Identify late eluters

[mohan_2008]

Hi guys,

Is there a quick way to analyze any late eluters when performing method development work. I know that this can be done by extending the normal isocratic run to several minutes (say 30 min).

But, it doesn't seem feasible and sometimes, difficult to track real late eluters.

[HW Mueller]

The problem starts if substances stick to the column or elute very slowly even when running high eluting phases (for instance, pure organic in RP). I have had the situation in UV detection where these finally break through the column and after some time produce a smooth but raised baseline. One can note that one has such a raised baseline by running mobile phase through the detector with the column removed. Sometimes I zeroed the detector during flow without the column, put in the column and took a spectrum of the raised baseline. The spectra were not interpretable.

[tom jupille]

Expanding a bit on bartjoosen's suggestion, compare the width of suspected late eluter to the widths of the neighboring peaks. If the widths are comparable, it's probably a contaminant in that sample. If the extra peak is significantly wider than its neighbors, it's probably a late eluter.