By AW on Tuesday, May 4, 2004 - 02:06 am:
I have summarized the needle wash solution from the forum:
1. 60% MeOH
2. ACN/IPA/H2O (5:1:1)
3. 20:80 MeOH: H2O with 1% HOAC
4. Pure Acetonitrile
5. Pure Methanol
I have carry-over problems from time to time, and am using 100% acetonitrile solution for needle wash (the drug has good solubility in ACN). I'm thinking of changing the needle wash solution to try to improve the problem.
Please give me some suggestions as to which solution to use.
Thanks!!!
By Mike on Tuesday, May 4, 2004 - 10:14 am:
AW,
since you said that the drug has good solubilty in ACN, needle wash with ACN should be ok.
However,
1 check that there is waste coming out when needle wash is performed,sometimes it get 'choked' by air trap. of course, be sure that the needle line is in the wash liquid, not hanging in the air.
2 is your this carry over at the RT where the drug is?
Mike
By Renata on Tuesday, May 4, 2004 - 01:16 pm:
If i use a buffer as a mobile phase, i mix some water with the organic to my needle wash...
it depends on the proportion of the buffer during my analysis, but it's common to use H2O/MeOH 50:50
or H20/ACN 50:50
:o)
Renata
By AW on Tuesday, May 4, 2004 - 07:42 pm: