What is tailing in column chromatography?
What is tailing in column chromatography?
The chromatographic peak in (a) is an example of tailing, which occurs when some sites on the stationary phase retain the solute more strongly than other sites. The peak in (b) is an example of fronting, which most often is the result of overloading the column with sample.
What causes fronting and tailing in chromatography?
Peaks fronting occurs when the sample capacity of the analytical column is exceeded, which can happen in both GC and HPLC experiments. This overloading effect results from poor sample solubility in the stationary phase, the injection of too much sample, or operating at a “k” value (capacity factor) that is too low.
What causes peak tailing in GC?
The most common cause of peak tailing for nonactive compounds is column contamination. These contaminants are relatively nonvolatile, and they accumulate in the column over time. These types of contaminants usually originate in the sample and are species such as polymeric materials, salts, and proteins.
How do you increase peak tailing in GC?
How do I improve early eluting peak shape for GC?
- Use a split injection. This limits the amount of solvent that gets onto the column and reduces how much analyte dissolves in pooled solvent.
- Decrease the injection volume.
- Use a pressure pulsed injection.
- Use a guard column.
- Increase the column film thickness.
What is meant by tailing factor?
Symmetry factor (S, also called “tailing factor”) is a coefficient that shows the degree of peak symmetry. Caution is required since both the theoretical plate number and symmetry factor can change depending on the type of analysis and analytical conditions used.
How do you calculate tailing?
The tailing factor is determined by drawing a perpendicular line from the peak centre to the baseline of the peak. Then the peak width and the front half-width are measured for the peak at 5% of the height of the peak. The tailing factor is simply the entire peak width divided by twice the front half-width.
What is peak tailing and fronting?
Peak Tailing Tailing is basically the inverse of fronting. The peak is presented asymmetrically, with a broader second half and a narrower first half – breaking away from the ideal peak shape, with its symmetrical Gaussian profile.
What is peak tailing in gas chromatography?
GC Diagnostic Skills I | Peak Tailing Peak tailing is a problem which is regularly encountered in capillary gas chromatography (GC). It can cause issues with resolution and peak integration, affecting both qualitative and quantitative analysis.
Why are the peaks of the column tailing?
If the column suffers from severe contamination of the stationary phase film (especially at the inlet end), then all peaks may also show tailing behaviour, due to the non-ideal partitioning of the analyte and/or analyte partial exclusion from the stationary phase.
Is there a problem with peak tailing in GC?
Peak tailing is a problem which is regularly encountered in capillary gas chromatography (GC). It can cause issues with resolution and peak integration, affecting both qualitative and quantitative analysis.
Is it possible to remove tailing from a peak?
This effect is most clearly seen close to the baseline and is known as peak tailing. It is very difficult to remove all of the tailing from a peak, even for new columns.