Patent Description:
Liquid chromatography is a technique in analytic chemistry where distinct components of a mixture are identified by separating the individual components by passing the mixture through an adsorbent medium using fluid flow so that the components elute at different rates. Liquid chromatography systems are typically comprised of a solvent delivery pump, an autosampler, a column, and a detector. The solvent delivery pump pumps mobile phase fluid through the system, the autosampler introduces the sample to be analyzed to the analytic flow path, the column contains the adsorbent packing material used to effect separation, and the detector detects the separated components as they elute out of the column.

Samples for chromatographic analysis can be stored in either vials or wellplates. Wellplates are typically flat, rectangular plates with an array of wells that hold the samples. Often times, seals are applied to a top surface of the wellplates over the openings of the wells to better contain the samples. The wellplates are inserted into liquid chromatography autosamplers, where a needle is inserted into the individual wells to aspirate the sample contained in the wellplate, and then to insert the sample into a flow path for chromatographic analysis. When a wellplate in an autosampler has a seal, the needle must pierce through the seal to aspirate the sample, but needle does not always cleanly pierce through the seal and instead the seal material will stretch before tearing leaving material wrapped around the tip of the needle. The torn material remaining on the needle tip can cause clogs when the needle aspirates the sample or inserts the sample into the analytic flow path.

Thus, a need exists for eliminating clogs resulting from sample source seals remaining on the needle, in liquid chromatography applications.

Prior art arrangements are known from: <CIT>, which discloses a drag reduction surface texture biopsy needle; <CIT>, which discloses a flow channel in a needle that is mechanically polished; and <CIT>, which discloses an analysis apparatus that is provided with a storage tank, an injection nozzle, a syringe, a collection nozzle, a test sample tank, a microchip having two or more separation channels, detectors, a waste liquid tank, a controller, and a power supply.

According to the present invention in a first aspect there is provided a needle for aspirating a sample from a sample source as recited by Claim <NUM>.

According to the present invention in a second aspect there is provided an autosampler of a liquid chromatography system as recited by Claim <NUM>.

According to the present invention in a third aspect there is provided a method of manufacturing a needle as recited by Claim <NUM>.

The foregoing and other features of construction and operation will be more readily understood and fully appreciated from the following detailed disclosure, taken in conjunction with accompanying drawings.

Some of the embodiments will be described in detail, with reference to the following figures, wherein like designations denote like members, wherein:.

A detailed description of the hereinafter described embodiments of the disclosed apparatus and method are presented herein by way of exemplification and not limitation with reference to the Figures. Although certain embodiments are shown and described in detail, it should be understood that various changes and modifications may be made without departing from the scope of the appended claims. The scope of the present disclosure will in no way be limited to the number of constituting components, the materials thereof, the shapes thereof, the relative arrangement thereof, etc., and are disclosed simply as an example of embodiments of the present disclosure.

As a preface to the detailed description, it should be noted that, as used in this specification and the appended claims, the singular forms "a", "an" and "the" include plural referents, unless the context clearly dictates otherwise.

Referring to the drawings, <FIG> depicts a current needle design with a smooth exterior surface piercing a seal of a sample source, wherein portions of a seal material <NUM> are clinging to the needle. It has been determined that a high coefficient of friction on a smooth exterior of current needle designs for liquid chromatography applications causes certain plastic seals <NUM> of a sample source to cling to the smooth exterior surface of the needle, and stretch around the needle during piercing, as shown in <FIG>. The stretching and clinging of the seal material <NUM> can results in parts of the seal material <NUM> to break-off, resulting in unwanted plastic sleeves, pieces, objects, wads, etc. caught on the needle tip, which may clog, block, or otherwise disrupt an injection into a system, such as a high performance liquid chromatography system. In particular, a smooth surface produces a gage block effect between the needle and the seal during piercing so that the seal clings to the surface of the needle and stretches as the needle is lowered into the well. <FIG> depicts stretched, leftover seal material <NUM> on a sample source <NUM>, such as a wellplate, caused by unwanted clinging of the seal material onto the current needle of <FIG>.

