WO2023123045A1

WO2023123045A1 - Automatic positioning of injection needle in an autosampler

Info

Publication number: WO2023123045A1
Application number: PCT/CN2021/142463
Authority: WO
Inventors: Cong MA; Jianguo Wu; Pan Wei; Haiyun CHEN
Original assignee: PerkinElmer Instruments (Suzhou) Co., Ltd.
Priority date: 2021-12-29
Filing date: 2021-12-29
Publication date: 2023-07-06

Abstract

An autosampler (100) includes a sample carrier (110) for receiving a plurality of sample containers; a probe arm (120) having a distal end and a proximal end, the probe arm (120) being mounted on the autosampler (100) at the proximal end thereof; a needle (122) located on the distal end of the probe arm (120), the probe arm (120) being configured to move the needle (122) from one of the plurality of sample containers to a receptacle (210) for an analytical instrument (200); an optical sensor (130) configured to output a position signal comprising information associated with a position of the needle (122); and a controller configured to receive the position signal from the optical sensor (130) and to control a position of the needle (122) in response to the position signal.

Description

AUTOMATIC POSITIONING OF INJECTION NEEDLE IN AN AUTOSAMPLER

FIELD

The present application relates to autosamplers and, more particularly, to autosamplers that automatically position the injection needle.

BACKGROUND

Autosamplers are often used to selectively supply sample components to an analytical device such as an atomic absorption spectrometer or gas chromatograph. An autosampler may include a platter or other sample carrier and vials or other containers that are held in the sample carrier. Solid, liquid or gaseous samples are provided in the vials. The autosampler may move a sampling device, such as a sampling syringe, to each vial to remove a sample from the vial and/or to expel the sample for analysis by the analytical device. The sample containers or vials may be held in a sample tray or carrier, which is loaded or mounted on the autosampler.

The needle of the sampling syringe may be inserted into a relatively small opening. For example, the sample may be expelled into an atomic absorption spectrometer via a graphite tube. These graphite tubes typically have a diameter of about 3 mm, and the needle diameter may be about 2 mm. Therefore, a high degree of accuracy is desired.

SUMMARY

According to some embodiments, an autosampler includes a sample carrier for receiving a plurality of sample containers; a probe arm having a distal end and a proximal end, the probe arm being mounted on the autosampler at the proximal end thereof; a needle on the distal end of the probe arm, the probe arm being configured to move the needle from one of the plurality of sample containers to a receptacle for an analytical instrument; an optical sensor configured to output a position signal comprising information associated with a position of the needle; and a controller configured to receive the position signal from the optical sensor and to control the position of the needle in response to the position signal.

In some embodiments, the optical sensor is configured to detect the position of the needle when the needle is in an entry region of an opening for the receptacle for the analytical instrument or an opening for one of the plurality of sample containers.

In some embodiments, the controller is configured to move the needle at the entry region to a centered position with respect to the opening.

In some embodiments, the opening has a diameter of three to five millimeters.

In some embodiments, the opening is an opening of a graphite tube receptacle for an analytical instrument comprising an atomic absorption graphite furnace.

In some embodiments, the optical sensor is mounted on the probe arm.

In some embodiments, the optical sensor has a field of view that includes the needle, and the output signal indicates the position of the needle with respect to objects in the field of view.

In some embodiments, the objects in the field of view of the optical sensor include an entry region of an opening for the receptacle for the analytical instrument or an opening for one of the sample containers.

In some embodiments, the controller comprises an actuator and a processor, and the processor is configured to identify the centered position and to control the position of the needle with the actuator so that the needle is at the centered position.

In some embodiments, the processor is configured to store position information for the receptacle of the analytical instrument and the plurality of sample containers, and the actuator is configured to adjusting a position of the autosampler and/or the probe arm to calibrate the position information for the receptacle of the analytical instrument and the plurality of sample containers.

In some embodiments, the processor is configured to determine a distance between the needle and the opening and to adjust a position of the needle to the centered position with respect to the opening.

