Sensitivity

The AP/MALDI technique routinely analyzes protein digests and peptides at low femtomole to attomole levels (spotted on the MALDI plate). Sensitivity of the AP/MALDI has recently been enhanced with the addition of pulsed dynamic focusing (PDF), a technique which focuses ions into the API inlet, thereby increasing ion transmission efficiency. Other significant enhancements to sensitivity have been made with special target plate coatings and sample preparation methods.

Typical Spectra:

AP/MALDI-MS of the peptide bradykinin at attomole levels

Relevant References:

Electrospray sample deposition for matrix assisted-laser desorption/ionization (MALDI) and atmospheric pressure MALDI mass spectrometry with attomole detection limits
H Wei, K Nolkrantz, DH Powell, JH Woods, M-C Ko, RT Kennedy
Rapid Commun. Mass Spectrom. 2004; 18: 1193-1200.

Increasing sensitivity and decreasing spot size using an inexpensive, removable hydrophobic coating for matrix-assisted laser desorption/ionization plates
SJ Owen, FS Meier, S Brombacher , DA Volmer
Rapid Commun. Mass Spectrom. 2003; 17: 2439-2449.

An atmospheric pressure matrix-assisted laser desorption/ionization ion trap with enhanced sensitivity
CA Miller, D Yi, PD Perkins
Rapid Commun. Mass Spectrom. 2003; 17: 860-868.

Atmospheric pressure MALDI with pulsed dynamic focusing for high-efficiency transmission of ions into a mass spectrometer
PV Tan, VV Laiko, VM Doroshenko
Anal. Chem. 2004; 76: 2462-2469