基于紫外吸收光谱的酚类衍生物含量检测研究

Study of Determination of Phenol Derivatives Based on Ultraviolet Absorption Spectra

研究了水溶液条件下苯酚及其酚类衍生物的紫外吸收光谱。2位、3位和4位引入取代基可使酚类化合物的最大吸收波长λmax发生红移,摩尔消光系数εmax明显提高。不同取代位置对λmax和εmax的影响程度不同。与2位和3位相比,4位取代能使最大吸收波长λmax发生较大红移,摩尔消光系数εmax增加较大,这是因为4位取代基能与苯环形成更多共轭结构的缘故。对硝基酚的λmax和εmax的特性研究表明—NO2是酚类化合物较好的助色基。由此,建立了快速测定酚类化合物含量的紫外分光光度法,并选择测定了εmax>10000的四种酚类化合物在土壤中的吸附率。结果显示,酚类化合物在质地粘重的土壤中吸附率较大;高浓度的无机盐溶液能够提高酚类化合物在土壤中的吸附率。

The ultraviolet absorption spectra of phenol and its derivatives were studied under water solution condition. The resuits show that the introduction of 2-, 3- and 4- substituent of group leads to a bathochromic shift of position of the maximum absorption wavelength λmax, and also increases the molar extinction coefficient εmax. However, the extent of influence of substituent of group on λmax and εmax differs with the introduction position. Compared with 2- and 3- substituent, the 4- substituent induces a bathochromic shift of λmax and the increase of εmax more greatly, due to the more formation of conjugated structure between 4- substituent of group and benzene ring. The characteristics of 4-nitrophenol＇s λmax and εmax 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 εmax〉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.