GC-MS Analysis – Identification and Quantification of Organic Compounds

BJL Laboratoires provides GC-MS analysis, using gas chromatography coupled with mass spectrometry, to identify and quantify organic compounds in various environmental and industrial matrices.

GC-MS combines the separation capabilities of gas chromatography with the molecular identification information provided by mass spectrometry. It is particularly useful for investigating volatile or semi-volatile organic substances, solvents, contaminants and pollutants.

What Is GC-MS?

GC-MS stands for Gas Chromatography–Mass Spectrometry, combining gas chromatography with mass spectrometry.

The analysis involves two complementary stages:

• Gas chromatography separates the different substances present in the sample;
• Mass spectrometry provides a characteristic spectrum that helps identify or confirm the detected compounds.

GC-MS is particularly suitable for compounds that are sufficiently volatile and thermally stable to be separated by gas chromatography.

Why Use GC-MS Analysis?

GC-MS can be used when it is necessary to separate, identify and quantify several organic compounds present in the same sample.

Applications include:

• identification of organic compounds;
• quantification of target compounds;
• testing for solvents;
• testing for contaminants;
• analysis of volatile or semi-volatile compounds;
• comparison of samples;
• raw material testing;
• investigation of organic pollution;
• development of specific methods.

Which Compounds Can Be Analysed by GC-MS?

GC-MS can investigate a wide range of volatile or semi-volatile organic compounds.

Feasibility depends on factors including:

• the compound’s volatility;
• its thermal stability;
• the matrix;
• the target concentration;
• sample preparation;
• the availability of analytical standards.

Depending on the application, suitable compounds may include:

• organic solvents;
• hydrocarbons;
• aromatic compounds;
• volatile organic compounds – VOCs;
• semi-volatile compounds;
• organic contaminants;
• certain environmental pollutants;
• substances originating from industrial processes.

Requests are assessed individually to determine whether GC-MS is the most appropriate technique.

Identification of Unknown Compounds by GC-MS

Mass spectrometry provides a characteristic fragmentation spectrum of the detected compounds.

In some situations, comparison with spectral libraries can provide a tentative identification.

This approach is particularly useful when an unknown substance appears:

• in a product;
• in a raw material;
• in an effluent;
• in a residue;
• in an extract;
• in a contaminated sample;
• in an industrial process.

However, identification depends on the compound’s concentration, the quality of the spectrum, the complexity of the matrix and whether the compound is represented in the available libraries.

Investigation of Organic Contaminants

GC-MS can support the investigation of unexplained organic contamination.

An analytical strategy may compare:

• a conforming product and a non-conforming product;
• different batches;
• a raw material;
• a finished product;
• a cleaning solution;
• an effluent;
• a control sample.

Comparing chromatographic profiles and identified compounds can help guide the investigation of the contamination source.

Explore our support for non-conformity investigations

Solvent Analysis by GC-MS

Gas chromatography is particularly suitable for analysing many organic solvents.

Requests may involve:

• testing for residual solvents;
• checking the composition of a mixture;
• investigating contamination;
• comparing batches;
• monitoring a process;
• identifying a volatile compound.

The method depends on the target solvent, matrix and concentration range.

Analysis of Volatile Organic Compounds – VOCs

Volatile organic compounds may be present in products, materials, water, process streams or effluents.

GC-MS is particularly suitable for analysing many VOCs.

Depending on the matrix and objective, preparation may require a specific sample introduction or extraction technique before analysis.

Water and Effluent Analysis by GC-MS

GC-MS can also be used to investigate certain organic pollutants in water, industrial effluents and aqueous discharges.

Depending on the target compounds, sample preparation may be required to:

• extract compounds from the aqueous matrix;
• concentrate the analytes;
• reduce interferences;
• improve quantitative performance.

The analytical strategy is defined according to the target compounds and expected concentrations.

Soil and Material Analysis by GC-MS

Certain organic contaminants present in soils, excavated earth or materials can also be analysed by GC-MS following suitable preparation and extraction.

Depending on the investigation, testing may target hydrocarbons, aromatic compounds or other organic pollutants.

Explore our soil and excavated earth testing services

GC-MS and PAH Analysis

Polycyclic aromatic hydrocarbons – PAHs are an important family of organic pollutants.

Different chromatographic techniques may be used for their analysis, depending on the method and matrix.

BJL Laboratoires provides PAH testing in asphalt and other matrices covered by its services.

Explore our PAH testing services for asphalt

Custom GC-MS Analysis

Do you need to test for a compound that is not covered by a standard service?

BJL Laboratoires can assess the feasibility of custom GC-MS analysis according to the compound, matrix and target concentration.

