Micromass Quattro
Micro API with a Waters 2695 Separations Module.
This
triple quadrupole system allows the quantification of complex organic
molecules at trace levels. The system is also equipped with a Waters 2996
photodiode array detector.
Introduction
Coupling the mass-spectrometer (MS) detector, to an HPLC instrument has
always constituted a particularly attractive option due to its potential
in providing high sensitivity, un equivocal detection of a wide range
of compounds.
Today, HPLC-MS provides the analyst with a practical problem-solving tool
of unrivalled sensitivity, selectivity and applicability. HPLC-MS has
become an indispensable tool for problem solving in virtually all analytical
fields requiring "information rich" chemical analysis thus aiding
industry, government, and academic analysts to solve many of their most
challenging analytical problems.
HPLC-MS
Liquid Chromatography-Mass Spectrometry allows separation of complex mixtures
of non-volatile compounds before introduction to the mass spectrmeter.
It is used extensively for compounds that have a high molecular weight
or are too sensitive to heat to be analyzed by GC. The most common ionization
methods that are interfaced to LC are ESI and Atmospheric Chemical Ionization
(APCI) in positive and negative-ion modes. The LC is done in most cases
by RP-HPLC, and the buffer system should not contain involatile salts
(e.g., phosphates). ESI can be used for m/z 500-2000 and is done at low
resolving power. LC-MS can be used to look at a wide variety of biologically
important compounds including peptides, proteins, oligonucleotides and
lipids.
Tandem
MS (HPLC-MS-MS)
Tandem MS or MS/MS is used fro structure determination of molecular ions
or fragments. In Tandem MS, the ion of interest is selected with the first
analyzer (MS-1), collided with inert gas atoms in a collision cell, and
the fragments generated by the collision are separated by a second analyzer
(MS-2). The information can be used to sequence peptides and small DNA.RNA
oligomers, to determine structure and connectivity of polysaccharides,
to determine the position and structure of fatty acids in complex lipids,
and to carry out other structure determinations. Useful structural information
can be gained.
