Mass spectrometry can analyse the chemical composition of substances by electrically charging the molecules and separating them by mass in an electrical field. This technology has been used since the 1990s for investigating proteins. The advantage of using mass spectrometry lies in the fact the scientists do not require antibodies, as is the case with the traditional western blot analysis. Additionally they can analyse many proteins simultaneously, more precisely and quantitatively.

As Markus Ralser reported in “Biotechnologie”, the new method makes it possible to quantify a larger amount of proteins compared to the traditional western blot method, which consists of gel electrophoresis, the transduction of the proteins onto a membrane and protein detection via specific antibodies, obtained mostly from animals.

The new method has been published in the journal Nature Protocols (2011, online reprint).

Long-term preparation of the samples and marking with expensive isotopes are not necessary.

Source: http://www.biotechnologie.de/BIO/Navigation/DE/root,did=127266.html
Bluemlein, K. & Ralser, M. (2011): Monitoring protein expression in whole-cell extracts by targeted label- and standard-free LC-MS/MS. Nature protocolls 6/6: 859-869. http://www.molgen.mpg.de/~molbiolmet/