Controllable liquid level parallel automatic solid phase extraction instrument

Abstract

The application discloses a controllable liquid level parallel automatic solid phase extraction instrument, and belongs to the field of analytical chemistry sample pretreatment. The extraction instrument comprises a liquid adding system, a solid phase extraction column array unit and a collecting tube device which are electrically connected with a control system. The solid phase extraction column array unit is arranged below the liquid adding system, and the collecting tube device is arranged below the solid phase extraction column array unit. The liquid adding system comprises a liquid adding pipe for adding reagents to the solid phase extraction column array unit. The extraction column has the function of automatically controlling or maintaining the liquid level, and the diameter and height of each component of the extraction column can be flexibly adjusted according to the requirement. The liquid level in the extraction column can be monitored, all the extraction columns can simultaneously and in parallel process samples, and the sample processing efficiency and reliability are improved.

Description

Technical Field

[0001] This invention belongs to the field of analytical chemistry sample pretreatment, and in particular relates to a controllable liquid level parallel automatic solid phase extraction instrument. Background Technology

[0002] Solid-phase extraction (SPE) is a sample separation, purification, and enrichment technique based on the principle of selective adsorption and selective elution in liquid chromatography. Typically, the sample solution is passed through a stationary phase, retaining the target component. Impurities are then eluted with reagents, followed by elution of the target component, thus achieving separation and enrichment. Alternatively, interfering impurities can be selectively adsorbed while the target component elutes; or both impurities and the target component can be adsorbed simultaneously, followed by selective elution of the target component using appropriate reagents.

[0003] The main steps of solid-phase extraction (SPE) include: column pre-equilibration, sample loading, impurity elution, target component elution, and column regeneration. The primary purpose of automated SPE instruments is to replace manual operation with automated procedures.

[0004] Automated solid-phase extraction (SPE) instruments come in a wide variety of types. Based on whether they share extraction columns during the processing of batches of samples, they can be broadly classified into two categories: serial and parallel. Serial SPE instruments sequentially pass the samples to be processed through one or more extraction columns in a chronological order; parallel SPE instruments use independent extraction columns to process each sample.

[0005] Disadvantages of serial solid-phase extraction (SPE): Residue from the previous sample treatment on the shared extraction column can easily lead to cross-contamination of subsequent samples. Advantages of parallel SPE: It avoids cross-contamination between samples compared to serial SPE.

[0006] Publicly available parallel solid-phase extraction (SPE) instruments can be further subdivided into gravity-driven and pressure-driven types based on the driving force of the mobile phase (extraction solvent) flowing in the extraction column. These will be referred to as gravity-driven SPE and pressure-driven SPE, respectively. Gravity-driven SPE relies on the gravity of the mobile phase itself to flow in the extraction column. The flow rate of the mobile phase in the stationary phase (extraction packing) is slow, resulting in a thorough physicochemical exchange process and narrow peak shapes in the obtained SPE chromatograms. Pressure-driven SPE uses positive or negative pressure to drive the mobile phase flow in the extraction column. Based on the pressure application method, it can be further subdivided into two modes: overall pressure and independent positive pressure. Overall pressure mode applies positive pressure to the inlet of all extraction columns or negative pressure to the outlet of all extraction columns; the purpose of overall pressure mode is to accelerate the flow rate of the mobile phase. Independent positive pressure mode applies positive pressure to the inlet of each individual extraction column. The publicly available parallel solid-phase extraction instruments have the following main problems:

[0007] The publicly available gravity solid-phase extraction apparatus and overall pressure solid-phase extraction apparatus cannot control and monitor the liquid level position (hereinafter referred to as liquid level) in each solid-phase extraction column. The solution in the extraction column is prone to run dry, causing air to enter the stationary phase of the extraction column and form air embolism. Air embolism in the extraction column will prevent the subsequently added solution from passing through the extraction column normally.

