Headspace solid-phase microextraction coupled to gas chromatography-mass spectrometry with selected ion monitoring for the determination of four food flavoring compounds and its application in identifying artificially scented rice

The adulteration of rice using synthetic aromatic flavorings to fraudulently imitate commercially valuable fragrant rice varieties has attracted extensive attention from regulatory authorities around the world. In order to get convincing evidence of adulteration, appropriate scientific analytical methods need to be developed. In this study, a simple and efficient headspace solid-phase microextraction (HS SPME) technique coupled with gas chromatography mass spectrometry using selected ion monitoring (GC-MS-SIM) for the determination of four food flavoring compounds which are possibly used as adulterants is proposed. The HS SPME operating under optimized conditions increased the selectivity and sensitivity of the analysis by eliminating matrix interferences. The method presented adequate precision and linearity with limits of detection ranging from 0.5 to 10 ng/mL. This HS SPME/GC-MS-SIM method is directly applicable to the analysis of volatiles in rice and has the advantages of minimal pretreatment. It was applied successfully to the analysis of six rice flavoring essences, ten fragrant rice and four artificially scented rice samples.