In-situ derivatization of Au nanoclusters via aurophilic interaction of triphenylphosphine gold (I) salt with neurotransmitters and its rapid MALDI-TOF-MS detection in mice brain tissue extracts
Matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS) have been attracted much attention for the detection of small molecules like neurotransmitters due to its softness, higher sensitivity, compatibility and diverse mass analyzers. However, it has been really a difficult challenge to develop a highly specific organic compound as matrix for rapid, sensitive and selective detection of neurotransmitters. Herein, we have reported tris(triphenylphosphine)gold oxonium tetrafluoroborate ([Ph3PAu]3O+BF4ˉ) for the first time as an efficient matrix for rapid and simultaneous MALDI-MS detection of neurotransmitters. [Ph3PAu]3O+BF4ˉ faciliates in-situ derivatization of gold nanoclusters (Au NCLs) during the interaction with neurotransmiters which increases the ionization energy by absorbing more ultra-violet (UV) light radiation during MALDI-TOF-MS detection. The result shows that [Ph3PAu]3O+BF4ˉ matrix can exhibit 10-folds faster response time than previously reported pyrylium matrices. In addition, [Ph3PAu]3O+BF4ˉ can also provide simultaneous derivatization of various neurotransmitters including dopamine (DA), noradrenaline (NAd), serotonin (5-HT), γ-aminobutyricacid (GABA), histamine (H) and tyramine (TY) in mice brain tissue extracts which can be detected through MALDI-TOF-MS spectra.