Reduced graphene oxide coating with high performance for the solid phase micro-extraction of furfural in espresso coffee

Furfural is a toxic compound that can be found in a wide variety of everyday food and beverages, notably espresso coffee. Given the toxicity of furfural, exposure could lead to liver and skin cancer. Recently, graphene oxide (GO) has been used for application in Solid Phase Micro-Extraction (SPME) due to its large surface area and wide variety of oxygenated functional groups, which makes it an excellent support for the adsorption of different organic compounds. Therefore, in this work a thermally reduced graphene oxide coating (rGOC) was synthetized for the micro-extraction of furfural in espresso coffee. This rGOC was able to absorb the furfural from espresso coffee despite having thickness of around only 1.9 μm. An analysis and optimization of extraction conditions of the furfural in the espresso coffee was carried out and then applied to the quantification of furfural. The furfural was quantified using a Gas Chromatograph coupled to a Mass Spectrometer (GC–MS). The concentration of furfural found was 2.1724 ± 0.0837 mg/L using rGOC whereas with commercial DVB/CAR/PDMS fiber was 2.0766 ± 0.0444 mg/L. The present work attempts to expand the applications of GO in SPME through the analysis of furfural in complex matrix foodstuffs such as espresso coffee. The application of rGOC, as presented in this article, has the advantage of being easy to prepare, requires a low quantity of material and together with its low cost, such application can easily be used instead of commercial fibers.