Photolyzing light sources

Measurements of NO and N02 by Chemiluminescence. Most balloon-borne in situ measurements of NO and NO published to date have been made with the chemiluminescence technique (6, 63,64). Reagent ozone is added to the ambient flow in a reaction chamber, and the chemiluminescence observed from the reaction NO + 03 —> NO + 02 is detected by a photomultiplier tube that views the volume. The amount of light observed is proportional to the amount of NO in the ambient air. N02 is detected by exposing the ambient air going into the detection cell to a strong light source this exposure photolyzes N02 to NO, which can then be detected. 

Suitable light sources for photolyzing include sunlamps manufactured by a number of companies, such as Philips Ultrapnil MLU 300 W, General Electric Sunlamp RSM 275 W, or National Self-Ballasted BHRF 240-250 V 250 W-P lamp. Irradiation for 15 min with such lamps while the sample is cooled in an ice bath will result in good photolysis of photoreactive cross-linkers and modification reagents. 

In addition to H2O2 (e = 18.61VT1 cm-1 at 254 nm), other species can absorb photons at these short wavelengths, and can act as light filters. However, if the contaminants can be directly photolyzed, this may improve the efficiency of the oxidative destruction process. As the intensity of UV radiation decays exponentially towards the bulk of the solution, it is necessary to establish conditions of turbulent flow to continuously renew the solution surrounding the luminous source. 

To anhyd benzene (300 mL) was added 6-chloro-2-iodo-9-) -(2,3,5-tri-0-acetyl-)S-D-ribofuranosyl)purine (0.284 g, 0.527 mmol). The solution was transferred to a Hanovia photochemical reactor, purged with Nj, and photolyzed for 16.5 h by employing a 450-W Hg UV source with a Vycor glass sleeve filter. The solvent was then removed (40 °C, reduced pressure) and the residue chromatographed (silica gel plates, EtOAc/hex-ane, 7 3), the band at = 0.63 afforded a light yellow low-melting solid yield 0.207 g (80%). 

Aryldlazonlum salts with complexed halide anions provide a convenient light-sensitive source of Lewis acids. As an example, aryldlazonlum fluoroborate Is photolyzed and yields the Lewis acid BF3 as a reaction product In the Schlemann reaction when It Is thermally activated ... 

In [2] only. - Photolyzed with light of 184.9 nm. - Photolyzed with Hg lamp. -y-irradiated (Co source). - Electron bombarded with 100 eV. - Electron bombarded between 8 and 30 eV. - MeV He" ion bombarded. — Electron bombarded. — In [13] only. - In [14] only. - Photolyzed with light of wavelengths>290 nm. 

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