What is the reasons for peak tailing and fronting?
Good separation and asymmetric peak shape are the goals of gas chromatography and high-performance liquid chromatography. The most common method development issues in chromatography are peak tailing and peak fronting. Chromatographer need to identify what causes peak tailing and front so that they know how to fix them.
A peak asymmetry factor (As) greater than 1.0 indicates peak tailing and peak asymmetry less than 1.0 indicates peak fronting, although peaks less than 2.0 appear acceptable in many of the tests.
Here are some common reasons for peak tailing and fronting in chromatography.
Reasons for Peak tailing in chromatography:
Overloading of sample solution:
After each analysis, if the column is not properly cleaned, it can form over time and change the surface chemistry of the stationary phase.
Flow path diffusion:
Peak tailing can be caused by incorrectly fitted connectors/fittings, or by a column with a capillary connection line that is too small.
pH of the mobile phase:
The peak tailing may occur if the pH of the sample is different from the mobile phase by 2 pH units, as well as if the sample is easily ionized.
Reasons for Peak fronting in chromatography:
Overload of sample solution:
During both GC and HPLC separations, peak fronting will show if the analytical column exceeds the sampling capacity.
Saturation of the peak detector:
When overloading of the column leads to a change in peak shape, overloading the detection range can also lead to distortion and loss of signal saturation.
Peak fronting is also caused by a poorly packed column, channeling in a packed column, dead volume inflow paths, and a weak mobile phase
Poor sample/Peak Capacity:
It occurs when the analyte does not retain on the HPLC column, causing no correct separation to occur.
These are some reasons for peak tailing and fronting in chromatography.
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