Patent Description:
In the fields of biochemistry and analytical chemistry, laboratory researchers generally prepare, manipulate, and analyze a multitude of samples for a variety of reasons. Many laboratories employ sophisticated, automated machines able to prepare or analyze hundreds of samples at a time.

Chromatography systems often utilize an autosampler having a gantry controlled by a user-defined program to analyze an array of samples. The needle arm forces the needle downward to pierce the septum or seal of a sample vial lid in the array. The needle is a key component of the autosampler as it is part of the liquid flow path and therefore is not only exposed to high pressure but also to any possible customer samples and system liquids. The gantry drives the needle into and out of sample vials, and it drives the needle into and out of engagement with various ports with sufficient force to pierce septa and engage ports creating leak-free connections. Accordingly, the needle must be durable enough to repeatedly pierce sample seals and seal with injection ports without degradation or deformation.

Many metals, including stainless steel, are often undesirable for sampling needles because sampling needles have a "wetted" component, which is any portion of the needle that directly contacts the sample material. And reactive metals may cause unwanted leaching and interference with the sample. In high-performance liquid chromatography (HPLC) and ion chromatography (IC) applications, metal can become corroded and/or interact with the sample or system components thereby diminishing system performance. Therefore, many inert materials do not corrode but are generally too soft to repeatedly pierce septa thousands of times, and thus many inert materials are not ideal for constructing sampling needles. For example, under certain circumstances, needles made of polyetheretherketone (PEEK) cannot be used for HPLC and keep its geometric shape.

Considering the above, it would be beneficial to have sampling needles that overcome the above and other disadvantages.

<CIT> discloses a sampling needle for piecing a septum of a vial containing a sample. The sampling needle includes a hollow rigid support member having an inner wall, an outer wall, and a septum-piercing end.

<CIT> discloses a surface of a needle for collecting samples which is coated with a coating material lower in chemical activity than the base material of the needle. More specifically, the surface of the needle may be coated with a layer of gold or platinum.

One aspect of the present invention is directed to a sampling needle for piercing a septum of a vial containing a sample and aspirating the sample from the vial in accordance with Claim <NUM>.

The sampling needle may include one or more of the following features.

The platinum alloy may include <NUM>% iridium.

The piercing end may be polished to an average surface roughness (Ra) of <NUM>.

The piercing end of the tubular core may include a passageway connected to the lumen, wherein the lumen has a first cross-sectional area and the passageway has a second cross-sectional area that may be smaller than the first cross-sectional area, whereby the passageway is a stop junction that may prevent inadvertent leakage from the sampling needle.

The support may be a nickel cobalt stainless steel alloy (e.g., MP-35N).

The support may include a tapered end adjacent the piercing end of the tubular core, and the tapered end may be polished to an average surface roughness (Ra) of <NUM>.

The support may include an outer wall, and the bioinert coating may cover a length of the outer wall adjacent the piercing end.

The length of the outer wall covered by the bioinert coating may be approximately one-half of an overall length of the support.

Another aspect of the present invention is directed to a chromatography system in accordance with claim <NUM>.

The methods and apparatuses of the present invention have other features and advantages which will be apparent from or are set forth in more detail in the accompanying drawings, which are incorporated herein, and the following Detailed Description, which together serve to explain certain principles of the present invention.

Reference will now be made in detail to various embodiments of the present invention(s), examples of which are illustrated in the accompanying drawings and described below. While the invention(s) will be described in conjunction with exemplary embodiments, it will be understood that the present description is not intended to limit the invention(s) to those exemplary embodiments. On the contrary, the invention(s) is/are intended to cover not only the exemplary embodiments, but also various alternatives, modifications, equivalents and other embodiments, which may be included within the scope of the invention(s) as defined by the appended claims.

Turning now to the drawings, wherein like components are designated by like reference numerals throughout the various figures, attention is directed to <FIG> which shows an exemplary bioinert sampling needle <NUM> that is particularly well suited for use in autosamplers of chromatography systems and other analytical equipment. For example, the needle is designed to interface with a robotic manipulator or gantry of an autosampler, which gantry positions the needle to aspirate and dispense precise amounts of liquid from sample vials. The construction of needle <NUM> allows for repeatedly puncturing septa and creating no-leak interfaces with various fluid ports of analytical equipment. The liquid flow path of the needle and all its surfaces in contact with liquid are inert thus promoting compatibility of the needle with high performance liquid chromatography (HPLC) systems and even with the corrosive eluents of ion chromatography (IC) systems. An inert or bioinert material does not interact or have a chemical reaction with the sample or eluent that is sufficient to cause an interference in the chromatographic analysis.

Needle <NUM> has a piercing end <NUM> designed to pierce the septum or seal of a sample vial lid and a mounting end <NUM> designed to support the sampling needle in the gantry of an autosampler thus allowing the needle to be precisely moved within the autosampler in order to aspirate samples from an array of sample vials. The sampling needle generally includes a dual-layer structure having a tubular bioinert core <NUM> and a hollow metal shell or support <NUM> surrounding the tubular core providing structural integrity to the sampling needle. The needle also includes a bioinert coating <NUM> covering the metal support adjacent the piercing end to isolate the metal support from sample in the sample vial. In addition, bioinert coating <NUM> may cover a portion or all of the outer surface of tubular core <NUM> at the piercing end <NUM>.