Referring now to <FIG>, which depicts a cross-sectional view of a needle <NUM> in accordance with embodiments of the present invention. Embodiments of needle <NUM> may be a needle, a sample needle, an injection needle, a textured needle, a liquid chromatography needle, an autosampler needle, an injector, a sample injector, and the like. Embodiments of the needle <NUM> may include a first end <NUM>, a second end <NUM>, and a needle body <NUM>. Embodiments of the needle body <NUM> may be a body, a body portion, or other structural element that defines a general structure of the needle <NUM>. The needle body <NUM> of the needle <NUM> may have an overall length, L. The overall length, L, may vary depending on the application, a size of a sample compartment of an autosampler, a volume of sample to be analyzed, etc. In an exemplary embodiment, the overall length, L, may be between <NUM>-<NUM> inches (<NUM>-<NUM>). Embodiments of the needle <NUM> may be comprised of metal, metal alloy, metal alloys, or a combination thereof. In an exemplary embodiment, the needle <NUM> may be comprised of stainless steel or a chromium alloy, such as MP35N®.

Moreover, embodiments of the needle <NUM>, or the needle body <NUM>, include a smooth surface region <NUM> and a textured surface region <NUM>, and may include a non-textured region <NUM>. In an exemplary embodiment, the needle <NUM> is a needle for aspirating a sample from a sample source <NUM> and injecting the sample into a liquid chromatography system, wherein the needle <NUM> includes a needle body <NUM> having a rough textured surface finish <NUM> applied to the textured region <NUM>, which is offset from a tip of the needle body <NUM> by the smooth surface region <NUM>, wherein the rough textured surface finish <NUM> reduces a coefficient of friction of the needle body <NUM>. By reducing the coefficient of friction of the needle <NUM>, at least in the area of the textured region <NUM>, a friction between the needle body <NUM> and the seal <NUM> can be reduced to prevent, hinder, or otherwise reduce a likelihood of a stretching of the seal <NUM> (e.g. plastic seal material over a wellplate) as the needle <NUM> pierces the seal <NUM> to aspirate the sample from within the sample source <NUM>.

With continued reference to <FIG>, and additional reference to <FIG>, which depicts a perspective view of the needle in <FIG>, in accordance with embodiments of the present invention, embodiments of the needle <NUM> include a smooth surface region <NUM>. Embodiments of the smooth surface region <NUM> may be a region, portion, section, etc. of an exterior surface of the needle body <NUM> having a smooth surface, or smooth surface finish <NUM>. The smooth surface finish <NUM> may have a max surface roughness Ra of 16µinch (<NUM>). Furthermore, the smooth surface region <NUM> is proximate a tip <NUM> of the needle body <NUM>. In an exemplary embodiment, the smooth surface region <NUM> may encompass the tip <NUM> of the needle body <NUM>. The tip <NUM> of the needle body <NUM> may be a tip, a nose, an aspirating end of the needle body <NUM>, and the like, which may be configured to initially engage and pierce a cover seal <NUM> of a sample source <NUM>. The smooth surface region <NUM> of the needle body <NUM> extends from the first end <NUM> of the needle <NUM>, or from a tip <NUM> of the needle body <NUM> a distance, prior to reaching the textured surface region <NUM>. In an exemplary embodiment, the smooth surface region <NUM> may extend at least <NUM> inches (<NUM>) from the first end <NUM> of the needle <NUM>. In another exemplary embodiment, the smooth surface region <NUM> may extend <NUM> inches ± <NUM> inches (<NUM> ± <NUM>) from the first end <NUM> of the needle <NUM>. In another exemplary embodiment, the smooth surface region <NUM> may extend from the first end <NUM> of the needle <NUM> less than <NUM> inches (<NUM>,<NUM>).

