UV spectroscopic analysis

Oligomeric hindered amine light stabilisers, such as Tinuvin 622 and Chimassorb 944, resist satisfactory analysis by conventional HPLC and have required direct UV spectroscopic analysis of a polyolefin extract [596], PyGC of an extract [618,648], or SEC of an extract [649]. Freitag et al. [616] determined Tinuvin 622 in LDPE, HDPE and PP by saponification of the polymer dissolution in hot toluene via addition of an... 

A comparable monodentate role, but without crystallographic support, was proposed on the basis of UV spectroscopic analysis for complex 77 from reaction of [(bpy)(tpy(RuCl]PF6 (tpy = 2,2 6,2"-terpyridine) with thianthrene and Ag" " at room temperature (85IC1464). 

Background and principles UV spectroscopic analysis was one of the first applications of spectroscopy in an analytical context. While a powerful technique of yesteryear, this method is now rather restricted in its use in a modem bioanalytical laboratory. However, UV/visible spectroscopy is still used in specific biochemical analyses, such as dyestuffs in forensic applications. Despite these limitations, a bench spectrophotometer that measures UV/visible absorbance is commonly found in both teaching and research laboratories. In order to better understand the underlying principles it is necessary to consider the excitation of electrons, electronic transition and how this is related to energy and absorbance. 

Microchip designs allow on-line monitoring of the reaction, for example, by UV-spectroscopic analysis of the effluent [141]. 

The interaction between the azo initiator and DC was researched by UV spectroscopic analysis. The DC is low solubility in most solvents and their concentrated solutions (more than 1 x lo mol/1) carmot be practically prepared. The DC concentration was 200 times less than AIBN, and the DC do not have ar absorption bands in the area of 345 nm. 

Suggest a method based on UV spectroscopic analysis of products that will distinguish whether 1,2 or 1,4 addition occurred when methylmagnesium bromide reacts with (E)-4-cyclopentyl-l-phenylbut-3-en-2-one. 

This baseline correction technique can obviously be applied to the determination of styrene monomer in PS only if any other UV absorbing constituents in the polymer extract (e.g., lubricant, antioxidants) absorb linearly in the wavelength range 288-300 nm. If the polymer extract contains polymer constituents other than styrene with non-linear absorptions in this region, then incorrect styrene monomer contents will be obtained. An obvious technique for removing such non-volatile UV absorbing compounds is by distillation of the extract followed by UV spectroscopic analysis of the distillate for styrene monomer as described next. 

JL Gerlock, RO Carter, M Agarwal. Photoacoustic FTIR and UV spectroscopic analysis of clearcoat photooxidation and UVA disposition in Florida test panels. Technical Report No. SR-95-041 Ford Motor Company, 1995. 

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