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The development of a fast in situ optical sensor based on a continuous-wave quantum cascade laser operating at 8 μm for the measurement of environmental gaseous nitrous acid (HONO) is reported. A strong absorption line at 1252.2109 cm–1 is found to be free of interferences and used for the first time for ambient HONO detection. Loss of HONO on the wall of the gas sample absorption cell is evaluated. The resulting 1-s detection limit for HONO is 110 pptv with a folded path length of 172 m. Continuous monitoring of HONO and NO2 mixing ratios variations along with the basic meteorological parameters was performed during a field campaign of several days. Typical photochemical reactions of HONO have been observed on sunny and snowy days. Atmospheric HONO mixing ratios observed in this study indicate that direct emission from traffic exhausts and local heterogeneous reactions is potentially important sources of HONO. [ABSTRACT FROM AUTHOR]

Sensitive detection of hydrogen sulfide (H2S) has been performed by means of wavelength modulation spectroscopy (WMS) near 1.578 μm. With the scan amplitude and the stability of the background baseline taken into account, the response time is 4 s for a 0.8 L multi-pass cell with a 56.7 m effective optical path length. Moreover, the linearity has been tested in the 0–50 ppmv range. The detection limit achievable by the Allan variance is 224 ppb within 24 s under room temperature and ambient pressure conditions. This tunable diode laser absorption spectroscopy (TDLAS) system for H2S detection has the feasibility of real-time online monitoring in many applications. [ABSTRACT FROM AUTHOR]

Compared with the expensive transitionmetal-catalyzed reaction, the new method shows synthetic advantages in term of mild reaction conditions, environmentally friendly, and low cost. [ABSTRACT FROM AUTHOR]

An intermolecular condensation reaction of 1,3,5-triarylenynols catalyzed by copper is developed. This reaction is a straightforward method for the synthesis of highly conjugated 1H-cyclopenta[b]naphthalene. Fluorescent properties have been determined for some of the products.