Embodiments of the needle <NUM> include the smooth surface region <NUM> so that smooth surface finish <NUM> of the tip <NUM> maintains a liquid tight seal between the tip <NUM> of the needle body <NUM> and an injection seat when the needle injects the sample into an analytic flow path of the liquid chromatography system. Preserving a smooth surface finish <NUM> on the tip <NUM> of the needle body <NUM> can maintain a proper sealing when the needle <NUM> inserts the sample in to the analytic flow path. For example, after the needle <NUM> aspirates the sample, the needle <NUM> moves to an inject station where the needle <NUM> is loaded against an inject seat creating a liquid-tight seal during injection. A smooth surface finish <NUM> on the needle tip <NUM> may ensure that a liquid tight seal forms between the needle tip <NUM> and the inject seat during injection.

Referring still to <FIG> and <FIG>, embodiments of the needle body <NUM> include a textured surface region <NUM>. Embodiments of the textured surface region <NUM> may be a textured region, a rough surface texture region, a region of reduced coefficient of friction, an enhanced surface roughness region, a region of increased roughness, and the like. The textured surface region <NUM> may reside next to or contiguous with the smooth surface region <NUM> along the exterior surface of the needle <NUM>. Further, the textured surface region <NUM> may be offset a distance from the tip <NUM> of the needle body <NUM>. Because the textured surface region <NUM> is offset from the tip <NUM> of the needle body <NUM>, a smooth surface finish <NUM> is preserved at the tip, while a total surface area of smooth surface finish of the needle <NUM> that causes problems with clinging of the seal material of the sample source <NUM> as described above, is limited.

In the textured surface region <NUM> of the needle body <NUM>, an exterior surface of the needle <NUM> includes a rough surface texture finish <NUM>. Embodiments of the rough surface texture finish <NUM> may have a roughness Ra greater than 15µinch (<NUM>). In an exemplary embodiment, the rough surface texture finish <NUM> may have a roughness Ra between 15µinch (<NUM>) and 30µinch (<NUM>). Embodiments of the rough surface texture finish <NUM> may have a roughness Ra greater than 30µinch (<NUM>), but a surface roughness Ra of the textured surface finish <NUM> may be limited because a surface that has been overly roughened will increase the coefficient of friction and the seal material may still cling and stretch. For instance, the textured surface finish <NUM> may have a max Ra of 80µinch (<NUM>). By applying a rough textured surface finish <NUM> to an exterior surface of a needle <NUM>, a coefficient of friction is reduced so that the plastic seal material <NUM> does not stretch or sleeve during piercing of the seal <NUM> of the sample source <NUM>. The addition of a textured surface finish <NUM> to the exterior of the needle body <NUM> may improve on current needle designs by improving piercing performance and decreasing a number of failures due to stretching or sleeving of plastic seals (e.g. wellplate seal).

Various methods may be used to form the rough surface texture finish <NUM> or otherwise roughen or texture the exterior surface of the needle body <NUM> in the textured surface region. In one embodiment, the textured surface finish <NUM> may be created using a bead blast technique. For example, the exterior surface of the needle body <NUM> may be bead blasted by spraying glass beads at a specific pressure to form the surface texture finish <NUM>. During the process of bead blasting, measurements may be taken to ensure that the roughness Ra falls within a certain range (e.g. 15µinch - 30µinch / <NUM> - <NUM>). In another embodiment, the textured surface finish <NUM> may be created using shot peening methods. For example, the surface texture may be formed using shot peening processes involving bombarding the needle body <NUM> with a stream of stainless steel balls being at a specific pressure to form the surface texture finish <NUM>. In another embodiment, the textured surface may be formed using a laser etching process. In further embodiments, the textured surface may be formed by a grinding technique. Other surface texturing and/or roughening methods may be used to accomplish a surface roughness Ra of the needle <NUM> described herein.

