Abstract:
In one embodiment, the present invention relates generally to a rotator sample introduction interface. In one embodiment, the rotary interface for collecting an analyte includes a valve body, a rotor coupled to the valve body and a stator coupled to the rotor. In one embodiment, the rotor is channel-free and the stator includes a first channel and a second channel, wherein the first channel comprises an inlet for receiving a liquid and an outlet for expelling the liquid, wherein a carrier gas is provided via an inlet of the second channel and an outlet of the second channel is coupled to an analyzer.

Description:
RELATED APPLICATIONS 
       [0001]    This application claims priority under 35 U.S.C. §119(e) to U.S. provisional patent application Ser. No. 61/288,217, filed on Dec. 18, 2009, which is hereby incorporated by reference in its entirety. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    Over the course of many years, various corporations and the United States government have dumped various pollutants into the ocean or other various bodies of water. These pollutants in the water can pose human health and safety risks and an environmental hazard. This could lead to economic effects and potential damage to marine resources. 
         [0003]    As a result, there is a need for underwater mass spectrometry to monitor these marine environments. Current underwater mass spectrometers typically use a membrane interface. However, membrane interfaces have limited detection capabilities. For example, membrane interfaces can only allow detection of relatively volatile, non-polar compounds. This limits the number of chemical classes that can be detected by an underwater mass spectrometer that uses a membrane. 
       SUMMARY OF THE INVENTION 
       [0004]    In one embodiment, the present disclosure is directed towards a rotator sample introduction interface. In one embodiment, the rotary interface for collecting an analyte comprises a valve body, a rotor coupled to the valve body, wherein the rotor is channel-free and a stator coupled to the rotor, wherein the stator comprises a first channel and a second channel, wherein the first channel comprises an inlet for receiving a liquid and an outlet for expelling the liquid, wherein a carrier gas is provided via an inlet of the second channel and an outlet of the second channel is coupled to an analyzer. 
         [0005]    In one embodiment, the present disclosure is directed towards a system for performing underwater mass spectrometry. The system for performing underwater mass spectrometry comprises an underwater mass spectrometer and a rotary interface coupled to the underwater mass spectrometer. The rotary interface comprises a valve body, a rotor coupled to the valve body, wherein the rotor is channel-free and a stator coupled to the rotor, wherein the stator comprises a first channel and a second channel, wherein the first channel comprises an inlet for receiving a liquid and an outlet for expelling the liquid, wherein a carrier gas is provided via an inlet of the second channel and an outlet of the second channel is coupled to an analyzer. 
         [0006]    In one embodiment, the present invention is directed towards a method for collecting an analyte underwater. The method comprises receiving water via an inlet of a first channel of a stator, adsorbing the analyte from the water onto a rotor free of any channels, rotating the rotor to transfer the analyte to a desorption area and carrying the analyte to an analyzer via an outlet of a second channel of the stator via a carrier gas that is provided via an inlet of the second channel. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]    So that the manner in which the above recited features of the present invention can be understood in detail, a more particular description of the invention may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments. 
           [0008]      FIG. 1  depicts one embodiment of a system for collecting an analyte underwater; 
           [0009]      FIG. 2  depicts an isometric view of a stator of a rotary interface; 
           [0010]      FIG. 3  depicts a side view of the stator; 
           [0011]      FIG. 4  depicts a bottom view of the stator; 
           [0012]      FIG. 5  depicts a cut-away side view of the stator; 
           [0013]      FIG. 6  depicts a cut-away side view of an inner portion of the stator; 
           [0014]      FIG. 7  depicts a top view of a rotor of the rotary interface; 
           [0015]      FIG. 8  depicts a side view of the rotor; 
           [0016]      FIG. 9  depicts one embodiment of how the rotary interface collects an analyte underwater; and 
           [0017]      FIG. 10  depicts a flow diagram of one embodiment of a method for collecting an analyte underwater. 
       
    
    
     DETAILED DESCRIPTION 
       [0018]      FIG. 1  illustrates one embodiment of a system  100  for underwater collection of analytes. For example, the system  100  may be used for in-situ underwater mass spectrometry. As a result, analytes do not need to be sent away to a laboratory for further analysis, which can cause the analyte to decompose or be contaminated. 
         [0019]    The system  100  provides many other advantages over previous systems for underwater collection of analytes such as the ability to detect non-volatile and semi-volatile compounds as well as volatile compounds. In addition, the design of the system  100  allows the system to be deployed underwater and withstand pressures greater than 5000 pounds per square inch (psi) and handle temperatures up to 330 degrees Celsius (° C.). 
         [0020]    In one embodiment, the system  100  includes a rotary interface  120  coupled to an analyzer  110 . The analyzer may be any type of analyzer, such as for example, an underwater mass spectrometer, a sensor and the like. 
