Patent Description:
Coated Blade Spray (CBS) is a solid phase microextraction (SPME)-based analytical technology previously described in the literature (<CIT>) that facilitates collection of analytes of interest from a sample and the subsequent direct interface to mass spectrometry systems via a substrate spray event (i.e., electrospray ionization).

"Coated blade spray," "CBS blade'", and "blade device" are used synonymously herein.

There are two basic stages to CBS-based chemical analysis: (<NUM>) analyte collection followed by (<NUM>) instrumental analysis. Analyte collection is performed by immersing the sorbent-coated end of the blade device directly into the sample. For liquid samples, the extraction step is generally performed with the sample contained in a vial or well plate.

After analyte collection, the blade device is removed from the sample and, following a series of rinsing steps, the blade device is then presented to the inlet of the mass spectrometer (MS) for analysis. In this fashion, the blade device undergoes several transfer steps. Reliable positioning of the blade device for each of these steps is therefore important, both for manual and robotic automation handling circumstances.

As a direct to MS chemical analysis device, the blade device requires a pre-wetting of the extraction material so as to release the collected analytes and facilitate the electrospray ionization process. Subsequently, a differential potential is applied between the non-coated area of the substrate and the inlet of the MS system, generating an electrospray at the tip of the CBS device. The electric field between the blade and the MS system must be reproducibly created in order to ensure reliable run-to-run precision. Proper positioning of the blade device with respect to the MS skimmer cone opening is therefore very important, including the radial (or rotational) orientation of the blade device.

In general, the blade portion of a blade device has two sides, an upper and a lower. In some cases, different sorbent coatings may be present on each of the flat sides of the blade, and two sample analyses may be therefore performed in sequence; first the analysis of the upper side, followed by a second analysis of the lower. In other examples, same sorbent coating may be present on each of the flat sides of the blade, and a two sample analyses may be therefore performed in sequence, but in different instruments: first the analysis of the upper side on instrument A, followed by a second analysis of the lower on instrument B. In either case, the radial orientation of the blade is also critical.

Previous disclosures describe either manually handling the individual blade devices to properly position them with respect to the entrance to the mass spectrometer. Other examples describe one- and two-dimensional arrays of blade devices in a bulk holder. These embodiments include a rigid support capable of housing more than one blade device. Examples of this arrangement include <CIT>. These examples are generally aligned to the standard laboratory sampling plasticware, most commonly microtiter trays having an <NUM> x <NUM> well arrangements, the wells having approximately <NUM> centers. Higher density trays are also commercially available, having smaller sample wells positioned even closer together, in order to maintain the standard sample tray footprint.

Because of the single inlet to the MS device, the sample analysis stage is still a serial process when using these array-based designs. A selected blade device within the greater array is positioned for electrospray ionization. This design has the disadvantage of also positioning the entire array of blade devices in the general proximity of the MS, which creates considerable risk of electrical and/or chemical cross talk between adjacent blade devices during the electrospray ionization processes. This in turn particularly undermines chain-of-custody sample analysis applications, such as clinical or forensic screening of biological fluids.

There is therefore a need for automated handling of CBS devices, where the close position array arrangement is maintained during the sample extraction processes using standard microtiter trays, and where individual blade devices are introduced to the ionization region of the mass spectrometer. The invention disclosed here addresses the additional requirement of radial positioning of the blade during the entire sampling-to-analysis process.

A common tool in laboratories for transporting accurate volumes of liquid is a micropipettor. Examples of this arrangement include <CIT>, <CIT>, and <CIT>. Micropipettors employ a variety of mechanisms to pull liquid volumes into the device and subsequently dispense the liquid. Precision volume capacities for standard pipettors range from <NUM>µL to <NUM>. In order to reduce the risk of sample contamination, disposable pipette tips are employed. The micropipette tips are mounted onto the pipettor by pushing the pipettor into the tip, and friction maintains the tip in place. After the liquid has been dispensed, the tip is ejected off the end of the pipettor, and the entire process is repeated.