Referring back to <FIG>, embodiments of the needle body <NUM> may also include a non-textured region <NUM>. Embodiments of the non-textured region <NUM> may potentially comprise a region, section, portion, etc. of the needle body <NUM> residing next to or contiguous with the textured surface region <NUM> between the textured surface region <NUM> and the second end <NUM> of the needle <NUM>. The non-textured region <NUM> may have a same roughness Ra as the smooth surface region <NUM> proximate the tip, or a different roughness Ra than both the smooth surface region <NUM> and the textured region <NUM>. In some embodiments, the needle <NUM> may not have a non-textured region <NUM>, wherein the needle body <NUM> comprised the rough surface texture finish <NUM> from an edge of the smooth surface region <NUM> to the second end <NUM> of the needle <NUM>. Furthermore, in exemplary arrangements, which are not independently claimed as such, an entire needle body <NUM> may be comprised of the textured region <NUM>. In another arrangement, which is not independently claimed as such, the needle body <NUM> may not include a smooth surface finish proximate the needle tip <NUM>, and may instead be textured as in the textured region <NUM>. For example, the textured region <NUM> may extend from a point between the first end <NUM> and the second end <NUM> of the needle body <NUM> to the tip <NUM> of the needle body <NUM>. The needle body <NUM> may thus in this arrangement be textured starting at a tip <NUM> of the needle body <NUM> and continuing for a certain length from the tip <NUM>, and even up to the second end <NUM> of the needle body <NUM>.

<FIG> depicts a detailed view of Detail B of <FIG>, in accordance with embodiments of the present invention. The detailed view of <FIG> depicts the tip <NUM> of the needle body <NUM>, the smooth surface region <NUM> and a portion of the textured surface region <NUM>. Embodiments of the tip <NUM> may have a diameter, referred to as a nose diameter ND. The ND may be a diameter of the needle body <NUM> at the tip <NUM>. In an exemplary embodiment, the ND may be about <NUM> inches (<NUM>). A diameter D of the needle body <NUM> may be a max diameter of the needle body <NUM>. The max diameter D of the needle body <NUM> may vary. In exemplary embodiments used in liquid chromatography autosamplers, the max needle diameter D may be about <NUM>. 04inches (<NUM>). Furthermore, embodiments of the needle <NUM> may include an inner fluidic pathway <NUM>. Embodiments of the inner fluidic pathway <NUM> may be an inner bore extending generally axially through the needle <NUM>. In liquid chromatography applications, the sample from the sample source <NUM> may flow through the fluidic pathway <NUM>. Embodiments of the fluidic pathway <NUM> may have a bore diameter BD that may vary depending on a volume of sample to be tested. In some embodiment, the BD of the fluidic pathway <NUM> of the needle <NUM> may be about <NUM> inches (<NUM>). In other embodiments, the BD may be about <NUM> inches (<NUM>). In yet another embodiment, the max diameter of the inner bore is <NUM> inches (<NUM>). Moreover, embodiments of the needle body <NUM> include a conical section CS. Embodiments of a conical section CS may be a portion of the needle body <NUM> that tapers towards the needle tip <NUM>. A majority of the needle body <NUM> may have a uniform max diameter D, but the conical section CS may have a gradually reducing max diameter moving towards the tip <NUM> of the needle body <NUM>. A length of the conical section CS of the needle body <NUM> may vary. In an exemplary embodiment, the length of the CS may be about <NUM> inches (<NUM>). An angle, φ, of the CS of the needle body <NUM> may be less than <NUM>°. However, the angle, φ, may vary and be greater than <NUM>°.

<FIG> depicts a detailed view of Detail C of <FIG>, in accordance with embodiments of the present invention. The detailed view of <FIG> depicts the second end <NUM> of the needle body <NUM>. Embodiments of the needle body <NUM> may include a component attachment region <NUM>. Embodiments of the component attachment region <NUM> may be configured to receive a component, fastener, element, part, etc. of a liquid chromatography system. <FIG> depicts a textured needle <NUM> attached to a tubing <NUM> of a liquid chromatography system, in accordance with embodiments of the present invention. The needle <NUM> may be operably connected to a tubing <NUM> of a liquid chromatography system. A ferrule <NUM> may surround portions of the tubing <NUM> and the needle <NUM>. <FIG> depicts an enlarged view of <FIG>, showing the tubing <NUM> connected to the textured needle <NUM>, in accordance with embodiments of the present invention. The needle <NUM> may be welded to the tubing <NUM>. In an exemplary embodiment, the needle <NUM> may be laser welded to the tubing <NUM>. <FIG> depicts a detailed view of Detail J of <FIG>, in accordance with embodiments of the present invention. The component attachment region <NUM> of the needle body <NUM> may receive an end of tubing <NUM>, which may be laser welded (welding spots shown schematically as <NUM>). Thus, embodiments of the needle <NUM> may be operably connected to a tubing <NUM> of a liquid chromatograph system.

