Technical information

QUALITY

• Infrared spectroscopy with Fourier Transformation (IR-FT)
• Mass spectrometry

2. Chemical Purity

EURISO-TOP's Standard deuterated solvents are evaluated after packaging on a 400 MHz FT NMR instrument and by gas chromatography. We warrant a chemical purity higher than 99.9%.

3. Water Content

As specified in the solvent list, water content is in weight percentage.

4. Storage

Chloroform-d, Methylene Chloride-d2 and Tetrachloroethane-d2 are not stabilised and are thus very sensitive to ultra-violet waves and oxidation. Their storage under refrigeration at less than +4°C (39.2°F) guarantees a longer shelf life. Before use, the vial should be left to warm to room temperature before opening under an anhydrous, inert atmosphere.
Tetramethylsilane (TMS) is a very volatile compound (bp=26°C). To minimise its loss it is packaged in a penicillin vial sealed with a Teflon faced septum. It is not necessary to keep it in a refrigerator.

5. Toxicity

All the hazard solvents of this range are labelled according to the hazard symbols and rules of advising in use.
Therefore, these solvents should be handled only by trained staff familiar with their potential hazards. They have similar properties to those of the non-isotope labelled counter parts. Appropriate precautions should be taken all times during their use and disposal. The products offered by EURISO-TOP are for laboratory research use only. Use in any other way than laboratory applications is the sole responsibility of the researcher.

CHOICE OF SOLVENT

• solubility of the sample,
• position of the peak of residual proton,
• consequence on the chemical shift of the solute due to interactions with solvent molecules,
• temperature of experiment,
• polarity of solvent.

HANDLING

All deuterated solvents must be handled in a strict anhydrous and inert atmosphere (dry nitrogen or argon) in order to minimise the absorption of moisture.
This absorption leads not only to an increase in the HDO concentration and the resultant signal in 1H NMR spectrum, but also to exchange of the easily labile protons (especially heteroatom-linked ones). Solvent vials must be immediately re-closed after use and the solvent removed from an ampoule transferred into a dry vial.
Very hygroscopic solvents (Deuterium oxide and Dimethylsulfoxide d6) are packed in ampoules or in " penicillin " vials equipped with a septum (Teflon faced for DMSO). Solvent is withdrawn with a syringe. It is recommended to flush into the vial an amount of dry nitrogen equivalent to the amount of solvents to be withdrawn.

SAMPLE CONCENTRATION

The signal of the protons of the dissolved substance should be greater than the signal of the residual proton of the solvent used. So the quantity of the product depends on the isotopic enrichment of the solvent.
For observing a proton in a compound of molecular weight 400: 5mg of product are required with a standard isotopic enrichment (99.8%D) solvent and 1.5mg of product is required with a 100% isotopic enrichment(99.96%D) solvent.

TUBE PREPARATION

Before use, the NMR tube must be perfectly cleaned (within and without) and dried.
To avoid contamination with residual water absorbed into the inner wall of the NMR tube, we recommend to keep 1ml or more of Deuterium oxide in the tube over-night, to decant and wash it with acetone d6 or Methyl alcohol d4 and to store it in a " dessicator " saturated with Deuterium oxide.
To clean the outer wall of the NMR tube use a soft piece of tissue.

SAMPLE PREPARATION

The sample is dissolved in approximately 0.5ml of deuterated solvent and slightly heated if necessary.Insoluble substances are eliminated with a suitable filter cartridge before the introduction of the solution into the NMR tube.
Paramagnetic oxygen dissolved in solvents produces a reduction of the relaxation times and a line broadening.To avoid this phenomenon, the sample may be purged by degassing techniques (distillation, bubbling of dry inert gas, sealing of the sample tube under vacuum...).

REFERENCE MATERIAL