title: [Rate of controlled-release urea pervasion through membrane determined by ultraviolet spectrophotometry].
abstract: Application of controlled-release nitrogenous fertilizers can improve the efficiency of fertilizers and reduce the environmental pollution. Controlled-release urea (coated urea) is one of the controlled-release nitrogenous fertilizers developed quickly in the recent years. The rate of controlled-release urea pervasion through membrane is the most important index of the capacity of controlled release. There is a maximum absorption at lambda=426 nm with complex in acidic solution, using p-dimethylaminozenzaldehyde as color reagent, and the absorbance exhibits a linear reponses to the urea concentration over the range of 7.5-210 microg x mL(-1). The method for determining the rate of controlled-release urea pervasion through membrane was realized through determining the content of urea in the liquor, the recovery efficiency of the method is 96.1%-103.9%.
authors.affiliation: Dalian Institute of Chemical Physics, Chinese Academy of Sciences.
authors.forename: Xiu-jin
authors.initials: XJ
authors.lastname: Zuo
authors.forename: Zhen-xin
authors.initials: ZX
authors.lastname: Wang
authors.forename: Xiao-min
authors.initials: XM
authors.lastname: Dai
authors.forename: Yi
authors.initials: Y
authors.lastname: Zhou
authors.forename: Xiao-jun
authors.initials: XJ
authors.lastname: Ma