If one or two peaks are experiencing poor or unstable recoveries while the other peaks are stable, the current to the suppressor might be set too high. Recalculate the correct current setting (see Calculate the electrical current for the suppressor, or use the “signal parameters” tool in Chromeleon). Do not exceed the recommended current setting unless necessary to stabilize a drifting baseline.
Alternatively, the system may be contaminated with a transition metal that is binding to the analyte of interest (see Metal contaminants or precipitates).