Specimen descriptions of experimental conditions for each of the facility’s instruments are given below for inclusion in your publications. For additional information, please contact the facility manager. Please acknowledge use of the facility’s instrumentation when using results for publication purposes.
FAB-MS
“FAB mass spectra were obtained using a VG70SE double focusing magnetic sector mass spectrometer (VG Analytical, Manchester, UK, now Micromass/Waters) equipped with a Cs ion gun (28kV @ 2uA), an off-axis electron multiplier and an MSS data system (MasCom, Bremen, Germany). The resolution of the instrument was set at 10,000 (100ppm peak width). Samples were mixed with m-nitrobenzyl-alcohol matrix deposited on the target of a direct insertion probe for introduction into the source. Spectra were acquired under control of the data system. Nominal mass scan spectra were acquired with a mass scan range of 10-1000 amu using a magnet scan rate of 25 sec/dec. For accurate mass measurements, a narrower mass scan range was employed, with the matrix containing 10% PEG or PEGMME mass calibrant”.
High Resolution EI (obtained using VG70S)
“High resolution EI mass spectra were obtained using a VG70S double-focusing magnetic sector mass spectrometer (VG Analytical, Manchester, UK, now Micromass/Waters) equipped with an MSS data acquisition system (MasCom, Bremen, Germany). The resolution of the instrument was set at 10,000 (100ppm peak width). Samples were introduced into the source (block temperature = 200degC) using a heated direct insertion probe fitted with a deep quartz cup, with a heating rate of 1C/sec. Spectra were acquired under control of the computer data system. The electron energy was 70eV. Nominal mass scan spectra were acquired for a scan mass range of 10-100 amu using a magnet scan rate of 20 sec/dec. Accurate mass measurements were obtained across a narrower mass range using high boiling Perfluorokerosene (PFK) as the reference.”
GC-MS (obtained using Shimadzu QP2020A)
“GC-MS analyses were performed using Shimadzu QP2020A GC/MS combination (Shimadzu Instruments, Columbia, MD). The GC17A is equipped with a low polarity (5% phenyl-, 95%methyl-siloxane) capillary column (30m length, 0.25mm ID, 0.25um film thickness, 10m length guard column). Samples were dissolved in (specify solvent) at a concentration of Xmg/mL and were injected into the instrument using an autosampler. The injector temperature was maintained at 280degC and the transfer interface at 280degC. The oven temperature was ramped from X degC to Y degC at a rate of Z degC/min. The QP5050A is an EI quadrupole based mass spectrometer with a maximum scan range of 900amu and an ionizing electron energy of 70eV. ”
ESI-MS (obtained using Finnigan LCQ Fleet)
“ESI mass spectra were acquired using a Finnigan LCQ Fleet ion-trap mass spectrometer equipped with an electrospray ionization source (Thermo Finnigan, San Jose, CA). Samples were dissolved in (specify solvent) with x% (specify modifier if you added one) and introduced into the instrument at a rate of 10uL/min using a syringe pump via a silica capillary line. The heated capillary temperature was 250 degC and the spray voltage was 4kV.”
ESI-MS (obtained using Finnigan LCQ DecaXP)
“ESI mass spectra were acquired using a Finnigan LCQ DecaXP ion-trap mass spectrometer equipped with an electrospray ionization source (Thermo Finnigan, San Jose, CA). Samples were dissolved in (specify solvent) with x% (specify modifier if you added one) and introduced into the instrument at a rate of 5 or 25uL/min using a syringe pump via a silica capillary line. The heated capillary temperature was 250 degC and the spray voltage was 4kV.”
Maldi-ToF
“Maldi-ToF mass spectra were obtained using a Bruker Autoflex Max Maldi ToF/ToF instrument (Billerica, MA). Samples were dissolved in (Specify solvent) and mixed with (specify matrix) before being deposited on the target plate. Samples were irradiated with a 355nm UV laser and mass analyzed by ToF mass spectrometry in the reflectron/linear mode.