Effect of folin reagent from different sources on protease determination

Folin reagent was one of the most important reagents in protease determination. The differences between Folin reagent from laboratory and Folin reagent sold were studied. The results showed that there was not significant difference between the absorbance of Folin reagent from lab replaced 30d and Folin reagent sold (p<0.05). The RSD of Folin reagent from lab was between 0.3and 1.67, and Folin reagent sold between 0.63 and 1.49. The precision of them was both higher. The maximum absorption wave length of the chromogenic agent of Folin reagent was with 736-755. And there was no significant difference of the value of the same sample protease between both Folin reagent (p<0.05). Folin reagent from lab based on GB/T23527-2009 was perfect.