CHNS Combustion Analysis
Combustion Analysis: Elementar Vario-El Cube
Combustion analysis provides a bulk measurement of compound stoichiometry or quantitative determination of organic content in environemntal samples. The analytical method is based on the complete and instantaneous oxidation of the sample by “flash combustion”, which converts all organic and inorganic substances into combustion products. The resulting combustion gases pass through a reduction furnace and are swept into the chromatographic column by the carrier gas (helium), where they are separated and detected by a thermal conductivity detector (TCD), which gives an output signal proportional to the concentration of the individual components of the mixture.
Sample analysis is performed by staff on a fee for service basis. Elements analyzed are C, H, N, and S. Other elements, O and Cl, need special arrangements. Request access to the the item and an IMSERC staff member will contact you to get started with your project.
For physical characterization of macromolecules that are soluable in water, this is a dedicated system with Water PBS as default solvent and Yara 3um, SEC-2000, 300×7.8 mm column (Phenomenex p/n OOH-4512-KO). The available detectors are an Agilent VWD UV Detector, MALS (18 Angles Dawn Heleos II) which connects via a fiber optic line to an external DLS (DynaPro NanoStar), and a Differential Refractive Index (OptiLab T-rex). This system can be used as open access. For training, request training through NUCORE and submit a representative sample for the initial evaluation.Features:
MALS (18 Angles Dawn Heleos II) –> 90o detector fiber optics to DLS (DynaPro NanoStar)
Differential Refractive Index (OptiLab T-rex)
For physical characterization of macromolecules that are soluable in organic solvents, this is a dedicated system with THF as default solvent and two PolyPore 300×7.5mm columns (Varian p/n 5M-POLY-008-112). The available detectors are MALS (18 Angles Dawn Heleos II), Viscometer (ViscoStar-II), Differential Refractive Index (OptiLab T-rex). This system can be used as open access. For training, request training through NUCORE and submit a representative sample for the initial evaluation.Features:
MALS (18 Angles Dawn Heleos II)
Differential Refractive Index (OptiLab T-rex)
GC-MSD: Agilent 5973
This is an open access time-of-flight GC mass spectrometer. Unknown compounds in a mixture can be identified using the NIST library of spectra. This instrument is ideal for quantitating known compounds in complex mixtures. The mass range is limited to 800 Daltons.
GC-TOF: Waters Micromass GCT Premier
This is an open access time-of-flight GC mass spectrometer with exact mass measurement capability. Exact mass capability is very useful for structural elucidation of unknown compounds in a sample and in the confirmation of the identity of known compounds that may not be found in the NIST library. The mass range is limited to 800 Daltons. The Agilent GC inlet makes it possible to identify compounds in fairly complex mixtures.
LC-MS: Bruker AmaZon SL Ion Trap
This is one of our new ion trap instruments for open-access ESI analysis. The instrument uses Compass Software version 1.3 SR2. Chemists can choose a suitable carrier solvent and negative or positive ionization mode. In addition, this instrument is capable of doing MSn fragmentation which can provide additional confirmation of molecular structures. This instrument is set up for analyzing compounds soluble in less polar solvents (e.g. isopropanol, methylene chloride).
LC-MS: Bruker AmaZon X Ion Trap
Equipped with an Agilent 1200 Series HPLC system, this is our new ion trap instrument for open-access LC-MS analysis. The instrument uses Compass Software version 1.4 and also has MaxEnt deconvolution software. Chemists can choose a suitable mobile phase system and either negative or positive ionization mode. In addition, like the AmaZon SL, this instrument is capable of doing MSn fragmentation which can provide additional confirmation of molecular structures. The AmaZon X is especially useful for determining the molecular weights of proteins and polynucleotides up to a molecular weight of about 50 kDa using the MaxEnt software. This instrument is targeted for analyzing compounds soluble in more polar solvents (e.g. water, methanol, acetonitrile).
LC-TOF: Agilent 6210A
Accurate-mass data can be obtained on an Agilent 6210A LC-TOF mass spectrometer in positive or negative ion mode. This instrument is equipped with an Agilent Series 1200 HPLC binary pump, and an Agilent Series 1200 autoinjector. The Agilent 6210A LC-TOF is ideal for obtaining publication quality exact mass data on small molecules. In addition, protein and oligonucleotide molecular weights can be obtained in ESI mode using MaxEnt deconvolution. Because the instrument configuration is changed over constantly, this instrument is not open access; samples should be submitted through the FOM system.
