Projects

GC:MS applications

Foods: GC:MS is extensively used to analyse free fatty acids, sterols, esters, aromatic hydrocarbons and aldehydes.
Perfumes and Essential oils: GC:MS can separate, closely related molecules and distinguish between volatile alcohols and terpenes.
Hydrocarbons: GC:MS separates isomers with the same molecular weight, distinguishing between structural isomers and even cis/trans isomers.
Environmental: GC:MS is routinely used in identifying pesticide, organic pollutants and plastic contamination.
Biofuels: GC:MS can analysis and quantify the components of biofuels to establish whether they are a good substitute for the petroleum industry.

Free Fatty Acid (FFA) and Sterol Analysis by GC:MS.
Fatty acids and long chain sterols must be derivatized before injecting into the GC:MS.
This procedure involves a TMS agent and heating. The TMS agent is chosen according to the availability of the oxygen atom to be derivatized. Hindered alcohol groups require a specialised agent and longer heating times.
We use TMS reagents purchased from Regis Technologies.

We can advise on pre-analysis clean up of samples to achieve the best results.
Quantification can be achieved by internal and external standards.
Kovats index can be calculated for chromatographic peaks.
Mass Spectra synchronised with reliable databases and our own database.
Typical analysis of FFA and Sterols, on oils, nuts, seeds and other plant material.

Analysis of essential oil components.
By mass spectral fingerprint, Kovats Index and comparisons with reliable databases.
These oils contain dozens if not hundreds of distinct compounds, some of which are incredibly similar.
These molecules have the same molecular weight MW: 204.35 g/mol, but are different compounds.
GC:MS will separate them.
Calculation of the Kovaks Index and the individual mass spectra aids in their identification.

Chromatography peaks tell you when and how much compound you have.
The Mass Spectrum shows you the compounds fragmentation pattern, which acts as a molecular finger print.
The Kovats Index, provides a dimensionless unit for comparison with other databases.

A dimensionless quantity that characterizes each GC:MS eluted compound, according to a linear retention index and eradicates instrument variations e.g. oven temperature, gas flow etc. but not column differences.
The retention times of a known C₇-C₄₀ alkane standard is used to calibrate KI.
We have a software program that then generates the KI from the retention times of the standard alkane above and below the analyte of interest .

We have various GC:MS methods for analysing hydrocarbons of different volatilities.
Equivalent Carbon Length (ECL) can be generated, to establish the number of carbons in each chromatographic peak. Mass Spectra and databases can then be used to identify each chemical species.

Applications:

A dimensionless quantity that characterizes each GC:MS eluted compound, according to a linear retention index and eradicates instrument variations e.g. oven temperature, gas flow etc…….but not column differences.
The retention times of a known C₇-C₄₀ alkane standard is used to calibrate ECL.
We have a software program that then generates the ECL numbers from the retention times of the standard alkane above and below the chromatographic peak of interest

Generally, the HP GC:MS can detect chemical species down to the 10ng per µL, quantities.
If your analyte is below this concentration we can get access to an, Agilent 5975 series MSD
Agilent 7820A GC System.
With a detection limit of the order, 1ng per µL, depending on the chemical species.

Garbage in Garbage OUT!
We can advise on the best pre GC:MS clean up procedures.
We have a number of solid phase extraction procedures (SPE) we use to chemically separate sample components. As well as liquid extractions.
Physical extraction can also be achieved by centrifuge techniques.
For larger projects we can train and assist you, to use the GC:MS instrument and achieve the best results.

Sharon Curtis was very proud to accept the UOttawa President's award for Service Excellence in 2017.
Sharon Curtis accepted the Platform Scientist Award 2021, for cutting edge research.
Sharon Curtis completed a mini course in Anatomy and Physiology with Aromahead Institute 2021.
Sharon Curtis became an Essential Oil Specialist in 2022, with Aromahead Institute.
Sharon Curtis qualified as a Certified Aromatherapist in 2022 with Aromahead Institute.