Peak Shape Problems: Sensitivity Loss

When sensitivity loss occurs, it can significantly impact the accuracy and reliability of analytical results. Several factors can contribute to sensitivity loss, such as column contamination, sample matrix effects, injector and detector issues, or improper sample preparation. This technical note aims to guide analysts in identifying the common causes behind sensitivity loss and implementing effective strategies to address the issue.

Symptom: Decreased Response

Some or all peaks are displaying decreased response.

Possible Cause  /  Suggested Remedy

• Contamination of column and/ or liner can lead to loss of sensitivity for active compounds.: 
  • Clean liner.
  • Bake out the column. Solvent rinse or replace the column.
• Injector leaks reduce the peak height of the most volatile components of a sample.: 
  • Find and fix any leaks
• If initial column temperature is too high for splitless injection, this prevents refocusing of sample. This affects the more volatile components most.: 
  • Lower temperature below the boiling point of the solvent. Decrease the initial column temperature, or use a less volatile solvent
• Inlet discrimination: injector temperature is too low. Later eluting and less volatile compounds have low response.: 
  • Increase the injection temperature or use on-column injection with direct connect liner
• Issues with the sample: 
  • Check the sample concentration, any sample preparation procedures, and shelf life. Prepare a fresh sample ensuring the proper concentration

In conclusion, sensitivity loss in GC is characterized by decreased response in one or more peaks, which can hinder accurate and reliable analysis. It is crucial to maintain a clean column and liner, address any injector leaks, optimize column conditions, and ensure proper sample preparation. Remember to regularly perform maintenance tasks and quality checks to ensure the ongoing performance of the GC system.

By implementing these countermeasures, you can overcome sensitivity loss and achieve more accurate and reliable analytical results.