         [0021]    In one embodiment, the rotary interface  120  includes a valve body  102 , a rotor  106 , a stator  104  and a printed circuit board  108 . The printed circuit board  108  may be coupled to the valve body  102  and provide the necessary circuitry and processing components to help control movement and positioning of the rotor  106  and the stator  104 . For example, the printed circuit board  108  may include a processor, a memory, one or more input/output devices and a module for having an algorithm that controls the positioning of the rotor  106  and the stator  104 . 
         [0022]    The design of the rotary interface  120  of the present disclosure makes several key modifications to the stator  104  and the rotor  106  from what is currently available. For example, channels that are typically machined into the rotor  106  are removed. That is, the rotor  106  is completely solid and is free from any channels, holes, openings, etc. 
         [0023]    The rotor  106  serves as an adsorption site for analytes that are collected underwater. In one embodiment, the rotor  106  is fabricated from a material that is hydrophobic. That is, the rotor  106  should repel water, while adsorbing the analyte. In one embodiment, the rotor  106  comprises a polymer material. In other embodiments, the rotor  106  may be comprised of other materials, such as stainless steel, silicon carbide, ruby, or ceramic. The rotor  106  may also be coated with a thin layer (e.g., by atomic layer deposition) of material to selectively adsorb analytes. 
         [0024]    As a result of the rotor design that allows it to serve as an adsorption site for the analyte, no membrane is needed. This allows the rotary interface  120  to collect and analyze non-volatile and semi-volatile compounds as well as volatile compounds. A heating means, e.g., a laser (e.g., a 655 nanometer (nm) laser), an infrared (IR) light, an ultraviolet (UV) light, a glow discharge (GD), a direct analysis in real-time (DART) or a desorption electrospray ionization (DESI) source and the like, may be used to help collection of the non-volatile and semi-volatile compounds. The membrane interfaces that were previously used required that analytes permeate through the membrane, rather than being adsorbed and desorbed from the same side of a surface. As a result, previous membrane interface devices could not collect and analyze non-volatile and semi-volatile compounds. 
         [0025]    The stator  104  is modified to include one or more channels. As the rotor  106  is rotated, the analyte collected by one of the channels in the stator  104  may be transferred to the analyzer  110  via another one of the channels in the stator  104 . This process is discussed in further detail below. 
         [0026]      FIG. 2  illustrates an isometric view of one embodiment of the stator  104 . The stator  104  may be fabricated from any material that forms a good seal with the material used to fabricate the rotor  106 , while still allowing the rotor  106  to rotate. For example, the stator  104  may be fabricated from stainless steel or a polymer. 
         [0027]    In one embodiment, the stator  104  comprises one or more holes  128 . Each one of the holes  128  corresponds to an end of a channel. As a result, each one of the holes  128  may serve a different purpose. The stator  104  also includes one or more mounting holes  130 . The mounting holes  130  may be used to couple the stator  104  to the valve body  120 . 
         [0028]      FIG. 3  illustrates a side view of one embodiment of the stator  104 .  FIG. 4  illustrates a bottom view of one embodiment of the stator  104 . As discussed above, one modification to currently available stators is that one or more channels  124  and  126  are cut into a center portion  122  of the stator  104 . As discussed above, each end of the channels  124  and  126  may be associated with one of the holes  128  and serves a different purpose. 
         [0029]      FIG. 5  illustrates a side cut away view of one embodiment of the stator  104 .  FIG. 5  illustrates in more detail how the holes  128  are coupled to an end  140  of the channels  124  and  126 . In one embodiment, one end  140  may serve as an inlet and another end  140  may serve as an outlet. 
         [0030]      FIG. 6  illustrates a side cut away view of one embodiment of the center portion  122  of the stator  104 . The center portion  122  also has holes  128 . However, the holes  128  of the inner portion do not flow all the way through. Rather, they are blocked and do not communicate with holes  142  and  144 . The holes  142  and  144  may be used to provide a carrier gas and move the analyte towards a vacuum of an analyzer  110  using the carrier gas. For example, the carrier gas may enter via hole  142  and the analyte may be carried away via hole  144 . In one embodiment, one of the holes (e.g., hole  142 ) may be considered an inlet and another one of the holes (e.g., hole  144 ) may be considered an outlet. 
         [0031]    In one embodiment, a fiber optic tube may be used to direct a heating means towards the rotor  106 . The heating means may be coupled to an inlet (e.g., hole  142 ) of the center portion  122  of the stator  104 . 
         [0032]    The heating means is used to heat a vacuum side of the rotor  106  to help evaporate the analyte. In one embodiment, the vacuum side may be defined as a side where the analyzer  110  pulls the analyte from via the vacuum. 
         [0033]    The heating means may heat only a localized area of interest on only the vacuum side of the rotor  106  rather than heating the entire rotor  106 . This allows the water side of the rotor  106  to remain cool to help adsorption of the analyte out of the water. Providing the heating means allows the rotary interface  120  to be used to collect non-volatile and semi-volatile compounds as well as volatile compounds. The heating means may include, for example, a laser, an infrared (IR) light, an ultraviolet (UV) light, a glow discharge (GD), a direct analysis in real-time (DART) or a desorption electrospray ionization (DESI) source and the like. 