In cases where many liquid transfer steps are performed for highly parallel processes, micropipettor devices employing more than one liquid dispensing channel are available. Examples of this arrangement include <CIT>. These devices still employ the friction fit attachment mechanism of the disposable tips.

For clarity, the terms "pipette," "pipettor," "micropipettor," and "multichannel pipettor" are used herein synonymously. The terms "pipette tip" and "micropipette tip" are also used synonymously.

Equivalent liquid volumes are drawn and delivered for each tip. Tip position in the pipettor array aligns with the tip positions in storage racks for ease of installation.

Multichannel pipette devices are used with pipette tips in <NUM>- and <NUM>-dimentional array storage racks, so a row of disposable tips can be mounted in parallel into the micropipettor.

Micropipettor technology has also been adapted to robotic systems, where the entire liquid transfer sequence is the same as employed for the manual units but is automated.

Because of the ubiquitous presence of micropipettors in laboratories, both for manual use and integrated into robotic automation setups, maintaining compatibility with the CBS device to the physical dimensions of micropipettor technology is advantageous.

Because many applications that employ micropipettors are sensitive to chemical contamination, disposable, single use pipette tips are available. Standard micropipette tips are loaded onto the pipettor device by centering the device over the docked tip and tapping the device gently onto the opening of the tip. The tip is mounted via friction and is ready for use. Following use, the dirty microtiter tip is removed from the device by means of a tip ejector, typically a slidable sheath around the shaft of the device that engages with the upper lip of the disposable tip and pushes to overcome the friction connection. An example of a pipette tip that has been modified for sample extraction includes <CIT>.

Common micropipette tips are conical and do not have a radial orientation requirement for normal operation.

Conductive tips are used to prevent carryover in automated pipetting robots. An example of a conductive tip is the addition of graphite to the raw material polypropylene makes the pipette tips electrically conductive and gives the tips an opaque black appearance. Alternative embodiments where a portion of the pipette tip is conductive are described in <CIT>. The relative position of the tips within robotic workstations is identified by measuring electric capacitance. The filling level of the liquid in the tip can be determined in sample and reagent containers by measuring electric currents, so that the depth of immersion of the tip can be adjusted to the filling level.

Because of the frequent tip replacement in standard sampling handling practices, multiple tips are stored in racks where the tips are protected from environmental contamination. In keeping with the array position standards described earlier, bulk storage of disposable tips commonly employs the <NUM> x <NUM>, <NUM> tip arrays or multiples of <NUM> tips with the standard tip center-to-center position. This allows for direct loading into multichannel pipette devices and maintains the standard rack footprint in laboratories and on the automation workstation platforms.

Rack containers for housing micropipette tips do not include elements to maintain the radial orientations of the standard pipette tips.

The object of the invention is solved by a solid phase microextraction system comprising a solid phase microextraction device and a solid phase microextraction repository according to claim <NUM>. Further, the object of the invention is solved by a solid phase microextraction system comprising a solid phase microextraction device and a slid phase microextraction manipulator according to claim <NUM>.

Wherever possible, the same reference numbers will be used throughout the drawings to represent the same parts.

To date, no microscale sampling device has been adapted to the mechanical elements of micropipette devices for loading and ejecting disposable tips, with the additional requirement of radial positioning.

Because CBS blades are nominally flat strips which require a specific radial orientation when loaded into the source of the analyzer (in most cases, a mass spectrometer), control of the radial orientation of the blade during all stages of use is desired. Disclosed are several examples where the radial orientation of the blade device is maintained throughout the sampling and analysis work flow. Examples are presented where the blade device orientation is maintained while the blades devices are stored in bulk. Also presented are examples where the blade devices may be interfaced with standard micropipette mechanical devices while maintaining the radial orientation.

A further requirement of CBS blades is the application of a voltage bias onto the blade during spray analysis. It is desirable that the modified CBS blade also contains elements that permit the application of a voltage bias onto the blade as part of the device. Embodiments of the invention described herein include the blade having a voltage bias applied during spray analysis. Examples of the invention are disclosed depicting electrode elements as well as the use of electrically conductive tips to apply the voltage required during sample analysis.

