Catechol 99+% (Nitrogen flushed) smelly and turns into brown colour, can it still be use?

Hi I am currently working on the determination of enzyme activity by using Polyphenol Oxidase(PPO) Assay Method. In this method, i am using polyvinylpolpyrrolidone(PVPP) mixed with citrate buffer...

25 July 2016 9,238 3 View