Patent Description:
This disclosure relates, generally, to the field of chromatography and, more particularly to a chromatography component for a chromatography column fitting and to a chromatography system including such fitting and component.

Modern chromatography columns are widely employed to undertake separation of mixtures and are utilized in a vast number of chemical, biological, environmental and medical science applications. Chromatographic separation of a sample that comprises a variety of analytes or solutes is achieved by dissolving the sample in a suitable solvent (consistent with the chromatographic conditions and the solubility of the sample components), after which this sample is loaded into the chromatography column and eluted through the packing bed using what is termed a mobile phase (a solvent having properties that allows for the chromatographic separation mechanism to be obtained). The mobile phase is usually a liquid, but it could also be a supercritical fluid. The packing bed is termed the stationary phase, which is generally made from chemically derivatised beads or even a monolithic material (often the beads or monolith are silica based, but they can be polymeric, zirconia, or other suitable materials).

The stationary phase is contained in what is usually a tubular column having an entry point and an opposed exit point. The mobile phase carries the sample through the column that contains the stationary phase. Separation of the analytes occurs through a variety of mechanisms, which reflect the interactions that are apparent between the analytes, the mobile phase and the stationary phase. The objective is to separate the analytes into their respective analyte types, and in doing so, each analyte type is contained within a distribution, ideally a normal distribution having a very narrow standard deviation.

As the mobile phase passes through the column, the analyte eventually leaves the column and its presence in the flow stream is detected as a function of time by a detector arranged downstream of the column. The variation in detection signal with time is referred to as a chromatogram. Peaks on this chromatogram show the presence of different components within the mixture. The degree of separation of the different components depends upon the separation efficiency or resolution of the column. The resolution of the column depends upon many factors, such as the packing bed uniformity, the flow through end fittings of the column, frits associated with the end fittings, etc. Other factors include the nature of the mobile and stationary phases.

Ideally, the packing material within the chromatography column should be homogeneously distributed, such that the packing density is constant across all sections of the bed. However, it is well known within the industry that this is not always the case. The packing of the chromatography column is heterogeneous, both in the axial direction and in the radial direction. Subsequently as an analyte migrates along the column it does so with a band profile that has a parabolic type profile that contains more solute in an axially centrally arranged zone than in a radially distributed zone near the walls of the column. An ideal profile of the analyte should, instead, be a flat thin band where the solute is uniformly distributed. Furthermore, an exit port or opening of the chromatography column contains just a single outlet hole and, as a result, mobile phase and analyte contained outside of the central zone of the column must migrate radially inwardly across the column to this outlet hole. A frit is located in the end fitting to assist in this radial migration but, nevertheless, analyte and mobile phase near the wall of the column require substantially more time to migrate to the outlet hole than analyte and mobile phase that traversed the column axially along the central region of the column. As a result, the chromatographic peak that is observed by the detector is broadened and usually contains a significant tailing factor. This broadening and tailing process reduces the efficiency of the separation and, hence, decreases the resolving power of the column.

Other factors contribute to decreasing the resolving power of the column, including connection of the outlet of the column to the downstream detection source during which the analyte bands continue to undergo band broadening, further contributing to the loss of resolving power of the separation process.

Another important factor in the application of chromatographic separation is the achievement of the separation process at high through-put so that many samples can be analysed meeting the demands of the modern process scale laboratory. High through-put demands high flow rates.

An undesirable aspect associated with the use of high flow rates is frictional heating effects that cause a mobile phase flow to heat up. This heating effect increases the temperature of a column outlet compared to a column inlet. In addition, a radially central region of a column bed becomes hotter than a wall region of the bed. This results in a decreased separation performance, especially as the pressure limitation of the column is reached, which is an important limitation in high through-put assays.

One of the most important detectors for chromatographic separations is the mass spectral (MS) detector. However, in order for the MS detector to function efficiently all solvent must be removed from the gas stream that feeds sample to the detector. As a result, the MS detector has a flow rate limited response, and often post column flow stream splitting is required so as to send only a portion of the mobile phase to the MS. Adding a post column flow stream splitter reduces the efficiency of the separation since extra column dead volume is added.

Undesirable factors in chromatographic separation are therefore the detrimental effects of heat generated at high flow rates and extra column dead volumes and their contributions to band broadening. That is especially important as the particle size decreases and volume of the column decreases.

Selectivity in a separation may also be achieved by selective methods of detection. For example, post column derivatisation (PCD) might be employed. In PCD, the sample analytes are reacted with another chemical to produce a different compound that responds to the detection source in a selective manner. Only certain compounds are chemically derivatised, and it is only the derivatised analytes that are seen by the detector. Typically in PCD reactions, the analyte flow stream is split into two or more parts, one portion sent to the derivatisation process and the other sent to a second detector. An unfortunate outcome of PCD processes is that the extra column dead volume is increased, and that increases band broadening, decreasing resolution.

It is also important to understand that separation between differing types of analytes is controlled in part by selectivity. Selectivity is governed by different intermolecular forces and is affected by the type of solute and the type of stationary phase. To enhance separation power, two or more different types of stationary phases may be utilized, in a process that is referred to as multidimensional chromatography or, in another technique, mixed mode chromatography. In both those types of processes, multiple columns may be employed for a single separation. Such columns, however, need to be connected which, in a conventional column coupling process, results in dead volume being added to the system between each column. This leads to a reduction in the efficiency of the separation process. Furthermore, since each column contains two end fittings, which in their own right lead to a reduction in performance for the passage of analyte through each fitting, ultimately coupling columns results in degraded performance.

Separation performance and, hence, peak capacity, can also be increased using gradient elution methods. In gradient elution chromatography, the solubility of the analyte in the mobile phase is initially poor, then the solubility is increased over a period of time by changing the strength of the mobile phase. While gradient elution is more conveniently undertaken using solvent programming, it could also be achieved by changing the 'strength' of the stationary phase. In high-performance liquid chromatography (HPLC), stationary phases cannot be changed dynamically as is the case for solvent programming; rather, separate columns are connected together. Each column has a different stationary phase loading. That is, for example, the first column might be a C4 phase, the second a C8 phase, the third a C18 phase. Retention increases successively across the columns, while the solvent strength stays constant. This process is less convenient than solvent programming because it is easier to change the mobile phase than the stationary phase. However, one limiting factor associated with solvent gradient elution is that the column must be regenerated with the initial solvent prior to the next analysis. This usually requires a minimum of five column volumes of the initial mobile phase solvent to be passed through the column. As such, that period of time represents a non-productive period since no analysis is being undertaken. On the other hand, stationary phase gradient systems utilize a constant - or isocratic mobile phase. Hence there is no period throughout the analysis where the column would have to be regenerated with mobile phase. Consequently, there is no dead time between the analysis of different samples.

Over the course of the development of HPLC it has become well understood that, if a detector could be located directly at the end of the packing bed in the column, then two factors could be resolved simultaneously: firstly, the detector could function as a point source detector so that only analyte that passes through the point source would be detected. In that way analyte bands that have a profile that resembles a partially filled bowl would instead appear to the detector as thin flat disks. Furthermore, the radial migration of mobile phase and solute from the wall region to the outlet hole is no longer important since that would occur after the detector. Secondly, since the detector is located directly at the end of the actual packing bed, no connective tubing is required minimising any dead volume that could contribute to the further column band broadening process. More efficient separations could therefore be achieved.