Disclosed herein is a solution to control the radial orientation of a solid phase microextraction device during the entire analytical workflow. The solution is mechanically compatible with both manual and automation laboratory applications. This solution conforms to the mechanical standards common in analytical laboratory systems, including by direct integration with installed laboratory devices such as pipettors and bulk storage devices to promote rapid adoption of the solid phase microextraction devices disclosed herein by laboratories.

As used herein, "about" indicates a variance of ±<NUM>% of the value being modified by "about," unless otherwise indicated to the contrary.

As used herein, "solid phase microextraction" includes, but is not limited to, a solid substrate coated with a polymeric sorbent coating, wherein the coating may include metallic particles, silica-based particles, metal-polymeric particles, polymeric particles, or combinations thereof which are physically or chemically attached to the substrate. In some non-limiting examples, the solid substrate has at least one depression disposed in or protrusion disposed on a surface of the substrate and said substrate includes at least one polymeric sorbent coating disposed in or on the at least one depression or protrusion. The term "solid phase microextraction" further includes a solid substrate with at least one indentation or protrusion that contains at least one magnetic component for the collection of magnetic particles or magnetic molecules onto the solid substrate.

<FIG> illustrates a common commercially available manual micropipettor <NUM>. The pipettor is a plunger displacement-based device capable of first drawing liquid into the pipette tip <NUM> and subsequently dispensing the liquid. The plunger mechanism is not shown and resides in the housing <NUM> of the pipettor between the plunger shaft <NUM> and the pipette end <NUM>.

Standard micropipette tips are loaded onto the pipettor device <NUM> by centering the device over the tip <NUM> (commonly docked in a separate holder, not shown) and tapping the device <NUM> gently onto the opening of the tip <NUM>. The tip <NUM> is mounted via friction against the conical outer surface <NUM> of the pipette end <NUM> and is ready for use.

The operator first depresses the push button <NUM> and immerses the pipette tip <NUM> into the liquid of interest. Releasing the push button draws a volume of liquid into the vessel portion <NUM> of the pipette tip. The liquid is transferred by depressing the push button <NUM> again, and the liquid is dispensed.

Following the desired number of liquid transfer operations, the pipette tip <NUM> is ejected from the pipettor by depressing the tip ejector button <NUM>. This operation pushes the tip ejector <NUM> down the length of pipette shaft <NUM> and the bottom surface of the ejector shaft <NUM> pushes the pipette tip <NUM> off the conical outer surface <NUM> of pipettor end <NUM>. The entire procedure is then repeated as required.

While the manual version of the pipette device is shown, automated and robotic versions include the same relevant mechanical elements.

The conical shape and dimensions of the pipette end <NUM>, the bottom surface of the ejector shaft <NUM>, and the pipette tip cup <NUM> are standardized in the art. In one embodiment, the solid phase microextraction devices disclosed herein are adapted to these standardized dimensions in order to interface easily with the installed laboratory equipment.

Referring to <FIG> the basic elements of a solid phase microextraction device <NUM> comprise a substrate <NUM> having at least one planar surface <NUM>, a sorbent layer <NUM> disposed on at least a portion of the at least one planar surface <NUM>, a tapering tip <NUM> extending from the substrate <NUM> toward an analysis end of the solid phase microextraction device <NUM>, and a receptacle mount <NUM> configured for removable attachment to an emplacement <NUM> of a receiving device <NUM>. The substrate <NUM> may have any suitable dimensions, including, but not limited to, about <NUM> wide x about <NUM> long x about <NUM> thick. The substrate <NUM> may be made from any suitable material, including, but not limited to, conductive materials such as, but not limited to, stainless steels. The sorbent layer <NUM> may include an extraction phase sorbent including, but not limited to, polymeric particles (e.g., silica modified with C18 groups) and a binder (e.g., polyacrylonitrile).

