摘要
研究对氨基苯甲酸(P-aminobenzoic acid,PABA)紫外吸收光谱的特征,并探究和比较不同测定条件下其吸收光谱的变化及影响。以0.005 mg/mL的对氨基苯甲酸溶液做全波长扫描,后分别调整对氨基苯甲酸的浓度、溶液的PH值以及溶剂极性,用以探究对氨基苯甲酸在测定过程中的影响因素。通过全波长扫描得到苯甲酸的最大吸收波长为265 nm;对氨基苯甲酸溶液的浓度从0.001mg/mL至0.1mg/mL增加的过程中,吸光度也逐渐增加,但并没有呈现一定的线性关系;PH在3.4-8.5的不同条件下的全波长扫描图显示,对氨基苯甲酸的最大吸收波长会发生蓝移,并且吸光能力也会发生变;以蒸馏水、无水甲醇、无水乙醇、二氯甲烷为溶剂时,随极性增加对氨基苯甲酸的最大吸收波长向短波方向移动。对氨基苯甲酸对紫外线具有良好的吸收作用,其在不同浓度、不同PH、不同溶剂的条件下测定会产生一定影响,研究结果对其测定规律进行了补充,为对氨基苯甲酸的测定条件的选择提供了一定借鉴。
This paper objective to research the characteristics of UV absorption spectra about p-aminobenzoic acid( PABA) and explore and compare the changes and effects of the absorption spectra under different measurement conditions. Method With 0. 005 mg/mL p-aminobenzoic acid solution to make the full-wavelength scanning,then exchange the concentration,pH and solvent polarity of p-aminobenzoic acid to explore the influence factors of p-aminobenzoic acid in the determination process. The maximum absorption wavelength of p-aminobenzoic acid was 265 nm by full wavelength scanning. In the process of increasing the concentration of p-aminobenzoic acid from 0. 001 mg/mL to 0. 1 mg/mL,the absorbance increased gradually,but it did not present a complete linear relationship. The full wavelength scan of PH in different conditions of 3.4-8. 5 shows that the maximum absorption wavelength of p-aminobenzoic acid will be hypsochromic shift,and the absorptive capacity will also change. The increasing polarity induced the maximum absorption wavelength of p-aminobenzoic acid was moved in the direction of short wave when with distilled water,anhydrous methanol,anhydrous ethanol and dichloromethane as solvent. The results shows that P-Aminobenzoic acid has a good absorption of ultraviolet light. The concentration,PH and solvents of P-Aminobenzoic acid solution have an important influence on determination. These outcomes would supplement the affection law of determination of p-aminobenzoic acid and provide a certain reference to select conditions for the determination of p-aminobenzoic acid.
出处
《运城学院学报》
2017年第6期32-35,共4页
Journal of Yuncheng University
基金
山西省应用基础研究项目(201701D221045)
关键词
对氨基苯甲酸
紫外吸收
测定条件
p-aminobenzoic acid
ultraviolet absorption
measurement conditions