In some embodiments, the analytical instrument comprises an atomic absorption spectrometer, a gas chromatography system, a liquid chromatography system, an inductively coupled plasma -optical emission spectrometer (ICP-OES) , or an Inductively coupled plasma –mass spectrometer (ICP-MS) .

In some embodiments, the optical sensor is a camera.

In some embodiments, the controller is configured to determine the position of the needle based on the position signal and control the position of the needle based on the determined position.

In some embodiments, a viewing angle of the optical sensor is aligned with a direction that the needle is moving.

In some embodiments, the position signal comprises an image.

According to some embodiments, methods for controlling a probe arm of an autosampler are provided. The probe arm has a distal end and a proximal end, and the probe arm is mounted on the autosampler at the proximal end of the probe arm and has a needle on the distal end of the probe arm and is configured to move the needle from one of a plurality of sample containers to a receptacle for an analytical instrument. The method includes receiving a position signal comprising information associated with a position of the needle of the probe arm; and controlling the position of the needle in response to the position signal.

In some embodiments, the method includes positioning the optical sensor to detect the position of the needle when the needle is in an entry region of an opening for the receptacle for the analytical instrument or an opening for one of the plurality of sample containers.

In some embodiments, the method includes moving the needle with the probe arm at the entry region to a centered position with respect to the opening.

In some embodiments, the method includes identifying the centered position based on the optical signal of the optical sensor and controlling the position of the needle with an actuator in communication with the probe arm so that the needle is at the centered position.

In some embodiments, the method includes storing position information for the receptacle of the analytical instrument and the plurality of sample containers, and adjusting a position of the autosampler and/or the probe arm to calibrate the position information for the receptacle of the analytical instrument and the plurality of receptacles.

In some embodiments, the method includes determining a distance between the needle and the opening and to adjust a position of the needle to the centered position with respect to the opening.

In some embodiments, the position signal comprises an image, and the method further includes analyzing the image to determine a position of the needle with respect to an opening of the receptacle or the plurality of sample containers.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the inventive concept and, together with the description, serve to explain principles of the inventive concept.

FIG. 1 is front view of an autosampler and atomic absorption spectrometer according to some embodiments.

FIG. 2 is top view of the autosampler of FIG. 1.

FIG. 3 is a perspective view of the autosampler of FIG. 1 with a probe arm and needle in an upright position for removing a sample from the auto ampler according to some embodiments.

FIG. 4 is a perspective view of the probe arm and needle in a rotated position for placement in the atomic absorption spectrometer of FIG. 1.

FIG. 5 is a perspective view of the probe arm and needle of the autosampler entering a receptacle of the atomic absorption spectrometer of FIG. 1.

FIG. 6 is an image of the probe arm and needle of the autosampler from the optical sensor of the autosampler of FIG. 1

FIG. 7 is a schematic diagram of systems, method, and computer program products according to some embodiments.

FIG. 8 is a flowchart illustrating operations according to some embodiments.

DETAILED DESCRIPTION

The inventors have recognized and appreciated that precise needle alignment with a graphite tube of an autosampler is time consuming and is typically performed manually by the user. In particular, the user must manually position the needle close to the graphite tube and then move the device in the horizontal and vertical plane to align the needle to the center of the graphite tube. This can be exceedingly time-consuming because it must be done every time the tube is replaced with a new tube.

The inventors have further recognized and appreciated that alignment performed by a user is not always repeatable or reliable, whereas accurate and repeatable alignment can be achieved using an automated control system.

The inventors have also recognized and appreciated that open loop control systems are not reliable for long periods of operation time. The inventors further recognized and appreciated that a closed-loop, feedback-based control system would result in reliable positioning over long periods of operation time. Conventionally, control systems using feedback were not possible for a number of reasons. For instance, it was not previously possible to accurately determine the position of the needle using an optical sensor. However, recent advances in optical sensor technology have made it possible to position low-cost, lightweight optical sensors such that they can accurately track the position of the needle relative to the graphite tube. For example, a lightweight image sensor may be mounted on the same arm as the needle, providing a clear field of view of the graphite tube and the needle. In some embodiments, images from such an image sensor may be used to move the needle until it is precisely placed in the center of the graphite tube.