Numerous researchers have shown the benefit of end column detection. Some research has used an array of micro-electrodes at the end of the column: Four gold electrodes were embedded into a frit at accurately known radial locations. One electrode was near the column centre, two others at approximately half the distance to the column wall and the fourth electrode was close to the wall. The research showed that the mobile phase velocity was systematically lower near the column wall than in the centre of the column and the most efficient region of the column was the central core with the efficiency decaying quickly with radial distance from the centre. The research concluded that localised end column detection would yield much higher performing separations than those recorded using bulk detectors.

In an attempt to improve the spatial resolution of the end column detection process, an optical sensor has been developed using fluorescence and a photo-diode detection array, operating with up to ten sensors simultaneously. The research using this array resulted in findings which supported prior works using electrochemical sensors.

Irrespective of the great potential offered by an end-column detection process, the commercial realisation of such a detection process has never been achieved, largely because those types of end column detectors are not well suited to mainstream applications: they are fragile and complex to operate and are difficult for users to implement on a day to day basis.

Any discussion of documents, acts, materials, devices, articles or the like which has been included in the present specification is not to be taken as an admission that any or all of these matters form part of the prior art base or were common general knowledge in the field relevant to the present disclosure as it existed before the priority date of each of the appended claims. <CIT> discloses a device for clamping and rapidly changing columns for use in liquid chromatography separation, wherein the device has connectors which are provided with inlets and outlets for the mobile phase passing through the column, and wherein the connection between column and connector has no dead volume due to the combined action of the sealing elements of the column and the connectors.

In a first aspect of the disclosure there is provided a chromatography column fitting which includes.

In this specification, the term "column" or "chromatography column" is to be understood as a tubular member in which a stationary phase of the chromatography system is received.

Further, unless the context clearly indicates otherwise, the term "open bore" is to be understood as a passage extending through the body member from one end to the other, the bore opening out into each end of the body member.

The insert and the body member may carry complementary mounting formations which facilitate removable insertion of the insert into the bore of the body member.

The bore may have a diameter approximating a diameter of a passage of the column.

A retention element may, in use, be arranged at an end of the column to which the body member is mounted, the bearing surface bearing against the retention element to minimise dead volume between the flow conduit and the retention element. It will be appreciated that, in some applications, the retention element may be omitted from the chromatography column with the contents of the column being monolithic media packed in the passage of the column. In such applications, the bearing surface of the insert may bear directly against the contents of the column.

The bore may be configured to accommodate the operatively inner end of the insert substantially flush with a retaining formation defined in the bore of the body member. The retaining formation may be configured to retain the retention element in position at the end of the column. The bore may be stepped part way along its length and the retaining formation may be a radially inwardly directed shoulder defined by the step in the bore of the body member.

The bearing surface of the insert may be defined by a boss having an outer diameter approximating that of the diameter of the passage of the column.

The insert may define a receiving formation, into which the flow conduit opens, in which a component is removably receivable. The receiving formation may be one or more ports and the component may be a carrier or plug carrying capillary tubing for conveying analyte to downstream chromatography equipment such as, for example, a detector.

The bore of the body member may be configured, upon removal of the insert, to receive one of a range of other chromatography components in the bore.

In a second aspect of the disclosure, there is provided a chromatography column assembly which includes.

The end fitting and the associated end of the column may have complementary mounting formations for releasably mounting the end fitting.

The contents may comprise a retention element arranged at each end of the passage of the column to retain the stationary phase within the passage. The end fitting may define a retaining formation for retaining the retention element in position at the end of the column.

An end fitting may be mounted at each end of the column.

The end fitting may be the chromatography column fitting of the first aspect of the disclosure described above.

In a third aspect of the disclosure, there is provided a chromatography component which includes.

The body may be mountable via an end fitting to the end of the chromatography column, the end fitting defining a bore within which the body is receivable. The body may be removably receivable in the bore of the end fitting, the body and the end fitting defining complementary mounting formations for mounting the body within the bore of the end fitting.

The operatively inner end of the body may have a peripheral dimension approximating a peripheral dimension of an interior passage of the chromatography column for bearing against the contents of the chromatography column. It will be appreciated that the contents of the chromatography column generally includes a stationary phase packed within a passage of the column. The "contents" of the column may thus be the stationary phase itself, if packed appropriately, or, instead, a retention element, such as a frit, arranged at the end of the column for retaining the stationary phase within the passage of the column. In an embodiment, the operatively inner end of the body of the component bears against such a frit to minimise dead volume between the first flow conduit and the frit.

In an embodiment, the first flow conduit may extend axially and centrally along the body with the at least one further flow conduit extending parallel to, but radially offset from, the first flow conduit. A flow directing path may be defined in the body for directing flow of a portion of the analyte to the at least one further flow conduit. The flow directing path may be in the form of a channel, typically an annular channel, defined in the operatively inner end of the body.

The first flow conduit may communicate with tubing to supply analyte from the chromatography column to downstream equipment of a chromatography system. The first flow conduit may open into a port defined in the body, the port being configured to receive a chromatography element which carries the tubing for connecting the chromatography column to the downstream equipment of the chromatography system. The downstream equipment may include a detector for analysing the analyte, the detector being connected to the column via capillary tubing. The chromatography element may be a plug carrying the capillary tubing for placing the tubing in flow communication with the first flow conduit of the body. In other embodiments, the capillary tubing may be carried directly by the body to communicate with the first flow conduit.

In an embodiment, the first flow conduit may extend axially and centrally along the body with the at least one further flow conduit branching off from the first flow conduit at a location spaced from the operatively inner end of the body.

The body may define a first portion extending substantially parallel to, and co-axially with, a longitudinal axis of the chromatography column and a second portion extending transversely from the first portion with the at least one further flow conduit being defined in the second portion.

In a further embodiment, the second portion may comprise two parts extending in radially opposite directions from the first portion with at least one further flow conduit being defined in each of the two parts.

In fourth aspect of the disclosure, there is provided a chromatography component which includes.

The operatively inner end of the body may have a peripheral dimension approximating a peripheral dimension of an interior passage of the chromatography column to bear against the contents of the chromatography column. It will be appreciated that the contents of the chromatography column generally includes a stationary phase packed within a passage of the column. The "contents" of the column may thus be the stationary phase itself, if packed appropriately, or, instead, a retention element, such as a frit, arranged at the end of the column for retaining the stationary phase within the passage of the column. In an embodiment, the operatively inner end of the body of the component bears against such a frit to minimise dead volume between the first flow conduit and the frit.

The body may define a plurality of secondary flow conduits, through each of which the reagent is injectable. Each secondary flow conduit may communicate indirectly with the primary flow conduit. More particularly, each secondary flow conduit may communicate with the primary flow conduit via a retention element arranged at the end of the chromatography column. In use, the secondary flow conduits, carrying the reagent, may communicate with the primary flow conduit, carrying the analyte, through the retention element to form a mixed sample. The mixed sample may be conveyed for detection by a detector of a chromatography system arranged downstream of the column or by a detection source contained within the body itself (as described below).

In a fifth aspect of the disclosure, there is provided a chromatography component which includes.

The sensing arrangement may comprise a pair of sensing elements arranged within the at least one flow conduit, the sensing elements of the pair being axially spaced from each other within the at least one flow conduit. In an embodiment, the sensing elements may be a pair of electrodes arranged in axially spaced relationship within the at least one flow conduit.

