Flow cell and liquid chromatographic unit having same

A flow cell and a liquid chromatographic unit are provided. The flow cell includes a housing, a cell core, a liquid-core waveguide, an inlet connection assembly and an outlet connection assembly. The cell core is provided in the housing, and is provided with a liquid feed recess, a liquid channel and a liquid discharge recess therein. The liquid-core waveguide is provided in the liquid channel. The inlet connection assembly is provided at an end of the cell core, and includes an inlet press block, a liquid feed tube, and a light entering tube. The outlet connection assembly is arranged at another end of the cell core and is provided with a light exit hole.

TECHNICAL FIELD

The present disclosure relates to the field of sample detection and analysis devices, and more particularly, to a flow cell and a liquid chromatographic unit having same.

BACKGROUND

High performance liquid chromatography (HPLC) is commonly used in the process of sample detection and analysis, and sample separation and purification. An ultraviolet (UV) spectrophotometer is a core component of the HPLC, and a flow cell is a core component of the UV spectrophotometer.

For existing UV spectrophotometers, most of internal structures of flow paths and optical path designs in flow cells adopted by different manufactures are made of stainless steel (SS316L) parts. In the actual use of a liquid chromatographic unit, surface roughness of small holes on a stainless steel part is usually 0.8. Due to scattering of light by a liquid and a deviation of an external light path, the light inevitably irradiates inner walls of small holes in an absorption region of a flow cell, thereby leading to the more stray light and the greater loss of light energy. At the same time, a physical size of the flow cell is restricted by a size of the external light path.

SUMMARY

The present disclosure aims to solve at least one of the technical problems in the prior art. To this end, the present disclosure provides a flow cell, which has small stray light and little loss of light energy.

The present disclosure also aims to provide a liquid chromatographic unit having the flow cell.

The flow cell according to embodiments of the present disclosure includes: a housing defining an installation cavity; a cell core arranged in the installation cavity and provided with a liquid channel, a liquid feed recess, and a liquid discharge recess therein, wherein the liquid feed recess and the liquid discharge recess are formed at opposite sides of the cell core, and two ends of the liquid channel are respectively connected to the liquid feed recess and the liquid discharge recess; a liquid-core waveguide fitted in the liquid channel and configured to circulate liquid and to propagate light; an inlet connection assembly, including: an inlet press block pressed against an end of the cell core provided with the liquid feed recess; a liquid feed tube penetrating through the inlet press block and in communication with the liquid feed recess; and a light entering tube penetrating through the inlet press block and in communication with the liquid feed recess; and an outlet connection assembly pressed against an end of the cell core provided with the liquid discharge recess, wherein the outlet connection assembly is provided with a light exit hole facing towards the liquid discharge recess, in such a manner that light passes through the light entering tube, the liquid feed recess, the liquid-core waveguide, the liquid discharge recess, and the light exit hole sequentially to exit the installation cavity.

With the flow cell according to embodiments of the present disclosure, light enters the liquid-core waveguide directly after entering the liquid feed recess from the light entering tube, so that a total reflection occurs on an inner wall of the liquid-core waveguide, which can reduce energy loss and the probability of occurrence of the stray light. In view of this, the affection of the energy loss of the light or the occurrence of the stray light can be reduced for the output intensity of the light, thereby improving the accuracy of concentration detection of the liquid. In addition, the structure of the inlet press block and the outlet press block may better seal the cell core and withstand a greater liquid pressure.

In some embodiments, the outlet connection assembly includes a window pressed against the end of the cell core provided with the liquid discharge recess. A light-shielding film is provided at a side of the window facing towards the liquid discharge recess. The light exit hole is provided on the light-shielding film. A light through hole corresponding to the light exit hole is provided on the housing.

In some embodiments, the outlet connection assembly further includes a gasket surrounding the light through hole and sandwiched between the housing and the window.

In some embodiments, the inlet connection assembly further includes a return pipe penetrating through the cell core, and the return pipe has an end connected to the liquid discharge recess.

In some embodiments, the inlet connection assembly further includes a pre-tensioning part arranged in the installation cavity and located at a side of the inlet press block facing away from a liquid feed port. An elastic member is provided between the pre-tensioning part and the inlet press block to achieve sealing abutment among the cell core, the inlet press block and the outlet connection assembly.

