Abstract:
The invention provides a cuvette apparatus having two cavities that are in fluid communication with each other. The first cavity is larger than the second cavity an receives a fluid to be studied. The second cavity holds the fluid for analysis and is bounded by at least two thin walled windows that allow superior transmission of UV waves.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
   This application claims priority under 35 U.S.C. 119(e) to U.S. Provisional Application No. 60/650,525 filed on Feb. 8, 2005, the disclosure of which is incorporated herein by reference. 

   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The invention relates to a cuvette for measuring the absorption or other optical characteristics of irradiation in liquid samples and to a cap apparatus for a cuvette or test tube that allows substances to be introduced into the cuvette, while providing a seal that prevents leakage of the substances and/or the escape of vapors from the cuvette. 
   2. Description of the Related Art 
   Cuvettes are typically used in laboratory, medical and/or chemical testing and manufacturing settings where they are used to store and also mix various substances. Cuvettes typically have a square shape, but may also be rounded. Cuvettes may be used for performing diagnostic tests on a sample, such as spectrophotometrical absorbance measurements or fluorescence polarization measurements. Conventional cuvettes typically require a large amount of the substance to be tested and are not made up of highly UV transmissive materials. In addition, many conventional cuvettes are not compatible with testing apparatuses. 
   In some cases, the substances being stored and/or mixed within the cuvettes may be toxic or otherwise hazardous. Thus, lab personnel or pharmacists who are mixing these types of substances may be exposed to hazardous materials. For example, pharmacy personnel may transfer chemotherapy drugs from an admixture compounding setup into a cuvette for subsequent testing. These drugs may vaporize or aerosolize when being injected into the cuvette, exposing the pharmacists to hazardous vapors. Thus, an apparatus that seals the cuvette so as to prevent the escape of vapors, while still allowing new substances to be injected into the cuvette is desirable. 
   SUMMARY OF THE INVENTION 
   The invention provides a cuvette for measuring the absorption or other optical characteristics of irradiation in liquid samples. The invention also provides for a cuvette cap that that allows the cuvette to be filled, while still providing a sufficient seal so that fumes and vapors do not escape from the cuvette. 
   In accordance with the invention, a cuvette is provided that has a thin-walled region or windows that allow for superior transmission of UV spectrographic transmissions. The thin-walled region in accordance with the invention is located along the comers of two adjacent edges at the base of the cuvette. The thin walled window region has an arch-like shape and has a thin wall thickness in contrast to the thickness of the remaining cuvette. For example, the thickness of the thin wall window region may be on the order of 0.25 mm or less. The positioning of the thin walled window region is such that it is in alignment with UV spectrographic emission devices. The arch-like shape of the thin walled window region allows the device to provide a thin walled region without compromising the structural integrity of the cuvette. The thin walled window region also forms an internal cavity within the cuvette so that only small amounts of the material to be detected are necessary. 
   Thus, the invention provides a substantially rectangular cuvette that has two cavities (also called recesses). The first cavity provides an opening for receiving the liquid to be analyzed. The second cavity is smaller than the first cavity and is bounded by at least two arch-shaped windows. The at least two windows are made of a UV transmissive material and have a thickness that is less than that of the other surfaces of the cuvette. This reduced thickness allows for better UV transmission. The smaller size of the second cavity means that less fluid is necessary for testing purposes. The smaller cavity also allows for positive indexing which assures the correct orientation of the cuvette when placed within a holder for testing. This is because the “send” and “receive” thin windows must align with the “send” and “receive” ports. The thinner shape of the windows also allows for less “play” when the cuvette is placed in the analysis system since the thin windows of the cuvette are pushed against the “send” and “receive” ports of the cuvette holder. The configuration of the cuvette in accordance with the invention also allows the cuvette to still have a square foot print allowing the cuvette to stand upright even though fluid is funneled into an area (cavity) of smaller volume. This is in contrast to a funnel shaped cuvette that cannot stand upright. 
   The invention includes a cuvette that has a first planar side wall, a second planar side wall disposed substantially parallel to and opposing the first planar wall, a front side wall, a back side wall disposed substantially parallel to and opposing the front side wall, wherein the first planer side wall, the second planar side wall, the front side wall and the back side wall form a substantially rectangular body having an inner space for receiving a sample liquid, and a planar floor perpendicular to and connected to each of the first and second planer side walls, the front side wall and the back side wall, the planar floor having a opening to a lower cavity, the lower cavity having at least two planar windows of a thickness less than a thickness of the first planer side wall, the second planar side wall, the front side wall and the back side wall. 
