Chromatography Forum

We be normally qualifying the HP1200 carryover using the UV detector. Howevers, the UV detector be out of available so we look at qualify carryover using CAD which also attached to HP1200. However, response from Caffine is very low. Is there anyone knowing more suitable alternative moecule to assess carryover on ChAD?

The evaporative detectors, as a group, do not show nearly the variation in response of a UV detector. In essence, they detect dust; dust is dust, and you get about the same response regardless of the composition.

My understanding is that the detection limit of the CAD is down in the low nanogram range. I you are doing significantly worse than that, you might try tweaking the parameters (nebulizer gas flow and temperature, mobile phase flow, and perhaps mobile phase viscosity). If you have already done that, your only option is to increase the mass injected.

Is this now accepted GLP, or whatever, procedure to check the carryover with a substance other than the analytes? In my experience there has been a strong dependence of carryover on type of analyte.

In OQ context, it is necessary and accepted to use some kind of generic standard/test material. Could be caffeine, uracil or whatever makes sense.

In PQ context, however, the carryover is/must be tested using the actual analyte.

Best Regards