. methanethiol, dimethyl sulfide, dimethyl disulphide), unsaturated compounds (e.g. isoprene, alpha pinene), nitriles (e.g. acetonitrile), esters, acids and compounds with multiple functional groups (e.g. vanillin, methyl salicylate).
OPO : Optical Parameter Oscillator-based system
QCL : Quantum Cascade Laser-based system
CO2-laser : CO2-laser based system