Mildly oxidized graphene: facile synthesis, characterization, and application as a matrix in MALDI mass spectrometry.

To be mild! Mild oxidization of chemically converted graphene with diluted nitric acid produces low-oxidation and low-defect acid-oxidized graphene (AOG) material with excellent water dispersibility. In MALDI MS, the AOG matrix yielded significantly higher signals than graphene, graphene oxide, and conventional organic matrices for nonpolar analytes.