How long does a GC column last?
A related question that we hear quite often is “what is the shelf life of a capillary GC column.” Once again, there are no right or wrong answers and GC columns usually don’t ship with an expiration date on them – but in general, a pretty good guideline guide line is to use the column within about two years to ensure …
What is column degradation?
First, columns are degraded by the build-up of nonvolatile sample residues that interact with target analytes to cause peak tailing, catalytic decomposition, and ultimately loss of separation. Proper sample preparation, the use of a retention gap, and inlet liner maintenance will help alleviate this problem.
How do you increase peak shape in GC?
Steps that can be taken to improve early eluting peak shape:
- 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 happens to columns over time?
Common symptoms of column deterioration include increased column pressure, decreased theoretical plates, shortened retention time, poor peak shape, and decreased resolution.
How do I clean my GC column?
Turn off the carrier gas. Remove the GC column. Remove all injection port consumables (including items such as the injection port liner, inlet seals, septa, fittings, etc). If possible, choose at least one polar solvent and one non-polar solvent which will not contaminate your instrument.
Why capillary column is more efficient than packed column?
A gas chromatography capillary column is a popular type which comes with its stationary phase being coated on its inner surface. These columns are mostly preferred over the packed variants because they require smaller amounts of sample for the chromatography process. The stationary phase gets absorbed by this material.
What causes peak splitting in GC?
Split peaks can show up in gas chromatography when our injection isn’t working right or things aren’t transferring from the inlet to the column correctly.
What are the different 5 phase GC columns?
• Intense QC specifications ensure column-to-column performance There are many different 5 phase GC column variations on the market. All utilize one of two main types of bonded phases: 5 %-Phenyl or 5 %-Phenyl-Arylene. The differences between the two phases can be slight but significant to the chromatographic result.
When does GC capillary column performance degradation occur?
Oxygen is an enemy to most capillary GC columns. While no column damage occurs at or near ambient temperatures, severe damage occurs as the column temperature increases.In general, the temperature and oxygen concentration at which significant damage occurs is lower for polar stationary phases.
What causes sharp edges on a GC column?
This usually occurs when a sharp point or edge is dragged over the tubing. Column hangers and tags, metal edges in the GC oven, column cutters, and miscellaneous items on the lab bench are just some of the common sources of sharp edges or points.
What causes a GC column to overheat?
Overheating a column with a leak or high oxygen levels in the carrier gas results in rapid and permanent column damage. Setting the GC’s maximum oven temperature at or only a few degrees above the column’s temperature limit is the best method to prevent thermal damage. This prevents the accidental overheating of the column.