In some embodiments, the outlet connection assembly further includes: an outlet press block pressed against the end of the cell core provided with the liquid discharge recess; a liquid discharge tube penetrating through the outlet press block and in communication with the liquid discharge recess; and a light exiting tube penetrating through the outlet press block and in communication with the liquid discharge recess, wherein the light exit hole is formed on the light exiting tube.

In some embodiments, the flow cell further includes a protective sleeve. The liquid-core waveguide is sleeved with the protective sleeve.

In some embodiments, the window is quartz glass. A diameter of the light exit hole is smaller than or equal to 0.5 mm.

In some embodiments, the light-shielding film is a metal film or a screen printing coating film.

The liquid chromatographic unit according to embodiments of the present disclosure includes the flow cell as described above.

Since the liquid chromatographic unit according to embodiments of the present disclosure includes the flow cell as described above, the accuracy of detection is high, and a relatively high liquid pressure may be withstood.

REFERENCE NUMERALS OF THE ACCOMPANYING DRAWING

DESCRIPTION OF EMBODIMENTS

Descriptions will now be made in detail to embodiments, examples of which are illustrated in the accompanying drawings. The same or similar elements and the elements having same or similar functions are denoted by like reference numerals throughout the descriptions. The embodiments described herein with reference to the drawings are explanatory and merely used to explain the present disclosure, and shall not be construed to limit the present disclosure.

In the description of the present disclosure, it is to be understood that, terms such as “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “over”, “below”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “in”, “out”, “clockwise”, “anti-clockwise”, “axial”, “radial” and “circumference” refer to orientations and location relations which are those shown in the drawings, merely for sake of describing the present disclosure and simplification, rather than indicating or implying that the device or the elements are disposed to locate at the specific orientations or are structured and performed in the specific orientations, and thus cannot be construed as the limitation of the present disclosure. In addition, the feature denoted by “first” and “second” may include one or more such feature distinctly or implicitly. In the description of the present disclosure, “a plurality of” means two or more, unless specified otherwise.

It should be noted that in the present disclosure, unless specified or limited otherwise, the terms “mounted,” “connected,” and “coupled” shall be understood broadly, such as fixed connection, detachable connection, or connection into one piece; mechanical or electrical connection; and direct connection, connection via an intermediate medium, or connection between two elements. Meanings of the terms in the present disclosure can be understood by those skilled in the art according to detail embodiments of the present disclosure.

The specific structure of a flow cell1according to embodiments of the present disclosure will be described below with reference toFIGS. 1 to 5.

As illustrated inFIG. 1, the flow cell1according to embodiments of the present disclosure includes a housing11, a cell core12, a liquid-core waveguide13, an inlet connection assembly14, and an outlet connection assembly15.

As illustrated inFIGS. 1 and 4, the housing11defines an installation cavity111. The cell core12is arranged in the installation cavity111, and is provided with a liquid channel121, a liquid feed recess122, and a liquid discharge recess123therein. The liquid feed recess122and the liquid discharge recess123are formed at opposite sides of the cell core12. Two ends of the liquid channel121are respectively connected to the liquid feed recess122and the liquid discharge recess123. The liquid-core waveguide13is fitted in the liquid channel121, and is configured to circulate liquid and to propagate light. The inlet connection assembly14includes an inlet press block141, a liquid feed tube142, and a light entering tube143. The inlet press block141is pressed against an end of the cell core12provided with the liquid feed recess122. The liquid feed tube142is pierced on the inlet press block141, and is in communication with the liquid feed recess122. The light entering tube143penetrates through the inlet press block141, and is in communication with the liquid feed recess122. The outlet connection assembly15is pressed against an end of the cell core12provided with the liquid discharge recess123. The outlet connection assembly15is provided with a light exit hole15afacing towards the liquid discharge recess123, so that light passes through the light entering tube143, the liquid feed recess122, the liquid-core waveguide13, the liquid discharge recess123, and the light exit hole15asequentially to exit the installation cavity111.

It may be understood that when a liquid flows through the liquid-core waveguide13, the liquid is irradiated by the light, so that the liquid will absorb a part of the light. According to an incident intensity and an output intensity of the light, a concentration of the liquid may be calculated by the Lambert-Beer law. Since stray light and energy loss may occur during the propagation of light, deviations may occur in the output intensity of the light, leading to deviations in the calculation of the concentration of the liquid.