While some embodiments described herein relate to an autosampler using graphite tubes for use in an atomic absorption spectrometer, it should be appreciated that similar techniques can be used for any instrument where samples are deposited into vials or tubes.

As illustrated in FIG. 1, an autosampler 100 and an analytical instrument 200 are controlled by a controller 300. The autosampler 100 includes a sample carrier 110 that is configured to hold sample containers, and a sample or probe arm 120 for collecting samples from the sample containers and providing the samples to the analytical instrument 200. The auto sampler 100 further includes an actuator 160, such as an XY stage or an XYZ stage, for positioning the autosampler 100 and/or the probe arm 120 with respect to the analytical instrument 200. As illustrated in FIG. 2, the sample carrier includes apertures 112 for holding sample containers or vials 114 of sample materials. The probe arm 120 has a needle 122, and an optical sensor 130 is on the probe arm 120 and is configured to output a position signal that comprises information associated with a position of the needle 122.

The analytical instrument 200 includes a receptacle 210 for receiving a sample from the needle 122 of the probe arm. As illustrated, the analytical instrument 200 is an atomic absorption spectrometer, such as an atomic absorption graphite furnace; however, other types of analytical instruments may be used, including a gas chromatography system, a liquid chromatography system, an inductively coupled plasma -optical emission spectrometer (ICP-OES) , or an Inductively coupled plasma –mass spectrometer (ICP-MS) .

The autosampler 100 is in communication with a controller 300 that is configured to receive the position signal from the optical sensor 130 and to control a position of the needle 122 using actuators connecting to the needle (not shown) and/or the positioning device 160 so that the needle 122 is at a centered position with respect to the receptacle 210 of the analytical instrument 200.

In particular, as illustrated in FIG. 3, the probe arm 120 raises the needle away from the sample carrier 110 after a sample is received in the needle 122 from one of the sample vials 114. As shown in FIG. 4, the probe arm 120 rotates so that the needle 122 faces the receptacle 210 of the analytical instrument 200. In FIG. 5, the probe arm 120 is lowered toward the receptacle 210.

The optical sensor 130 is positioned on the probe arm 120 to provide an optical signal, such as an image of the needle 122. An image from the optical sensor 130 as the needle 122 is lowered into the receptacle 210 is shown in FIG. 6. As the needle 122 is lowered into the receptacle 210, the optical sensor 130 outputs an optical signal, such as the image of the needle 122 as it is lowered into the receptacle 210. The optical sensor 130 may be a camera, such as a digital camera, for generating images or video data. If the needle 122 is not positioned in a central location with respect to the receptacle, then the position of the needle 122 is adjusted.

As illustrated, the optical sensor 130 is on the probe arm 120 and can have a field of view that is fixed with respect to the needle 122, which is also mounted on the probe arm 120. The optical sensor 130 may be sufficiently to the distal end of the probe arm 120 and the needle 122; however, the optical sensor 130 may be positioned at any suitable location on the probe arm 120 or on or adjacent the autosampler 100 so that the needle 122 is in the field of view of the optical sensor 130. In some embodiments, the viewing angle of the optical sensor 130 may be aligned with the needle moving direction so that the optical sensor 130 has the receptacle 210 and/or vials 144 in the field of view together with the needle 122. The field of view of the optical sensor 130 may be used to generate an output signal that indicates the position of the needle 122 with respect to other objects in the field of view, such as the receptacle 210 and/or vials 114. Alternatively, the optical sensor 130 may be mounted on the autosampler 100 or the analytical instrument 200 to provide a view of the entry region of the receptacle 210 and/or vials 114. In some embodiments, two or more optical sensors may be used at different locations to provide two different views from different locations. The two or more optical sensors may provide overlapping fields of view with additional depth information regarding the position of the needle 122 with respect to the receptacle 210. In some embodiments, two or more optical sensors may be positioned with non-overlapping fields of view to provide an optical signal indicating the position of the needle 122 in different regions, such as the entry region of the receptacle 210 and/or vials 114. In addition, the optical sensor 130 may be mounted in a fixed position or the optical sensor 130 may be moved with an actuator to maintain a desired field of view and/or viewing angle.

