Protective photo-sensitive

Consequently conventional antioxidant mechanisms must be expected to protect against photo-oxidation. Thus hydroperoxide decomposition to inert molecular products will reduce the rate of photoinitiation and scavenging of any of the free radical species will be beneficial, although the effectiveness of conventional antioxidants in photo-oxidations is limited by their own stability and the photo-sensitizing propensity of their products (3,). 

This material, normally supplied or stored in sealed ampoules and used as a paper chromatography spray reagent, is photo-sensitive. Exposure to UV light causes exothermic decomposition to acetone and chloromethane. Ampoules have burst because of pressure build-up after exposure to fluorescent or direct day light. Store cool and dark, and open ampoules with personal protection. The material also reacts violently with rubber [1,2], It should not be heated to above its boiling point [3], There is also a preparative hazard. 

Removal of photo-sensitive N-protective groups NCOOCHgAr NH... 

Outstanding properties high UV protection efficiency, improved gloss retention, reduced yellowing of clear coats, preservation of photo-sensitive substrates (e. g. wood) ... 

Removal of photo>sensitive protective groups 2,4-Dmitrophenylsulfenyl as O-protective group Protection of carboxyl groups as acyl sulfenates... 

Carboxylic acids from carboxylic acid amides Removal of photo-sensitive carboxyl-protective groups... 

Removal of photo-sensitive protective groups Azidoarylalkoxyl as O-protective group... 

Selective removal of the photo-sensitive protective groups as benzofurans... 

Again, polyesters based on naphthalene-2,6-dicarboxylic acid can meet the desired properties, plus have other additional advantages. Food components containing double bonds or conjugated double bonds are extremely sensitive to light-induced reactions, such as photo-oxidation. The addition of UV stabilizers is therefore necessary to protect the content of PET bottles against UV irradiation. PET, in contrast to PEN, does not show intrinsic UV protection properties. 

The primary advantage of CD complexation is to stabilize and protect sensitive host molecules, such as flavors, odors, or pharmaceuticals. CDs sharply reduce the volatility, chemical, thermal and photo reactivity of guest moleciiles. More recently, CDs have been used for separation of components in solution. For example, CDs can remove reactive components from fhiit juices to prevent oxidation or eUminate bitterness. Attachment of CDs to chromatographic supports provides chiral separation, selective component removal and modified chemical reactivity. A number of modified and pol3nnerized CD materials have gained acceptance as separation media (9). 

In a passive detector developed by the National Radiological Protection Board (Wrixon et al., 1988), the etched pits in the detectors are filled with scintillator fluid. After exposure to radon, the detector is irradiated with an alpha source, and the resulting scintillations counted with a photo-multiplier tube. In this way, track density over 1 cm2 of detector can be measured in a few seconds. Passive detectors used in the UK National Survey were sensitive down to 20 kBq m-3 h of accumulated exposure, equivalent to a radon concentration of 5 Bq m-3 measured over 4000 h exposure. 

It was necessary to use a film thickness of 200 pm for the total photo protection of multivitamin infusions containing ascorbic acid, thiamine hydrochloride, nicotin-amid, and pyridoxine hydrochloride. For amiodarone hydrochloride and a special quinolone infusion, which showed sensitivity to all wavelengths in the UV region up to 400 nm, the photo protection was considerably lower. However, a reduction of drug losses from 59% and 75% to 5% and 7% was still attainable using this cover thickness. It was concluded, that the limit of application for these particular UV protective covers is photolability of drug solutions with activation spectra above 385 tun. 

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