   The invention also provides a cuvette having a rectangular body having a first recess for receiving a sample liquid and a second rectangular recess smaller than the first recess and in fluid communication with the first recess, the second recess having at least two UV transmissive windows. 
   In accordance with one embodiment of the invention, a Luer Lock and cuvette cap is provided. In this embodiment, a user, such as a pharmacists or technician takes a cuvette, snaps the square cuvette cap into the cuvette opening, then places the Luer Lock valve device onto the top of the cap and fits the Luer Lock valve to the cap. This seals the cuvette. Substances can be introduced into the cuvette via the Luer Lock valve and cap. The valve can be either manually closed or may be self sealing. In one embodiment, the Luer Lock valve can receive a syringe which can be used to inject a substance into the cuvette. In this configuration, the cuvette is sealed preventing spillage of the substances as well as the escape of any vapors. The cap is configured so as to form a seal between itself and the cuvette. In this embodiment, the cuvette can be constructed from any polymer or plastic material capable of being shaped so that it can be adapted to the opening of a cuvette. In addition, this embodiment contemplates both square shaped cuvettes as well as rounded test tubes. 
   In accordance with another embodiment, the cap is a hardened rubber stopper. The cap in this embodiment has a thin bladder on the top surface that is capable of being pierced by a syringe needle. In this embodiment, a user fits the cap into the cuvette forming a tight seal between the cuvette and the cap, thus preventing leakage liquids and vapors from the cuvette. A syringe needle can be stuck through the cap seal and the contents of the syringe can be injected into the cuvette. In this embodiment, the cuvette can be constructed from any rubber or rubber-type material or polymer that can be shaped so that it can be adapted to the opening of a cuvette. In addition, this embodiment contemplates both square shaped cuvettes as well as rounded test tubes. 
   The invention provides a cuvette cap which prevents substances from leaking or spilling from a cuvette and also prevents vapors from escaping the cuvette. The invention has application in a variety of industries where harmful substances are collected for mixing and/or testing, including medical, biological and chemical research, testing and manufacture. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     A more complete understanding of the present invention and advantages thereof may be acquired by referring to the following description taken in conjunction with the accompanying drawings, in which like reference numbers indicate like features, and wherein: 
       FIG. 1  is a perspective view of a cuvette in accordance with an embodiment of the invention; 
       FIG. 2  is a view of the back side portion of a cuvette in accordance with an embodiment of the invention; 
       FIG. 3  is a view of a first side portion of a cuvette in accordance with an embodiment of the invention; 
       FIG. 4  is a view of a second side portion of a cuvette in accordance with an embodiment of the invention; 
       FIG. 5  is a view of a front side portion of a cuvette in accordance with an embodiment of the invention; 
       FIG. 6  is a view of the bottom portion of a cuvette in accordance with an embodiment of the invention; 
       FIG. 7  provides various views of the cuvette cap in accordance with an embodiment of the invention; 
       FIG. 8  provides various views of the cuvette cap in accordance with an embodiment of the invention; 
       FIG. 9  provides various views of the cuvette cap in accordance with an embodiment of the invention; 
       FIG. 10  provides perspective views of the cuvette cap mounted to a cuvette and fitted with a Luer Lock adapter and Luer Lock in accordance with one embodiment of the invention; and 
       FIG. 11  provides perspective views of the cuvette cap mounted to a cuvette and fitted with a Luer Lock in accordance with one embodiment of the invention. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1  shows a perspective view of the cuvette  100  in accordance with an embodiment of the invention.  FIG. 1  shows the front portion or wall  105  and the first side wall  110  of the cuvette. A back side wall and second side wall are not visible in  FIG. 1  but are shown in the subsequent Figures. The side walls  110  and  145 , the front wall  105  and the back side wall  135  of the cuvette form a well shaped opening  112  that allows liquids and other substances to be held in the cuvette. The base of the first side wall  110  is defined by two regions,  115  and  120 . The region  115  has the same thickness as the rest of the cuvette structure. The second region  120 , or arched window region is made of a material that is thinner than that of the rest of the cuvette. In one embodiment of the invention, the arched region is about 0.25 mm or less thick. As shown in  FIG. 1 , a base plane  125  is formed that is perpendicular to the side walls of the cuvette. The base plane  125  creates a first cavity (or recess)  127  that is bounded by the first and second side walls  110  and  135  and the front and back side walls  105  and  135 . The base plane  125  has an opening  130  that opens to a second cavity (or recess)  132  within the cuvette. The cavity  132  is capable of holding a small amount of liquid. The cavity  132  is also bounded by the arched region  115  or window which thin wall relative to the thickness of the remaining cuvette structure. The cavity  132  is also bounded by at least one more thin walled arched region (window) (not shown) and may be bound on all four sides by such thin walled arched windows. The liquid to be examined occupies this second cavity  132 . 
