Dectecting Furan: Method

The method below will demonstrate a rapid method for the identification and quantification of
furan in food samples, using gas chromatography with headspace sampling and mass spectrometry.
In addition to method optimization and standard analysis,  a number of food samples were analysed for furan.

Coffee containing drinks, sauces, and canned foods, were chosen for the study as previous studies
demonstrated high levels of furan in these foods. The samples were randomly collected from the local market.

1) Preparation of Standard 

A stock solution of 1000 μg/mL of furan and furan-d4 was used as the starting point for all standard

solutions. 10 μL of the stock furan solution was diluted to 10 mL in methanol to give a solution of 1 μg/mL. 20 μL of the stock furan-d4 solution was diluted to 10 mL in methanol to give a solution of 2 μg/mL.

2) Calibration 

3) Sample Preparation

Samples were collected from the local market. All the samples were refrigerated before analysis. 10 mL of sample was transferred into a headspace vial; 4 g of NaCl was added to it to decrease miscibility of furan with water. Milk and other viscous liquids are subjected to dilution of 1:2  or 1:4. Coffee was brewed as stated on the package and is treated like a non-viscous liquid sample. Semi solid samples are grounded post experiment and 5g of the powder is added together with 5 ml of saturated NaCl solution.

4) Method Validation

The method was validated by spiking the coffee sample with furan at 3 different levels. at 2, 5 and 10 μg/L. The measured amount was 2.03, 5.44, 9.54 μg/L demonstrating that the headspace technique is quantitative
in its extraction of furan from an aqueous matrix.


Why specifically headspace sampling as a method?

Headspace sampling is the most suitable method for the analysis of very volatile compounds. This is a relatively simple and well-proven methodology in which a food sample in liquid or slurry form is heated in a sealed vial to achieve equilibrium partition between the liquid phase and the gaseous headspace. The headspace gas is sampled and the vapour injected into a GC. The detection can be carried out by non-selective means such as FID or by mass spectrometry.