         [0034]      FIG. 7  illustrates a top view of one embodiment of the rotor  106 . As discussed above, the rotor is completely solid and is free from any channel, holes, openings, etc. This is illustrated by the top view of the rotor  106  in  FIG. 7 .  FIG. 8  illustrates a side view of one embodiment of the rotor  106 . 
         [0035]      FIG. 9  illustrates one embodiment of how the rotary interface  120  is operated to collect an analyte underwater.  FIG. 9  illustrates the center portion  122  and may be viewed as looking up at the rotor  106  and the stator  104 . The rotor  106  may be considered “transparent” in  FIG. 9  for the purpose of illustration to simultaneously illustrate the channels and openings of the stator  104  relative to the rotor  106 . 
         [0036]    In one embodiment, seawater flows in via a hole  128  into the stator  104  and contacts the rotor  106  via one end  140  of the channel  124 . As the seawater flows through the channel  124 , the analyte is adsorbed into an adsorption region  160  of the rotor  106 . As discussed above, the rotor  106  should be fabricated from a material that is hydrophobic, for example a polymer, to repel the seawater away while adsorbing the analyte. 
         [0037]    In one embodiment, a fiber optic tube  146  may be coupled to an inlet hole  142  to provide a carrier gas  162  via an opening  148  and a heating means  152 , e.g., a laser, via an opening  150 . The fiber optic tube  146  may be coupled to the opening  142  of the channel  126 . The heating means  152  may be used to heat the vacuum side of the rotor  106  to help evaporate the analyte. This allows the rotary interface  120  to be used to collect non-volatile and semi-volatile compounds as well as volatile compounds. In one embodiment, the heating means may be a laser (e.g., a 655 nanometer (nm) laser), an infrared (IR) light, an ultraviolet (UV) light, a glow discharge (GD), a direct analysis in real-time (DART) or a desorption electrospray ionization (DESI) source and the like. 
         [0038]    The analyte evaporates towards the vacuum side of the rotor  106  and the carrier gas carries the analyte. After a predetermined amount of time or based upon a monitoring of the amount of analyte that is collected, the rotor  106  may be rotated, as shown by arrow  158 , such that the ends of the channels  124  and  126  are aligned with different locations on the rotor. By rotating the rotor  106 , the carrier gas carries the analyte towards an outlet hole  144  of the channel  126  towards a vacuum of an analyzer as illustrated by arrow  154 . In addition, the seawater flows out of another end  140  of the channel  124  and another hole  128  back into the sea. In one embodiment, the rotor could also be rotated continuously during analysis. 
         [0039]      FIG. 10  illustrates a flow diagram of one embodiment of a method  1000  for collecting an analyte in a liquid, for example underwater, as described above. In one embodiment, the method  1000  may be carried out by the system  100  illustrated in  FIG. 1 . The method  1000  begins at step  1002 . 
         [0040]    At step  1004 , the method  1000  receives a liquid via an inlet of a first channel of a stator. In one embodiment, the liquid may be water. For example, the rotary interface  120  may be placed underwater in a water-proof housing. The water may flow into a hole  128  of the stator  104 . 
         [0041]    At step  1006 , the method  1000  adsorbs the analyte from the liquid onto a rotor free of any channels. As discussed above, the rotor  106  should be completely solid and free of channels, holes, openings, etc. 
         [0042]    In one embodiment, a heating means may be used to help evaporate the analyte into a carrier gas. This allows the rotary interface  120  to collect non-volatile and semi-volatile compounds for analysis as well as volatile compounds. In one embodiment, the heating means may be a laser (e.g., a 655 nanometer (nm) laser), an infrared (IR) light, an ultraviolet (UV) light, a glow discharge (GD), a direct analysis in real-time (DART) or a desorption electrospray ionization (DESI) source and the like. 
         [0043]    At step  1008 , the method  1000  rotates the rotor to transfer the analyte to a desorption area. By rotating the rotor  106 , different ends of the channels in the stator  104  may be aligned with different locations of the rotor  106 . For example, rotating the rotor  106  allows the liquid (e.g. water) to exit out of an outlet of the first channel  124  of the stator  104  and allows the analyte to be carried out to an analyzer  110 . 
         [0044]    At step  1010 , the method  1000  carries the analyte to an analyzer via an outlet of a second channel of the stator via a carrier gas that is provided via an inlet of the second channel. In one embodiment, the analyzer  110  may be a mass spectrometer, e.g., a linear quadrupole mass analyzer, an ion trap mass spectrometer, tandem mass spectrometer, and the like. In one embodiment, the carrier gas may be any inert gas such as, for example, helium, argon, nitrogen and the like. The type of carrier gas may depend on the type of analyzer that is being used. The method  1000  ends at step  1012 . 
         [0045]    While various embodiments have been described above, it should be understood that they have been presented by way of example only, and not limitation. Thus, the breadth and scope of a preferred embodiment should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents.