# In Ion Chromatography instrument, Does the specific conductivity (peak area) of an analyte depends upon background conductivity?

In Ion Chromatography instrument, Does the specific conductivity (peak area) of an analyte depends upon background conductivity ?

Assume Specific Conductivity (peak area) of fluoride ion is 4 unit for 1 ppm fluoride standard with background conductivity of 15 uS/cm (Carbonate/ bicarbonate eluent with suppression.

What will happen if the background conductivity increases to 30 uS/cm or 50 uS/cm.

Pl do not consider the change in retention time.

https://www.metrohm.com/easyDB/Web-61006520_std_carbonate/orig

The heart of an ion chromatograph is the suppressor, whose sole purpose is to minimize the background conductivity and convert analytes into highly conductive ions for example fluoride ion becomes HF, chloride becomes HCl and so on. If your background conductivity is high, it means that the conversion of F(-), Cl(-) into corresponding acids is also not 100% efficient-peak height can potentially decrease as a result. The peak areas will also change. Although the background is higher, one can still make a calibration curve (it will be less sensitive than the one with low background). Remember that peak area in chromatography is not an absolute measure like mass; it is only true for one particular condition and set-up.

Does the specific conductivity (peak area) of an analyte depends upon background conductivity?

It depends on how the background measurement is made by the instrumentation. (How overlapping peaks are handled would be a different but related problem...)

In this day and age I'd expect the spectra to be digitized and processed by a microprocessor system at least. One way to handle the background would be to sample regions on both sides of the peak and then draw a best fit line through those two regions to serve as the background for the peak. Thus the S/N ratio decreases as background increases and the area would be measured with less precision, but the same accuracy.