The body may define at least one further flow conduit through which analyte can flow. In an embodiment, the at least one further flow conduit may channel a radial component of the analyte to a downstream location. However, in a further embodiment, the at least one further flow conduit may be used in a reference sensing configuration in an electrochemical detector. Thus, the sensing arrangement may include a sensing element arranged in the at least one further flow conduit.

The sensing arrangement may include connections for connecting the sensing elements to downstream signal processing circuitry.

In a sixth aspect of the disclosure, there is provided a chromatography component assembly which includes.

In a seventh aspect of the disclosure, there is provided a chromatography component which includes.

In an embodiment, the chromatography component may be operable as an ultraviolet (UV) radiation detector, the inlet port and the outlet port being aligned in the body member to provide a straight-through path for UV radiation. The at least one flow conduit may define a tortuous path having a part in axial alignment with the inlet and outlet ports, the UV radiation being transmitted through the part of the at least one flow conduit.

In an embodiment, the chromatography component may be operable as a fluorescence detector, the inlet port and the outlet port being arranged at an angle relative to each other and to the at least one flow conduit so that electromagnetic radiation emitted by a fluorescing analyte is emitted at an angle to excitation electromagnetic radiation. An included angle between the inlet port and the outlet port may be in the region of <NUM>° or less.

The inlet port and the outlet port may indirectly communicate with the at least one flow conduit via the end of the chromatography column.

In an eighth aspect of the disclosure, there is provided a chromatography component which includes.

The body may be removably receivable in the bore of the end fitting, the body and the end fitting defining complementary mounting formations for mounting the body within the bore of the end fitting.

The passageway of the body may have a peripheral dimension approximating a peripheral dimension of an interior passage of the chromatography column. It will be appreciated that the contents of the chromatography column generally includes a stationary phase packed within a passage of the column. The "contents" of the column may thus be the stationary phase itself, if packed appropriately, or, instead, a retention element, such as a frit, arranged at the end of the column for retaining the stationary phase within the passage of the column. In an embodiment, the operatively inner end of the body of the component bears against such a frit to minimise dead volume between the passageway and the frit.

The medium contained within the passageway of the body may be a monolithic medium. The monolithic medium may be the same phase as a stationary phase contained within the chromatography column.

The body may define a radially outwardly extending collar substantially centrally arranged, in an axial direction of the body, on opposite sides of which the mounting formations are arranged. The collar may thus define an abutment surface for an end of the end fitting in which the body is received, in use.

Embodiments of the disclosure are now described by way of example with reference to the accompanying drawings in which: -.

In <FIG> of the drawings, reference numeral <NUM> generally designates a chromatography system. The chromatography system <NUM> is, in particular, a high-performance liquid chromatography (HPLC) system. The system <NUM> comprises one or more reservoirs <NUM> of solvent used for conveying a sample to be analysed through a chromatography column <NUM>. A solvent delivery module <NUM> is arranged downstream of the one or more reservoirs <NUM>. The module <NUM> comprises one or more pumps to deliver a desired mobile phase solvent, or mixtures thereof, from the reservoir/s <NUM> through a sample-injection port or valve <NUM>, which mixes the solvent with the sample, to an inlet end <NUM> of the column <NUM>.

The chromatography column <NUM> has the inlet end <NUM> communicating with the valve <NUM> via which the sample is introduced into an interior of the column <NUM>. The column <NUM> has an opposed, outlet end <NUM> which communicates with a detection source <NUM> via capillary tubing. The detection source <NUM> detects the constituent parts of the analyte to provide a chromatogram (not shown). In the illustrated embodiment, an optional splitter <NUM>, which may be a T-piece splitter or radial splitter, is interposed between the outlet end <NUM> of the column <NUM> and the detection source <NUM>. The splitter <NUM> is used for splitting off a portion of the analyte discharged from the chromatography column for other purposes, for example, post column derivatisation (PCD) analysis, or the like, or to send a portion of the analyte to waste.

Referring now to <FIG> of the drawings, an embodiment of a chromatography column fitting is illustrated and is designated generally by the reference numeral <NUM>. The fitting <NUM> is configured to be mounted either on the inlet end <NUM> or the outlet end <NUM> of the column <NUM>. In this regard, it is to be noted that the column <NUM> comprises a tubular member <NUM> defining an open passage <NUM>. Typically, the tubular member <NUM> of the column <NUM> is circular cylindrical but it will be appreciated that the tubular member <NUM> could have cross sections (at right angles to a longitudinal axis of the tubular member <NUM>) of other shapes, such as elliptical, polygonal, or the like.

The passage <NUM> of the tubular member of the column <NUM> is packed with a stationary phase <NUM>. The stationary phase <NUM> is made from a chemically derivatised material such as beads, a monolithic material, or the like. The beads or monolith may be silica based, polymeric, zirconia, or other similar materials. The stationary phase <NUM> is tightly packed within the passage <NUM> of the tubular member <NUM> of the column <NUM> and is retained in position by a retention element <NUM>, a retention element <NUM> being arranged at each end <NUM>, <NUM> of the tubular member <NUM>. The retention element <NUM> is in the form of a frit which is porous to the analyte passing through the passage <NUM>.

For ease of explanation, the fitting <NUM> will be described with reference to its attachment to the outlet end, or downstream end, <NUM> of the column <NUM>. However, it will be appreciated that a fitting <NUM> of the same configuration is mountable to the inlet end, or upstream end, <NUM> of the column <NUM>.

The fitting <NUM> includes a body member <NUM> configured to be received at the end <NUM> of the tubular member <NUM> of the chromatography column <NUM>. The body member <NUM> defines an axially extending, centrally arranged open bore <NUM>, illustrated most clearly in <FIG> of the drawings. An insert <NUM> is received in the bore <NUM> of the body member <NUM>. The insert <NUM> defines a flow conduit <NUM>, the flow conduit <NUM> being configured to minimise dead volume between an inlet end <NUM> of the flow conduit <NUM>.

An operatively inner end <NUM> of the insert <NUM> defines a bearing surface <NUM> which bears against an operatively outer surface of the frit <NUM>. The inlet end <NUM> of the flow conduit <NUM> opens out into the bearing surface <NUM> and, therefore, is in direct contact and flow communication with the operatively outer surface of the frit <NUM>. This results in there being minimal dead volume between the flow conduit <NUM> and the frit <NUM> as well as the contents of the passage <NUM> of the column <NUM>.

The bore <NUM> has an inner diameter approximating the diameter of the passage <NUM> of the chromatography column <NUM> so that the bearing surface <NUM> of the insert <NUM> bears on the frit <NUM> over a circular area approximating that of the circumference of the passage <NUM>.

The body member <NUM> and the end <NUM> of the tubular member <NUM> of the chromatography column <NUM> carry complementary mounting formations <NUM> via which the body member is attached to the end <NUM> of the tubular member <NUM>. In the embodiment illustrated, the complementary mounting formations <NUM> comprise an external screw thread <NUM> at the end <NUM> of the tubular member <NUM> and an internal screw thread <NUM> defined by a skirt portion <NUM> of the body member <NUM> of the fitting <NUM>.