In one embodiment, the solid phase microextraction device <NUM> is a CBS device that has been adapted to standard pipette tip <NUM> dimensions. The blade portion <NUM> is fitted with a cup as the receptacle mount <NUM> which is configured to attach to the emplacement <NUM> on the pipettor end <NUM>. The receptacle mount <NUM> is fixed to the substrate <NUM> and is positioned at the opposite end from the sorbent layer <NUM> and tapering tip <NUM>. The inner surface <NUM> of the receptacle mount <NUM> is shaped to employ a friction fit mechanism, consistent with the standard commercial pipette tip cup <NUM>. The receptacle mount <NUM> may be made from electrically insulating polymers consistent with standard pipette tips, such as, but not limited to, polypropylene or electrically conductive polymers such as, but not limited to, carbon impregnated polypropylene.

Referring to <FIG>, in one embodiment, the solid phase microextraction device <NUM> includes a clocking feature <NUM>, which is configured to fix a radial orientation of the planar surface <NUM> with respect to the receiving device <NUM>. "Clocking" is intended to connotate the passage of a hand around an analogue clockface as a paradigm for indicating radial orientation of the planar surface <NUM>. In one embodiment, the clocking feature <NUM> includes at least one of an indentation or a protrusion corresponding to at least one of a complimentary protrusion or complimentary indentation of the receiving device <NUM>, such that when the solid phase microextraction device <NUM> is mounted to the receiving device <NUM>, the clocking feature <NUM> limits the radial orientation of the solid phase microextraction device <NUM> with respect to the receiving device <NUM> to a predetermined number of radial positions. The predetermined number of radial positions may consist of a single radial position, two radial positions, or may include any suitable larger number of radial positions. The solid phase microextraction device <NUM> may include visual indicia of the radial orientation of the at least one planar surface <NUM> on the receptacle mount <NUM>. Such visual indicia may serve to indicate the radial orientation of the at least one planar surface <NUM> when the planar surface <NUM> itself is not visible.

In one embodiment, the solid phase microextraction device <NUM> is a pipettor-compatible CBS device <NUM>, the receptacle mount <NUM> is a pipette-tip receptacle mount <NUM>, and the emplacement <NUM> is a pipettor tip emplacement <NUM> configured to removably engage the pipette tip receptable mount <NUM>. As used herein, "removably" indicates removal without damage to the pipettor tip emplacement <NUM> or the pipette-tip receptacle mount <NUM>. The receiving device <NUM> may be any suitable device, including, but not limited to, a pipettor <NUM> or a solid phase microextraction device manipulator <NUM> (described below).

In a further embodiment, the pipette-tip receptacle mount <NUM> has two fin protrusions <NUM> extending equidistant from the pipette tip receptacle mount <NUM> serving as the clocking feature <NUM>. The presence of the two fin protrusions <NUM> in this configuration reduces the radial position conditions <NUM> of the blade to two discreet equivalent positions (i.e., <NUM>° and <NUM>°). The two-fin design depicted here is for illustration purposes; other configurations employing greater or fewer fins may be used, or other features on the pipette tip receptacle mount <NUM> may be conceived where the radial rotation of the solid phase microextraction device <NUM> is restricted when engaged with an emplacement <NUM>. In order for the fin protrusions <NUM> to control radial position they engage with the receiving device <NUM> in a lock-and-key arrangement.