Accordingly, images or other positional information from the optical sensor 130 may be received by the controller 300 so that the controller 300 may adjust movement of the needle 122 at the entry region to a centered position with respect to the opening of the receptacle 210 or vial 114. The position of the needle 122 may be repeatedly adjusted based on optical feedback from the optical sensor 130 until the needle 122 is in a centered position with respect to the opening of the receptacle 210 or vial 113. In some embodiments, the receptacle 210 has an opening with a diameter of three to five millimeters. The diameter of the needle may be one to two millimeters. For example, the receptacle 210 may be an opening of a graphite tube receptacle for an analytical instrument that includes an atomic absorption graphite furnace. The optical sensor 130 may provide optical information that increases the accuracy of the placement of the needle 122 with respect to small opening receptacles.

In some embodiments the controller 300 includes a processor that is configured to store position information for the receptacle 210 of the analytical instrument 200 and the sample vials 114. The controller 300 can also include actuators for moving the needle 122 and/or moving the autosampler 100 to adjust or calibrate the position information for the receptacle 210 of the analytical instrument 200 and/or vials 114 with respect to the needle 122. The controller 300 may receive position information from the optical sensor 130 to determine a distance between the needle 122 and the receptacle 210 and/or vials 114 and to adjust a position of the needle to a centered position with respect to the opening of the receptacle 210 and/or vials 114.

As illustrated in FIG. 7, an example data processing system that may be included in devices operating in accordance with some embodiments, e.g., to carry out the operations described herein. As illustrated in FIG. 7, a data processing system or controller 300, which can be used to carry out or direct operations includes a processor 310, a memory 320 and input/output circuits 330. The data processing system can be incorporated in a portable communication device and/or other components of a network, such as a server. The processor 310 communicates with the memory 320 via an address/data bus 350 and communicates with the input/output circuits 330 via an address/data bus 149. The input/output circuits 330 can be used to transfer information between the memory (memory and/or storage media) 320 and another component, such as the optical sensor 130 and the positioning actuator (s) 160A. These components can be conventional components such as those used in many conventional data processing systems, which can be configured to operate as described herein.

In particular, the processor 310 can be a commercially available or custom microprocessor, microcontroller, digital signal processor or the like. The memory 320 can include any memory devices and/or storage media containing the software and data used to implement the functionality circuits or modules used in accordance with some embodiments. The memory 320 can include, but is not limited to, the following types of devices: cache, ROM, PROM, EPROM, EEPROM, flash memory, SRAM, DRAM and magnetic disk. In some embodiments, the memory 320 can be a content addressable memory (CAM) .

As further illustrated in FIG. 7, the memory (and/or storage media) 320 can include several categories of software and data used in the data processing system: an operating system 322; application programs 324; input/output device circuits 326; and data 328. As will be appreciated by those of skill in the art, the operating system 322 can be any operating system suitable for use with a data processing system. The input/output device circuits 330 typically include software routines accessed through the operating system 322 by the application program 324 to communicate with various devices. The application programs 324 are illustrative of the programs that implement the various features of the circuits and modules according to some embodiments. Finally, the data 328 represents the static and dynamic data used by the application programs 324, the operating system 322 the input/output device circuits 330 and other software programs that can reside in the memory 320.

The application programs 324 can include several modules, including a position controller 324A. The modules can be configured as a single module or additional modules otherwise configured to implement the operations described herein for analyzing the motility profile of a sample. The data 328 can include optical data 328A, for example, from the optical sensor (s) 130. The data 328 can be used by the position controller 324A to detect and/or analyze a position of the needle 122 and/or to control the optical sensor 130 and/or actuators for controlling the position of the needle 122, such as the position actuators 160A.