It will, however, be appreciated that the mounting formations <NUM> could adopt any of a number of other forms and a person of skill in the field will understand that such mounting formations could include welds, snap fittings, press fittings, bayonet fittings, or the like.

Similarly, the insert <NUM> is removably received within the bore <NUM> of the body member <NUM>. The insert <NUM> and the body member <NUM> also carry complementary mounting formations <NUM> to facilitate removable insertion of the insert <NUM> into the bore <NUM> of the body member <NUM>. In the illustrated embodiment, the complementary mounting formations <NUM> comprise an external screw thread <NUM> carried on the insert <NUM> which screw-threadedly engages with an internal screw thread <NUM> defined on a wall of the bore <NUM> of the body member <NUM>. Once again, the mounting formations <NUM> could adopt any of a number of other forms including snap fittings, press fittings, bayonet fittings, or any other formations which facilitate removable insertion of the insert <NUM> into the bore <NUM> of the body member <NUM>.

The body member <NUM> is internally stepped between the threads <NUM> and <NUM> to define a shoulder <NUM> which bears against the frit <NUM> to assist in retaining the frit <NUM> and the contents <NUM> of the passage <NUM> of the column <NUM> in position.

The insert <NUM> includes a manipulating formation, in the form of an enlarged head portion, <NUM> via which the insert <NUM> can be inserted into, and removed from, the bore <NUM> of the body member <NUM> with the use of appropriate tools.

The insert <NUM> defines a receiving formation in the form of a port <NUM> having an operatively inner end into which the flow conduit <NUM> opens out. In an embodiment, a chromatography element, in the form of a plug, <NUM> (<FIG>) is removably received in the port <NUM>. The plug <NUM> carries capillary tubing <NUM> of the same, or similar, internal diameter to the flow conduit <NUM> and, as described above, conveys analyte from the chromatography column <NUM> to the detection source <NUM>. The plug <NUM> is removably received in the port <NUM> via complementary mounting formations <NUM>.

In an embodiment, the mounting formations <NUM> comprise complementary screw threads <NUM>, <NUM> carried by the wall of the insert <NUM> defining the port <NUM> and an external wall of the plug <NUM>, respectively. However, once again, the mounting formations <NUM> could adopt other forms such as snap fittings, press fittings, bayonet fittings, or the like.

It will, however, be appreciated that, in other embodiments, the port <NUM> and plug <NUM> can be omitted and the capillary tubing <NUM> could be carried directly by the insert <NUM>.

The chromatography column <NUM> is typically a liquid chromatography column but may be a supercritical fluid chromatography column, the column <NUM> having the open inlet end <NUM> and the open outlet end <NUM>. A mobile phase, containing a solvent and sample to be separated, is introduced from the valve <NUM> into the interior passage <NUM> of the column <NUM> through the inlet end <NUM>. The mobile phase is flowed along the passage <NUM> column <NUM> to the outlet end <NUM>.

End fittings <NUM>, of the type described, are attached to the inlet end <NUM> and the outlet end <NUM> of the body member <NUM> of the column <NUM> and serve to retain the stationary phase <NUM> within the passage <NUM> of the column <NUM> while allowing solvent to flow into the stationary phase <NUM>.

The principles described are particularly useful for, in different embodiments, analytical chromatography, e.g. high performance liquid chromatography (HPLC), ultra-high performance liquid chromatography (UHPLC), multidimensional or two dimensional high performance liquid chromatography (MDHPLC or 2DHPLC), flash column chromatography, fast protein liquid chromatography (FPLC), parallel detection chromatography, supercritical fluid chromatography (SFC), and other chromatography applications.

With regard to the type of mobile phase and stationary phase to be used, any suitable type of mobile phase and stationary phase, e.g. any suitable and/or known phases, may be used which are appropriate for the type of chromatography being performed, e.g. any known HPLC mobile phase and stationary phase when performing HPLC. With regard to the type of separation method that may be used, any suitable conventional methods may be used, for example, either isocratic or gradient elution, or displacement elution, either normal phase or reverse phase, hydrophilic, ion exchange or ion exclusion, affinity, chiral, or size exclusion LC, etc..

Where the chromatography is supercritical fluid chromatography (SFC), the mobile phase may be a conventional supercritical fluid, such as carbon dioxide, but is not limited thereto. The fluid used in SFC could also be sub-critical, but operated at higher pressure and temperature than in HPLC, thereby reducing the viscosity, enabling faster separations.

The chromatography system <NUM> may be used for a wide variety of applications, including, for example, purity analysis, component analysis, quality analysis, quantitative analysis, and isolation or purification on an analytical scale, a pilot scale, an industrial scale, or the like. Market applications include, for example, drug discovery, clinical analysis, environmental analysis, and diagnostic marker research in the fields of proteins, glycoprotein, phosphoprotein, metabolites and nucleic acids, for example. The system <NUM> is thus suitable for use in, for example, the pharmaceutical, chemical, biotechnology, biopharmaceutical, and manufacturing industries.

In an embodiment, the column <NUM> is a packed column, i.e. a column containing any suitable bed for the stationary phase. Any conventional bed media may be packed inside the column as the column bed, depending on the type of chromatography being performed. The bed media may comprise, for example, particles or porous monolithic material (e.g. polymeric or ceramic monolithic beds). Instead, the bed media may comprise a membrane bed or any other bed. Particle sizes of the preferred particulate media may range, for example, between <NUM> and <NUM>, but in use, there is no lower or upper limit on particle size. A wide range of pore diameters may be used with porous media utilized depending on the type of chromatography; preferably pore sizes range between <NUM>Å and <NUM>Å (<NUM> and <NUM>). Porosities of a wide range may be used; preferably porosities lie in the range from <NUM> % to <NUM> %. Packing media may include various chemistries depending on the type of chromatography, for example, alkyl bonded phases, typical polar bonded phases, chiral stationary phases, or the like.

Integrated chip columns may use particles or porous monolithic beds. The column <NUM> may also be very useful when utilised with fragile particles since, depending on the application, end column detection processes will substantially reduce the inefficiency associated with packing fragile particles into a tube at low back pressure.

The type of detection source <NUM> that may be used in the system <NUM> may comprise any conventional detector for column chromatography, e.g. ultraviolet or visible (UV/Vis), mass spectrometric (MS), fluorescence (FL), chemiluminescence (CL), refractive index (RI), conductivity (CD), evaporative light scattering (ELSD), electrochemical detectors, or the like. Moreover, any non-conventional detector for column chromatography may be used, e.g. nuclear magnetic resonance (NMR) or infrared (IR) or antioxidant detectors, or any other bio-type detector.

The system <NUM> is controlled by a control and data collection module <NUM> comprising a computer and associated control electronics. The module <NUM> is configured for controlling the pump/s of the solvent delivery module <NUM> for pumping mobile phase to the valve <NUM>. The module <NUM> further controls the valve <NUM> for mixing the mobile phase with the sample for injection into the column <NUM>. The module <NUM> further receives and, optionally, processes data from the detection source <NUM>. In addition, the module <NUM> also provides an output of the data, e.g. with or without processing thereof, as required, and may additionally control other components of the system <NUM>.

The control and data collection module <NUM> is illustrated as communicating with the components of the system <NUM> wirelessly. However, it will be appreciated that the module <NUM> may communicate with the components such as the solvent delivery module <NUM>, the valve <NUM> and the detection source <NUM> in a wired manner.