[0008] Existing independent positive pressure solid-phase extraction (SPME) systems require providing independent positive pressure to each working extraction column. However, the structure of an independent positive pressure system is complex and occupies instrument space. Therefore, existing independent positive pressure SPME systems can only provide positive pressure to a limited number of extraction columns simultaneously. These devices are often called multi-channel SPME systems, where "multi-channel" refers to the number of positive pressure extraction columns the instrument provides simultaneously. Consequently, these independent positive pressure SPME systems need to reuse the same positive pressure system in a time-sharing manner, preventing the simultaneous processing of samples by all solid-phase extraction columns and reducing the efficiency of batch sample processing.

[0009] In summary, the main problems with the disclosed solid phase extraction instruments are: (1) Gravity-driven solid phase extraction instruments and overall pressure solid phase extraction instruments cannot control and monitor the liquid level in each solid phase extraction column. The solution in the extraction column is prone to run dry, causing air to enter the stationary phase of the extraction column and form an air embolism. When an air embolism occurs in the extraction column, the solution added later cannot pass through the extraction column normally. (2) Independent positive pressure solid phase extraction instruments need to reuse the same positive pressure system in a time-sharing manner, which cannot realize the simultaneous processing of samples by all solid phase extraction columns of the instrument. The efficiency of batch processing of samples by the instrument is low. Summary of the Invention

[0010] To address the aforementioned problems in the prior art, this invention aims to provide a controllable liquid level parallel automatic solid phase extraction instrument, which solves the problems of uncontrollable liquid level in the extraction column and inability to monitor the liquid level inside the extraction column in the previously disclosed gravity-driven solid phase extractor.

[0011] To achieve the above-mentioned objectives, the technical solution adopted by the present invention is as follows:

[0012] A controllable liquid level parallel automatic solid phase extraction instrument is provided, which includes a liquid addition system, a solid phase extraction column array unit, and a collection tube device electrically connected to a control system; the solid phase extraction column array unit is arranged below the liquid addition system, and the collection tube device is arranged below the solid phase extraction column array unit; the liquid addition system includes a liquid addition tube for adding reagents to the solid phase extraction column array unit.

[0013] The solid phase extraction column array unit includes a first fixed frame, on which multiple support plates are arranged. Each support plate is equipped with multiple extraction columns and multiple sensors electrically connected to the control system. The sensors are matched one-to-one with the extraction columns and are used to monitor the liquid level of the solution in the extraction column.

[0014] Each extraction column includes a vertically arranged packing tube, the inside of which is used to fill the solid phase extraction stationary phase. The top of the packing tube is detachably connected to a column head tube, and a first hydrophilic sieve plate is installed inside the column head tube.

[0015] The collection tube device includes a collection tube rack movement mechanism electrically connected to the control system. Multiple collection tubes are mounted on the collection tube rack movement mechanism and are located below the extraction column.

[0016] The basic principle of the spliced ​​solid-phase extraction column in this invention is as follows: the liquid addition system can automatically complete the liquid addition operation of the solid-phase extraction column array unit. Due to the setting of the first hydrophilic sieve plate in each extraction column of the solid-phase extraction column array unit, when the liquid level of the hydrophilic aqueous solution in the entire extraction column drops to the surface of the first hydrophilic sieve plate, a strong surface tension is formed on the surface of the first hydrophilic sieve plate, thereby preventing the aqueous solution in the extraction column from continuing to drop. This enables the extraction column to have the function of automatically controlling and maintaining the liquid level of the hydrophilic solution, preventing the liquid level from continuing to drop, avoiding air from entering the packing tube and forming an air embolism. At the same time, the upper surface of the first hydrophilic sieve plate is the monitoring surface of the sensor, which facilitates the monitoring of the liquid level in each extraction column and provides a signal basis for subsequent actions. When the liquid level reaches the designated position, the liquid level sensor sends a signal to realize automatic liquid addition. This solves the problems of uncontrollable liquid level and inability to monitor the liquid level in the extraction column of the previously disclosed gravity-driven solid phase instrument.

[0017] Furthermore, the column head tube is a transparent tube; multiple first arc-shaped slots are evenly spaced along the length of the front sidewall of each support plate, each first arc-shaped slot is vertically arranged and penetrates the support plate, and an extraction column is installed in each first arc-shaped slot, the diameter of the column head tube is matched with the inner diameter of the first arc-shaped slot; each sensor includes an emitting tube and a photosensitive receiving tube respectively arranged on both sides of the first arc-shaped slot; the sensor monitoring light path emitted by the emitting tube is located 1-2 mm above the upper surface of the first hydrophilic sieve plate.

