Ozone vacuum-ultraviolet (VUV) ozone generators, employ a light source that generates a narrow-band ultraviolet light, a subset of that produced by the Sun. The Sun's UV sustains the ozone layer in the stratosphere of Earth. UV ozone generators use ambient air for ozone production, no air prep systems are used (air dryer or oxygen concentrator), therefore these generators tend to be less expensive. However UV ozone generators usually produce ozone with a concentration of about 0.5% or lower which limits the potential ozone production rate. Another disadvantage of this method is that it requires the ambient air (oxygen) to be exposed
S-Nitrosothiol exist for their synthesis. They can be synthesized from thiols using NaNO/H+, NO, NO, HNO, NOCl, RONO, NO, HNO, bovine aortic endothelial cells, among others. NaNO/H+ and "tert"-butyl nitrite (tBuONO) are commonly used. Once formed, these deeply colored compounds are often thermally unstable with respect to formation of the disulfide and nitric oxide: "S"-Nitrosothiols release NO upon treatment with acids: and they can transfer nitroso groups to other thiols: "S"-Nitrosothiols can be detected with UV-vis spectroscopy. S-Nitrosothiol "S"-Nitrosothiols, also known as thionitrites, are organic compounds or functional groups containing a nitroso group attached to the sulfur atom of a thiol.