The materials used to manufacture the column <NUM> and the end fittings <NUM>, including the insert <NUM> and plug <NUM>, could be metal, most preferably stainless steel, but any noncorrosive metal could be employed, for example, titanium. The column <NUM>, end fittings <NUM> and plug <NUM> could also be made from a suitable plastics material, for example, PEEK, acetal, or polytetrafluoroethylene, but any plastics material could be employed provided it was not susceptible to dissolution by the mobile phase employed. The end fittings <NUM> could also be made from glass. Glass fittings might be used in applications involving fast protein liquid chromatography which is conducted at low pressures. Still further, the column <NUM> and end fittings <NUM> could also be constructed from mixtures of metals, plastics and glass. There is no limitation to the materials used to manufacture the column <NUM> and end fittings <NUM> provided the chosen materials are able to withstand the properties of the solvents and the pressures utilised.

The column <NUM> can be fitted with any type of frit <NUM>, i.e., any porosity, provided that the frit <NUM> can retain the particles of the stationary phase <NUM> within the passage <NUM> of the column <NUM>. The frit <NUM> can be made of any material, provided the frit <NUM> is able to withstand the pressure within the passage <NUM> of the column <NUM> and is not soluble in the mobile phase. In applications where the detection source <NUM> uses an electrochemical detector, it is desirable that the frit <NUM> be constructed of a suitable plastics material.

In some applications, the stationary phase <NUM> may be made from monolithic materials, either silica or other ceramics, or polymers. Further, radial transport from a wall region of the passage to an axially central region of the passage <NUM> may be of less importance. In those applications, the frit <NUM> may be omitted with the bearing surfaces <NUM> of the inserts <NUM> of the end fittings <NUM> bearing directly against the stationary phase <NUM>.

In use, one or more solvents are delivered, under control of the module <NUM>, to the pump/s of the solvent delivery module <NUM> via tubing, the pump/s pumping at high or low pressures, depending on the application and requirements. The mobile phase, whether a homogenous or a heterogeneous mixture, discharged from the solvent delivery module <NUM> is fed to the sample-injection port or valve <NUM> where the sample to be analysed is introduced into the solvent flow.

The inlet end <NUM> of the chromatography column <NUM> carries a fitting <NUM> as described above having a similar plug to that at the outlet end <NUM>. The plug at the inlet end <NUM> also carries capillary tubing via which the mobile phase, containing the sample, is introduced into the passage <NUM> of the chromatography column <NUM> through the flow conduit of the insert of the end fitting <NUM>. As indicated above, the passage <NUM> of the column <NUM> is packed with the stationary phase or bed or provided with a monolithic stationary phase <NUM>. The stationary phase <NUM> is retained in position within the column <NUM> by the end frits <NUM>.

In the column, chromatographic separation occurs, both temporally and spatially, as the sample is carried by the mobile phase through the stationary phase <NUM>. The separated constituent parts of the sample are delivered through the end fitting <NUM> via the plug <NUM> and capillary tubing <NUM> and to the detection source for generation, under control of the module <NUM>, of a chromatogram representative of the analysis of the sample.

Optionally, a component of the separated constituent parts is split using the splitter <NUM> for other analysis purposes or to be sent to waste. Thus, in some applications, analyte discharged from the outlet end <NUM> of the chromatography column <NUM> may be fed to another HPLC column or to other equipment.

As described above, the operatively inner end of the insert <NUM> defines the bearing surface <NUM> which bears against the frit <NUM>. In contrast to conventional end fitting arrangements of HPLC chromatography systems, the body member <NUM> of the end fitting <NUM> of the described embodiment defines a bore <NUM> having a diameter approximating that of the passage <NUM> of the body <NUM> of the column <NUM>. In the illustrated embodiment, the bearing surface <NUM> has a surface area approximating that of a transverse cross-sectional area of the passage <NUM> of the column <NUM> and bears against the frit <NUM>.

While the bearing surface <NUM> has been illustrated and described as having a diameter approximating that of the passage <NUM>, in some applications the diameter of the bearing surface <NUM> of the insert <NUM> may be anywhere between <NUM>% to <NUM>% of the diameter of the passage <NUM> of the column <NUM>. Ideally, there is no lower limit on the size of the bore <NUM> of the body <NUM> provided the bore <NUM> can accommodate other components, apart from the insert <NUM>, as described elsewhere in this specification.

Further, as described, the flow conduit <NUM> which conveys the analyte downstream of the column <NUM> has an inner diameter significantly less than that of the passage <NUM>. In an example, the inner diameter of the conduit <NUM> is about <NUM>, but it could be smaller or larger depending on whether the column <NUM> is used for preparative scale separations, analytical scale or microbore scale separations.

Due to the significant difference between the diameters of the conduit <NUM> and the passage <NUM> and with the bearing surface <NUM> bearing directly against an outer surface of the frit <NUM>, dead volume between the conduit <NUM> and the frit <NUM> is minimised thereby maintaining the integrity of the analyte to be detected by the detection source <NUM>.

As described in the Background section to the specification, as an analyte migrates along the column it does so with a band profile that is substantially parabolic and contains more solute in an axially centrally arranged zone in the passage <NUM> of the column <NUM> than radially distributed near the walls of the column. Ideally, the profile of the analyte should instead be a flat thin band where the solute is uniformly distributed. Because the inlet opening <NUM> into the flow conduit <NUM> of the insert <NUM> is of significantly smaller diameter than that of the passage <NUM> of the column <NUM>, mobile phase and analyte contained outside of the axially centrally arranged zone of the passage <NUM> of the column <NUM> must migrate radially inwardly across the passage <NUM> of the column <NUM> to the inlet opening <NUM> of the flow conduit <NUM>. The frit <NUM> located at the end of the column <NUM> assists in this radial migration but, nevertheless, analyte and mobile phase near the wall of the column require substantially more time to migrate to the inlet opening <NUM> of the flow conduit <NUM> than analyte and mobile phase that traversed the column axially centrally. As a result, with conventional chromatography systems <NUM>, a chromatographic peak that is observed by the detection source <NUM> is broadened and usually contains a significant tailing factor. This broadening and tailing process reduces the efficiency of the separation and, hence, decreases the resolving power of the column.

However, with the provision of the end fitting <NUM> and its associated insert <NUM> and plug <NUM>, the dead volume normally encountered by the analyte and mobile phase is significantly reduced resulting in a corresponding reduction in the broadening and tailing process and resulting in improved, discrete peaks in the chromatogram.

Referring now to <FIG> of the drawings an embodiment of a chromatography component is illustrated and is designated generally by the reference numeral <NUM>. With reference to the previous drawings, like reference numerals refer to like parts, unless otherwise specified.

The component <NUM> includes a body <NUM> which, in use, replaces the insert <NUM> in the bore <NUM> of the body <NUM> of the end fitting <NUM>. As in the case of the insert <NUM>, the body <NUM> has threads <NUM> as its part of the complementary mounting formations <NUM> which engage the threads <NUM> in the bore <NUM> of the body member <NUM> of the end fitting <NUM>.

Once again, it will be appreciated that, instead of the mounting formations <NUM> being in the form of threads <NUM>, <NUM>, other mounting formations such as snap fittings, press fittings, bayonet fittings, or the like, may be employed.