[0018] Furthermore, the column head tube is detachably connected to the top of the packing tube via a first connector. When the extraction column is installed in the first arc groove, the lower end face of the column head tube coincides with the lower end face of the support plate. The bottom of the packing tube is detachably connected to an adapter tube via a second connector, and a second hydrophilic sieve plate is provided inside the second connector.

[0019] Furthermore, a small amount of the same stationary phase as that in the packing tube is added to the upper surface of the first hydrophilic sieve plate; the first and second hydrophilic sieve plates are made of acid and alkali resistant and hydrophilic ultra-high molecular weight polyethylene or hydrophilic modified polytetrafluoroethylene.

[0020] Furthermore, a collimation mechanism is provided between the solid-phase extraction column array unit and the collection tube device. The collimation mechanism includes a second fixing frame located below the adapter tube. The second fixing frame is provided with multiple collimation plates. Each collimation plate has multiple second arcuate slots evenly spaced along its length on its front sidewall. Each second arcuate slot is vertically arranged and penetrates the collimation plate. A collimation tube is vertically installed in each second arcuate slot. The bottom end of the adapter tube is inserted into the collimation tube, and the bottom end of the collimation tube is located at the top of the collection tube.

[0021] In the vertical direction, the second arc-shaped slot is matched with the first arc-shaped slot in a one-to-one relationship, and the axis of the second arc-shaped slot coincides with the axis of the first arc-shaped slot.

[0022] Furthermore, the collection tube rack motion mechanism includes a first motion mechanism, a second motion mechanism, and a drive component electrically connected to the control system. The first motion mechanism includes two horizontally spaced first slide rails, each with a first slider slidably mounted on it, and a first sliding plate fixedly connected to the upper end face of the two first sliders.

[0023] The second motion mechanism includes two horizontally spaced second slide rails, each with a groove. The second slide plate is slidably mounted on the two second slide rails and can move back and forth on the grooves of the second slide rails. The second slide rails are fixed on the first slide plate.

[0024] A large collection pipe rack is detachably installed on the second slide rail, and multiple large collection pipes are installed on the large collection pipe rack.

[0025] The second slide is equipped with a small collection tube rack, which has multiple small collection tubes.

[0026] The motion directions of the first motion mechanism and the second motion mechanism are perpendicular to each other, and the driving component is used to drive the first motion mechanism and the second motion mechanism to move.

[0027] Furthermore, the collection tube rack includes a large collection tube rack and a small collection tube rack that are detachably mounted to the second slide rail and the second slide plate, respectively; the large collection tube rack has multiple large collection tubes arranged in an array; and the small collection tube rack has multiple small collection tubes arranged in an array.

[0028] Furthermore, each support plate includes a mounting plate and a reinforcing plate. The reinforcing plate is disposed on the upper end face of the mounting plate, and both sides of the reinforcing plate are fixedly connected to the first fixing frame. Multiple first slots and multiple second slots are vertically through the front side walls of the mounting plate and the reinforcing plate, respectively. In the vertical direction, the multiple first slots and multiple second slots correspond one-to-one and are coaxially fitted. The first slots and second slots are connected to form a first arc slot. The inner diameter of the first slot is larger than the outer diameter of the column head tube, and the inner diameter of the second slot is smaller than the outer diameter of the column head tube for tight fit. When the extraction column is installed in the first arc slot, the lower end face of the column head tube is on the same plane as the lower end face of the mounting plate, and the emitting tube and the photosensitive receiving tube are located on both sides of the first slot, respectively.

[0029] Furthermore, the liquid addition tube can be accurately positioned above each solid-phase extraction column via a three-dimensional motion mechanism to add extraction reagents into the extraction column.

[0030] The beneficial effects of the present invention are as follows: 1. The controllable liquid level parallel automatic solid phase extraction instrument of the present invention has a controllable liquid level in the extraction column, can monitor the liquid level in the extraction column, and all extraction columns can process samples simultaneously and in parallel, which greatly improves the efficiency and reliability of solid phase extraction of samples.