In some embodiments, the optical data 328A can include the position signal from the optical sensor 130, including information associated with the position of the needle. For example, the optical data 328A may include raw image data from the optical sensor 130, and the optical sensor may be a camera. The raw image data may include images that are analyzed, e.g., by the position controller 324A, to determine the position of the needle. Accordingly, the position controller 324A may determine the position of the needle based on the position signal, e.g., optical data from the optical sensor 130, and control the position of the needle based on the determined position. For example, optical data may be analyzed to calculate or estimate a relative distance between the needle and other elements of the autosampler, such as the receptacle of the spectrometer or vials on the autosampler, and/or optical data may be analyzed to determine if the needle is centered with respect to an opening, such as an opening of the receptacle of the spectrometer or vials on the autosampler. The position controller 324A may move the needle to a position that is centered with respect to the opening based on the optical data 328A.

While some embodiments are illustrated with reference to position controller 324A and the optical data 328A in FIG. 7, it should be understood that other configurations fall within the scope of the inventive concepts. It should be understood that the controller 300 may be provided as a separate computer as illustrated in FIG. 1, or the operations and functions of the controller 300 may be incorporated into the autosampler 100 or other components of the system. The position controller 324A is illustrated in a single data processing system, and as will be appreciated by those of skill in the art, such functionality can be distributed across one or more data processing systems. Thus, the present invention should not be construed as limited to the configurations illustrated in FIG. 7, but can be provided by other arrangements and/or divisions of functions between data processing systems. For example, although FIG. 7 is illustrated as having various circuits and modules, one or more of these circuits or modules can be combined, or separated further, without departing from the scope of the present invention.

As shown in FIG. 8, a position signal, e.g., from an optical sensor 130 or sensors, may be received by the controller 300 at Block 400. The position signal can include information associated with the position of the needle 122 with respect to the opening of the receptacle 210 and/or vials 114. If the needle 122 is not centered at the opening of the receptacle 210 and/or vials 114 at Block 410, then the position of the needle is adjusted or controlled at Block 420.

In this configuration, the needle position may be controlled and placed with respect to small openings, e.g., without touching the sides of the openings.

The present inventive concepts are described hereinafter with reference to the accompanying drawings and examples, in which embodiments are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the inventive concepts to those skilled in the art.

Like numbers refer to like elements throughout. In the figures, the thickness of certain lines, layers, components, elements or features may be exaggerated for clarity.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting thereof. As used herein, the singular forms "a, " "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising, " when used in this specification, specify the presence of stated features, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and/or groups thereof. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items. As used herein, phrases such as "between X and Y" and "between about X and Y" should be interpreted to include X and Y. As used herein, phrases such as "between about X and Y" mean "between about X and about Y. " As used herein, phrases such as "from about X to Y" mean "from about X to about Y. "

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the specification and relevant art and should not be interpreted in an idealized or overly formal sense unless expressly so defined herein. Well-known functions or constructions may not be described in detail for brevity and/or clarity.

It will be understood that when an element is referred to as being "on, " "attached" to, "connected" to, "coupled" with, "contacting, " etc., another element, it can be directly on, attached to, connected to, coupled with or contacting the other element or intervening elements may also be present. In contrast, when an element is referred to as being, for example, "directly on, " "directly attached" to, "directly connected" to, "directly coupled" with or "directly contacting" another element, there are no intervening elements present. It will also be appreciated by those of skill in the art that references to a structure or feature that is disposed "adjacent" another feature may have portions that overlap or underlie the adjacent feature.

Spatially relative terms, such as "under, " "below, " "lower, " "over, " "upper" and the like, may be used herein for ease of description to describe one element or feature's relationship to another element (s) or feature (s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is inverted, elements described as "under" or "beneath" other elements or features would then be oriented "over" the other elements or features. Thus, the exemplary term "under" can encompass both an orientation of "over" and "under. " The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly. Similarly, the terms "upwardly, " "downwardly, " "vertical, " "horizontal" and the like are used herein for the purpose of explanation only unless specifically indicated otherwise.

It will be understood that, although the terms "first, " "second, " etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. Thus, a "first" element discussed below could also be termed a "second" element without departing from the teachings of the present invention. The sequence of operations (or steps) is not limited to the order presented in the claims or figures unless specifically indicated otherwise.

