This service includes ESI-MS analysis with a short purification step on HPLC column, followed by MS analysis. The combined data is deconvoluted using MaxEnt 1 software. Final report includes both raw data and deconvoluted information.
Introduction
By ESI-MS, proteins and peptides in liquid phase are sprayed through a capillary at high voltage into the MS instrument where the mass over charge ratio (m/z) is measured. For large biomolecules the electrospray process results in multiply protonated molecules with a distribution of ion species at m/z range from 1-3000. The mass of the molecule is determined using a deconvolution algorithm that calculates the mass of the intact non-protonated protein or peptide. The ESI process requires that the sample preparation is quite pure without interfering salts or detergents.
The sample is purified by reversed phase HPLC (Agilent 1200 system) using a short C8 column before being analyzed on a Q-TOF mass spectrometer (Bruker Maxis Impact system). The mass of the sample is determined by deconvolution of the obtained raw spectra using the MaxEnt algorithm. The high resolution and accuracy of the Q-Tof instrument result in very accurate mass determination within 0-3 Da of the theoretical mass.
Sample Preparation Guidelines
Protein samples can be submitted in liquid or as lyophilized material.
The chromatographic protein purity should be >90%
Avoid detergents and keep buffer concentration at a minimum. LC-ESI MS analysis can be done on samples containing small amounts of salts and urea, but the best results are obtained with low buffer strength in volatile solvents without detergents keeping buffer concentration at a minimum. Detergents should be avoided if at all possible – otherwise please consult us before shipping samples so we can evaluate if the sample can be cleaned up for analysis.
Minimum amount ~ 10-50 micrograms
Put the protein/peptide into microcentrifuge tube
Use Eppendorf Safe Lock tubes, or similar tubes from your lab
Lyophilize or speed vac the protein to a solid sample to ensure protein stability during shipment
Alternatively, freeze or refrigerate to +4°C for cold shipment of the liquid sample
Attention
Please note that MW determination of intact proteins by mass spectrometry CANNOT be conducted on samples from gels or PVDF membranes!
Place your samples into micro tubes and pack in a suitable transport box. Remember to print and include the sample submission form.
| Customers in the USA Alphalyse, Inc. 299 California Avenue, Ste 200 Palo Alto, CA 94306 USA Att: Thomas Kofoed Tel: (650) 543-3193 |
Customers outside of USA Alphalyse A/S Unsbjergvej 4 D DK-5220 Odense SO DENMARK Att: Anette Rasmussen Tel: +45 6310 6500 |
NB: The US office is CLOSED 24 DEC – 1 JAN.
Make sure that your samples are delivered OUTSIDE of this period
A prepaid FedEx Air Waybill can be used for fast and easy shipment of samples in packages up to 1 lb./ 500g.
We will generate a prepaid Air Waybill, prefilled with the correct information, and send it to you by e-mail (PDF-format) within 24 hours.
Then follow these simple instructions:
If you plan to send your samples stored at room temperature, this option is usually the right choice. If you fill your box with cooling packs, the weight will most often exceed 1 lb./500g.
This prepaid FedEx Air Waybill can be used for shipment of samples in packages up to 10 lb./ 5kg, with or without cooling packs (do not use dry ice!).
We will generate a prepaid Air Waybill, prefilled with the correct information, and send it to you by e-mail (PDF-format) within 24 hours.
Then follow these simple instructions:
If you plan to fill your transportation box with cooling packs, select this shipping option. If you plan to use dry ice, you cannot use this Waybill!
The World Courier service can be used for shipment of samples of all types. If you select this option, we will contact you to provide a quotation based on location and shipping conditions. You will receive a prepaid Air Waybill which will be invoiced together with your analysis results. This is usually a good option if FedEx does not service your location.
With the prepaid World Courier service you get:
My name is Anette and I am customer support scientist at Alphalyse. I make sure we take good care of your samples. If you need help, e.g. ordering or shipping samples, send me a message - I'm here to help.
