Continuous flow mobility classifier interface with mass spectrometer
A continuous flow mobility classifier provide the ability to perform two-dimensional separation in mass spectrometry. An ionization system is used to ionize a sample. A differential mobility analyzer (DMA) (e.g., a nano-radial DMA) is coupled to the ionization system and to a mass spectrometer. The nano-RDMA is configured to separate the ionized sample by mobility for subsequent mass analysis by the mass spectrometer.
1. A continuous flow mobility classifier-mass spectrometer system comprising:
(a) a first ionization system configured to ionize analyte molecules in a sample;
(b) a continuous flow radial differential mobility analyzer (RDMA) configured to analyze the ionized analyte molecules in a first dimension, wherein:
(i) the RDMA is coupled to the first ionization system;
(ii) the RDMA is coupled to a mass spectrometer;
(iii) the sample is introduced into the RDMA;
(iv) the RDMA is configured to employ axial electric fields to separate the ionized analyte molecules by mobility; and
(c) the mass spectrometer configured to analyze the ionized analyte molecules in a second dimension, wherein:
(i) a continuous flow of the ionized analyte molecules that have been separated by mobility are introduced to the mass spectrometer to determine a mass-to-charge ratio of a charged particle within the mobility separated ionized analyte molecules; and
wherein:
a sheath flow rate provided by the RDMA is lower as compared to a sheath flow rate produced by a continuous flow mobility classifier-mass spectrometer system without the RDMA;
an instrument resolution of the RDMA has a value of at least seven (7);
a sample outlet of the RDMA is aligned with an atmospheric pressure inlet (API) of the mass spectrometer; and
a gap between the sample outlet and the API is minimized by adjusting a position of the RDMA.
2. The continuous flow mobility classifier-mass spectrometer of claim 1 , wherein the ionization system comprises an electrospray source.
3. The continuous flow mobility classifier-mass spectrometer of claim 2 , wherein the electrospray source comprises an electrospray ionization emitter (ESI).
4. The continuous flow mobility classifier-mass spectrometer of claim 1 , wherein the ionization system comprises an atmospheric pressure chemical ionization system.
5. The continuous flow mobility classifier-mass spectrometer of claim 1 , wherein a second ionization system was removed from the mass spectrometer prior to coupling the mass spectrometer to the RDMA.
6. The continuous flow mobility classifier-mass spectrometer of claim 1 , wherein the mass spectrometer comprises a liquid chromatography-mass spectrometer (LC-MS).
7. The continuous flow mobility classifier-mass spectrometer of claim 1 , wherein the first ionization system is coupled to the RDMA using standard Swagelok™ fittings.
8. The continuous flow mobility classifier-mass spectrometer of claim 1 , wherein a sheath flow rate of the RDMA is a maximum of fifty (50) liters per minute.
9. A method for analyzing a sample comprising:
(a) ionizing analyte molecules in a sample using a first ionization system;
(b) analyzing the ionized analyte molecules in a first dimension by separating the ionized analyte molecules by mobility using a continuous flow radial differential mobility analyzer (RDMA) that employs axial electric fields, wherein:
(i) the RDMA is coupled to the first ionization system;
(ii) the RDMA is coupled to a mass spectrometer; and
(iii) the sample is introduced into the RDMA;
(c) introducing a continuous flow of the ionized analyte molecules that have been separated by mobility to the mass spectrometer;
(d) analyzing the ionized analyte molecules in a second dimension by mass analyzing the ionized analyte molecules that have been separated by mobility using the mass spectrometer to determine a mass-to-charge ratio of a charged particle within the mobility separated ionized analyte molecules; and
wherein:
a sheath flow rate provided by the RDMA is lower as compared to a sheath flow rate produced by a continuous flow mobility classifier-mass spectrometer system without the RDMA;
an instrument resolution of the RDMA has a value of at least seven (7);
a sample outlet of the RDMA is aligned with an atmospheric pressure inlet (API) of the mass spectrometer; and
a gap between the sample outlet and the API is minimized by adjusting a position of the RDMA.
10. The method of claim 9 , wherein the ionization system comprises an electrospray source.
11. The method of claim 10 , wherein the electrospray source comprises an electrospray ionization emitter (ESI).
12. The method of claim 9 , wherein the ionization system comprises an atmospheric pressure chemical ionization system.
13. The method of claim 9 , wherein the mass spectrometer comprises a liquid chromatography-mass spectrometer (LC-MS).
14. The method of claim 9 , wherein a sheath flow rate of the RDMA is a maximum of fifty (50) liters per minute.