The optimum performance from solvent suppression methods can now be achieved with the ultra high field homogeneity of the Spinsolve ULTRA. Solvent suppression methods are especially useful when measuring compounds that have been dissolved in protonated solvents.
Applications include:
- On-line reaction monitoring
- Synthesis control
- Fermentation monitoring in bioreactors
- Contaminant quantitation.
Solvent Suppression with the Spinsolve ULTRA
The advantages of solvent suppression using the Spinsolve ULTRA can be seen in the example below comparing spectra acquired with and without solvent suppression on a sample of neat urine. The red lower spectrum is acquired with solvent suppression, and the upper black spectrum acquired without solvent suppression.
Urine is mainly water but with various metabolites dissolved at very small concentrations in the water. The large water signal almost covers the entire spectrum with its tails, and in the upper spectrum overlaps with all of the signals of interest. A solvent supression sequence can suppress the water peak by irradiating the water signal at its resonance frequency.
Homogeneity of the Spinsolve ULTRA
Advances in the patented shimming technology of Magritek’s High Homogeneity Halbach Magnets* have led to the creation of Magritek’s most powerful benchtop NMR system in the Spinsolve ULTRA. The homogeneity of a magnet is quantified by measuring the line width (LW) of a reference sample at different heights of the peak. For the Spinsolve ULTRA, the LW isspecified at <0.2 Hz at 50%, <6 Hz at 0.55%, and 12 Hz at 0.11% of the peak height.
The Spinsolve ULTRA is also capable of multiple peak solvent suppression with carbon decoupling. This is a particularly useful experiment to carry out when users are measuring samples with organic solvents which often have multiple solvent peaks and associated carbon sattelites that may be at the same amplitude as your signals of interest.
Quantifying Sugar Content in Water
A good test of solvent supression is measuring glucose dissolved in water at low concentrations. The NMR peaksof the α and β protons often overlap with the large water peak. Using solvent supression the Spinsolve ULTRA can resolve and quantify the concetration of glucose in water.
Measuring Sugar Content in Soft Drinks
This feature enables the Spinsolve ULTRA to measure sugar content soft drinks where a mixture of sucrose, glucose and fructose sugars can be found. Remarkably the Spinsolve spectrometers can also quantify the small amounts of ethanol that can be present at very low concentrations in some natural fruit juices.
The samples illustrated below are all neat, and show how the different componets in the soft drinks can be quantified using the Spinsolve ULTRA spectrometer. The table beneath shows good agreement with the information on the drink lable.
| |
Sucrose |
Glucose |
Fructose |
Total(NMR) |
Total(Label) |
Ethanol |
| Grape |
0.0 |
10.0 |
6.2 |
16.2 |
16.0 |
0.16 |
| Apple |
1.1 |
2.4 |
6.4 |
9.8 |
9.8 |
0.03 |
| Orange |
3.7 |
2.0 |
3.8 |
9.5 |
9.0 |
0.02 |
| Coke |
6.0 |
2.8 |
1.9 |
10.7 |
10.7 |
0 |
| Pepsi |
1.1 |
5.6 |
4.4 |
11.2 |
10.7 |
0 |
| Zero |
0 |
0 |
0 |
0 |
0 |
0 |
*All units g/100 ml. Ethanol is % vol.
Applications
The high homogeneity of the Spinsolve ULTRA is of particular value when working with samples in which the compounds that need to be identified and quantified are dissolved in protonated solvents like water.
The range of applications for the Spinsolve ULTRA include:
- Quantification of sugars and alcohol in beverages
- Identification and quantification of metabolites in urine
- Analysis of contaminants in waste water
- Reaction monitoring in the presence of protonated solvents
- qNMR for samples where important signals overlap
- Monitoring fermentation processes in bioreactors
It was possible to achieve the high homogeneity seen in the Spinsolve ULTRA because of advances in the patented shimming technology used in the Magritek High Homogeneity Halbach Magnets* that are inside every Spinsolve ULTRA system.
*Patent US 8,148,988 and EP 2,144,076