Mass Spectrometry Core

Managed by:

Lew Hryhorczuk Ph.D. Title Co-Manager Mass Spec Lab Office Chem 37.1 Phone (313)577-7788 E-Mail

Brian Shay Ph.D. Title Co-Manager, Mass Spec Lab Office Chem 75 Phone (313)577-2564 E-Mail

The mass spectrometry laboratory is housed within the Department of Chemistry, Room 30. We have a wide range of capabilities including:

• Accurate mass analysis by EI or CI including high resolution GC-MS (MS80 sector and GCT TOF)
• MALDI-TOF analysis of biomolecules, synthetic polymers, and organometallics (Ultraflex TOF)
• Electrospray/APCI for direct injection, LC-MS/MS and low resolution accurate mass studies (QuattroLC triple quad and ZQ single quad)

Our Instrumentation

We employ a Waters' GCT time-of-flight mass spectrometers for high resolution exact / accurate mass analysis of volatiles and semi-volatiles. Samples are introduced via an Agilent 6890 GC/autosampler and also by either conventional solids probes or by a rapid-heating direct evaporation probe for DCI (Direct Chemical Ionization) work. DCI extends the useful molecular weight range to semi-volatiles and allows the analysis of thermally labile compounds by volatilizing the entire sample in < 4 seconds. DCI is quite valuable for mixture analysis by using a 6 minute temperature ramp thus allowing the separation (by volatility) and detection of a range of compounds. This has many applications including simulated distillation and reaction monitoring. For example, one can analyze derivitized sugars and look for incomplete reaction. Incompletely derivitized products do not pass through a GC column and injection port but will often be observed by DCI. Our GCT allows full scan accurate mass analysis extending to 1500 Da but is most often operated in the 10 to 1000 Da range.

Our MALDI-TOF instrument is a Bruker Ultraflex with a 384 well sample plate, reflectron and PSD fragmentation capability. We perform peptide mass mapping/protein identifications, synthetic peptide MW confirmations, and protein/RNA/DNA MW determinations. We also analyze synthetic polymers, organometallics, and low MW species that absorb the 337 nm laser wavelength. The instrument is capable of resolving isotopes for species in the 5000 Da range and has a demonstrated useful mass range from 10 to approximately 150,000 Da. (Masses below 500 Da are obscured if matrices are used.) Positive and negative ion modes are installed and automated acquisition of 384 samples is possible for larger projects. Anchor Chip (sample concentration) targets are available for ultralow detection of peptides and proteins. TOF/TOF and megadalton detection options are available from Bruker if required for future projects. This instrument is available for walk-up use for trained users. Basic training takes 5 hours.

We have a Micromass QuattroLC triple quadrupole mass spectrometer with an electrospray/APCI source and Waters Alliance 2695 LC, autosampler and photodiode array UV detector. This instrument is used to analyze polar and high molecular weight compounds ranging from under 100 Da to proteins over 80 kDa. The m/z range covers 2 to 4000 Da but higher MW species can be measured since they take on multiple charges. We employ the best available (Maximum Entropy) method for protein or oligonucleotide electrospray spectral deconvolution. We perform MW determinations by direct injection and can also provide MS/MS spectra. We take on LC/MS/MS projects for qualitative or quantitative analysis. The QuattroLC has an accurate mass option that allows us to acquire accurate mass data at low resolution (0.15 dalton FWHM, 128 points/Da) but high accuracy (within 5 ppm). This instrument is available to trained internal and external users (at reduced rates) for larger projects. Please call to discuss training as the time investment and associated costs are significant.

Our second LCMS instrument is a Waters' ZQ2000 single quadrupole mass spectrometer. It has a combined electrospray/APCI ionization source, termed "ESCi". In one injection the ZQ can acquire positive/negative/APCI and electrospray spectra which will improve MW confirmation ability. The unit has an attached Waters Alliance HT 2795 LC and an autosampler with 2 mL vial or 384 well plate capabilities. This spectrometer is also set up for direct injection or for LC. The ZQ scans at 5000 Da/second which is critical to the coupling with fast LC methods with narrow chromatographic peak widths. The mass (m/z) range is 2 to 2000 Da but higher molecular weight species such as proteins and oligonucleotides can also be determined as stated above for the QuattroLC.

Signup for usage of the CIF mass spectrometers is via. the CIF Resource Management System. External sample analysis or instrument usage is possible (University, External, Corporate). Contact CIF Director, Dr. David M. Coleman for information, fee structure, etc.