Multiple component analysis of cigarette smoke using THz spectroscopy, comparison with standard chemical analytical methods

Terahertz time domain spectroscopy and photomixing have been used alongside one another for the detection and the quantification of small polar species in mainstream cigarette smoke. The broadband submillimeter source used in time domain spectroscopy allowed a rapid and simultaneous detection of several pure rotational transitions of hydrogen cyanide (HCN) and carbon monoxide (CO) in realistic conditions of pressure and temperature. The spectral purity of the continuous wave terahertz source produced by photomixing, permitted the concentrations of these molecules to be measured at pressures of tens of hPa. Moreover, at lower pressure, traces of formaldehyde (H2CO) have been unambiguously identified at frequencies above 1 THz. A comparison with chemical analytical methods has been completed for each molecule highlighting the advantages of the direct measurement by THz spectroscopy.