Dealing with high salt samples
Posted: Tue Feb 02, 2016 2:46 pm
I am running into a bit of a snag with CE. A lot of my samples are very high in salt mainly NaCl. I work with dried flavor powders. They average 25% weight NaCl but can go even higher. Anyways the high salt is causing terrible peak shape from destacking and significant migration time shifts.
I am running a method for Inosinate, Guanylate, and Thiamine on a 50um-50cm cap using 60 mmol/L borate/2-amino-2-methyl-1-propanol-80 mmol/L sodium dodecyl sulfate (pH 9.6) BGE. My LOQ is 10ppm injection so with a 1/10 dilution my sample LOQ is 100ppm.
Is there anything I can do other than dilute the sample more and lose more sensitivity? I am playing with increasing the borate/AMP to as high as 500mM though that will slow the EOF and may cause heating issues. I am also unsure of the solubility of the SDS in that high salt.
I am running a method for Inosinate, Guanylate, and Thiamine on a 50um-50cm cap using 60 mmol/L borate/2-amino-2-methyl-1-propanol-80 mmol/L sodium dodecyl sulfate (pH 9.6) BGE. My LOQ is 10ppm injection so with a 1/10 dilution my sample LOQ is 100ppm.
Is there anything I can do other than dilute the sample more and lose more sensitivity? I am playing with increasing the borate/AMP to as high as 500mM though that will slow the EOF and may cause heating issues. I am also unsure of the solubility of the SDS in that high salt.