The body <NUM> defines the flow conduit <NUM>, which, once again, is configured to minimise dead volume between the inlet end <NUM> of the flow conduit <NUM> and the frit <NUM> at the outlet end <NUM> of the tubular member <NUM> of the chromatography column <NUM>.

An operatively inner end <NUM> of the body <NUM> defines the bearing surface <NUM> which bears against the operatively outer surface of the frit <NUM>, as is the case with the insert <NUM>. This further contributes to minimising dead volume between the flow conduit <NUM> and the frit <NUM>.

The body <NUM> also includes the manipulating formation in the form of the enlarged head portion <NUM> via which the body <NUM> can be inserted into and removed from the bore <NUM> of the body member with the use of appropriate, manipulating tools. Further, the body <NUM> defines the port <NUM> in which the plug <NUM>, which carries the capillary tubing <NUM>, is receivable.

The body <NUM> defines at least one, axially extending flow conduit <NUM> radially offset with respect to the flow conduit <NUM>. The conduit <NUM> has an inlet opening <NUM> opening out into a flow directing path, in the form of an annular channel or groove, <NUM> defined in the bearing surface <NUM> of the body <NUM>. In use, a major portion of the radial component of the solute discharged from the chromatography column <NUM> is directed into the conduit <NUM> via the channel <NUM> to be conveyed to waste rather than needing to migrate radially inwardly to the flow conduit <NUM> through the frit <NUM>.

In an embodiment, the component <NUM> functions as the splitter <NUM> of the chromatography system <NUM>.

The body <NUM> is made of any of the same materials as the insert <NUM>, as described above.

Referring now to <FIG> of the drawings, reference numeral <NUM> designates a further embodiment of a chromatography component. With reference to <FIG> of the drawings, like reference numerals, refer to like parts, unless otherwise specified.

The component <NUM> functions identically to the component <NUM> but is intended for use with dedicated, commercially available chromatography detectors provided by various providers. The component <NUM> is thus intended to be bespoke to a particular make of detector.

Therefore, the port <NUM> and related plug <NUM> are omitted. Instead, the flow conduit <NUM> extends the full length of the body <NUM> opening out into an operatively outer surface <NUM> of the body <NUM>. The capillary tubing <NUM> connects to, or forms an extension of, the conduit <NUM> at the outer surface <NUM> for connection to its associated detector.

The embodiments described above with reference to <FIG> of the drawings relate to so-called "radial" splitters. Referring now to <FIG> of the drawings, two embodiments of "axial" flow splitter are described and which could function as the splitter <NUM> of the system <NUM>.

In <FIG> of the drawings, reference numeral <NUM> designates an embodiment of an axial flow T-piece splitter. As in previous embodiments, like reference numerals refer to like parts, unless otherwise specified.

The splitter <NUM> has a body <NUM> defining the threads <NUM> for removable insertion into the bore <NUM> of the body <NUM> of the end fitting <NUM>. The body <NUM> defines a first, axially extending portion <NUM> which, in use, is coaxially arranged with the passage <NUM> of the chromatography column <NUM>. The portion <NUM> defines the conduit <NUM> opening out into the port <NUM>, the port <NUM>, in use, receiving the plug <NUM> carrying the capillary tubing <NUM> (neither of which is shown in this figure).

The body <NUM> defines a second portion <NUM> extending radially outwardly upstream of the outlet opening of the conduit <NUM> into the port <NUM>. In the illustrated example, the portion <NUM> extends orthogonally relative to the portion <NUM> but it will be appreciated that the portion <NUM> could extend in any transverse direction relative to the portion <NUM>.

The portion <NUM> defines a secondary flow conduit <NUM> branching off the flow conduit <NUM> and opening out into a secondary port <NUM>. The secondary port <NUM>, in use, receives a secondary plug and capillary tubing (neither of which is shown) for conveying an axially flowing component of the analyte traversing the flow conduit <NUM> to other equipment or to waste.

Referring now to <FIG> of the drawings, an alternative arrangement to that shown in <FIG> of the embodiment of the component <NUM> is illustrated. In this embodiment, the second portion <NUM> of the body <NUM> comprises two, radially oppositely extending parts <NUM> and <NUM>, each part defining its associated secondary conduit <NUM>.

With this, cross-piece arrangement, one of the parts <NUM> or <NUM> could be used to convey a component of the analyte to further equipment of the system <NUM> while the other of the parts <NUM> or <NUM> could be used to convey another component of the analyte to waste.

In <FIG> of the drawings, a further version of the T-piece component is illustrated. In this embodiment, it is to be noted that the operatively inner surface of the body <NUM> defines a raised formation or boss <NUM>. The boss <NUM> defines the bearing surface <NUM> which has a peripheral dimension approximating that of the inner diameter of the passage <NUM> of the chromatography column <NUM>. It will be appreciated that, it is a reasonably simple exercise to modify this embodiment of the component <NUM> to have the cross-piece arrangement as illustrated in <FIG> of the drawings.

It will be appreciated that, by diverting a portion of the axial component of the analyte, the efficiency of the chromatography system <NUM> is improved.

Referring to <FIG> of the drawings, a version of the radial splitter <NUM> of <FIG> is illustrated mounted to a chromatography column <NUM>. In this embodiment, the secondary conduit <NUM> projects at an acute angle relative to the flow conduit <NUM> and opens out into a port <NUM> which receives a plug carrying capillary tubing (neither of which is shown) for conveying a radial portion of the analyte to waste.

Referring now to <FIG> of the drawings, a chromatography component operable as a post-column reactor is illustrated and is designated generally by the reference numeral <NUM>. With reference to <FIG> of the drawings, like reference numerals refer to like parts, unless otherwise specified.

The reactor <NUM> includes a body <NUM> which is shaped and configured to fit within the bore <NUM> of the body member <NUM> after removal of the insert <NUM>. Hence, the body <NUM> carries the threads <NUM> for mounting within the bore <NUM> of the body member <NUM>.

In this embodiment, the flow conduit <NUM> extends through the full length of the body <NUM> opening out into an operatively outer end <NUM> of the body <NUM>. It will, however, be appreciated that, instead, the body <NUM> could define a socket <NUM> similar to that shown in the insert <NUM> in <FIG> of the drawings with the socket <NUM> to receive the plug <NUM> and capillary tubing <NUM> (neither of which is shown).

The body <NUM> further defines at least one secondary flow conduit <NUM>. In the illustrated embodiment, the embodiment defines a plurality of radially and circumferentially spaced secondary flow conduits <NUM>. The flow conduits <NUM> are radially spaced from the flow conduit <NUM> and extending parallel to the flow conduit <NUM> and to each other, each flow conduit <NUM> opening out into the operatively inner end <NUM> of the body <NUM> via an outlet <NUM>.

The flow conduit <NUM> communicate with a source (not shown) of a suitable reagent for reacting with the analyte to enhance detectability of the analyte by the detection source <NUM>. In the illustrated embodiment, the outlet <NUM> of each flow conduit <NUM> communicates indirectly with the inlet <NUM> of the flow conduit <NUM> via the frit <NUM> arranged at the outlet end <NUM> of the chromatography column <NUM>. In other embodiments, the outlet <NUM> may open directly into the flow conduit <NUM> proximate its inlet end <NUM>.