<FIG> and <FIG> illustrates a solid phase microextraction device repository <NUM> which orients the solid phase microextraction device <NUM> while it is docked. The solid phase microextraction device repository <NUM> includes a repository wall <NUM> surrounding and defining a chamber <NUM>, a plurality of orifices <NUM> disposed in the repository wall <NUM>, each configured to receive and retain a substrate <NUM> and a receptacle mount <NUM> of a solid phase microextraction device <NUM>, and a plurality of clocking feature interfaces <NUM> disposed in the repository wall <NUM>, each configured to guide a clocking feature <NUM> of the solid phase microextraction device <NUM> into a predetermined radial orientation and fix the solid phase microextraction device <NUM> in the predetermined radial orientation. The chamber <NUM> is configured to accept the substrate <NUM> of the solid phase microextraction device <NUM> with the substrate <NUM> and a tapering tip <NUM> extending from the substrate <NUM> being remote from contact with the repository wall <NUM> or any adjacent solid phase microextraction devices <NUM> disposed in the solid phase microextraction device repository <NUM>. The plurality of orifices <NUM> may be arranged in any suitable pattern or without pattern, including, but not limited to, a one-dimensional array or a two-dimensional array. The radial orientations of the individual solid phase microextraction devices <NUM> docked in the solid phase microextraction device repository may all be the same or different as required by the sample handling and analysis operations.

In one embodiment, the solid phase microextraction device repository <NUM> includes two slits <NUM> as the clocking feature interfaces <NUM>, radially positioned consistent with clocking feature <NUM> of the solid phase microextraction device <NUM>. In a further embodiment, the taper of the blade fins <NUM> provides an additional mechanism to assist the successful docking of slightly offset solid phase microextraction devices <NUM> with respect to the axial center of the tapering tip <NUM> and the orifices <NUM> of the solid phase microextraction device repository <NUM>. The blade fins <NUM> and the corresponding clocking feature interfaces <NUM> may include asymmetrical configurations so as to further limit the positioning of the solid phase microextraction device <NUM> to a single position while engaged with the solid phase microextraction device repository <NUM>.

In one embodiment, the clocking feature interface <NUM> includes guidance protrusions <NUM> surrounding the orifice <NUM> to promote proper alignment of solid phase microextraction devices <NUM> when they are docked into the solid phase microextraction device repository <NUM>. If the solid phase microextraction device <NUM> is radially off axis with respect to the orientation of the clocking feature <NUM> to the clocking feature interface <NUM>, the guidance protrusions <NUM> are tapered to a point <NUM> and join to create a valley shape <NUM> at the base of the orifice <NUM>. The taper of the guidance protrusions <NUM> provides a mechanism to guide and realign an off-axis solid phase microextraction device <NUM> so that it is properly positioned while docked in the solid phase microextraction device repository <NUM>.

The orientation of the solid phase microextraction device <NUM> in the solid phase microextraction device repository <NUM> may be configured to remain consistent with the positioning requirements of either a manual operator or automated usage. <FIG> illustrates three possible, but not exclusive, arrangements of the solid phase microextraction device <NUM> docked in solid phase microextraction device repository <NUM>. The chamber <NUM> of the solid phase microextraction device repository <NUM> may be configured so as to ensure that individual solid phase microextraction devices <NUM> are not in contact with the repository wall <NUM> or each other. Additional wall or barrier structures (not shown) may also be employed in the solid phase microextraction device repository <NUM> to ensure solid phase microextraction device integrity.

Referring to <FIG>, in one embodiment, an electrically conductive solid phase microextraction device <NUM> includes a substrate <NUM> having an electrically conductive portion <NUM>. The receptacle mount <NUM> includes an electrically conductive terminal <NUM> disposed on an inner surface <NUM> of the receptacle mount <NUM> configured to be in electrical communication with the emplacement <NUM> of the receiving device <NUM> when the electrically conductive solid phase microextraction device <NUM> is mounted to the receiving device <NUM>. At least a portion of the receptacle mount <NUM> may include an electrically conductive layer <NUM> (or the receptacle mount <NUM> may include an electrode) in electrical communication with the electrically conductive portion <NUM> of the substrate <NUM> and the electrically conductive terminal <NUM> of the receptacle mount <NUM>.

The electrically conductive terminal <NUM> may cover all or part of the inner surface <NUM> of the receptacle mount <NUM>. In one embodiment, the presence of the electrically conductive terminal <NUM> does not interfere with the friction fit mechanism used to attach the electrically conductive solid phase microextraction device <NUM> to the emplacement <NUM>, or the use of the ejector shaft <NUM> to remove the electrically conductive solid phase microextraction device <NUM> from the receiving device <NUM> after use.

