Solution State CryoProbes
All of the spectrometers (500 MHz, 3 x 800 MHz, 2 x 900 MHz) for solution NMR applications are equipped with either 5 mm TXI/TCI Cryogenic probes. The lower temperature probes reduce the thermal noise and increase overall probe sensitivity. The higher proton sensitivity of cryogenic probes offers a four-fold signal enhancement in non-polar solvent and two-fold increase in aqueous samples compared to room temperature probe. This allows NMR experiments to be performed at very low concentrations in the ~10 micromolar range. In the TXI CryoProbe, the proton and deuterium circuits are in the cold state and in the TCI CryoProbe proton, deuterium and carbon are in the cold state. In the latter, the direct observe carbon sensitivity increases by a factor of two enabling improved performance of experiments that do not depend on proton detection. The 1.7 mm TCI MicroCryoProbe compatible with 800 MHz US2 systems has the ability to observe signal from very small volumes (30 μl). The incredibly high mass sensitivity of the probe makes it an ideal tool for applications which are sample limited. With the SampleJet the microprobe can be used in high throughput screening and metabolomics.
|Spectrometer||CryoProbe||2 mM Sucrose
|500 MHz||5mm TXI||470:1||4795:1||4.3/9.9/0.53|
|800 MHz||5mm TXI||766:1||7602:1||4.1/5.4/0.54|
|800 MHz US2 #1||5mm TCI||830:1||7164:1||6.3/11.9/0.82|
|800 MHz US2 #2||5mm TCI||930:1||9212:1||4.8/8.5/0.75|
|900 MHz||5 mm TCI||1035:1||8863:1||8.3/14.8/0.88|
|900 MHz US2||5 mm TCI||956:1||9097:1||7.8/15.6/0.62|
Summary of Solid State Probes
|Probes||Tuning Range||S/N 1,2||Fields. kHz 1H/13C/15N||90% B1 homogeneity volume||Lower Temperature
range 0C3, 10kHz/15kHz
|750MHz Wide Bore/89mm|
|HXY wide bore, 4mm||X: 150-200
|HFX wide bore, 4mm||X: 35-225||13C: 240:1 15N: 30:1||120/50/50||35-40 μl||-40/-30|
|HRMAS, HCND, 4mm||Narrowband||1H: 250:1||900 pulse
|900MHz Standard Bore/54mm|
|HCN 3.2mm Efree||Narrowband||13C: 110:1
|HCN 3.2mm||Narrowband||13C: 120:1
|HX 3.2mm||X: 40-250||13C: 180:1
|HCN 4mm||Narrowband||13C: 180:1
1CPMAS Probes: Sensitivity is measured on fully packed natural abundance Glycine samples, 4 scans, C-H cross-polarization
2HRMAS Probes: Sensitivity is measured on 45 ml sample of 0.1% Ethylbenzene in CDCl3.
3These probes have reliably achieved the sample temperatures at the indicated spinning speeds using either a Airjet cooler or Bruker cooling unit as a source of cold gas.