Imagine, you’re reveling in being at your favorite Italian restaurant as your waitress, Maria, (also your favorite) places before you their house special spaghetti. She knows that you always want a healthy sprinkling of Parmesan cheese. Mmmm. It all taste so good. Did you know that’s this is due to the complex combinations of volatile organic compounds that work to create the distinctive aromas and flavors of foods and beverages? We didn’t think so.
What you probably didn’t know is that the cheese had likely been tested for flavor using headspace analysis prior to full production.
What is Headspace Analysis?
“Headspace” is the gas space above the sample in a chromatography vial. Volatile sample components diffuse into the gas phase, forming the headspace gas. Headspace analysis is therefore the analysis of the components present in that gas.
There are two types of headspace analysis: dynamic headspace and static headspace.
Dynamic Headspace (DHS) utilizes a “purge and trap” method to collect and concentrate outgassed materials for GC/MS by a gas chromatograph and mass selective detector. Dynamic headspace is done to increase the headspace sample size, thus, the sensitivity of the technique.
DHS is best used for analysis of heavy molecular weight materials, such as plasticizers. It’s not something that will necessarily smell like a solvent but will still give you a transfer of materials.
In Static Headspace (SHS), a liquid or solid sample is placed into a vial, sealed and heated to a specific temperature. All of the components that are volatile at or below the pre-set temperature escape from the sample to form a gaseous “headspace” above the sample. The term “static headspace” refers to the sealed environment in which the outgassed products are collected.
SHS analysis is an ideal choice for volatile compounds, such as residual solvents or low molecular weight additives.
A Tale of Two Cheeses
Headspace Analysis has been used to identify spoiled foods, fragrances from botanical material, the determination of plasticizers in plastics and for forensic samples involving arson. It was used to not only determine that New Zealand parmesans did not match the aroma of Italian parmesans, but also to discern the aroma emanating from the spaghetti sauce, an organic compound, furaneol. Buon appetito!
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