Example embodiments of the present inventive concepts may be embodied in various devices, apparatuses, and/or methods. For example, example embodiments of the present inventive concepts may be embodied in hardware and/or in software (including firmware, resident software, micro-code, etc. ) . Furthermore, example embodiments of the present inventive concepts may take the form of a computer program product comprising a non-transitory computer-usable or computer-readable storage medium having computer-usable or computer-readable program code embodied in the medium for use by or in connection with an instruction execution system. In the context of this document, a computer-usable or computer-readable medium may be any medium that can contain, store, communicate, or transport the program for use by or in connection with the instruction execution system, apparatus, or device.

The computer-usable or computer-readable medium may be, for example but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device. More specific examples (a nonexhaustive list) of the computer-readable medium would include the following: an electrical connection having one or more wires, a portable computer diskette, a random access memory (RAM) , a read-only memory (ROM) , an erasable programmable read-only memory (EPROM or Flash memory) , an optical fiber, and a portable compact disc read-only memory (CD-ROM) . Note that the computer-usable or computer-readable medium could even be paper or another suitable medium upon which the program is printed, as the program can be electronically captured, via, for instance, optical scanning of the paper or other medium, then compiled, interpreted, or otherwise processed in a suitable manner, if necessary, and then stored in a computer memory.

Example embodiments of the present inventive concepts are described herein with reference to flowchart and/or block diagram illustrations. It will be understood that each block of the flowchart and/or block diagram illustrations, and combinations of blocks in the flowchart and/or block diagram illustrations, may be implemented by computer program instructions and/or hardware operations. These computer program instructions may be provided to a processor of a general purpose computer, a special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means and/or circuits for implementing the functions specified in the flowchart and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer usable or computer-readable memory that may direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer usable or computer-readable memory produce an article of manufacture including instructions that implement the functions specified in the flowchart and/or block diagram block or blocks.

The computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions that execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart and/or block diagram block or blocks.

The foregoing is illustrative of the present inventive concept and is not to be construed as limiting thereof. Although a few example embodiments have been described, those skilled in the art will readily appreciate that many modifications are possible in the exemplary embodiments without materially departing from the novel teachings of this inventive concept. Accordingly, all such modifications are intended to be included within the scope of this inventive concept as defined in the claims. Therefore, it is to be understood that the foregoing is illustrative of the present inventive concept and is not to be construed as limited to the specific embodiments disclosed, and that modifications to the disclosed embodiments, as well as other embodiments, are intended to be included within the scope of the appended claims. The invention is defined by the following claims, with equivalents of the claims to be included therein.

Claims

An autosampler comprising:

a sample carrier for receiving a plurality of sample containers;

a probe arm having a distal end and a proximal end, the probe arm being mounted on the autosampler at the proximal end thereof;

a needle on the distal end of the probe arm, the probe arm being configured to move the needle from one of the plurality of sample containers to a receptacle for an analytical instrument;

an optical sensor configured to output a position signal comprising information associated with a position of the needle; and