In one embodiment, the receptacle mount is composed of an electrically conductive polymer, is in electrical communication with the electrically conductive portion <NUM> of the substrate <NUM>, and is configured to be in electrical communication with the emplacement <NUM> of the receiving device <NUM> when the electrically conductive solid phase microextraction device <NUM> is mounted to the receiving device <NUM>.

Referring to <FIG>, in one embodiment, a solid phase microextraction device manipulator <NUM> (also shown in magnified detail <NUM>) includes a manipulator shaft <NUM>, an emplacement <NUM> disposed at an end of the manipulator shaft <NUM>, the emplacement <NUM> being a pipettor tip emplacement <NUM> configured to removably engage a pipette tip receptacle mount <NUM> of a solid phase microextraction device <NUM>. An electrically conductive contact <NUM> is disposed at the emplacement <NUM> such that when the pipette tip receptacle mount <NUM> of the solid phase microextraction device <NUM> is mounted to the emplacement <NUM>, the electrically conductive contact <NUM> is in electrical communication with an electrically conductive terminal <NUM> of the pipette tip receptacle mount <NUM>. An ejector <NUM> is configured to dismount the pipette tip receptacle mount <NUM> from the emplacement <NUM>, and a clocking feature interface <NUM> is configured to guide a clocking feature <NUM> of the solid phase microextraction device <NUM> into a predetermined radial orientation and fix the solid phase microextraction device <NUM> in the predetermined radial orientation. The ejector <NUM> may be an ejector shaft <NUM>. The ejector <NUM> may be composed in whole or in part of an electrically insulating material. Electrically insulating materials may be incorporated in various portions of the solid phase microextraction device manipulator <NUM> as needed to isolate the flow of electricity to necessary pathways.

In one embodiment, the electrically conductive contact <NUM> is a conductive layer applied to the outer surface of the pipettor tip emplacement <NUM>.

In one embodiment, the electrical circuit incorporated in the solid phase microextraction device manipulator <NUM> provides the electrically conductive solid phase microextraction device <NUM> with voltage during sample analysis, and includes a high voltage power supply <NUM> wired to the electrically conductive contact <NUM> of the solid phase microextraction device manipulator <NUM>. When the electrically conductive solid phase microextraction device <NUM> is engaged with the pipettor tip emplacement <NUM>, electrification of the blade portion <NUM> is enabled. Preferably, the presence of the electrically conductive contact <NUM> does not interfere with the friction fit mechanism used to attach the electrically conductive solid phase microextraction device <NUM> to the pipettor tip emplacement <NUM>, or the use of the ejector shaft <NUM> to remove the electrically conductive solid phase microextraction device <NUM> from the receiving device <NUM> after use.

While the solid phase microextraction device manipulator <NUM> has been modified to enable electrification of the electrically conductive solid phase microextraction device <NUM>, in one embodiment, all of the liquid handling functions of the standard pipettor are maintained. This enables the use of a single hand tool or automation accessory to individually perform either basic liquid handling with standard pipette tips or CBS-related tasks. Hence, the ejector shaft <NUM> on the solid phase microextraction device manipulator <NUM> may be compatible with conductive tips and may be made of one or multiple layers of electrically insulating materials.

Simpler solid phase microextraction device manipulators <NUM> are also included which eliminate all of the liquid handling elements of the standard pipettor, while maintaining the elements necessary to mount, electrify, and eject an electrically conductive solid phase microextraction device <NUM>. These solid phase microextraction device manipulator <NUM> embodiments consist of a basic pipette shaft <NUM> with a pipettor end <NUM> having the standardized emplacement <NUM>, the ejector shaft <NUM>, and the electrically conductive contact <NUM>. Manual use versions and robotic use versions of the simplified solid phase microextraction device manipulators <NUM> may be adapted.