In use, the reactor <NUM> is inserted into the end fitting <NUM> after removal of the insert <NUM> with the operatively inner end <NUM> of the body <NUM> bearing against the frit <NUM>. Once again, the shape and configuration of the body <NUM> ensures that there is minimal dead volume between the inlet opening <NUM> of the flow conduit <NUM> and the contents at the outlet end <NUM> of the column <NUM> to improve detection of the analyte by the detector <NUM>.

Referring to <FIG> of the drawings, two embodiments of a detection source, or detector, <NUM> are illustrated and described. With reference to <FIG> of the drawings, like reference numerals refer to like parts, unless otherwise specified.

In the embodiment illustrated in <FIG> of the drawings, the detector <NUM> is a conductivity detector and includes a body <NUM> mountable to the outlet end <NUM> of the chromatography column <NUM> via the body member <NUM> of the end fitting <NUM> after removal of the insert <NUM>. Hence, the body <NUM> has a shape and configuration to be received within the bore <NUM> of the body member <NUM> of the end fitting <NUM>.

In contrast to the insert <NUM>, the flow conduit <NUM> extends from the operatively inner end of the body <NUM> to an operatively outer end <NUM> of the body <NUM>.

The body <NUM> further defines a secondary flow conduit <NUM> which, in the illustrated embodiment, is radially offset with respect to the flow conduit <NUM> and extends parallel to the flow conduit <NUM> for conveying a radial component of the analyte to waste.

A sensing arrangement <NUM> is contained within the flow conduit <NUM>. The sensing arrangement <NUM> comprises a pair of spaced electrodes <NUM> and <NUM> isolated from each other via a dielectric element such as a dielectric ferrule <NUM>. The electrodes <NUM> and <NUM> of the sensing arrangement <NUM> are connected to signal processing circuitry <NUM>. In the illustrated embodiment, the signal processing circuitry <NUM> comprises a Wheatstone bridge arrangement <NUM> with the analyte and electrodes <NUM> and <NUM> functioning as an impedance <NUM> in one of the legs of the bridge <NUM>.

An output <NUM> of the Wheatstone bridge arrangement <NUM> is connected to further processing circuitry (not shown) to generate the chromatogram.

It will be appreciated that, in a variation of this embodiment, the secondary flow conduit <NUM> could be omitted so that the entire flow from the column <NUM> passes through the flow conduit <NUM>.

In the embodiment illustrated in <FIG> of the drawings, the detector <NUM> is an electrochemical detector. With reference to <FIG> of the drawings, like reference numerals refer to like parts, unless otherwise specified.

In this embodiment, the secondary conduit <NUM> contains a reference electrode <NUM> connected via a connection <NUM> and an earth connection <NUM> into a further leg of the Wheatstone bridge arrangement <NUM> to provide the variable impedance <NUM> of the Wheatstone bridge arrangement <NUM>.

It is an advantage of both embodiments described above that, due to the configuration of the body <NUM> of the detector <NUM>, the detector <NUM> fits like the insert <NUM> within the bore <NUM> of the body <NUM> of the fitting <NUM> with the bearing surface <NUM> bearing against the frit <NUM> at the outlet end <NUM> of the chromatography column <NUM>. As a result, dead volume between the detector <NUM> and the contents of the chromatography column <NUM> is minimised thereby greatly improving the efficiency of the system <NUM>. As indicated above, the detector <NUM> effectively detects the axially, centrally arranged part of the analyte as a point source resulting in improved peak discrimination in the chromatogram.

Referring to <FIG> of the drawings, two embodiments of a detection source, or detector, <NUM> are illustrated and described. With reference to <FIG> the drawings, like reference numerals refer to like parts, unless otherwise specified.

In the embodiment illustrated in <FIG> of the drawings, the detector <NUM> is an ultraviolet (UV) detector and includes a body <NUM> mountable to the outlet end <NUM> of the chromatography column <NUM> via the body member <NUM> of the end fitting <NUM> after removal of the insert <NUM>. Hence, the body <NUM> has a portion having a shape and configuration to be received within the bore <NUM> of the body member <NUM> of the end fitting <NUM>.

In the illustrated embodiment, the body <NUM> has a cross-piece configuration with a first, axially extending portion <NUM> and a transversely extending portion <NUM> intersecting the axially extending portion <NUM>. In the illustrated embodiment, the transversely extending portion <NUM> is orthogonally arranged relative to the axially extending portion <NUM>.

The axially extending portion carries the threads <NUM> which engage the threads <NUM> of the body member <NUM> of the fitting <NUM> to be received in the bore <NUM> of the body member <NUM>. Further, the axially extending portion <NUM> defines the flow conduit <NUM>. However, in this embodiment, the flow conduit <NUM> has a tortuous, zigzag shape to provide a straight-through path <NUM> between a first port <NUM> and an opposed second port <NUM>, the ports <NUM> and <NUM> being defined in the transversely extending portion <NUM> of the body <NUM>. An outlet end of the conduit <NUM> downstream of the straight-through part <NUM>, opens out into the socket <NUM>.

The ports <NUM> and <NUM> are axially aligned with each other and with the flow path <NUM> to provide a straight through path for UV radiation. Hence, the port <NUM> is an input port connected to a source of UV radiation (not shown) and the port <NUM> is an output port to which a UV radiation detection element (not shown) is connectable. The UV radiation detection element may, for example, be a photodiode or other photodetector with or without a beam splitter, a beam splitter and secondary photodiode normally being provided for improving optical performance.

In operation, the detector <NUM> of <FIG> of the drawings works in the same way as a conventional UV radiation detector but with the benefit of being mountable directly to the outlet end <NUM> of the chromatography column <NUM> to minimise dead volume between the detector <NUM> and the outlet end <NUM> of the chromatography column <NUM>.

If desired, the body <NUM> may define a further flow conduit radially spaced from the flow conduit <NUM> through which a radial component of the analyte flows to be conveyed to waste.

Referring to <FIG> of the drawings, a fluorescence detector <NUM> is illustrated and described. With reference to <FIG> of the drawings, like reference numerals refer to like parts, unless otherwise specified.

In this embodiment, the body <NUM> defines the flow conduit <NUM> opening out into the port <NUM>. The body <NUM> further defines a first, input port <NUM> and a second, output port <NUM> each communicating with a flow conduit <NUM> and <NUM>, respectively. The conduits <NUM> and <NUM> communicate with an annular groove or channel <NUM> defined at the operatively inner end <NUM> of the body <NUM>.

In this regard, it is to be noted that the operatively inner end <NUM> of the body <NUM> carries a raised formation, or boss, <NUM> which defines the bearing surface <NUM>. The boss <NUM> has a peripheral dimension approximating that of the peripheral dimension of the passage <NUM> of the column <NUM>. In use, the boss <NUM> bears against the outer surface of the frit <NUM>.

The input port <NUM> receives a source of electromagnetic radiation, for example, from a laser and the port <NUM> is configured to receive an electromagnetic radiation carrier such as an optical fibre cable (not shown). Similarly, the port <NUM> is configured to receive an electromagnetic radiation carrier such as an optical fibre cable (not shown) for conveying electromagnetic radiation arising from fluorescence of the sample to a detection element such as a diode array detector (not shown).

