Sample analysis for mass cytometry
The invention relates to methods and devices for analysis of samples using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The invention provides methods and devices in which individual ablation plumes are distinctively captured and transferred to the ICP, followed by analysis by mass cytometry.
1. A laser ablation system comprising:
a) a laser capable of producing laser illumination;
b) a target, the target including a sample holder wherein the target and the laser are oriented such that the laser illumination produced by the laser is directed at the target; and
c) an injector tube configured to carry an ablation plume to an ICP, wherein the system is configured so that a laser ablation plume produced by ablation by the laser of a sample held by the target is formed in the injector tube.
2. The laser ablation system of claim 1 , further comprising a laser ablation cell.
3. The laser ablation system of claim 1 , configured to perform ablation on a micrometer scale.
4. The laser ablation system of claim 1 , wherein the laser ablation plume is completely formed within the injector.
5. The laser ablation system of claim 1 , wherein the injector comprises a single gas inlet for transferring the laser ablation plume into the ICP.
6. The laser ablation system of claim 1 , wherein the injector comprises a injector inlet configured for capturing the laser ablation plume and a gas inlet coupled to the injector inlet for transferring the laser ablation plume into the ICP.
7. The laser ablation system of claim 1 , wherein there is no separate capture and transfer gas flow.
8. The laser ablation system of claim 1 , wherein the injector has a length of no more than 10 centimeters.
9. The laser ablation system of claim 1 , wherein the centerline of the injector is aligned with the orientation of plume expansion.
10. The laser ablation system of claim 1 , wherein the laser is on the other side of the sample holder from the injector.
11. The laser ablation system of claim 1 , wherein the laser is a femtosecond laser.
12. The laser ablation system of claim 1 , wherein the target comprises a movable stage.
13. The laser ablation system of claim 1 , wherein the injector passes through an objective lens.
14. The laser ablation system of claim 1 , wherein the injector is joined with the target.
15. The laser ablation system of claim 1 , wherein the laser illumination can be scanned across a stationary sample.
16. A system for sample analysis, comprising the laser ablation system of claim 1 coupled to an ICP-MS.
17. The system for sample analysis of claim 16 , wherein the system can provide a cumulative time broadening on the order of 200 μs.
18. A method of sample analysis comprising using the system for sample analysis of claim 16 , the method comprising ablating a sample held by the target to form the laser ablation plume, and analyzing the laser ablation plume by ICP-MS.
19. The laser ablation system of claim 1 , wherein the system is configured to provide a gas flow to the injector tube upstream of where the laser ablation plume is formed.
20. The laser ablation system of claim 1 , wherein the direction of plume formation is transverse to the injector tube.
21. The laser ablation system of claim 1 , wherein plume formation begins in the injector tube.
22. The laser ablation system of claim 1 , wherein at least a portion of the injector tube is positioned directly above the ablation spot.