Referring now to <FIG> which depicts a schematic fluidic diagram of an autosampler <NUM> of a liquid chromatography system, having a needle <NUM> of <FIG>, in accordance with embodiments of the present invention. The needle <NUM> may be used to aspirate sample <NUM> from a sample source <NUM> for injection into an analytic flow path and eventually to a column for chromatographic analysis. The position shown in <FIG> is an aspirate position of the needle <NUM>, which has pierced a seal <NUM> of the sample source <NUM>, such as a well plate, for aspirating the sample <NUM>. Embodiments of the autosampler <NUM> (e.g. sample manager) may include a sample compartment <NUM> and an injection valve <NUM>, as well as other features and components of an autosampler for liquid chromatography applications. Embodiments of the injection valve <NUM> may be inject the sample <NUM> into an analytic flow path of the liquid chromatography system to a column for chromatographic analysis. Embodiments of the sample compartment <NUM> may be configured to receive at least one sample source <NUM> having a seal <NUM>. For example, the sample compartment <NUM> may house, receive, or otherwise cooperate with an array of wellplates containing sample <NUM>. Components of autosampler <NUM>, such as a process sample manager, may automatically programmatically obtain sample <NUM> from the sample sources <NUM>, for ultimately injecting into the column via the injection valve <NUM>.

The needle <NUM> may be a part of the sample compartment <NUM> for cooperating with the sample source containers <NUM>. For instance, the needle <NUM> may be housed within the sample compartment <NUM> of the autosampler <NUM> for liquid chromatography processes. Moreover, the needle <NUM> may be fluidically connected to the injection valve <NUM>, wherein the needle <NUM> may be configured to aspirate the sample <NUM> from the at least one sample source <NUM> by piercing the seal <NUM> of the at least one sample source <NUM>, and then inject the sample <NUM> into the analytic flow path of a liquid chromatography system.

<FIG> depicts a schematic diagram of a liquid chromatography system <NUM>, in accordance with embodiments of the present invention. Embodiments of a liquid chromatography system <NUM> may include a mobile phase, such as a solvent reservoir/source, one or more pumps, the autosampler <NUM> in fluid communication with the sample, a column, and a detector, , as known to those skilled in the art of liquid chromatography.

Referring now to <FIG>, a method of improving a piercing performance of a needle <NUM> in a liquid chromatography system <NUM> may include reducing a coefficient of friction of the needle <NUM> by forming a rough textured surface region <NUM> on an exterior surface of the needle <NUM>, such that when the needle pierces a seal <NUM> of a sample source <NUM>, the seal <NUM> does not cling to the rough textured surface region <NUM> of the needle <NUM> as a result of the reduced coefficient of friction.

Claim 1:
A needle (<NUM>) for aspirating a sample from a sample source and injecting the sample into a liquid chromatography system, the needle comprising:
a needle body (<NUM>) including a tip (<NUM>) and a conical section (CS) adjacent to the tip, the conical section having a rough textured surface finish (<NUM>) in a region (<NUM>) that is offset from the tip, the needle body further having a smooth surface finish (<NUM>) in a region (<NUM>) extending from the tip to the rough textured surface region (<NUM>);
wherein the rough textured surface finish (<NUM>) reduces a coefficient of friction of the needle body to avoid a seal material covering the sample source from clinging to the needle body as the needle enters or exits the sample source;
wherein the smooth surface finish (<NUM>) maintains a liquid tight seal between the tip of the needle body and an injection seat when the needle injects the sample into an analytic flow path of the liquid chromatography system.