[0031] 2. This invention provides a controllable liquid level parallel automatic solid-phase extraction instrument. The extraction column has the function of automatically controlling or maintaining the liquid level, and the diameter and height of each component of the extraction column can be flexibly adjusted as needed. The structure of the extraction column, from top to bottom, includes seven components: a column head tube, a first hydrophilic sieve plate, a first connector, a packing tube, a second hydrophilic sieve plate, a second connector, and an adapter tube. The column head tube, packing tube, and adapter tube are connected to the first and second connectors using a quick-insertion connection method: the outer diameter of the upper end of the first connector is inserted into the inner diameter of the lower end of the column head tube, the lower end of the first connector is inserted into the inner diameter of the upper end of the packing tube, the outer diameter of the upper end of the second connector is inserted into the inner diameter of the lower end of the packing tube, and the outer diameter of the upper end of the adapter tube is inserted into the inner diameter of the lower end of the second connector. The solid-phase extraction stationary phase is filled in the packing tube, and the upper surfaces of the first and second connectors are respectively equipped with the first and second hydrophilic sieve plates. The column head tube is made of transparent materials, such as PFA, FEP, quartz glass, or borosilicate glass. By changing the outer diameter of the lower end of the first connector and the outer diameter of the upper end of the second connector, packing tubes with different inner diameters can be matched. The length of the packing tube can be flexibly adjusted according to the amount of stationary phase used in solid-phase extraction. The length of the adapter tube can be adjusted so that the total length of the lower end face of the adapter tube and the upper end face of the column head tube remains constant, ensuring that the positions of the upper end face of the column head tube and the lower end face of the adapter tube remain unchanged within the instrument. The first and second hydrophilic sieve plates are made of acid- and alkali-resistant, hydrophilic ultra-high molecular weight polyethylene or hydrophilic modified polytetrafluoroethylene. Due to the hydrophilic effect of the first hydrophilic sieve plate, when the polar aqueous solution level in the extraction column drops to the surface of the first hydrophilic sieve plate, a strong surface tension is formed on the sieve plate surface, thereby preventing the aqueous solution in the extraction column from continuing to drop. This gives the solid-phase extraction column the function of automatically controlling and maintaining the liquid level of the polar solution, preventing further drop in liquid level and avoiding air embolism by entering the packing tube. This extraction column differs from existing extraction columns in that it has the characteristic of automatically controlling and maintaining the liquid level of the solution in the extraction column at the surface of the first hydrophilic sieve plate.

[0032] Meanwhile, a small amount of the same stationary phase as that in the packing tube is added to the upper surface of the first hydrophilic sieve plate, so that a thin covering layer is formed on the upper surface of the first hydrophilic sieve plate. The thickness of the covering layer is 1-2 mm. This small amount of stationary phase keeps the surface of the first hydrophilic sieve plate wet, prevents the upper surface of the first hydrophilic sieve plate from being exposed to the air and prevents air from seeping into the surface of the first hydrophilic sieve plate to form an air embolism.

[0033] 3. The present invention provides a controllable liquid level parallel automatic solid phase extraction instrument, wherein the support plate includes two independent components: a mounting plate and a reinforcing plate. The mounting plate can be made of a material with good toughness and self-lubricating properties, which can prevent the outer surface of the extraction column from being worn during installation and extend the service life of the extraction column. The reinforcing plate is made of a material with good rigidity, which can maintain the structural stability of the mounting plate and reinforcing plate assembly, improve the overall structural strength of the support plate, and prevent the mounting plate from deforming during use.

[0034] 4. The present invention provides a controllable liquid level parallel automatic solid phase extraction instrument. When the extraction column is installed in the first arc groove, the lower end face of the first connector coincides with the lower end face of the support plate, so that the installation positions of multiple extraction columns are consistent, and the sensor monitoring optical path is located exactly 1-2 mm above the upper surface of the first hydrophilic sieve plate inside the extraction column, thus solving the problem of uneven liquid levels in multiple extraction columns disclosed in the prior art.

