Chromatography Forum

Hi
I have Thermo Fisher IC1100 IC with AS9-HC column and AG9-HC guard column.
I have recently completed anaysis of 1000 coal sample for floride and chloride.
After that I run a quality check analysis. Everything looks fine for the 12-13 minutes. Then phosphate and sulphate started comes and they started to overlap. Before these analysis phosphate retention was 17:30 and sulphate 19:30. Now, 14:30 and 16:00.
Need a suggestion for maintance... Or do you suggest to replace guard column or both column.

Good Morning,

Usually a 10X-concentrated eluent is recommended for cleaning Dionex IC anion exchange columns...you could try this, but my feeling is that more likely it would be better to procure a new guard and analytical column. The cleaning may not work...and it would take some quite time to do, I'd guess. Let us see how others weigh in, and thank you.