Chemically heterogeneous carbon dots enhanced cholesterol detection by MALDI TOF mass spectrometry

A binary system composed of carbon dots (CDs) and N-doped CDs (N-CDs) embedded in an organic matrix was used for the analysis cholesterol by MALDI (matrix-assisted laser desorption ionization time-of-flight) mass spectrometry, as a model detection small, biologically relevant molecules. The results showed that both are sensitive to can be either alone or with 2,5-dihydroxybenzoic acid (DHB) enhance process. It found COOH NH2 groups on surface contributed enhancement spectrometry presence inorganic cations. Nevertheless, NaCl, N-CDs led better reproducibility results. due coexistence positive negative charge homogeneous analyte/substrate distribution, which is important parameter. enhancing effect linked Gibbs energy complex formation between CDs, Na+, DHB, it supported theoretical calculations. Moreover, upon addition CDs/N-CDs, such features low potential, vertical excitation, dipole moment oscillator strength positively affected Na+.