• Created : 
  • Modified : 
  • Category :  Agilent Knowledge Portal
  • Entry Type :  Article
  • Product Type :  GC Systems
  • Component :  GC Inlets GC System
  • Product Name :  6820 GC System 6850 GC System 6890 GC System 7820 GC System 7890 GC System 8850 GC System 8860 GC System 8890 GC System Intuvo 9000 GC System
  • Task :  Best Practices Operation
Related Articles

  • Agilent GC Calculators

    This Information Applies To: Agilent GCs Issue Agilent provides free GC calculators and tools to assist with method development. Background Tips : The calculators are available for downloading at Agilent.com . Vapor Volume Calculator Determines the expansion volume of a GC sample solvent at a given inlet temperature and pressure for a specific liner. Performing this calculation ensures that the liner is not overloaded, which can cause backflash. This phenomenon...

  • Peak Size Changes in GC

    This Information Applies To: Agilent GC Systems Issue A change in peak size can occur for single, multiple or all peaks. Other chromatographic problems are identified in Basic Troubleshooting for GC Systems . Regular maintenance of your instrument in accordance with the recommended maintenance schedule will reduce the incidence of chromatography problems. Background Changes in peak size can be the result of changes analytical conditions, sample concentration, or injector problems (...

  • Inlet Liners for GC Trace Analyses

    This Information Applies To: Agilent GC Systems with Split/Splitless (S/SL) inlet Issue Different liners are required for different splitless trace analysis techniques including: General use liners Pressure, temperature, volume (PTV) Hot inlet High recovery Cold multimode Headspace (HS) and purge and trap (P&T) Solid phase micro extraction (SPME) . Inlet liner choice is part of method validation, and the same liner type must be used consistently while running that method...

  • Baseline Instability in GC

    This Information Applies To: Agilent GC Systems Issue Baseline instability that is not reproducible across multiple runs can be introduced at different points including sample introduction, separation, and the detector. The baseline instability causes integration problems, which can lead to inaccurate quantitative or qualitative results. Baseline rises reproducibly, are normal for ramped temperature programs. The change in baseline will be consistent across multiple runs and multiple days...

  • Source of Ghost and Carryover Peaks in GC

    This Information Applies To: Agilent GC Systems Issue Contamination that creates ghost and carry over peaks can be introduced at different points including sample preparation, introduction, and separation. The additional peaks can cause false positive identifications and/or inaccurate quantitative results. Other chromatographic problems are identified in Basic Troubleshooting for GC Systems. Regular maintenance of your instrument in accordance with the recommended maintenance schedule will...

Using the GC Vapor Volume Calculator

Answer

This Information Applies To: The Agilent GC Vapor Volume Calculator.

Issue

The Vapor Volume Calculator determines the vapor volume based on the injection volume, solvent type, inlet head pressure, and the inlet temperature. This calculated vapor volume is compared to the selected inlet liner volume, and the compatibility of the liner and settings is displayed in a color-coded status bar. 

Background

The Vapor Volume Calculator is preinstalled in the OpenLab CDS software. It is available free for use with all other systems and is included in a suite of GC calculators can be downloaded and installed from Agilent.com. 

If the sample gas phase volume exceeds the injection liner volume, the excess vapor will expand into the split vent and septum purge tubing. The volume reaching the column may not be consistent between injections, which may cause poor sample reproducibility. 

Steps to Follow

  1. In the Windows search bar type GC Calculators, double click the GC Calculators App to open the Agilent GC Calculators window. (If not installed, see article link above to download and install). Double click the Vapor Volume Calculator (Figure 1).



    Figure 1. Open the GC calculator app
    1. Search for the app, 2. Double click the app

  2. Enter the relevant data into the calculator (Figure 2).
  3. From the drop-down menus, select the Solvent Properties and the Injection Liner for the current application. The Liner Volume (μL) is displayed below the selected liner.
      
    Tips: The liner part number is written on the side of each liner and also on the liner packaging. Check to make sure the liner installed in your GC matches the liner part number in the drop-down menu on the calculator to ensure an accurate calculation. Remember you can add other liners and/or solvents to your list of available options in the calculator, if necessary.  
  4. Enter the parameters for Injection volume (μL), Inlet Temperature (°C), and Inlet Pressure (gauge). The calculator will calculate the Estimated Volume and the % Capacity of the selected inlet liner. The selected and entered values can be adjusted until you have found a combination that meets the analysis and the vapor volume requirements (green status bar). If the calculated value:
    • Is less than the capacity of the selected liner. The displayed status bar will turn green.
    • Is greater than the capacity of the selected liner. The displayed status bar will turn red.
      
    Tips: After entering a value, place the cursor in a different box a click to ensure that the calculation is updated. 

        

Figure 2. Using the Vapor Volume Calculator

 
Learn how to effectively operate your Agilent Gas Chromatograph: 
GC-MULTI-21903 - GC Calculators: An Introduction eLearning course available from Agilent education
Was this helpful?
Privacy Statement
Terms of Use
Contact Us
Site Help