Method and apparatus for chemical and biological sample separation
View Patent ↗The present invention describes a method and apparatus for separating chemical and/or biological samples based on selective ion-molecular interactions in the gas phase. A chemical modifier is added to the drift gas that interacts selectively with a targeted molecule in at least one component of the sample in a drift tube. The component may be impurities and/or interferences in the sample whereby the chemical modifier enhances sample resolution by shifting the components drift times. In addition, reagents can be added to the sample prior to, during, or after ionization to form a complex with selected components in the sample. In addition, one or more internal and/or external standard can also be added to the sample as a calibration for the measurement.
1. A structure selective resolution method, comprising:
a) providing a sample with at least one component having a targeted molecular geometry to an ion mobility based spectrometer;
b) ionizing the sample;
c) adding at least one chemical modifier having a complementary molecular geometry that interacts selectively with the targeted molecular geometry of said at least one component of the sample; and
d) resolving at least one component from the other components of the sample based on the ion flight path under influence of high field and/or low field conditions in the ion mobility based spectrometer.
2. The structure selective resolution method of claim 1 , wherein the complementary and/or targeted molecular geometry is: linear (planar), trigonal planar, or bent.
3. The structure selective resolution method of claim 1 , wherein the complementary and/or targeted molecular geometry is: tetrahedral, octahedral, or pyramidal.
4. The structure selective resolution method of claim 1 , wherein the complementary and/or targeted molecular geometry is: the entire molecule, one or more functional groups in the molecule, the geometric frame, or the topology of the molecule.
5. The structure selective resolution method of claim 1 , wherein said at least one component having a targeted molecular geometry comprises at least one chiral center.
6. The structure selective resolution method of claim 1 , wherein said at least one chemical modifier comprises at least one chiral center.
7. The structure selective resolution method of claim 1 , wherein said at least one component of the sample comprises: explosives, chemical warfare agents, toxic industrial chemicals, toxins, biological warfare agents and/or other chemical, biological compounds.
8. The structure selective resolution method of claim 1 , wherein said at least one chemical modifier is added to the sample prior to ionization and/or directly into a ionization source, reaction region, drift region of a drift tube.
9. The structure selective resolution method of claim 1 , wherein the component of the sample that the chemical modifier interacts preferentially with are a impurity(ies) and/or interference(s) in the sample.
10. A structure selective resolution method, comprising:
e) providing a sample with at least one component having a targeted molecular geometry to an ion mobility based spectrometer;
f) ionizing the sample;
g) adding at least one chemical modifier having a complementary molecular geometry that interacts selectively with the targeted molecular geometry of said at least one component of the sample;
h) resolving at least one component from the other components of the sample based on their measured ion mobility characteristics; and
i) correlating the ion mobility characteristic under different operating conditions as a calibration method.
11. The structure selective resolution method of claim 10 , wherein the measured ion mobility characteristic is a measured drift time of the components.