The detector <NUM> of <FIG> operates as a fluorescence detector fluorescing the sample causing emission of light when an electron returns from an excited state to its ground state after having been irradiated with the electromagnetic radiation. When this occurs, light is emitted in all directions so, unlike a UV detector, it is preferable to monitor emissions at an angle relative to the excitation source otherwise the detection element would have to filter out the light at the excitation wavelength. Thus, typically, the ports <NUM> and <NUM> are arranged at an acute angle relative to each other or may be orthogonally arranged relative to each other.

As is the case with the UV detector of <FIG> of the drawings, the fluorescence detector of <FIG> of the drawings operates in the same manner as a conventional fluorescence detector but with the benefit of being mounted directly to the outlet end <NUM> of the chromatography column <NUM> to minimise dead volume. As indicated above, the boss <NUM> bears directly against the frit <NUM> and the inlet opening <NUM> of the flow conduit <NUM> opens out into the bearing surface <NUM> defined by the boss <NUM>. Thus, dead volume between the flow conduit <NUM> and the outer surface of the frit <NUM> is substantially reduced.

It is therefore an advantage of both embodiments described above that, due to the configuration of the body <NUM> of the detector <NUM>, dead volume between the detector <NUM> and the contents of the chromatography column is minimised thereby greatly improving the efficiency of the system <NUM>. As described above, the detector <NUM> effectively detects the axially, centrally arranged part of the analyte as a point source resulting in improved peak discrimination in the chromatogram.

<FIG> of the drawings show an embodiment of a further version the UV detector <NUM> of <FIG>. It is noted that, in this embodiment too, the body <NUM> has the boss <NUM> at its operatively inner end defining the bearing surface <NUM>, the boss <NUM> having a peripheral dimension approximating that of the passage <NUM> of the chromatography column <NUM>.

In this embodiment, the fluid conduit <NUM> is not a zig-zag path but, instead, the straight through path <NUM> of the fluid conduit <NUM> communicating with the ports <NUM> and <NUM> is orthogonally arranged relative to the remainder of the fluid conduit <NUM>.

Referring to <FIG> of the drawings, a chromatography component in the form of a column-to-column coupler is illustrated and is designated generally by the reference numeral <NUM>. With reference to <FIG> of the drawings, like reference numerals refer to like parts, unless otherwise specified.

The coupler <NUM> includes a body <NUM> mountable to an outlet end <NUM> of the column <NUM>, operating as an upstream column in the configuration of the system <NUM> shown in <FIG> of the drawings. The body <NUM> is further mountable to an inlet end <NUM> (<FIG>) of a second, downstream chromatography column <NUM>, operating as a downstream column in the configuration of the system shown in <FIG> of the drawings. It will be appreciated that each column <NUM>, <NUM> has end fittings <NUM> attached to both its inlet end <NUM> and its outlet end <NUM> to enable the columns <NUM> and <NUM> to be connected bi-directionally.

The body <NUM> defines a passageway <NUM> extending through it to be in flow communication, in use, with contents of each of the chromatography columns <NUM>, <NUM>. A medium <NUM> is contained within the passageway <NUM> through which an analyte, exiting the chromatography column <NUM> can pass, before the analyte enters the chromatography column <NUM>.

In an embodiment, the medium <NUM> is a meshed material which is either a monolithic medium or a stationary phase the same as that of at least the chromatography column <NUM>. An internal diameter of the passageway <NUM> approximates that of the passage <NUM> of the chromatography columns <NUM>, <NUM> and bears against frits <NUM> at the outlet end <NUM> of the chromatography column <NUM> and at the inlet end <NUM> of the chromatography column <NUM> in cases where the frits <NUM> are used. Where the stationary phase is a monolithic medium, the frits may be omitted with the medium <NUM> of the coupler <NUM> being in direct contact with the monolithic media in each of the columns <NUM>, <NUM>.

The body <NUM> contains threads <NUM> on its external surface for being screw-threadedly received in the bore <NUM> of the body <NUM> of the end fitting <NUM> at each of the outlet end <NUM> of the chromatography column <NUM> and the inlet end <NUM> of the chromatography column <NUM>. The two sets of threads <NUM> are separated by a substantially longitudinally, centrally arranged, radially outwardly extending collar <NUM>. The collar <NUM> thus defines a pair of opposed abutment surfaces, against each of which an end of the body member <NUM> of the relevant end fitting <NUM> abuts, in use, firmly to retain the columns <NUM> and <NUM> in axial alignment with each other.

Hence, in use, a first end of the body <NUM> of the coupler <NUM> is received in the bore <NUM> of the body member <NUM> of the end fitting <NUM> arranged at the outlet end <NUM> of the column <NUM> after removal of the insert <NUM> from the bore <NUM>. Similarly, a second end of the body <NUM> of the coupler <NUM> is received in the bore <NUM> of the body member <NUM> of the end fitting <NUM> arranged at the inlet end <NUM> of the column <NUM> after removal of the insert from the bore <NUM>. The coupler <NUM> thus serves to couple the columns <NUM> and <NUM> axially.

In an embodiment, the columns <NUM> and <NUM> contain different stationary phases for facilitating different reactions with the mobile phase as the mobile phase passes through the columns <NUM> and <NUM>.

Once again, it is an advantage of the coupler <NUM> that the body <NUM>, with its contents <NUM>, bears against the contents of the respective columns <NUM> and <NUM> and, in so doing, minimises dead volume between the interior of the coupler <NUM> and the contents of the columns <NUM>, <NUM>.

It is a primary advantage of the described embodiments of the end fittings <NUM> that, due to the configuration of the insert <NUM>, or any other component received within the bore <NUM> of the body <NUM> in place of the insert <NUM>, dead volume between the outer surface of the frit <NUM>, or the stationary phase <NUM> itself if the frit <NUM> is omitted, and the inlet end <NUM> of the flow conduit <NUM> is substantially reduced thereby maintaining the integrity of the analyte as it is conveyed to the detection source <NUM>. This results in more discrete peaks being generated in the chromatogram providing for improved analysis.

In addition, greater throughput of samples through the system <NUM> can be achieved allowing for a higher rate of analysis.

Also, by minimising dead volume, as described, the resolution of the column <NUM> is improved.

Claim 1:
A chromatography column fitting (<NUM>) which includes:
a body member (<NUM>) configured to be received at an end (<NUM>) of a chromatography column (<NUM>), the body member (<NUM>) defining an axially extending open bore (<NUM>) having a portion defining a diameter approximating that of a passage (<NUM>) of the column (<NUM>), the body member being internally stepped to define a shoulder (<NUM>) configured to bear against a frit (<NUM>) at the end (<NUM>) of the chromatography column (<NUM>) to retain the frit (<NUM>) in position at the end (<NUM>) of column (<NUM>); and
an insert (<NUM>) removably received in the bore (<NUM>), the insert defining a flow conduit (<NUM>) opening out into an operatively inner end (<NUM>) of the insert (<NUM>) to be in flow communication, in use, with an interior (<NUM>) of the chromatography column (<NUM>), the operatively inner end (<NUM>) defining a planar bearing surface (<NUM>) which has a diameter approximating that of the passage (<NUM>) of the column (<NUM>), the bearing surface (<NUM>) configured to bear against the frit (<NUM>) to minimise dead volume between the flow conduit (<NUM>) and the frit (<NUM>), characterised in that
each of the insert (<NUM>) and the body member (<NUM>) carry complementary mounting formations (<NUM>) which facilitate removable insertion of the insert (<NUM>) into the bore (<NUM>) of the body member (<NUM>).