   It should be noted that the first cavity  127  is larger than the second cavity  132 . The second cavity is bounded by at least two thin walled windows. The entire cuvette may be made of any UV transmissive material, such as Lexan. In order to provide structural integrity to the cuvette, the entire cuvette cannot be made of a thin walled material. Thus, only the arched region  115  (window), where the UV spectrographic device will be utilized, is thin walled. The arched structure of the windows also provides the cuvette with further structural integrity despite the thin walled region. The resulting cuvette has a thin walled detection region that allow for better UV transmission while still allowing the cuvette to have excellent structural integrity. The fact that the second cavity  132  is relatively small means that less sample volumes are required for testing. 
     FIG. 2  shows a planar view of the back portion or wall  135  of the cuvette in accordance with the invention.  FIG. 2  also shows a second arched (window) region  140  that is adjacent to the arched region  115  shown in  FIG. 1 . Together, the arched (window) region  115  and the second (window) arched region  140  form two of the four side walls of the cavity  132  for holding the liquid to be tested. The two other side walls that make up the cavity are internal to the cuvette but may also be thin walled arched windows. 
     FIG. 3  shows a planar view of the first side wall  110  also shown in  FIG. 1 .  FIG. 3  also shows the arched (window) region  120  which is a thin walled region allowing superior UV wave transmissions. The arched region  120  is one of the side walls forming the cavity  132  also described in reference to  FIG. 1  above.  FIG. 4  shows a view of a second side wall  145  of the cuvette in accordance with the invention. The wall  145  is formed to reinforce the structure of the cuvette and has a thickness that is the same or about the same as the cuvette body. The second side wall  145  does not have a window.  FIG. 5  illustrates a front view of the cuvette showing a front wall  155 . As can be seen in  FIG. 5 , the front wall  155  has a section that is cut way near its base. The cut away exposes a third arched (window) region  160  that forms the third wall of the cavity  132  shown in  FIG. 1 .  FIG. 6  illustrates a bottom view of the cuvette. The shaded region  165  is bottom view of the cavity  132 . The cavity is bounded by the three thin walled windows  160 ,  140  and  120  and a fourth wall  175  that has a thickness that is the same as the rest of the cuvette body. A plane  172  also reinforces the cuvette providing additional structural integrity. 
     FIGS. 7A-D  shows various views of the cuvette cap  700  in accordance with embodiments of the invention.  FIG. 7A  shows a top view the cuvette cap  700  that includes an opening  710  that allows access to the cuvette and also allows coupling to a Luer Locking device.  FIG. 7B  shows a perspective view of the cuvette cap. The cap can be described as having three regions which are denoted in the  FIG. 7 , as regions  715 ,  720  and  725 . Region  715  provides ridges which extend downward from the cap  700  surface so as to ensure that the cap provides a tight seal with the cuvette. These ridges as fitted into the cuvette so that their surfaces are in close contact with the inner walls of the cuvette. Region  720  in  FIG. 7B  is the base top surface of the cuvette cap which forms a seal with the cuvette. In other words, when the cuvette cap  700  is mounted onto a cuvette, Region  720  forms a flat surface covering the cuvette opening, thereby preventing the leakage of substances from the cuvette as well as vapors from escaping the cuvette. Region  725  in  FIG. 7B  shows an opening through which substances can be deposited in the cuvette. Region  725  can also be mated to a Luer Lock device which allows substances to be injected from a syringe into the cuvette without any of the substances leaking.  FIG. 7C  also another view of the three distinct regions  715 ,  720  and  725 . Region  715  is a ridged region that extends into the cuvette to form a tight seal. Region  720  is the top surface of the cap which forms a seal with the cuvette opening. Region  725  provides a opening which allows access to the cuvette and also allows the cap to be coupled to a Luer Lock.  FIG. 7D  shows another perspective view of the cuvette cap. As described earlier, in this embodiment, the cap  700  may be constructed from a variety of materials including various plastics and polymers capable of being formed to the configuration as shown. 