According to the embodiments of the present disclosure, the light enters the liquid-core waveguide13directly after entering the liquid feed recess122from the light entering tube143, so that a total reflection occurs on an inner wall of the liquid-core waveguide13, which can reduce energy loss and the probability of occurrence of the stray light. In view of this, the affection of the energy loss of the light or the occurrence of the stray light can be reduced for the output intensity of the light, thereby improving the accuracy of concentration detection of the liquid. In addition, according to the present disclosure, the inlet press block141is pressed against the end of the cell core12provided with the liquid feed recess122, and the outlet connection assembly15is pressed against the end of the cell core12provided with the liquid discharge recess123, so that the sealing performance of the flow cell1can be better guaranteed, and a greater liquid pressure may be withstood.

With the flow cell1according to embodiments of the present disclosure, the light enters the liquid-core waveguide13directly after entering the liquid feed recess122from the light entering tube143, so that a total reflection occurs on an inner wall of the liquid-core waveguide13, which can reduce energy loss and the probability of occurrence of the stray light. In view of this, the affection of the energy loss of the light or the occurrence of the stray light can be reduced for the output intensity of the light, thereby improving the accuracy of concentration detection of the liquid. In addition, the structures of the inlet press block141and the outlet connection assembly15may better seal the cell core12while withstanding a greater liquid pressure.

In some embodiments, the liquid-core waveguide13uses a TEFLON tube with a lower refractive index than that of the liquid, such as TEFLON2400.

In some embodiments, as illustrated inFIG. 1, the light entering tube143is an optical fiber, and a light entering sleeve147is provided around the optical fiber for protecting the optical fiber. This can ensure stable propagation of the light in the light entering tube143while protecting the optical fiber, thereby prolonging the service life of the flow cell1.

In some embodiments, as illustrated inFIG. 1, a part of a cross section of the liquid feed recess122facing towards the light entering tube143is in a bow shape, and a part of a cross section of the liquid feed recess122facing towards the liquid feed tube142is in a long strip shape. This not only ensures that the light may be well incident into the liquid-core waveguide13, but also ensures that the liquid flows into the liquid-core waveguide13, thereby reducing the energy loss of incident light while avoiding the occurrence of liquid accumulation in the liquid feed recess122.

In some embodiments, as illustrated inFIG. 1, the outlet connection assembly151includes a window151. The window151is pressed against the end of the cell core12provided with the liquid discharge recess123. A light-shielding film152is provided at a side of the window151facing towards the liquid discharge recess123. The light exit hole15ais provided on the light-shielding film152. A light through hole112corresponding to the light exit hole15ais provided on the housing11. It may be understood that in the related art, generally, small holes are provided on a sealing gasket to achieve the function of a slit or a light diaphragm. In the present disclosure, the light exit hole15ais provided on the light-shielding film152at the side of the window151facing towards the liquid discharge recess123, such that the possibility of the occurrence of the stray light is reduced, and a greater liquid pressure may be withstood. In addition, the window151is easier to manufacture.

In some embodiments, the window151is quartz glass. A diameter of the light exit hole15ais smaller than or equal to 0.5 mm By adopting the quartz glass, the window151may withstand a greater liquid pressure. At the same time, if the light exit hole15ais too large, external light will enter the liquid discharge recess123, thereby affecting the detection result. Therefore, setting the diameter of the light exit hole15ato be smaller than or equal to 0.5 mm may better prevent the external light from entering, thereby ensuring the accuracy of detection. Of course, it should be noted that the size of the light exit hole15amay be selected based on practical requirements, and is not limited to the above range.

In some embodiments, the light-shielding film152is a metal film or a screen printing coating film, so that the light-shielding film152can be in close contact with the window151, thereby avoiding a gap between the light-shielding film152and the window151, which would otherwise cause the stray light. Of course, the light-shielding film152may also be made of other light-shielding materials, which will not be illustrated here.

In some specific embodiments, the outlet connection assembly15further includes a gasket157. The gasket157surrounds the light through hole112and is sandwiched between the housing11and the window151. It may be understood that the gasket157sandwiched between the housing11and the window151may improve the sealing performance of the flow cell1while protecting the window151to a certain extent. It should be noted that the gasket157is mainly used to enhance the sealing performance and to protect the window151. The specific type and material of the gasket157are not limited here, and may be determined based on practical requirements.

