MALDI-TOF/MS

(Matrix Assisted Laser Desorption Ionization – Time Of Flight – Mass Spectrometry)

Description

The Voyager-DE™ PRO Biospectrometry Workstation is a mass spectrometer with time of flight analyzer, and matrix assisted laser desorption ionization (MALDI). The device is equipped with nitrogen laser (337nm) and the TOF analyzer allows work in linear and reflector modes.

The range of theoretical masses "unlimited" TOF and the "soft ionization" characteristic of MALDI allow this technique to be one of best choice for the analysis of macromolecules with high sensitivity and resolution, including peptides, proteins of high molecular weight, oligonucleotides, polysaccharides and synthetic polymers. In reflective mode, molecules of mass less than 10 kDa can be analyze (peptides, organic molecules, complexes, polymers and proteins of low molecular weight), with a resolution of ~7,000 (or > 7,000 for m/z <6 kDa). The linear mode allows the analysis of molecules of high molecular weight, with a resolution of > 2,000 for small proteins (m/z < 20 kDa) and ~50 for large proteins (m/z ~100 kDa).

Equipment

MALDI-TOF-MS (Matrix Assisted Laser Desorption Ionization – Time Of Flight – Mass Spectrometry) Applied Biosystems, model Voyager DE-PRO Biospectrometry Workstation.

Sample

In MALDI-TOF-MS analysis samples are first dissolved and dispersed in a matrix (usually an organic acid), placed on a MALDI plate and, after evaporation of the solvent, the sample is introduced into the MALDI source where the sample-matrix crystals are irradiated by a laser beam.

The concentration of the sample to be delivered depends on the type of analyte, taking already into account the dilutions required with the matrix. Thus:

1 - For polymers, organic compounds and complexes the amount of sample needed is about 1 mg. The sample is dissolved in the solvent indicated by the requester, which is preferably miscible with the solvent matrix.

2 - For peptides and proteins in solution, the concentration depends on molecular weight. For proteins with a mass below 10 kDa are needed about 10 to 20 pmol / mL. For proteins with masses exceeding 10 kDa the quantity to be delivered must be 100 to 200 pmol / mL. The proteins (or a mixture of peptides) may also be sent lyophilized.

3 - Samples of protein from electrophoresis, separated on polyacrylamide and stained with Coomassie blue or silver (silver compatible with mass spectrometry), can be delivered on the same gel hydrated. In the case of separate bands, the band/protein stain should be trimmed to the minimum possible gel and placed in eppendorf tube covered with milli-Q water. It is essential to send a copy or a scanner image of the gel along with samples.

Reagents compatible with MALDI-TOF/MS

Always use reagents with purity and HPLC water milli-Q.

A) The compounds that do not interfere with the MALDI-TOF are: trifluoroacetic acid, formic acid, beta-mercaptoethanol, DTT, volatile organic solvents, HCl, NH₄OH, acetic acid.

B) Compounds with concentrations below 50 mM do not interfere with mass spectrometry: HEPES, MOPS, Tris, NH₄OAc, octilglucoside.

C) To avoid the following compounds: glycerol, sodium azide, DMSO, SDS, phosphates, NaCl, 2M urea, 2M Guanidine.

Price analysis (€)  

Request Analysis 

The analysis request should be filled and signed by the head of the institution that makes the request (Download the application form). Analyses are performed by order of submission of application in laboratory analysis. The results are given within 24 hours. In the case of samples for method development and in the case of large numbers of samples, the response time is agreed with the authority solicitor.

The equipment is operated solely by the technician in charge. If requested by the client it is allowed direct contact with the equipment which provides a brief technical/theoretical accompanied demonstration working practice.

Upon request of an analysis the client should contact the technician directly responsible for the equipment to clarify all issues that involve the analysis.

Download the application form

The application form should be sent to Dr. Luz Fernandes:

luz.fernandes@dq.fct.unl.pt 

Laboratório de Análises

REQUIMTE - Rede de Química e Tecnologia

Departamento Química / Faculdade de Ciências e Tecnologia

 Universidade Nova de Lisboa

2829-516 Caparica

Portugal
Tel: 351 212947805  (ext: 10993)

Fax:351 212948550

Delivery and receipt of samples

1 - Samples must be clearly identified, so that during manipulation does not erase the identification, and should be delivered well packaged.

2 - Samples from the electrophoresis must be accompanied by a scanner or copy of the gel image.

3 - Delivery of results will be made by e-mail in PDF format, to be sent simultaneously to the applicant and responsible. In the case of complaints, they should be made within 15 working days.

4 - The remainder of the samples will be stored in the laboratory for 15 days after completion of the analysis, after which will be eliminated.