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Anyone ever worked on Idarubicin, Doxrubicin, etc?
Posted: Fri Nov 30, 2007 6:51 pm
by firework1
I am working on HPLC assay of idarubicin and doxrubicin. These compounds are so sticky to metals, I got huge carry-over peaks.
Could anyone tell me what did you use as needle wash solvent so that they could get out? Or, do you ever has similar problems?
Posted: Fri Nov 30, 2007 9:30 pm
by unmgvar
what are the solvent used for the sample preparation?
what type of instrument are you using; what is the model of the autosampler?
Posted: Fri Nov 30, 2007 9:40 pm
by Bryan Evans
Have you tried adding EDTA to your mobile phase?
Posted: Fri Nov 30, 2007 9:42 pm
by firework1
what are the solvent used for the sample preparation?
what type of instrument are you using; what is the model of the autosampler?
I am using 0.1M phosphate buffer (pH=2.2) 79% and ACN 21%
Thermo Surveyor
Thanks for your quick reponse, I am so desperate.
Posted: Sat Dec 01, 2007 6:32 am
by unmgvar
just to be sure; the solvents with which you make up your sample are your mobile phase?
almost all cases of carry over are due to a contamination of the external part of the needle when the injection system like in your case is a split loop type.
you need to make sure of 2 things:
1.that in your software you have the correct settings that tell the needle to perform a wash, especially after you have drawn sample from the vial.
2. have the correct wash solvent. sometimes this needs to be tested in order to get the right mixture. becasuse it seems that you have buffer in your sample solution i would start with a solution made up of 85-90% water and 15-10% isopropanol.
be aware that in the case of buffers in the sample solution you need to make sure that your wash solvent can deal with the salts, otherwise you will find yourself with a reproducability issue after you solve your carry over problem, and also maybe leaks from the injection port.
Posted: Thu Dec 20, 2007 11:46 am
by kmaudens
I don't know if your problem in the meanwhile has been solved. If not, you could try the following:
Replace your phosphate buffer in the mobile phase by 0.1% formic acid (resulting pH about 2.7). This will probably not have a major impact on the retention of your anthracyclines.
For injection, use also the water:acetonitrile:formic acid mixture (79:21:0.1). In this way you can use pure methanol as washing solvent.
Washing your needle and injection port 4 times with 100% methanol will normally eliminate carry-over.