ºÝºÝߣshows by User: eemperor / http://www.slideshare.net/images/logo.gif ºÝºÝߣshows by User: eemperor / Mon, 20 Sep 2010 01:52:39 GMT ºÝºÝߣShare feed for ºÝºÝߣshows by User: eemperor Measurements of Peroxy Radicals Using Chemical Amplification-Cavity Ringdown Spectroscopy /slideshow/measurements-of-peroxy-radicals-using-chemical-amplificationcavity-ringdown-spectroscopy/5237651 es901146t-12849654329476-phpapp01
The peroxy radical chemical amplification (PERCA) method is combined with cavity ringdown spectroscopy (CRDS) to detect peroxy radicals (HO2 and RO2). In PERCA, HO2 and RO2 are first converted to NO2 via reactions with NO, and the OH and RO coproducts are recycled back to HO2 in subsequent reactions with CO and O2; the chain reactions of HO2 are repeated and amplify the level of NO2. The amplified NO2 is then monitored by CRDS, a sensitive absorption technique. The PERCA-CRDS method is calibrated using a HO2 radical source (0.5-3 ppbv), which is generated by thermal decomposition of H2O2 vapor (permeated from 2% H2O2 solution through a porous Teflon tubing) up to 600 °C. Using a 2-m long 6.35-mm o.d. Teflon tubing as the flow reactor and 2.5 ppmv NO and 2.5-10% vol/vol CO, the PERCA amplification factor or chain length, Δ[NO2]/([HO2]+[RO2]), is determined to be 150 ( 50 (90% confidence limit) in this study. The peroxy radical detection sensitivity by PERCA-CRDS is estimated to be ∼10 pptv/60 s (3σ). Ambient measurements of the peroxy radicals are carried out at Riverside, California in 2007 to demonstrate the PERCA-CRDS technique.]]>
The peroxy radical chemical amplification (PERCA) method is combined with cavity ringdown spectroscopy (CRDS) to detect peroxy radicals (HO2 and RO2). In PERCA, HO2 and RO2 are first converted to NO2 via reactions with NO, and the OH and RO coproducts are recycled back to HO2 in subsequent reactions with CO and O2; the chain reactions of HO2 are repeated and amplify the level of NO2. The amplified NO2 is then monitored by CRDS, a sensitive absorption technique. The PERCA-CRDS method is calibrated using a HO2 radical source (0.5-3 ppbv), which is generated by thermal decomposition of H2O2 vapor (permeated from 2% H2O2 solution through a porous Teflon tubing) up to 600 °C. Using a 2-m long 6.35-mm o.d. Teflon tubing as the flow reactor and 2.5 ppmv NO and 2.5-10% vol/vol CO, the PERCA amplification factor or chain length, Δ[NO2]/([HO2]+[RO2]), is determined to be 150 ( 50 (90% confidence limit) in this study. The peroxy radical detection sensitivity by PERCA-CRDS is estimated to be ∼10 pptv/60 s (3σ). Ambient measurements of the peroxy radicals are carried out at Riverside, California in 2007 to demonstrate the PERCA-CRDS technique.]]> Mon, 20 Sep 2010 01:52:39 GMT /slideshow/measurements-of-peroxy-radicals-using-chemical-amplificationcavity-ringdown-spectroscopy/5237651 eemperor@slideshare.net(eemperor) Measurements of Peroxy Radicals Using Chemical Amplification-Cavity Ringdown Spectroscopy eemperor The peroxy radical chemical amplification (PERCA) method is combined with cavity ringdown spectroscopy (CRDS) to detect peroxy radicals (HO2 and RO2). In PERCA, HO2 and RO2 are first converted to NO2 via reactions with NO, and the OH and RO coproducts are recycled back to HO2 in subsequent reactions with CO and O2; the chain reactions of HO2 are repeated and amplify the level of NO2. The amplified NO2 is then monitored by CRDS, a sensitive absorption technique. The PERCA-CRDS method is calibrated using a HO2 radical source (0.5-3 ppbv), which is generated by thermal decomposition of H2O2 vapor (permeated from 2% H2O2 solution through a porous Teflon tubing) up to 600 °C. Using a 2-m long 6.35-mm o.d. Teflon tubing as the flow reactor and 2.5 ppmv NO and 2.5-10% vol/vol CO, the PERCA amplification factor or chain length, Δ[NO2]/([HO2]+[RO2]), is determined to be 150 ( 50 (90% confidence limit) in this study. The peroxy radical detection sensitivity by PERCA-CRDS is estimated to be ∼10 pptv/60 s (3σ). Ambient measurements of the peroxy radicals are carried out at Riverside, California in 2007 to demonstrate the PERCA-CRDS technique. <img style="border:1px solid #C3E6D8;float:right;" alt="" src="https://cdn.slidesharecdn.com/ss_thumbnails/es901146t-12849654329476-phpapp01-thumbnail.jpg?width=120&amp;height=120&amp;fit=bounds" /><br> The peroxy radical chemical amplification (PERCA) method is combined with cavity ringdown spectroscopy (CRDS) to detect peroxy radicals (HO2 and RO2). In PERCA, HO2 and RO2 are first converted to NO2 via reactions with NO, and the OH and RO coproducts are recycled back to HO2 in subsequent reactions with CO and O2; the chain reactions of HO2 are repeated and amplify the level of NO2. The amplified NO2 is then monitored by CRDS, a sensitive absorption technique. The PERCA-CRDS method is calibrated using a HO2 radical source (0.5-3 ppbv), which is generated by thermal decomposition of H2O2 vapor (permeated from 2% H2O2 solution through a porous Teflon tubing) up to 600 °C. Using a 2-m long 6.35-mm o.d. Teflon tubing as the flow reactor and 2.5 ppmv NO and 2.5-10% vol/vol CO, the PERCA amplification factor or chain length, Δ[NO2]/([HO2]+[RO2]), is determined to be 150 ( 50 (90% confidence limit) in this study. The peroxy radical detection sensitivity by PERCA-CRDS is estimated to be ∼10 pptv/60 s (3σ). Ambient measurements of the peroxy radicals are carried out at Riverside, California in 2007 to demonstrate the PERCA-CRDS technique.
Measurements of Peroxy Radicals Using Chemical Amplification-Cavity Ringdown Spectroscopy from Yingdi Liu
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