MALDI-TOF: Bruker Autoflex III
This is our MALDI-TOF instrument (matrix assisted laser desorption ionization – time of flight) for open access use. The instrument uses Compass™ 1.4 for Flex-series. Both negative and positive ionization modes can be used on the same spot. This instrument is ideal for biopolymers (proteins, RNA, DNA, oligosaccharides), organometallic salts, and many synthetic polymers. The instrument can be operated in linear mode for larger molecules or in reflectron mode – which gives better resolution for molecules that weigh less than 4 kDa.
The Bruker Avance III 600 MHz system has three RF channels. It is used for extended variable temperature and hetero-nuclear NMR experiments besides regular proton and carbon ones.
The Bruker Avance III 500 MHz system is equipped with DCH CryoProbe. It is fully automated with a BACS-60 autosampler.Features:
Best C13 S/N
Au400 is a fully automated 400 MHz Agilent DD MR-400 system equipped with Agilent 7600 96-sample autosampler. It is used for walkup access for hetero-nuclear NMR experiments besides regular proton and carbon ones.
The Agilent DD2 500 MHz system has three RF channels. It is used for extended variable temperature and hetero-nuclear NMR experiments besides regular proton and carbon ones.Features:
This Agilent DD2 600 MHz system is primarily used for macro-molecular NMR studies, including protein, dna, rna, and carbohydrate.
The Hg400 is a 400 MHz Agilent DD MR-400 system equipped with autoX probe. It is used for extended hetero-nuclear NMR experiments besides regular proton and carbon ones. It also has wide variable temperature capability.
The Varian Inova 500 is our primary NMR walkup instrument. It is setup for regular proton and carbon experiment only.
The Varian 400 MHz VNMRS system is dedicated for solids NMR studies. It has two probes (for 5 and 3 mm samples) available.
Bruker Tensor 37 FTIR (MiD IR / ATR)
The Bruker Tensor 37 FTIR Spectrometer is equipped with an Mid IR detector and KBr beamsplitter for use between 400 and 7000 cm-1. Sample can be analyzed using the ATR attachment, a gas cell or by pressing KBr pellets. In addition to the Bruker software a ~50,000 sample library aids in the interpretation of spectra and identification of unknowns.
Delta Nu Raman
The DeltaNu Raman system uses a 785 nm CW laser and has a spectral range from ~200 to 2000 cm-1. The system is equipped with a polarizer and can be used with vials, NMR tubes and capllary tubes. The 785 nm laser was choosen as a compromise between optimizing sensitivity (Raman scattering increased with decreasing wavelength) and avoiding flourescence which overwhelms the Raman system. For systems which require very long collection times, users should switch to the NUANCE Raman microscope..
Photon Technology International model QM-2 is a modular spectrofluorimeter for recording excitation or emission spectra, synchronous scans, and lifetime phosphorescence studies. It is equipped with two lamps–a 75 watt Xenon arc lamp, used in steady state measurements, and a pulsed lamp, used for phosphorescence or gated and delayed fluorescence measurements. The system allows for addition and subtraction of data, spectral correction and output of files in ASCII and binary forms. The instrument accepts 2mL samples. Excitation and emission measurements from 190 -900 nm can be performed.
This instrument runs both a CuKa microsource and a MoKa sealed tube. Larger crystals that diffract well can be run on this instrument. The anode can be changed on the fly in the middle of an experiment, so a dual-wavelength dataset can be collected as one experiment. This instrument is available for student use Saturday-Tuesday.
This instrument runs our brightest CuKa microsource, with a small beam, perfect for small crystals (~10-100 microns) or weakly diffracting samples. The Prospector is available for student use on weekends, and can accommodate small powder-diffraction samples for phase identification.
This instrument runs a MoKa sealed tube source with an enhanced monochromator to give a 7x improvement over regular sealed-tube sources. The Triumph is best for small inorganic crystals with high absorption. This instrument is available for student use Thursday-Sunday.
Varian Vista MPX ICP-AES
New users should request training throu QBIC at: http://qbic.facilities.northwestern.edu/ .
The Varian Vista MPX ICP Spectrometer is used for quantitation of most metals, sulfur and phosphorous in concentrations down to the ppb level in aqueous solutions. ICP offers a number of advantages over atomic absorption spectrometry: 1) a greater number of elements can be determined, 2) an array of elements can be analyzed essentially simultaneously, and 3) a wider dynamic range of concentration can be determined for each element.