a controller configured to receive the position signal from the optical sensor and to control the position of the needle in response to the position signal.
The autosampler of Claim 1, wherein the optical sensor is configured to detect the position of the needle when the needle is in an entry region of an opening for the receptacle for the analytical instrument or an opening for one of the plurality of sample containers.
The autosampler of Claim 2, wherein the controller is configured to move the needle at the entry region to a centered position with respect to the opening.
The autosampler of Claim 2 or 3, wherein the opening has a diameter of three to five millimeters.
The autosampler of any of Claims 2-4, wherein the opening is an opening of a graphite tube receptacle for an analytical instrument comprising an atomic absorption graphite furnace.
The autosampler of any preceding claim, wherein the optical sensor is mounted on the probe arm.
The autosampler of any preceding claim, wherein the optical sensor has a field of view that includes the needle, and the output signal indicates the position of the needle with respect to objects in the field of view.
The autosampler of Claim 7, wherein the objects in the field of view of the optical sensor include an entry region of an opening for the receptacle for the analytical instrument or an opening for one of the sample containers.
The autosampler of any of Claims 3-8, wherein the controller comprises an actuator and a processor, and the processor is configured to identify the centered position and to control the position of the needle with the actuator so that the needle is at the centered position.
The autosampler of Claim 9, wherein the processor is configured to store position information for the receptacle of the analytical instrument and the plurality of sample containers, and the actuator is configured to adjusting a position of the autosampler and/or the probe arm to calibrate the position information for the receptacle of the analytical instrument and the plurality of sample containers.
The autosampler of Claims 9 or 10, wherein the processor is configured to determine a distance between the needle and the opening and to adjust a position of the needle to the centered position with respect to the opening.
The autosampler of any preceding claim, wherein the analytical instrument comprises an atomic absorption spectrometer, a gas chromatography system, a liquid chromatography system, an inductively coupled plasma -optical emission spectrometer (ICP-OES) , or an Inductively coupled plasma –mass spectrometer (ICP-MS) .
The autosampler of any preceding claim, wherein the position signal comprises an image.
The autosampler of any preceding claim, wherein the optical sensor comprises a camera.
The autosampler of any preceding claim, wherein the controller is configured to determine the position of the needle based on the position signal and control the position of the needle based on the determined position.
The autosampler of any preceding claim, wherein a viewing angle of the optical sensor is aligned with a direction that the needle is moving/
A method for controlling a probe arm of an autosampler, the probe arm having a distal end and a proximal end, the probe arm being mounted on the autosampler at the proximal end of the probe arm and having a needle on the distal end of the probe arm and being configured to move the needle from one of a plurality of sample containers to a receptacle for an analytical instrument, the method comprising:

receiving a position signal comprising information associated with a position of the needle of the probe arm; and

controlling the position of the needle in response to the position signal.
The method of Claim 17, wherein the position signal is generated by an optical sensor.
The method of Claim 18, further comprising positioning the optical sensor to detect the position of the needle when the needle is in an entry region of an opening for the receptacle for the analytical instrument or an opening for one of the plurality of sample containers.
The method of Claim 19, further comprising moving the needle with the probe arm at the entry region to a centered position with respect to the opening.
The method of Claims 19 or 20, wherein the opening has a diameter of three to five millimeters.
The method of any of Claims 20-21, wherein the opening is an opening of a graphite tube receptacle for an analytical instrument comprising an atomic absorption graphite furnace.
The method of any of Claims 18-22, wherein the optical sensor is mounted on the probe arm.
The method of any of Claims 18-23, wherein the optical sensor has a field of view that includes the needle, and the position signal indicates the position of the needle with respect to objects in the field of view.
The method of Claim 24, wherein the objects in the field of view of the optical sensor include an entry region of an opening for the receptacle for the analytical instrument or an opening for one of the sample containers.
The method of any of Claims 20-25, further comprising identifying the centered position based on the optical signal of the optical sensor and controlling the position of the needle with an actuator in communication with the probe arm so that the needle is at the centered position.
The method of Claims 26, further comprising storing position information for the receptacle of the analytical instrument and the plurality of sample containers, and adjusting a position of the autosampler and/or the probe arm to calibrate the position information for the receptacle of the analytical instrument and the plurality of receptacles.
The method of Claims 26 or 27, further comprising determining a distance between the needle and the opening and adjusting a position of the needle to the centered position with respect to the opening.
The method of any of Claims 17-28, wherein the analytical instrument comprises an atomic absorption spectrometer, a gas chromatography system, a liquid chromatography system, an inductively coupled plasma -optical emission spectrometer (ICP-OES) , or an Inductively coupled plasma –mass spectrometer (ICP-MS) .
The method of any of Claims 17-29, wherein the position signal comprises an image, the method further comprising analyzing the image to determine a position of the needle with respect to an opening of the receptacle or the plurality of sample containers.
The method of any of Claims 18-30, wherein the optical sensor comprises a camera.
The method of any of Claims 17-31, further comprising determining the position of the needle based on the position signal, wherein controlling the position of the needle is based on the determined position.
The method of any of Claims 17-32, further comprising aligning a viewing angle of the optical sensor with a direction that the needle is moving.