[0035] 5. A controllable liquid level parallel automatic solid-phase extraction instrument of the present invention includes a collimation mechanism between the solid-phase extraction column array unit and the collection tube device. The collimation mechanism has a collimation tube for connecting the adapter tube and the collection tube, ensuring the outlet of the adapter tube is positioned at a designated location on the lower collection tube device. The inner diameter of the collimation tube is larger than the outer diameter of the extraction column adapter tube, facilitating insertion of the adapter tube into the collimation tube. The collimation tube is fixed to a collimation plate to ensure it is vertical. The collimation tube is easily disassembled for cleaning.

[0036] 6. The present invention provides a controllable liquid level parallel automatic solid phase extraction instrument. By setting the collection tube in a large collection tube rack and a small collection tube rack, the large collection tube rack and the small collection tube rack do not need to be used simultaneously. When the solid phase extraction instrument processes batch samples, the large collection tube rack is used; when the solid phase extraction instrument explores the elution curve conditions of the extraction column, the small collection rack is used. This allows for the realization of two working modes on the same set of equipment: batch sample processing and extraction column elution curve condition research. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of a solid-phase extraction instrument in batch sample processing mode.

[0038] Figure 2 This is a schematic diagram of the solid phase extraction instrument in the working mode of the extraction column elution curve.

[0039] Figure 3 This is a schematic diagram of a structure with multiple extraction columns mounted on a single support plate.

[0040] Figure 4 This is a top view of the mounting plate.

[0041] Figure 5 This is a top view of the reinforcing plate.

[0042] Figure 6 This is a cross-sectional view of a single extraction column.

[0043] Figure 7 This is a schematic diagram of the structure of the tube rack motion mechanism.

[0044] Among them, 1-liquid addition tube; 2-support plate; 21-reinforcing plate; 211-second slot; 22-mounting plate; 221-first slot; 23-extraction column; 231-column head tube; 232-first connector; 233-packing tube; 234-second connector; 235-adapter tube; 236-first hydrophilic sieve plate; 237-second hydrophilic sieve plate; 24-first fixing frame; 25-sensor; 251-transmitting tube; 252-receiving tube; 253-sensor monitoring optical path; 31-collimating plate; 32-collimating tube; 33-second fixing frame; 41-first slider; 42-first slide plate; 43-first slide rail; 44-second slide rail; 45-large collection tube rack; 451-large collection tube; 46-second slide plate; 47-small collection tube rack; 471-small collection tube. Detailed Implementation

[0045] The specific embodiments of the present invention are described below to enable those skilled in the art to understand the present invention. However, it should be understood that the present invention is not limited to the scope of the specific embodiments. For those skilled in the art, various changes are obvious as long as they are within the spirit and scope of the present invention as defined and determined by the appended claims. All inventions utilizing the concept of the present invention are protected.

[0046] like Figures 1-7 As shown, the present invention provides a controllable liquid level parallel automatic solid phase extraction instrument, which includes a liquid addition system electrically connected to the control system, a solid phase extraction column 23 array unit and a collection tube device; the solid phase extraction column 23 array unit is arranged below the liquid addition tube 1, and the collection tube device is arranged below the solid phase extraction column 23 array unit; the liquid addition system includes a liquid addition tube 1 for adding reagents to the solid phase extraction column 23 array unit.

[0047] The solid phase extraction column 23 array unit includes a first fixing frame 24, on which multiple support plates 2 are arranged. Each support plate 2 is equipped with multiple extraction columns 23 and multiple sensors 25 electrically connected to the control system. The sensors 25 are matched one-to-one with the extraction columns 23 and are used to monitor the liquid level of the solution in the extraction column 23.

[0048] Each extraction column 23 includes a vertically arranged packing tube 233, the interior of which is used to fill the solid phase extraction stationary phase. The top of the packing tube 233 is detachably connected to a column head tube 231, and a first hydrophilic sieve plate 236 is provided inside the column head tube 231.

[0049] The collection tube device includes a collection tube frame movement mechanism electrically connected to the control system. Multiple collection tubes are arranged on the collection tube frame movement mechanism, and the multiple collection tubes are located below the array of extraction columns 23.

