CIBEST operates two HPLC-MS/MS systems. The first is a
TSQ Quantum triple quadrupolar spectrometer from Thermo. The second and more recent apparatus is a
SCIEX 6500+ QTrap. This spectrometer is built on a triple quadrupolar technology but the last quadruple can be used as a linear ion trap. In this configuration, a higher sensitivity is reached in MS/MS methods and other signal monitoring approaches are possible compared to classic triple quadrupolar systems. On this recent equipment, the HPLC system has been upgraded with a high capacity autosampler and a switch valve that makes possible analyses with on-line purification.
The ExionLC – 6500 QTrap system (SCIEX)
At CIBEST, HPLC-MS/MS analyses are used for several applications:
The
characterization of the component of a mixture by determining their molecular weight and gathering information of their structures based upon their fragmentation pattern.
The
search of derivatives of a same compound in mixtures based on similarities of mass spectrometry features. For example, identification of modified DNA nucleoside is often done by looking for compounds losing a 116 mass unit fragment that correspond the 2 deoxyribose.
The
quantification of small molecules at the trace level. For this purpose, the first quadrupole isolates the molecular ion of the targeted compound, which is then fragmented in the second quadrupole, the collision cell. The fragments produced are selected on the third quadrupole (or the linear ion trap) and quantified. This detection mode (Multiple Ion Monitoring) has a very low noise and is thus very sensitive (in the range of the fmol injected). In addition, it is highly specific. A condition to the development of such MRM quantitative methods is the access to the reference molecules and their derivative labelled with stable isotopes. The expertise of CIBEST in chemistry is a major advantage in that respect.
At CIBEST, HPLC-MS/MS has become key to many investigations, including mechanistic studies at low dose, quantification of DNA damage in cellular DNA or detection of biomarkers in biological fluids.
Our systems have also be used in collaborative works for the elucidation of enzymatic mechanisms, biochemical processes in plants and protein modifications.