To help us assess your request, please provide:

• the substance name;
• its CAS number, if available;
• the sample matrix;
• the approximate expected concentration;
• the required limit of quantification;
• the number of samples;
• the background to your request.

Learn more about our custom chemical analysis services

GC-MS Method Development

When a suitable method is not readily available, BJL Laboratoires can assess the development or adaptation of a GC-MS method.

Development may address:

• sample preparation;
• the extraction method;
• injection conditions;
• selection of the chromatographic column;
• the temperature programme;
• separation conditions;
• ions used for identification or quantification;
• calibration ranges;
• internal standards;
• limits of detection and quantification;
• quality controls.

Analytical method development and adaptation

Qualitative and Quantitative GC-MS Analysis

Qualitative Analysis

Qualitative analysis primarily aims to determine which compounds are present in a sample.

It may use:

• retention times;
• mass spectra;
• reference standards;
• spectral libraries.

Quantitative Analysis

Quantitative analysis aims to determine the concentration of one or more target substances.

It generally requires:

• analytical standards;
• a calibration range;
• quality controls;
• a method suited to the matrix.

Sample Preparation before GC-MS

Preparation depends strongly on the matrix and target compounds.

It may include:

• dilution;
• liquid–liquid extraction;
• solid-phase extraction;
• concentration;
• clean-up;
• filtration;
• derivatisation where necessary;
• specific preparation for volatile compounds.

Appropriate preparation helps improve selectivity and limit matrix effects.

Spectral Libraries and GC-MS Identification

When an unknown compound is detected, its mass spectrum can be compared with reference spectra.

This comparison may provide a tentative identification.

Depending on the required level of certainty, confirmation using an analytical standard and comparison of retention times may be necessary.

Limits of Detection and Quantification in GC-MS

Analytical performance depends on factors including:

• the target compound;
• the matrix;
• sample preparation;
• the acquisition mode;
• the concentration;
• interferences;
• the available sample volume or mass.

There is therefore no single GC-MS limit of quantification applicable to every analysis.

If a particular LOQ is required, it should be specified before the analytical study begins.

GC-MS or LC-MS/MS: Which Technique Should You Choose?

GC-MS and LC-MS/MS are complementary techniques.

GC-MS is particularly useful for many volatile or semi-volatile compounds.

For polar, low-volatility or thermally sensitive compounds, LC-MS/MS may be more suitable.

Explore our LC-MS/MS analysis services

GC-MS or GC-FID: What Is the Difference?

Gas chromatography can be coupled with different types of detectors.

A flame ionisation detector (FID) responds to many carbon-containing organic compounds and is widely used for quantification.

Mass spectrometry additionally provides information that helps identify compounds from their mass spectra.

GC-MS is therefore particularly useful when separation, identification and quantification are required together.

Raw Material and Product Testing

GC-MS can be used for industrial quality control.

Applications may include:

• checking for the presence of a substance;
• testing for impurities;
• comparing materials from different suppliers;
• comparing batches;
• testing for an organic contaminant;
• monitoring a manufacturing process.

Non-Conformity Investigations by GC-MS

When a product has an unusual odour, residue or behaviour, GC-MS analysis can form part of a broader investigation.

Comparing a conforming sample with a non-conforming sample may reveal differences in chromatographic profiles or detected compounds.

This information can help identify:

• contamination;
• a residual solvent;
• a different raw material;
• process-related contamination;
• a cleaning product;
• degradation.

Subcontract GC-MS Analysis

BJL Laboratoires assesses requests from companies and laboratories wishing to outsource GC-MS analysis.

Requests may concern:

• one-off analyses;
• series of samples;
• a method available at BJL;
• a client-specific method;
• additional analytical capacity;
• analytical method development;
• ongoing subcontract testing.

GC-MS Testing for Samples from Across France

BJL Laboratoires is based in Sèvres, in the Hauts-de-Seine department, near Paris.

Samples whose characteristics and preservation requirements permit transport can be sent to the laboratory from anywhere in France.

Before sending samples for a specific analysis, please provide:

• the sample type;
• the target compound or compound family;
• the approximate expected concentration;
• the number of samples;
• the available quantity;
• the required limit of quantification, where applicable.

Accreditation and GC-MS Analysis

BJL Laboratoires is a Cofrac-accredited laboratory.

However, an analysis performed by GC-MS is not automatically covered by the laboratory’s accreditation.

The scope depends on the parameter, matrix and method concerned. The accreditation status of the analysis can be clarified when your request is assessed.

Frequently Asked Questions about GC-MS Analysis

Related Services

• LC-MS/MS analysis
• Custom chemical analysis
• Analytical method development
• Analytical investigation of non-conformities
• PAH testing
• Analytical expertise and consultancy