     FIGS. 8A-D  shows various views of a cuvette cap in accordance with another embodiment of the invention.  FIG. 8A  shows a top view of the cuvette cap  800  which shows the flat top surface of the cap along with an opening  810  through which substances can be deposited into the cuvette.  FIG. 8B  shows a side view of the cuvette cap  800  in accordance with this embodiment.  FIG. 8B  can be described in conjunction with three separate regions denoted by the numerals  815 ,  820  and  825 . Region  815  shows a ridged region which is inserted into the cuvette and which forms a tight seal between the cuvette and the cuvette cap  800 . Region  820  is a top surface of the cap  800  which forms the seal between the cap  800  and the cuvette thus preventing leakage of substances as well as the escape of vapors from the cuvette. Region  825  acts as an adaptor which allows the cuvette cap  800  to be coupled to a Luer Lock and also allows those substances to be deposited into the cuvette.  FIG. 8C  is a side view of the cuvette cap which can also be described in conjunction with three regions  815 ,  820  and  825 . Region  815  is a ridged portion which is inserted into and extends into the cuvette. Region  820  is the top surface of the cap  800  which forms a seal between cuvette and the cap  800 . Region  825  allows the cuvette cap  800  to be coupled to a Luer Lock. Region  825  also allows substances to be flowed through into the cuvette.  FIG. 8D  also shows another side view of the cuvette cap  800 . 
     FIGS. 9A-D  shows the cap  900  in accordance with another embodiment of the invention.  FIG. 9A  is a top view showing both the top surface of the cuvette cap which forms a seal with the cuvette as well as an opening  910  which allows the cuvette to receive various substances.  FIG. 9B  shows a side view of the cuvette cap  900  in accordance with this embodiment.  FIG. 9B  shows the cuvette cap  900  in the form of a stopper which is inserted into the cuvette forming a tight seal which prevents leakage of various substances, including vapors from the cuvette. A rounded nub  920  is located on the top surface of the cap  900  which forms an opening through which substances can be deposited into the cuvette. For example, a syringe may be inserted into this opening and substances from the syringe can be injected into the cuvette with risk of leakage.  FIG. 9C  shows another side view of cuvette cap  900 .  FIG. 9D  shows another perspective view of the cap  900  in accordance with this embodiment.  FIG. 9D  shows the bottom surface of the cuvette cap  900  which shows a bottom opening  930  through substances are flowed into the cuvette. As described above, in this embodiment, the cuvette cap  900  may be formed of a rubber or rubber like plastic or polymer. 
     FIGS. 10A-C  show the cap  1000  in accordance with an embodiment of the invention along with various components that are used in conjunction with the cap.  FIG. 10A  shows three components, a cuvette  1010  itself in which various substances are poured and/or mixed for study and analysis. A cuvette cap  1020  is shown in accordance with an embodiment of the invention, which has been inserted into cuvette to form a seal. A Luer Lock  1030  is shown which is fitted onto the top surface of the cuvette cap.  FIG. 10B  shows a second perspective view of this embodiment whereby the Luer Lock  1030  is not fitted onto the top surface of the cuvette cap  1020 .  FIG. 10C  shows all three components, the cuvette  1010 , the cuvette cap  1020  and the Luer Lock  1030  before they are coupled. Thus, a pharmacist or other technician places the cuvette cap  1020  firmly into the cuvette  1010  forming a seal between the cuvette  1010  and the cuvette cap  1020  which prevents leakage of substances. Luer Lock valve device  1030  is then fitted and sealed on to the cap. The Luer Lock  1030  is then capable of receiving an instrument, such as a syringe, which can inject substances into the cuvette via the lock and the cuvette cap. 
     FIG. 11  shows another embodiment of the cuvette cap.  FIG. 11  shows an embodiment of the cuvette cap where the cuvette cap may be a rubber or rubber like plastic or polymer.  FIG. 11A  shows a cuvette cap inserted into the cuvette so as to form a seal therebetween. The cuvette cap is then mated to a Luer adaptor capable of receiving Luer Lock. Once the Luer Lock in  FIG. 11A  is fitted into the Luer adaptor, a syringe can then be inserted via the Luer Lock and can puncture the cuvette cap allowing the contents of the syringe to be deposited into the cuvette.  FIG. 11B  shows the components of  FIG. 11A  before those components are fully assembled. In  FIG. 11B , the cuvette, cuvette cover, Luer adaptor and Luer Lock can all be seen. In  FIG. 11C  also shows another view of each of the components described above before they are entirely assembled. In  FIG. 11C , the cuvette cap is still inserted into the cuvette. In this figure, the Luer adaptor and the Luer Lock have not yet been assembled.  FIG. 11D  shows all of the components described above prior to assembly. Thus,  FIG. 11D  shows the cuvette, the cuvette cap which has not yet been inserted into the cuvette, the Luer adaptor which has not yet been connected with the cuvette cover and the Luer Lock which has not yet been connected with the Luer adaptor. Once these components are assembled, as shown in  FIG. 11A , any pharmacist or other technician can insert a syringe into the cuvette via the Luer Lock, a Luer Lock adaptor and cap. In this manner, substances can be injected into the cuvette without any of the substance escaping.