Detection of Single Ag Nanoparticles Using Laser Desorption/Ionization Mass Spectrometry

The detection of a single entity (molecule, cell, particle,etc.)was always a challenging subject. Here we demonstrate the detectionof single Ag nanoparticles (NPs) using subatmospheric pressure laserdesorption/ionization mass spectrometry (LDI MS). The sample preparation,measurement conditions, generated ions, and limiting experimentalfactors are discussed here. We detected from 84 to 95% of the deposited80 nm Ag NPs. The presented LDI MS platform is an alternative to laserablation inductively coupled plasma mass spectrometry for imagingdistribution of individual NPs across the sample surface and has agreat potential for multiplexed mapping of low-abundance biomarkersin tissues.