Absolute quantification of proteins using element mass spectrometry and generic standards.

Elemental mass spectrometry is a powerful analytical technique widely established in inorganic analysis. However, despite its quantitative capabilities, it is not yet fully integrated or considered in Life Sciences fields like proteomics. Whereas it is true that ICP-MS has suffered from several instrumental and analytical limitations that have hindered its applicability in protein analysis, significant developments during the last decades have turned ICP-MS into an interesting and, in our opinion, a powerful tool to consider for accurate protein quantification without recourse to specific protein standards.

Combined Molecular and Elemental Mass Spectrometry Approaches for Absolute Quantification of Proteomes: Application to the Venomics Characterization of the Two Species of Desert Black Cobras, and .

We report a novel hybrid, molecular and elemental mass spectrometry (MS) setup for the absolute quantification of snake venom proteomes shown here for two desert black cobra species within the genus , and . The experimental design includes the decomplexation of the venom samples by reverse-phase chromatography independently coupled to four mass spectrometry systems: the combined bottom-up and top-down molecular MS for protein identification and a parallel reverse-phase microbore high-performance liquid chromatograph (RP-μHPLC) on-line to inductively coupled plasma (ICP-MS/MS) elemental mass spectrometry and electrospray ionization quadrupole time-of-flight mass spectrometry (ESI-QToF MS). This allows to continuously record the absolute sulfur concentration throughout the chromatogram and assign it to the parent venom proteins separated in the RP-μHPLC-ESI-QToF parallel run via mass profiling.