CURRENT
INSTRUMENTATION
Autospec-Q
(VG/Micromass) Photo The
hybrid high resolution quadrupole mass spectrometer was purchased in
1992 when the demand for new ionization techniques, elemental composition,
high mass, and MS/MS data exceeded the capabilities of our existing
quadrupole mass spectrometers. Samples can be introduced into the Autospec-Q
from the GC, in-source glass cup, in-source resistively heated platinum
wire coil, or from static or dynamic liquid secondary ion mass spectrometry
probes (“LSIMS”; similar to fast atom bombardment or “FAB”). Samples
are ionized by electron ionization (at energies from 8 to 250eV), chemical
ionization or the LSIMS technique. Our system has a mass range up to
4500 Da (“a.m.u.”) at full accelerating potential (8KV) and is quite
capable of achieving 5000 resolution at scan speed and range appropriate
for use with GC introduced samples. At slower scan speeds or narrower
mass range, actual resolutions of more
than 20,000 are quite possible. MS/MS is possible either by
linked scan techniques, or using the quadrupole stage.
DeltaPlus
(Finnigan-MAT) Photo The
stable light isotope mass spectrometer was added in 1997 particularly
to provide compound specific d13 C isotopic data. In compound specific mode, compounds are
separated using an HP 6890 GC with Gerstel PTV/CIS4 injection system
and modified for two-dimensional GC then oxidized to CO2
in the Finnigan GC combustion interface before being sent into
the MS source. We have significantly modified the combustion interface
to increase robustness and serviceability. If isotopic data is desired
for bulk samples such as sediments or biological materials, the GC is
replaced with the elemental analyzer. Using this mode, and with significant
modifications to the EA, we have determined d15N in pigments at levels as low as 150nM.
Elemental
Analyzer Model 1108 (Carlo Erba) Photo
Avance 400
DPX (Bruker) Photo This nuclear magnetic resonance spectrometer was acquired by the Facility in 2000 and replaced our vintage 1989 Bruker AC-300. The actively shielded magnet and fully digital electronic brings us once again to the state-of-the-art in NMR. This system is outfitted with three sample probes. The 5mm inverse broadband probe with gradients, tunable from 109Ag to 31P, is our most commonly used probe for 1H, 13C and 15N. The gradient option is particularly useful with protium spectra from marine or biological samples containing large amounts of water. The 10mm broadband observe probe covers the same spectral range as the 5mm inverse probe, but is optimized to directly observe the non-protium nucleus and holds large volumes of material. The 7mm cross polarization-magic angle spinning (“CPMAS”) probe again covers the same spectral range, but allows for the acquisition of NMR spectra from solid samples. © 2002 Woods Hole Oceanographic Institution. |