Hemoglobin (Hb) present in the blood and meat juice samples was selectively adsorbed by graphene oxide (GO) particles functionalized with amylopectin (AP) and was sensitively detected by direct internal extractive electrospray ionization mass spectrometry (iEESI-MS) analysis for the identification of meat type. Various samples including the whole blood samples of chicken, duck, sheep, mouse, pigeon, turtledove, and meat juice mixtures were successfully identified based on the difference in molecular composition of Hb reflected in MS. The adulteration of sheep blood with only 2% chicken blood could be detected, which demonstrated the high chemical specificity of the approach. The established method is featured by the high speed of analysis (4 min per sample, including the analyte extraction and sample loading), high sensitivity, minimal sample preparation, and low sample consumption (0.9 μL of whole blood or 300 mg of raw meat). In perspective, the reported method can be extended for the sensitive detection of trace analytes in complex matrices in broad molecular range by using the selective enrichment on functionalized graphene oxide particles followed by iEESI-MS analysis.
Keywords: Internal extractive electrospray ionization; functionalized graphene oxide; hemoglobin; mass spectrometry; meat species.