Identification of sample cells in a chromatography autosampler
Methods and systems are provided for the identification of sample cells in a sample tray that is placed in a chromatography autosampler. A cell gripper and labels are also provided to facilitate such identification.
1 . A system for identification of sample cells of a sample tray for placement in a chromatography autosampler, each sample cell having (i) a container having a side wall and (ii) a cap having an end surface visible from the sample tray, the system comprising:
a machine vision (MV) module within the autosampler, the MV module including a camera assembly, the camera assembly comprising a horizontally-directed camera to scan the side wall of each sample cell and a vertically-directed camera configured to scan the end surfaces of all the sample cells of the sample tray;
a gripper assembly configured to selectively grip, lift, and rotate respected sample cells relative to the sample tray; and
a computing device that controls the MV module, wherein the computing device is configured to (i) controller the gripper assembly to grip, lift, and rotate one of the sample cells above adjacent sample cells of the sample tray, (ii) control the horizontally-directed camera to scan the side wall of the one sample cell while rotated by the cell gripper assembly, (iii) determine an identity of the sample in the sample cell based upon the scanned side walls and/or end surfaces of each sample cell, (iv) determine a bottom liquid level based upon the scanned side walls, (v) identify an inner bottom surface of the sample cell and a foreign object within the sample cell, and (vi) control the sampling needle assembly and limit the insertion depth of a sample needle of the sampling needle assembly based on a position of the bottom liquid level, the bottom surface, and the foreign object of a respective sample cell to avoid damaging the sample needle.
2 . The system according to claim 1 , wherein each sample cell of the sample tray is provided with a label having an annular section mounted to a respective end surface and/or a side section mounted to a respective side wall, the annular section including (i) a machine-readable end identifier including machine-readable characters and (ii) an open center configured for unobstructed access to a septum in each respective cap, and a side section including a machine-readable side identifier having a bar code.
3 . The system according to claim 1 , wherein the cell gripper further comprises:
a jaw assembly configured to selectively grip, lift, and rotate the one of the samples cells, the jaw assembly including gripper jaws movable between an open position in which the jaw assembly can be positioned about the one of the sample cells and a closed position in which the gripper jaws are biased against the one sample cell to grip the one sample cell;
a motor assembly configured to rotate the jaw assembly about a motor axis, the motor assembly including a motor body and a hollow motor shaft rotatably supporting the jaw assembly relative to the motor body; and
a solenoid assembly configured to move the gripper jaws between the open and closed positions, the solenoid assembly including a plunger extending through the hollow motor shaft and operably connected to the jaw assembly to move the gripper jaws.
4 . The system according to 1 , the system further comprising a sampling needle assembly for aspirating a sample from each of the sample cells, a chromatography column for separating analytes of the sample, and a chromatography detector for detecting said analytes of the sample.
5 . The system according to claim 1 , wherein the cell gripper assembly is further configured to rotate one of the sample cells by 360° or more.
6 . The system according to claim 1 , wherein machine vision is used to recognize a variety of barcodes, characters, colors, landmarks, shapes, and/or other unique identifiers used to identify a sample within a sample cell.
7 . The system according to claim 1 , wherein the container and/or cap of each sample cell includes identifying colors, and one color may be utilized to identify the sample cells containing standards as opposed to samples.
8 . A chromatography autosampler comprising a system for identification of sample cells of a sample tray according to claim 1 .
9 . The system according to claim 4 , wherein the computing device further controls the sampling needle assembly and limits the insertion depth of a sample needle of the sampling needle assembly based on a position of the bottom liquid level of a respective sample cell.