Introduction
Gas chromatography (GC) is a common analytical technique used in many scientific laboratories. However, like many complex pieces of equipment, GC units can sometimes encounter problems. This article will detail tips for troubleshooting the most common issues faced by technicians and present solutions to get your GC system up and running again.
Low Peak Height
The sample being too large or too small may cause low peak height. First, inspect the sample size. If it’s too small, increase it and check if the peak height improves. Too much sample can overload the detector, so if your sample is too large, reduce it. Regular upkeep of the injector parts, such as o-rings, seals, and liners, is also essential as damaged parts can cause sample losses.
Noisy Baseline
Contamination is a common reason for a noisy baseline. Systematically check the GC system for leaks, contamination in the gas lines, carrier gas purity, and injector or detector contamination. Replacing old carrier gas tanks, cleaning the injector, and using a refurbished Agilent GC can help solve this problem.
Split Peaks
Split peaks often happen due to insufficient sample vaporization. Use temperature programming to ensure complete vaporization of the sample. Also, make sure the split ratio isn’t too high as this can cause sample discrimination. The use of improper or irregularly sized liners can cause split peaks; therefore, the right liner size is essential.
Ghost Peaks
Ghost peaks can be a result of contamination from previous samples, especially if highly concentrated samples were run. To prevent this, it’s critical to thoroughly clean the injector and sampling system and replace the septa regularly. Use a solvent rinse between injections for thorough cleaning.
Retention Time Variability
Uneven pressure or flow in the carrier gas line often contributes to retention time variability. Checking and adjusting the pressure and flow rate can help. Temperature instability can also play a role. Make sure the oven is properly functioning by checking and adjusting the temperature to the required level.
Broad Peaks
If peaks are broad, first check the temperature program to ensure it isn’t too slow. Examine the injector parts and the columns for any damage. Replace worn-out or damaged parts promptly.
Conclusion
These are common GC troubleshooting tips for technicians. Regular preventive maintenance can help prevent some of the issues. If specific parts are damaged, consider purchasing a refurbished Agilent GC to replace worn out parts.
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