Sample quantitation with a miniature mass spectrometer
The invention generally relates to sample analysis with a miniature mass spectrometer. In certain embodiments, the invention provides methods that involve generating ions of a first analyte and ions of a second analyte. Those ions are transferred through a discontinuous sample introduction interface into a first ion trap of a mass spectrometer in a manner in which the discontinuous sample introduction interface remains open during the transferring. The discontinuous sample introduction interface is closed and the ions are sequentially transferred to a second ion trap of the mass spectrometer where they are sequentially analyzed.
1. A method for analyzing a plurality of analytes, the method comprising:
generating ions of a first analyte and ions of a second analyte;
transferring the ions of the first and second analytes through a discontinuous sample introduction interface into a first ion trap of a miniature mass spectrometer, wherein the discontinuous sample introduction interface remains open during the transferring;
closing the discontinuous sample introduction interface;
sequentially transferring the ions of the first and second analytes to a second ion trap of the miniature mass spectrometer within one scan cycle;
sequentially analyzing the ions of the first and second analytes in the second ion trap;
fragmenting the first and second analytes in the second ion trap; and
measuring fragment intensities with two scans in the second ion trap within 100 ms of each other.
2. The method according to claim 1 , wherein the first analyte is a sample and the second analyte is an internal standard.
3. The method according to claim 1 , wherein transferring the ions of the first and second analytes through the discontinuous sample introduction interface into a first ion trap occurs simultaneously.
4. The method according to claim 1 , wherein the first ion trap is a linear quadrupole ion trap.
5. The method according to claim 1 , wherein the second ion trap is a rectilinear ion trap.
6. The method according to claim 1 , wherein analyzing comprises taking MS/MS measurements.