Sample transferring apparatus for mass cytometry

Abstract

In a mass cytometer or mass spectrometer, a sample of elemental tagged particles is transferred from a dispersion to a gas flow through a carrier aerosol spray for atomization and ionization by inductively coupled plasma (ICP) source. The configuration of the sample transfer apparatus allow for total consumption of the sample by passing the sample spray through a deceleration stage to decelerate the spray of particles from its high velocity expansion. Following the deceleration stage, the decelerated sample of particles can be accelerated and focused through an acceleration stage for transferring into the ICP. This effectively improves the particle transfer between the sample spray and the ICP.

1 . An apparatus for transferring a dispersion of particles in a sample spray for mass analysis, the apparatus comprising:
 a decelerator tube having an inlet end adapted to receive the sample spray, a confinement passage downstream of the inlet end, the inlet end being closed around the sample spray to promote spray recirculation and spray deceleration in the confinement passage, and a discharge end transition downstream from the confinement passage to pass the decelerated sample spray; and   an elongate accelerator chamber having an entrance end concentrically spaced out from the discharge end of the decelerator tube, the discharge end is positioned within the entrance end, and an outlet end displaced downstream of the entrance end to define a flow acceleration channel therebetween.   
     
     
         2 . The apparatus according to  claim 1  wherein the elongate accelerator chamber comprising a gas inlet port adapted to receive a sheath gas, the gas inlet port having a flow path with the entrance end. 
     
     
         3 . The apparatus according to  claim 1 , wherein the flow acceleration channel is configured to reduce the pressure through the outlet end such that the sheath gas and the decelerated sample spray accelerate along the flow acceleration channel to the outlet end. 
     
     
         4 . The apparatus according to  claim 3  wherein the flow acceleration channel comprising a conical shaped bore tapered towards the outlet end. 
     
     
         5 . The apparatus according to  claim 1 , wherein the outlet end is a constriction. 
     
     
         6 . The apparatus according to  claim 2 , wherein the concentric space between the entrance end of the accelerator chamber and the discharge end of the decelerator tube defines an annular channel for passing through the sheath gas. 
     
     
         7 . The apparatus according to  claim 4 , wherein the conical shaped bore is adapted to guide the sheath gas flow in a direction towards the outlet end. 
     
     
         8 . The apparatus according to  claim 1 , wherein the discharge end of the decelerator tube includes a taper transition. 
     
     
         9 . (canceled) 
     
     
         10 . The apparatus according to  claim 1 , wherein the decelerator tube has a predetermined length and the confinement passage has a predetermined bore diameter; and wherein the ratio of the predetermined length to the predetermined bore diameter is greater than 1.5 and less than 4. 
     
     
         11 .- 22 . (canceled) 
     
     
         23 . A sample transfer device for transferring a dispersion of particles in a sample spray into an instrument for mass analysis by a mass spectrometer, the apparatus comprising:
 a decelerator for receiving the sample spray from a nebulizer, the decelerator being adapted to promote spray recirculation and spray deceleration in a confinement passage defined by the decelerator and to conduct the spray from the nebulizer through the confinement passage to a decelerator outlet at the opposite end of the confinement passage; and   an accelerator positioned to receive the spray from the decelerator outlet, the accelerator being adapted to accelerate the spray away from the decelerator through an accelerator outlet.   
     
     
         24 . A sample transfer device as set forth in  claim 23  wherein the decelerator is sealed between the nebulizer and the decelerator outlet so matter can enter or leave the confinement passage substantially only at the nebulizer and at the decelerator outlet. 
     
     
         25 . A sample transfer device as set forth in  claim 23 , wherein the accelerator has an acceleration chamber having a segment that is tapered from a wider upstream end to the accelerator outlet at a narrower downstream end of the acceleration chamber. 
     
     
         26 . A sample transfer device as set forth in  claim 25  wherein the accelerator has an upstream end positioned upstream of the decelerator and the downstream end of the decelerator is tapered from a wider diameter to a narrower diameter at the decelerator outlet. 
     
     
         27 . A sample transfer device as set forth in  claim 26  wherein the taper angle of the tapered accelerator chamber segment is about the same as the taper angle of the decelerator at the decelerator outlet. 
     
     
         28 . A sample transfer device as set forth in  claim 23 , wherein the accelerator has an upstream end positioned upstream of the decelerator outlet. 
     
     
         29 . A sample transfer device as set forth in  claim 23 , wherein the decelerator outlet extends into the accelerator and there is an annular space between the decelerator outlet and the accelerator at the downstream end of the decelerator. 
     
     
         30 . A sample transfer device as set forth in  claim 29  wherein the accelerator has a gas inlet at its upstream end for receiving a flow of a sheath gas into the annular space between the decelerator outlet and the accelerator. 
     
     
         31 . A sample transfer device as set forth in  claim 29 , wherein the annular space is divided into a plurality of channels extending from upstream of the decelerator outlet downstream to the decelerator outlet. 
     
     
         32 . A sample transfer device as set forth in  claim 23 , wherein the decelerator outlet is concentrically positioned within the accelerator. 
     
     
         33 . A sample transfer device as set forth in  claim 23 , wherein the decelerator comprises segment extending downstream from the upstream end of the decelerator and having a diameter, the decelerator having a length extending from its upstream end to the decelerator outlet, the ratio of the decelerator diameter to the decelerator length being in the range of about 1.5 to about 5. 
     
     
         34 .- 37 . (canceled)