Homework on Quantitation

The file with GC-MS data for MassHunter (alternatively ChemStation) should be copied to the desktop in the computer lab, Abbott Hall 343, UND. The instructions and videos on how to work with the data are provided below in the Lab assignment.

MassHunter

Instructions for homework using MassHunter

MassHunter Datafiles to Download

ChemStation

Instructions for homework using ChemStation

ChemStation Datafiles to Download

Lab: GC-MS Quantitation

Gas chromatography coupled with mass spectrometry (GC-MS) is an analytical method used for the identification and quantification of numerous volatile compounds. The qualitative GC-MS analysis is conducted by matching the retention time of given unknowns and mass spectra of known chemicals, typically electron ionization (EI) mass spectra with known standards or libraries. The quantitative analysis in a total ion current mode (TIC) can be performed as a traditional GC analysis based on the total peak area, however, the correct approach to quantification is based on the peak area of a specific ion. In addition to the instrumentation, quantification is also dependent on the type of calibration method used. Various calibration methods such as external standard calibration, internal standard calibration, and method of standard addition, may be performed. Today, the most common in gas chromatography is the internal standard calibration.

The aim of this lab assignment is to pursue GC-MS analyses using the internal standard calibration with selected compounds of interest to the trainee; determine their instrumental limits of quantification, and validate the method based on replicate determination of the targeted compound in an evaluation sample of a defined (known) and unknown composition.

Assignment Materials

GC-MS Quant Lab Assignment Instruction

Solution Preparation in Pictures

Sample Preparation Excel Example

Prelab Test

Test Mix Processing

Test Mix Processing Training

Video Tutorials

Labs

• Lab stock preparation from a chemical in a solid state

• Lab stock preparation from a chemical in a liquid state

• Performing serial dilution for internal standard calibration

MassHunter Data Processing

• Navigating MassHunter Qual 10

• Viewing data in MassHunter (scaling and zoom)

• Identification in GC-MS analysis

• General peak integration (TIC)

• Quantification using extracted ion current (EIC) chromatograms 

ChemStation Data Processing

• Storing and transferring the data for GC-MS data processing

• View chromatograms and mass spectra in MSD Chemstation

• Extracted ion integration in MSD ChemStation

Advanced Processing

• ChemStation - Creating an automatic quantification method

• ChemStation - Creating database for peak areas (from quant method)

MS Excel Data Processing

• How to organize data in MS Excel - Stock solutions

• Serial dilution in MS Excel

• Internal standard calibration in Excel Part 1

• Internal standard calibration in Excel Part 2: Charts

• LOD and LOQs with LINEST