Referring to <FIG>, in one embodiment, the solid phase microextraction device <NUM> includes a discreet electrode <NUM>, connected to the substrate <NUM> and located within the receptacle mount <NUM>, and the solid phase microextraction device manipulator <NUM> includes the electrically conductive contact <NUM>, electrically connected to the high voltage power supply.

Referring to <FIG>, in one embodiment the clocking feature <NUM> includes slots <NUM> provided equidistant along the outer rim of the receptacle mount <NUM>. A conductive layer <NUM> is attached to the inner surface <NUM> of the receptacle mount <NUM>. In cases where a conductive polymer is employed for the receptacle mount <NUM>, the conductive layer <NUM> may be eliminated.

Referring to <FIG>, a magnified detail <NUM> of a solid phase microextraction device <NUM> is positioned to be loaded onto a solid phase microextraction device manipulator <NUM>, and the pipettor shaft <NUM> and emplacement <NUM> include protrusions <NUM> as the clocking feature interface <NUM> for engagement with the two slots <NUM> as the clocking feature <NUM>. The protrusions <NUM> and slots <NUM> operate as a keyed mechanism to limit the position of solid phase microextraction device <NUM> in either a <NUM>° or <NUM>° position with respect to solid phase microextraction device manipulator <NUM>. The two-slot design depicted here is for illustrative purposes and is not intended to be limiting. Other configurations employing more or fewer slots <NUM> may be used, or other features on the receptacle mount <NUM> may be conceived where the radial rotation of the solid phase microextraction device <NUM> is restricted while engaged with the solid phase microextraction device manipulator <NUM>, or the slots <NUM> could be disposed in the solid phase microextraction device manipulator <NUM> and the protrusions <NUM> could extend from the solid phase microextraction device <NUM> instead, or there could be slots <NUM> and protrusions <NUM> for both the solid phase microextraction device <NUM> and the solid phase microextraction device manipulator <NUM>.

Referring to <FIG> and <FIG>, in one embodiment, a solid phase microextraction device <NUM> has three slots <NUM> in an asymmetrical arrangement with respect to the radial center of the receptacle mount <NUM>. This arrangement limits the radial positioning of the blade portion <NUM>. The pipettor shaft <NUM> and emplacement <NUM> have protrusions <NUM> as the clocking feature interface <NUM> to engage with the three slots <NUM> of solid phase microextraction device <NUM> as the clocking feature <NUM> allowing for a single radial orientation of the blade portion <NUM>.

Claim 1:
A solid phase microextraction system comprising a solid phase microextraction device (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) and a solid phase microextraction device repository (<NUM>),
the solid phase microextraction device (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) comprising:
a substrate (<NUM>) having at least one planar surface (<NUM>);
a sorbent layer (<NUM>) disposed on at least a portion of the at least one planar surface (<NUM>);
a tapering tip (<NUM>) extending from the substrate (<NUM>);
a receptacle mount (<NUM>) configured for removable attachment to a receiving device, the receiving device being the solid phase microextraction device repository (<NUM>); and
a clocking feature (<NUM>) configured for fixing a radial orientation of the planar surface (<NUM>) with respect to the receiving device;
the solid phase microextraction device repository (<NUM>) comprising:
a repository wall (<NUM>) surrounding and defining a chamber (<NUM>);
a plurality of orifices (<NUM>) disposed in the repository wall (<NUM>), each configured to receive and retain the substrate (<NUM>) and the receptacle mount (<NUM>) of the solid phase microextraction device (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>); and
a plurality of clocking feature interfaces (<NUM>) disposed in the repository wall (<NUM>), each configured to guide the clocking feature (<NUM>) of the solid phase microextraction device (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) into a predetermined radial orientation and fix the solid phase microextraction device (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) in the predetermined radial orientation; and
wherein the chamber (<NUM>) is configured to accept the substrate (<NUM>) of the solid phase microextraction device (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) with the substrate (<NUM>) and the tapering tip (<NUM>) extending from the substrate (<NUM>) being remote from contact with the repository wall (<NUM>) or any adjacent solid phase microextraction devices (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) disposed in the solid phase microextraction device repository (<NUM>).