In some embodiments, as illustrated inFIG. 1, the inlet connection assembly14further includes a return pipe144. The return pipe144penetrates through the cell core12. The return pipe144has an end connected to the liquid discharge recess123. It should be understood that the liquid may flow into the return pipe144after passing through the liquid discharge recess123, and then flow out of the return pipe144, so that an inlet and an outlet of the liquid are located on the same side of the cell core12, thereby reducing a volume of the flow cell1and facilitating liquid circulation.

In some embodiments, as illustrated inFIG. 1, a part of a cross section of the liquid discharge recess123facing towards the liquid-core waveguide13is in a bow shape, and a part of a cross section of the liquid discharge recess123facing towards the return pipe144is in a long strip shape. This not only ensures that the light may be better transmitted from the liquid-core waveguide13to the light exit hole15a, but also ensures that the liquid flows into the return pipe144, which not only reduces the energy loss of the exit light, but also avoids the liquid accumulation in the liquid discharge recess123. Of course, in other embodiments of the present disclosure, the inlet connection assembly14may not include the return pipe144, and instead, a pipe connected to the liquid discharge recess123and located at the other end of the cell core12is provided as a liquid discharge tube154.

In some embodiments, as illustrated inFIGS. 1 and 4, the inlet connection assembly14further includes a pre-tensioning part145. The pre-tensioning part145is arranged in the installation cavity111and located at a side of the inlet press block141facing away from a liquid feed port. An elastic member146is provided between the pre-tensioning part145and the inlet press block141, so as to form sealing abutment among the cell core12, the inlet press block141and the outlet connection assembly15. It may be understood that the presence of the pre-tensioning part145and the elastic member146may form the sealing abutment among the cell core12, the inlet press block141and the outlet connection assembly15, thereby avoiding liquid leakage. It should be noted that the pre-tensioning part145and a side wall of the installation cavity111may be connected by a thread, which not only facilitates the installation of the pre-tensioning part145, but also ensures the sealing abutment of the pre-tensioning part145and the elastic member146against the cell core12, the inlet press block141and the outlet connection assembly15. In addition, the type of the elastic member146is not limited here. The elastic member146may be a spring, a disc elastic sheet, or an elastic cushion. The specific type and material of the elastic member146may be determined based on practical requirements.

In some embodiments, as illustrated inFIG. 4, the outlet connection assembly15further includes an outlet press block153, the liquid discharge tube154, and a light exiting tube155. The outlet press block153is pressed against the end of the cell core12provided with the liquid discharge recess123. The liquid discharge tube154penetrates through the outlet press block153, and is in communication with the liquid discharge recess123. The light exiting tube155penetrates through the outlet press block153, and is in communication with the liquid discharge recess123. The light exit hole15ais formed on the light exiting tube155. It may be understood that the presence of the outlet press block153and the inlet press block141may better ensure the sealing performance of the flow cell1, thereby avoiding liquid leakage. In addition, with the light exiting tube155provided to be connected to the liquid discharge recess123, the light may directly enter the light exiting tube155after passing through the liquid discharge recess123, such that the energy loss is reduced, and the possibility of stray light generation is lowered. In view of this, the affection of the energy loss of the light or the occurrence of the stray light can be reduced for the output intensity of the light, thereby improving the accuracy of concentration detection of the liquid.

In some embodiments, the light exiting tube155is an optical fiber, and the optical fiber is sleeved with a light exiting sleeve156for protecting the optical fiber. This can ensure the stable propagation of light in the light exiting tube155while protecting the optical fiber, thereby prolonging the service life of the flow cell1.

In some embodiments, as illustrated inFIGS. 1 and 4, the flow cell1further includes a protective sleeve16. The liquid-core waveguide13is sleeved with the protective sleeve16. It may be understood that the protective sleeve16may protect the liquid-core waveguide13. Of course, the protective sleeve16mainly plays a role of protecting the liquid-core waveguide13. The specific type of the protective sleeve16is not limited herein.

The flow cell1according to a specific embodiment of the present disclosure will be described below with reference toFIGS. 1 to 3.

