Mass spectrometry analysis in Teaching Labs are provided by the Mass Spectrometry Service. Samples will need to be prepared following the guidance below alongside completion of the submission form which is available on the Submission Hub.

Samples will need to be prepared as detailed below for the different techniques. Please note that mass spectrometry is particularly sensitive as a technique, and it is very easy for contamination to occur. Be particularly careful handling Pasteur pipettes as contamination from pipette teats is particularly problematic. Guidance on proper Pasteur pipette use can be found on the Pasteur pipette pages.

A small sample (ca. 0.5 - 1 mg) of pure compound which is free from solvent and other contaminants should be placed in to a sample vial. The quantity should not be measured accurately, but should be the smallest quantity which can be transferred into a vial.

The following solvents can be used for ESI or APCI. The solvents should be attempted in the following order. If the sample does not dissolve in the first solvent attempted, try to prepare a sample using the next solvent in the list.

1. Ethanol

2. Methanol

3. Acetonitrile

If none of these solvents are successful, you should seek advice regarding your sample submission. Samples must not be prepared using (or contain any) DMSO or DMF as these may damage the instruments.

A small sample of pure compound which is free from solvent and other contaminants should be placed in a mass spec sample vial. For masses in the 0.5-1 mg range is not nescessary to weigh the sample. For solid samples, one crystal or spec of powder is sufficient, and for liquid samples one pipette drop will be fine.

A sample vial label will need to be attached to the submission vial. Numbererd stickers are provided at the submission point and the next submission number should be used.

Labelled sample vials should be placed into the mass spectrometry sample submission tray once the submission form has been completed.

Information on completing the sections of the mass spectrometry form are provided below.

Two services are provided:

• Mass spectrometry measurement only

• Chromatography with mass spectrometry detection

Mass spectrometry measurement only will provide mass spectrometry recordings of the sample, which is useful as characterisation for pure samples, or to confirm the presence of a compound for a mixture. Chromatography allows the identification of multiple components in a mixture. More information can be found on the ionisation methods pages and the tandem methods pages to assist with method selection.

Sample vial stickers are provided at the sample submission point. Use the sticker with the next available number and attach this to the vial. Ensure the correct number is input into the submission form.

The sample should be given a short title which you can use to identify the compound. This should be no more than 10 characters.

Details of one or more solvents in which your sample is soluble need to be provided. Solvent will be added to the sample vial by the service, and a small quantity of the solution will be injected into the mass spectrometer in order to run the analysis.

Only certain solvents are suitable for use with mass spectrometry. In order of preference these are:

• Ethanol

• Methanol

• Acetonitrile

• Water

• Ethyl acetate

• Acetone

• Isopropanol

• Cyclohexane

• Hexane

• Toluene

• Diethyl ether

• Dichloromethane

• Chloroform

Please ensure that your sample is soluble in the indicated solvent (at least 1 mg per mL) prior to submission.

Solvents which are not suitable include dimethylsulfoxide (DMSO) and N,N-dimethylformamide (DMF).

In general solvents want to be highly volatile and of high purity, particularly free from any salts. For ESI, solvents need to be polar to aid the formation of ions.

Mass spectrometry

Choose the appropriate ionisation method required for your sample. See the ionisation methods pages for guidance with method selection.

Chromatography and mass spectrometry

Choose the appropriate ionisation method required for your sample. See the tandem methods pages for guidance with method selection.

Provide the molecular formula for the compound using Hill Notation. Include counterions?

The monoisotopic mass is the 

(what about counterions for salts etc?)

This should be obtained by drawing the molecule in ChemDraw and using the analysis tool (View | Analysis).

Provide a ChemDraw structure showing the compound, including any counterions in the case of salts. The image should be submitted as an image (PNG or JPG).

Brief details of the preparation for the compound should be provided. This should note starting materials, solvents used, workups and purifications involved. The purpose of this information is to provide the mass spectrometrist information about the preparation, which may help with the identification of other compounds which may be observed in the analysis, or to identify if a marticular mass spec technique is not suitable due to something in the preparation.

Provide any other informaton which might be useful to the mass spectrometrist. This might include information on other compounds to look for in the analysis (e.g. side reactions), or what information you are aiming to obtain from the analysis (e.g. identification of an unknown compound).

Any known or suspected safety information should be included to ensure that this information is available to the person recording data for the sample. However, it is also recognied that for most samples, safety information is unlikely to be known, particularly where compounds are novel. This can be indicated by listing "Unknown: treat as toxic" or similar.