Matrix-Assisted Ionization on a Portable Mass Spectrometer: Analysis Directly from Biological and Synthetic Materials.

Matrix-assisted ionization (MAI)-mass spectrometry (MS) eliminates the need for high voltage, a heat source, lasers, and compressed gases in the ionization process and uses minimal solvents in sample preparation, thus making MAI ideal for field-portable mass spectrometers. The broad applicability of MAI is demonstrated by simple, rapid, and robust positive and negative detection mode analyses of low and high mass compounds including some pesticides, dyes, drugs, lipids, and proteins (186 Da to 8.5 kDa) from various materials including urine, biological tissue sections, paper, and plant material on a low pumping capacity, single-quadrupole mass spectrometer. Different sample introduction methods are applicable, including the use of a pipet tip or glass melting point tube, allowing integration of sample preparation with sample introduction for increased analytical utility and ease of operation, even when sampling directly from surfaces.