- The facility uses iLab to track usage. You have to submit a service request form through iLab.
- If dropping off the sample in person: Place labeled samples in the wooden block located in the small brown refrigerator by the entrance (sample label should match sample name on the iLab form).
If mailing samples, please address them to:
ATTN: Papa Nii Asare-Okai (MS LAB)
C.O. Gary in Stockroom
163 The Green
063 Brown Lab
University of Delaware
Newark, DE 19716
- EI/MS and CI/MS Accurate Mass Measurement:
For Submission of samples for EI and CI GC/MS accurate mass measurement: The same sample that is submitted should be preferably run first on the Agilent 5973 (walk on instrument). For samples submitted from an external university or industry please submit a neat sample ~1 mg, and indicate what solvent the analite is soluble in.
Concentrations for accurate mass measurement submission should be:
EI: 0.1 to 0.3 mg/ml (roughly double concentration for high boiling and polar compounds) CI: 0.5 to 2 mg/ml or around of 10,000 counts on the Agilent 5973 GCMS. Provide the printout of the chromatogram Agilent 5973 GCMS.
For High Boiling compounds please try the High Boiling method on the Agilent 5973 GCMS by right clicking in the method field in the sequence and selecting it from the browser.
- Liquid Injected Field Desorptions Ionization (LIFDI). *Accurate mass measurement is available for MW150-1,200, however adequate ionization is nessesary.
For LIFDI Submission: Please submit the form with a neat sample of your analite. 0.1 mg is sufficient (if you can see it in the vial it is enough). Please indicate what solvents can solubilize your compound. If you are an external customer submitting an oxygen sensitive sample, the best way to do so is ~1.0 mg neat in a sealed ampule. We can prepare dilutions in nitrogen atmosphere, but an additional charge may occur.
For “In-House” LIFDI Samples that are Oxygen Sensitive: Please prepare multiple concentrations from 0.1 mg/ml to 1.0 mg/ml. PLEASE CONTACT THE LAB AND PREPARE SAMPLES IMMEDIATELY BEFORE HAND. Otherwise submit a sealed ampule.
Good Solvents For LIFDI: toluene, methanol, DCM, ethylacetate, hexanes (not cyclohexane), diethyl-ether, THF, DMF. (Basically any solvent that has a low enough freezing point that it will not freeze when entering the high vacuum in the source) Even solvents that freeze can be used in special cases, Please discuss this with us if needed.
In our experience the M+radical is the most common ion produced, however, M+H, M+Na, M+K, and even M-H is sometimes observed.
- Q-Exactive Orbitrap Accurate Mass Measurement:
For submission of samples for the Orbitrap accurate mass measurement, it is preferred that the same sample is first run on either ESI-MS or the Shimadzu LC/MS system.
Concentrations for the Orbitrap should be around 50 fmol/uL. Please submit your sample free of salt, strong acids/bases including TFA, and surfactants (such as SDS) and in LC/MS friendly solvents (water, ACN, MeOH, etc). The default ionization for this method is electrospray, but APCI is available upon specific request.
For LC/MS analysis, it is preferable that samples have already been run on an LC system using a mass spectrometry compatible LC method with a suitable (e.g. UV, fluorescence, etc) detector (flow rate at 0.2 ml/ml and preferably using water and acetonitrile in 0.05% formic acid as mobile phases) to ensure the elution of all components (and the separation of compounds of interest from others) of the samples from the column at the end of the analysis. Samples should be dissolved in water, methanol or acetronitrile at a concentration of 0.1 mg/ml or less. Avoid using DMSO and DMF. All sample solutions should be filtered prior to sample injection.
In order to obtain the most accurate results, please consider the following guidelines:
Sample concentration to be ~ 0.1 mg/ml for ESI ; no salts or buffers. Use “Zip tip” to desalt or C18 column for larger quantities.
Weak acids like formic or acetic are OK in 0.1% amounts and aid protonation of peptides and proteins (ESI of organics usually does not require use of these acids to give a good signal and may even benefit from addition of Na to give a M+Na cation).
Please feel free to discuss with a mass spectrometry facility personnel about the nature of your samples and the type of information you expected from the experiments prior to your sample submission.
Greasy organic molecules under 500amu or if polar under 300amu can typically work on GCMS, granted they do not have delicate functional groups.
The High Resolution GCT-Premeire has a 0-4,000 amu range, and resolution of ~7,000.
For special handling of thermally unstable or air/moisture sensitive samples contact us before sending or dropping off samples.