Determination of m-cresol content in waste water by differential spectrophotometry

The m-cresol content in waste water is determined by differential spectrophotometry,which is yielded in preparation of m-cresol by diazotization and hydrolyzation with m-toluidine in the paper.On the basis of m-cresol reference solution,m-cresol in NaOH is scanned with ultraviolet spectrometer under determination wave length 237 nm.△A is determined,and the content of m-cresol in waste water is obtained.The average rate of recovery of m-cresol is 100.3%,the relative standard deviation of m-cresol is 2.1%.The comparison between the results by differential spectrophotometry and those by 4-amido antipyrine spectrophotometry indicates that the difference between the m-cresol content in waste water with these two methods is insignificant.The experiments show that the determination method of differential spectrophotometry is simple,rapid and accurate.