【摘要】 运用分光光度法对对二甲氨基苯甲醛和尿素在酸性条件下生成的黄棕色化合物进行测定,确定测定的最佳波长后,通过单因素实验确定了影响测定的主要因素,并以尿素用量、对二甲氨基苯甲醛用量、反应温度和浓硫酸用量等为考察因素设计正交实验以优化测定条件。结果表明:尿素的最佳测定波长为426nm;最佳测定条件为:200mg·L-1尿素溶液用量14mL、对二甲氨基苯甲醛用量10mL、反应温度30℃、浓硫酸用量0.4mL。尿素浓度在100~800mg·L-1范围内与吸光度呈现良好的线性关系,线性回归方程为A=0.0006c+0.0168,相关系数R=0.9996。该方法操作方便、快速、准确度高、重现性好,能够用于溶液中尿素浓度的测定。更多还原

【Abstract】 A yellow brown compound had been synthesized under acidic condition by using PDAB(paradimethyl-amino-benzaldehyde)and urea,which was studied by spectrophotometry.After the optimum wavelength was determined,the single factor experiment was carried out to find the major influential factors on the determination.Then orthogonal experiment was designed with urea amount,PDAB amount,reaction temperature and concentrated sulfuric acid amount as the factors explored to optimize the determination conditions.The results showed that the optimum wavelength was 426nm and the optimum determination conditions were as follows:200mg·L-1 urea amount was 14mL,PDAB amount was 10mL,reaction temperature was 30 ℃ and concentrated sulfuric acid amount was 0.4mL.Absorbance was linear with urea concentration in the range of 100~800mg·L-1 and the corresponding regression equation was A=0.0006c+0.0168with a correlation efficient of 0.9996.The method is simple,rapid and accurate for the determination of urea concentration in solution.更多还原