[booya]

Hi everyone! Thanks for the help in advance.

So I'm doing an experiment that deals with High Performance Ion Chromatography. I'm using a carbonate/bicarbonate buffer as the competing ion on an anion resin. My analyte ion is Cl(-), NO3(-) and SO4(2-).
Let's say for the first run, I prepare an eluent solution of 0.0019M NaHCO3 and 0.0120M Na2CO3 in 250mL water). I know I can calculate the pH of the system by taking the ratio between the carbonate and bicarbonate amounts and using their pKa's.
I'm supposed to plot log((tr - to)/to) vs. -log carbonate concentration. I was wondering if the -log carbonate concentration is the total carbonate (bicarbonate + carbonate) or just the carbonate part? The experiment adds the same amount of carbonate, but varying amounts of bicarbonate... So is it really asking for the bicarbonate concentration? Or the sum of both? If the latter is true, do I just add the two concentrations together?

Thanks so much!

[booya]

Never mind! I figured it out! =)