With reference to <FIG>, tubular core <NUM> includes a lumen <NUM> extending therethrough extending from mounting end <NUM> through piercing end <NUM> providing a flow path for sample aspirated from a sample vial and then delivered to an injection port of a chromatography system. The tubular core is formed of a bioinert material to limit reactivity with the sample and/or potentially corrosive eluents.

Hollow support <NUM> surrounds tubular core <NUM> and provides overall structural integrity to the needle. The support may include any metal with the structural properties and tensile strength to resist bending and other deformation of the needle when mounted in an autosampler. Since the tubular core provides an inert flow path that is isolated from the support, the support may be formed of less-expensive rigid materials that provide overall structural integrity to the needle. The rigid material should be sufficiently rigid so as to prevent the needle from bending or deforming during the operation of mating with a needle seat under a force. For example, the needle should bend less than <NUM> degrees, preferably less than <NUM> degrees, and more preferably less than <NUM> degree with respect to a longitudinal axis of the needle. Various metals for support <NUM> include, but are not limited to, stainless steels and other suitable materials may be used. For example, MP-35N is particularly well suited for the support as it is a nickel cobalt stainless steel alloy with high tensile strength and great corrosion resistance.

With reference to <FIG>, hollow support <NUM> encircles tubular core <NUM> with piercing end <NUM> extending outwardly from the support. While support <NUM> provides the main structural integrity of the needle, the bioinert material should have sufficient structural integrity to minimize deformation of piercing end <NUM> of tubular core <NUM> that protrudes beyond support <NUM>. As an example, support <NUM> may have an outer diameter of about <NUM> and an inner diameter of about <NUM>. Support <NUM> may have about a <NUM> degree tapered portion at the piercing end.

Suitable bioinert materials for the tubular core are platinum alloys including iridium which are particularly well suited to provide the tubular core with sufficient strength. Other noble metals such as ruthenium (Ru), rhodium (Rh), palladium (Pd), silver (Ag), osmium (Os), iridium (Ir), and gold (Ag), and alloys thereof are also suitable as bioinert materials for the tubular core, but do not form a part of the present invention. Preferably the platinum alloy includes at least approximately <NUM>% iridium to provide beneficial strength and minimize or prevent deformation, which in turn promotes both fluid-tight engagement of piercing end <NUM> with injection ports and high wear resistance in repeatedly piercing sample vial septa. As an example, tubular core may have an outer diameter of about <NUM> and a tapered portion at the end to form a sharper piercing point.

Such a dual-layer configuration significantly reduces the cost of the needle. For example, platinum/iridium alloys are generally very expensive, while MP-35N and other stainless steels are relatively far less expensive. Using less-expensive stainless steels to provide overall structural integrity to the needle allows for minimal use of very-expensive noble metal alloys to provide an inert flow path and piercing end of the needle.

In addition, the piercing end may be polished to further promote fluid-tight engagement with injection ports. For example, the piercing end without any coating may be polished to an average surface roughness (Ra) in the range of <NUM> to <NUM>, and more preferably to an average surface roughness (Ra) of <NUM>.

With reference to <FIG>, piercing end <NUM> of tubular core <NUM> may include a constricted passageway <NUM> fluidly connected to lumen <NUM> to provide a stop junction that prevents inadvertent leakage from needle <NUM>. For example, the lumen may have a first cross-sectional area (e.g., with a larger diameter DL) and the passageway may have a second cross-sectional area (e.g., with a smaller diameter DS) that is smaller than the first cross-sectional area. Such a smaller cross-sectional area may promote increased pressure, lower flow rate and/or increased fluid surface tension thereby minimizing and/or preventing undesirable leakage from the needle. The DS may be approximately <NUM>% to <NUM>% less than the DL and/or the DS may be on the order of approximately <NUM> for adequately preventing such leakage.

With continued reference to <FIG>, piercing end <NUM> may be slanted or beveled to provide a sharp point that facilitates in piercing the septa or seal of a sample vial. Preferably, the bevel is approximately <NUM>-<NUM> degrees.

The outside of the needle may be covered with a specialized coating to prevent corrosion or contamination between the metal support and the sample. In particular, bioinert coating <NUM> is applied to an outer wall <NUM> of support <NUM> to prevent any cross-contamination when the needle pierces a sample vial. As shown in <FIG>, coating <NUM> completely coats the outside surface of support <NUM> adjacent piercing end <NUM> of tubular core <NUM> such that the tubular core and coating completely isolate the support material from contacting any sample, eluants or contaminants.

