Study on the Optimum Condition by Colorimetry

China is a large agricultural country,a great amount of urea are used,it causes soil and water quality pollutions. When urea content is above 1%,the using of dimethylamino-benzaldehyde method is more accurate,quick,simple operation. dimethylamino-benzaldehyde colorimetry in the determination of trace urea of reproducibility is poor,sample recovery rate is low,not conducive to guide the production process. In order to effectively monitor the production,and ensure the quality of the qualified rate of recovery and control the future of the analysis of the data in the error within the allowable range,dimethyl- amino- benzaldehyde colorimetry was improved properly,it can greatly improve the sensitivity and accuracy. The method of optimal conditions was studied through the different conditions of dimethylaminobenzaldehyde colorimetry.