water soluble vitamin - (Mar/02/2009 )

hai
the hydrolysate of water soluble vitamins prefer to store at chiller or -20 degree celcius befroe hplc injection?
since the extraction of water soluble vitamins take a whole day, therefore hard to make an injection in same day.
so everybody got any suggestion

tq very much

-mimosa-

we never did anything more than chill them on ice. most are stable at room temperature.

-mdfenko-

Just wondered what extraction process you use for the water soluble vits and what sample you are analysing (blood, urine, fresh fruit?). I thought the stability of e.g. Vit C in blood was in the order of 3 hours.

How does the HPLC method compare against DCIP titration?

-Paraboxa-

one of the journal got mention that the extractant can store at frozen stage.
but i afraid that in frozen stage the water soluble vitamins will degrade.

-mimosa-

my sample is coconut meat. i using the acid and enzyme hydrolysis.
after the hydrolysis, any clean up procedure required?
should i defat the sample first?
i simultaneous analyze the vitamin b1, b2, b3, b6 and c.
so i don't the different between the DCPIP and HPLC.

tq :ph34r:

-mimosa-

mimosa on Mar 11 2009, 03:34 AM said:

my sample is coconut meat. i using the acid and enzyme hydrolysis.
after the hydrolysis, any clean up procedure required?
should i defat the sample first?

only if there is enough to interfere with the analysis. we removed the fat from samples extracted from blood.

-mdfenko-

should i defat the sample first?

i never use the guard column.
but i think better defat the sample because i observed the fat obtained in the hydrolysate.
then i cleaned up the sample with sep-pak c18 under gravity.
but the vitamins was retained in the sep-pak.
so, what should i do to solve the problem?
my brain is freezed, right now still cannot figure out the ways...
anybody got the opinions?
or who was done this experiment before?
if you don't mind then can send me you protocol?

thank you very much