[Study of determination of phenol derivatives based on ultraviolet absorption spectra]

The ultraviolet absorption spectra of phenol and its derivatives were studied under water solution condition. The results show that the introduction of 2-, 3- and 4- substituent of group leads to a bathochromic shift of position of the maximum absorption wavelength lambda(max), and also increases the molar extinction coefficient epsilon(max). However, the extent of influence of substituent of group on lambda(max) and epsilon(max) differs with the introduction position. Compared with 2- and 3- substituent, the 4-substituent induces a bathochromic shift of lambda(max) and the increase of epsilon(max) more greatly, due to the more formation of conjugated structure between 4-substituent of group and benzene ring. The characteristics of 4-nitrophenol's lambda(max) and E(max) supply evidence that nitro is a better auxochrome for phenol derivatives. So UV methods were established for the determination of the contents of phenol derivatives. Using these methods, the adsorptive percentage of four phenol derivatives with epsilon(max) >10 000 was determined, which indicates that phenol derivatives have larger adsorptive percentage in soils with heavy texture, and the solution of inorganic compound with larger concentrations could increase its adsorptive percentage.