Spectroscopic investigation of methylated amines by a cavity-ringdown-based spectrometer

High-resolution absorption spectra of gas-phase monomethylamine (MMA, [CH.sub.3][NH.sub.2]) and dimethylamine [DMA, [([CH.sub.3]).sub.2]NH] in the region of the first overtone of the NH stretch vibration are reported. Measurements were performed with a near-infrared laser spectrometer based on the cavity-ringdown (CRD) detection technique. The minimum detectable absorption coefficient for the CRD detection setup is [[alpha].sub.min] = 1.55 x [10.sup.-8] [cm.sub.-1] (for SNR = 1). This corresponds to detection limits of 350 parts in [10.sup.9] (ppb) for MMA and 1.6 parts in [10.sup.6] (ppm) for DMA in synthetic gas mixtures under interference-free conditions, or 10 ppm and 60 ppm for MMA and DMA, respectively, in the case of gas mixtures such as exhaled human breath containing [H.sub.2]O, C[O.sub.2], and other absorbing gases in this range. OCIS codes: 300.6360, 140.3600, 170.4580.