The flow cell1according to the embodiment includes the housing11, the cell core12, the liquid-core waveguide13, the inlet connection assembly14, and the outlet connection assembly15. The housing11defines the installation cavity111. The cell core12is arranged in the installation cavity111, and is provided with the liquid channel121, the liquid feed recess122, and the liquid discharge recess123therein. The liquid feed recess122and the liquid discharge recess123are formed at opposite sides of the cell core12. Two ends of the liquid channel121are respectively connected to the liquid feed recess122and the liquid discharge recess123. The liquid-core waveguide13is fitted in the liquid channel121, and is configured to circulate liquid and to propagate light. The liquid-core waveguide13is sleeved with the protective sleeve16. The inlet connection assembly14includes the inlet press block141, the liquid feed tube142, the light entering tube143, the return pipe144, the pre-tensioning part145, and the elastic member146. The inlet press block141is pressed against the end of the cell core12provided with the liquid feed recess122. The liquid feed tube142penetrates through the inlet press block141, and is in communication with the liquid feed recess122. The light entering tube143penetrates through the inlet press block141, and is in communication with the liquid feed recess122. The outlet connection assembly15is pressed against the end of the cell core12provided with the liquid discharge recess123. The return pipe144penetrates through the cell core12. The return pipe144has an end connected to the liquid discharge recess123. The light entering tube143is the optical fiber. The light entering tube143is sleeved with the light entering sleeve147. The pre-tensioning part145is arranged in the installation cavity111and located at a side of the inlet press block141facing away from the liquid feed port. The elastic member146is provided between the pre-tensioning part145and the inlet press block141, so as to form sealing abutment among the cell core12, the inlet press block141and the outlet connection assembly15. The outlet connection assembly15includes the window151and the gasket157. The window151is pressed against an end of the cell core12provided with the liquid discharge recess123. The light-shielding film152is provided at a side of the window151facing towards the liquid discharge recess123. The light exit hole15ais provided on the light-shielding film152. The light through hole112corresponding to the light exit hole15ais provided on the housing11.

A flow cell1according to another specific embodiment of the present disclosure will be described below with reference toFIGS. 4 to 5.

The flow cell1according to the embodiment includes a housing11, a cell core12, a liquid-core waveguide13, an inlet connection assembly14and an outlet connection assembly15. The housing11defines an installation cavity111. The cell core12is arranged in the installation cavity111, and is provided with a liquid channel121, a liquid feed recess122, and a liquid discharge recess123therein. The liquid feed recess122and the liquid discharge recess123are formed at opposite sides of the cell core12. Two ends of the liquid channel121are respectively connected to the liquid feed recess122and the liquid discharge recess123. The liquid-core waveguide13is fitted in the liquid channel121, and is configured to circulate liquid and to propagate light. The liquid-core waveguide13is sleeved with a protective sleeve16. The inlet connection assembly14includes an inlet press block141, a liquid feed tube142, a light entering tube143, a return pipe144, a pre-tensioning part145, and an elastic member146. The inlet press block141is pressed against an end of the cell core12provided with the liquid feed recess122. The liquid feed tube142penetrates through the inlet press block141, and is in communication with the liquid feed recess122. The light entering tube143penetrates through the inlet press block141, and is in communication with the liquid feed recess122. The outlet connection assembly15is pressed against an end of the cell core12provided with the liquid discharge recess123. The return pipe144penetrates through the cell core12. The return pipe144has an end connected to the liquid discharge recess123. The light entering tube143is an optical fiber. The light entering tube143is sleeved with the light entering sleeve147. The pre-tensioning part145is arranged in the installation cavity111and located at a side of the inlet press block141facing away from the liquid feed port. The elastic member146is provided between the pre-tensioning part145and the inlet press block141, so as to achieve sealing abutment among the cell core12, the inlet press block141and the outlet connection assembly15.

The outlet connection assembly15further includes an outlet press block153, a liquid discharge tube154, and a light exiting tube155. The outlet press block153is pressed against the end of the cell core12provided with the liquid discharge recess123. The liquid discharge tube154penetrates through the outlet press block153, and is in communication with the liquid discharge recess123. The light exiting tube155penetrates through the outlet press block153, and is in communication with the liquid discharge recess123. The light exit hole15ais formed on the light exiting tube155. The light exiting tube155is an optical fiber. The light entering tube143is sleeved with the light exiting sleeve156.

The liquid chromatographic unit according to embodiments of the present disclosure includes the flow cell1described above.

Since the liquid chromatographic unit according to embodiments of the present disclosure includes the flow cell1as described above, the accuracy of detection is high, and a relatively high liquid pressure may be withstood.

Although embodiments of present disclosure have been shown and described above, it should be understood by those skilled in the art that changes, alternatives, and modifications may be made to the embodiments without departing from spirit and principles of the present disclosure. The scope of the present disclosure is limited by the attached claims and its equivalents.