Graphdiyne (GD) is a new kind of carbon nanomaterial which has carbon-carbon triple bonds to form a layered structure. Here, we report the application of GD as the matrix for small molecule analysis in laser desorption ionization mass spectrometry (LDI MS). The GD matrix displayed two advantages: little background in the low mass range and good molecular ion signal in negative ion mode for many small molecules, e.g., fatty acids, amino acids, peptides, and drugs can be obtained in negative ion mode. By comparing the signal intensity of tetraphenylborate and juglone with and without GD existing, it was found that GD can enhance both of the desorption efficiency and ionization efficiency in LDI. Through analysis of the serum samples from liver cancer patients and healthy people, the GD-assisted LDI MS results showed that fatty acids could be used as potential biomarkers for the early diagnosis of liver cancer.
Keywords: graphdiyne; mass spectrometry; serum analysis; small molecule; surface-assisted laser desorption ionization.