Hye all...
i got prob with methyl salicylate assay..
im not sure whether i understand the procedure..
but everytime i did the analysis.. i didnt get the result..
so i have to do GC analysis to get the assay rather than do it by titration..
here is the procedure for methyl salicylate assay by titration
1.Dsolve 0.500 g in 25 ml of alcohol R.
2.Add 0.05 ml of phenol red solution R and neutralise with 0.1M sodium hydroxide.
3.To the neutralised solution add 50.0 ml of 0.1M sodium hydroxide and heat under a reflux condenser on a water-bath for 30 min.
4.Cool and titrate with 0.1M hydrochloric acid.
5.Calculate the volume of 0.1M sodium hydroxide used in the saponification.
6.Carry out a blank titration.
1 ml of 0.1M sodium hydroxide is equivalent to 15.21 mg of C8H8O3.
i really want to know what does it mean by Add 0.05 ml of phenol red solution R and neutralise with 0.1M sodium hydroxide
coz when i add with phenol red solution the colur of solution became red. when it says neutralised with sodium hydroxide does it mean i have to add with NaOH untill the colur become deep pink?
reallt need your attention... thanx all