Preferably, the bioinert coating is a diamond-like carbon (DLC) coating, such as, but not limited to those provided by Acree Technologies Incorporated of Concord, California. DLC is a class of amorphous carbon material that displays some of the typical properties of diamond, and DLC generally contains significant amounts of sp<NUM> hybridized carbon atoms. A DLC coating is particularly well-suited to isolate the needle's support because a DLC coating has high hardness, low friction, wear resistance, high biocompatibility, and chemical inertness.

Preferably, the DLC coating completely coats the outside surface of the support in the area adjacent the piercing end. One will appreciate that the DLC coating need not cover the entire support, but should cover any area of the support at risk of contacting sample or eluents. As shown in <FIG>, approximately one-half the overall length of support <NUM> may be covered with coating <NUM> to ensure that the support is sufficiently protected. And preferably, the DLC coating has a thickness of at least approximately <NUM>-<NUM>. Preferably, the coated areas of the needle have an average surface roughness (Ra) in the range of <NUM> to <NUM>, and more preferably to an average surface roughness (Ra) of <NUM>. Such minimal surface roughness is desirable to facilitate piercing of vials and to reduce wear of the coated needle.

Such a DLC coating may also advantageously reduce wear of the needle. It is common for pure metal needles to exhibit significant wear over <NUM>,<NUM> cycles, whereas a DLC may significantly reduce or prevent wear of a DLC-coated needle over similar usage.

With reference to <FIG>, needle <NUM> is particularly well suited for use in an autosampler <NUM> of a chromatography system <NUM>, however one will appreciate that the needle may be used in other analytical equipment. Autosampler <NUM> may include an array <NUM> of sample vials <NUM> held on a carousel rack or tray, and a gantry <NUM> for moving needle <NUM> as needed to pierce into a select vial, aspirate sample from the vial, and deliver the aspirated sample. To this end, piercing end <NUM> of the needle is configured to engage with an injection port <NUM>. The autosampler may also have other needle-receiving ports such as a flush port and/or a waste port. The injection port may be fluidly connected to a chromatography column <NUM>, a detector <NUM>, a waste reservoir <NUM> and/or other components of a chromatography system.

Mounting end <NUM> of needle <NUM> may be configured for secure and ready mounting to gantry <NUM>. With reference to <FIG> and <FIG>, the mounting end may be bent at a right angle, in which case, support <NUM> may have an annular recess <NUM> that facilitates bending without crimping or kinking, thus ensuring that lumen <NUM> remains unobstructed for use. Recess <NUM> is also shown in <FIG> and <FIG> prior to the optional bending of the needle.

As shown in <FIG>, the mounting end may also include an annular shoulder <NUM> at one end of the recess. As shown in <FIG>, the shoulder is dimensioned and configured to cooperate with a compression fitting <NUM> having a threaded collar <NUM> and knob <NUM>. In particular, a complementary-shaped flange of the collar abuts against shoulder <NUM> and tightens the terminal end of tubular core <NUM> against a capillary <NUM> for fluid communication with a sample loop or other component.

Piercing end <NUM> of needle <NUM> may be configured for engaging injection port <NUM> to form a fluid-tight seal. With reference to <FIG>, the injection port may include a polyetheretherketone (PEEK) collar or receptacle <NUM> housed within a metal housing or port base <NUM>. The PEEK receptacle allows for some deformation to create a better seal with piercing end <NUM>, while the metal housing prevents the PEEK from deforming too much. This configuration, along with the geometry of the PEEK receptacle allows tightly abutting contact between the piercing end of the needle and the PEEK receptacle thereby promoting a repeatable fluid-tight seal with minimal degradation. The PEEK receptacle may include a radiused intersection <NUM> between a tapered opening <NUM> and a bore <NUM>, whereby a conical surface of piercing end <NUM> engages the radiused intersection to form a fluid-tight seal that is capable of withstanding elevated pressures. In addition, the radiused intersection is configured to engage the piercing end behind its tip end thus avoiding unwanted wear and tear on the piercing end.

Advantageously, a sampling needle constructed in accordance with the above description was shown capable of soaking in <NUM> hydrochloric acid (HCL) for <NUM> days at <NUM> without visual discoloration of the needle or the liquid. And the needle was shown to withstand long-term performance testing including puncturing sample vial septum, sealing with an injection port, injecting over <NUM> cycles without visible degradation or deformation.

For convenience in explanation and accurate definition in the appended claims, relative terms such as "outside" are used to describe features of the exemplary embodiments with reference to the positions of such features as displayed in the figures.

Claim 1:
A sampling needle (<NUM>) for piercing a septum of a vial (<NUM>) containing a sample and aspirating the sample from the vial, the needle comprising:
a tubular core (<NUM>) having a lumen (<NUM>) extending therethrough and a piercing end (<NUM>), wherein the tubular core is formed of a bioinert material;
a hollow support (<NUM>) encircling the tubular core and the piercing end extending outwardly from the support, wherein the support is formed of a rigid material; and
a bioinert coating (<NUM>) covering a portion of the support adjacent the piercing end;
wherein the tubular core and the bioinert coating isolates the support from contacting the sample;
characterized in that the bioinert material is a platinum alloy which includes iridium.