The Bruker AutoFlex Max is our most recent addition to the facility and is a MALDI-TOF mass spectrometer that is used for qualitative analysis of high mass “delicate” bio-molecules that cannot be analyzed by other means. It is an updated version of our previous Bruker AutoFlex III instrument and uses the same software and sample target plates,, so users already familiar with our earlier instrument will have little trouble in transitioning to this new instrument. It is equipped with a 355nm pulsed UV laser and can operate in the linear, reflectron or ToF/ToF modes of operation, studying both positive and negative ion species. This makes it an extremely flexible analytical tool.
A range of different target plates are available for this instrument, including standard 384 spot MTP plates, pre-spotted anchor chip plates and NALDI plates (for matrixless analysis of very small molecules). An adapter is also available to accommodate target plates designed for the Applied Biosystems Voyager DE-STR located at the Johns Hopkins Medical School Mass Spectrometry Facility, allowing existing users of that instrument to utilize the Autoflex without having to purchase a separate target plate. Sample target plates suitable for the AutoFlex can be obtained from the Chemistry Department stockroom.
A guide to Maldi matrix selection and sample preparation for this instrument can be found here. However, in general, you need to mix and deposit your sample on the target plate in a 1:10 sample:matrix ratio. Typical matrices used are a-cyano-4-hydroxycinnamic acid and sinapinnic acid. A quick method of MALDI sample preparation is to prepare a solution mixture containing 1uM (1pmol/uL) of sample and 10uM (10pmol/uL) of matrix. 0.5uL of the mixture is deposited on the target and allowed to dry. Several repeat depositions can yield improved spectra. Allowable sample concentrations can range from 0.1uM to 50uM, with matrix concentration scaled accordingly.
This instrument is located in Room B06, Remsen Hall and is operated on a “self-service” basis following training by the Facility Manager.