[0050] The basic principle of the spliced ​​solid-phase extraction column 23 in this invention is as follows: the liquid addition system can automatically complete the liquid addition operation of the solid-phase extraction column 23 array unit. Specifically, the liquid addition system selects different types of eluents through a fluid distribution system, such as a solenoid valve, pneumatic valve, rotary switching valve, multi-position valve, etc., and then provides power through a fluid power system, such as a syringe pump, plunger pump, peristaltic pump, metering pump, etc., to quantitatively extract specific eluents. Then, the required eluents are quantitatively added to the inlet of the solid-phase extraction column 23 through the liquid addition pipe 1. The liquid addition pipe 1 is accurately positioned to the inlet of the target extraction column 23 in the solid-phase extraction column 23 array through a three-dimensional motion mechanism.

[0051] In the solid-phase extraction column 23 array unit, due to the setting of the first hydrophilic sieve plate 236, when the liquid level of the hydrophilic aqueous solution in the entire extraction column 23 drops to the surface of the first hydrophilic sieve plate 236, a strong surface tension is formed on the surface of the first hydrophilic sieve plate 236, thereby preventing the aqueous solution in the extraction column 23 from continuing to drop. This enables the extraction column 23 to have the function of automatically controlling and maintaining the liquid level of the hydrophilic solution, preventing the liquid level from continuing to drop, and avoiding air from entering the packing tube 233 and forming an air embolism. At the same time, the upper surface of the first hydrophilic sieve plate 236 is the monitoring surface of the sensor 25, which facilitates the monitoring of the liquid level in each extraction column 23 and provides a signal basis for subsequent instrument actions. When the liquid level reaches the designated position, the liquid level sensor 25 sends a signal to realize automatic liquid addition, which solves the problems of uncontrollable liquid level and inability to monitor the liquid level in the extraction column 23 of the previously disclosed gravity-driven solid phase instrument.

[0052] Specifically, such as Figure 1 , Figure 2 and Figure 7 As shown, the collection tube device collection tube frame motion mechanism includes a first motion mechanism, a second motion mechanism, and a drive component electrically connected to the control system. The first motion mechanism includes two horizontally spaced first slide rails 43, each of which has a first slider 41 slidably mounted on it. The upper end face of the two first sliders 41 is fixedly connected to a first sliding plate 42.

[0053] The second motion mechanism includes two horizontally spaced second slide rails 44, and the second slide plate 46 is slidably mounted on the two second slide rails 44 and can move back and forth on the slide grooves of the second slide rails 44.

[0054] The first and second motion mechanisms move in directions perpendicular to each other. Specifically, the first motion mechanism moves in a forward-backward direction, while the second motion mechanism moves in a left-right direction. By controlling the first and second motion mechanisms, the collection tube rack on them can be moved to any position on a horizontal plane.

[0055] The drive unit is used to drive the first and second motion mechanisms. The drive unit can be a motor with a pulley or a linear motor, etc., to drive the first and second motion mechanisms.

[0056] The collection tube rack includes a large collection tube rack 45 and a small collection tube rack 47, which are detachably connected to the second slide rail 44 and the second slide plate 46, respectively. Multiple large collection tubes 451 are arranged in an array on the large collection tube rack 45, and multiple small collection tubes 471 are arranged in an array on the small collection tube rack 47. The large collection tube rack 45 and the small collection tube rack 47 do not need to be used simultaneously. When the solid-phase extraction instrument processes batch samples, the large collection tube rack 45 is installed on the second slide rail 44; when the solid-phase extraction instrument is used to investigate the elution curve conditions of the extraction column 23, the large collection tube rack 45 is detached from the second slide rail 44, and the small collection tube rack is then installed on the second slide plate 46. Both batch sample processing and extraction column 23 elution curve condition research can be achieved on the same solid-phase extraction instrument.

[0057] Specifically, such as Figures 3-5 As shown, the column head tube 231 is a transparent tube; multiple first arc-shaped slots are evenly spaced along the length of the front sidewall of each support plate 2, each first arc-shaped slot is vertically arranged and penetrates the support plate 2, and an extraction column 23 is installed in each first arc-shaped slot. The diameter of the column head tube 231 matches the inner diameter of the first arc-shaped slot. The above arrangement facilitates the installation and removal of the extraction column 23. Each sensor 25 includes an emitting tube 251 and a photosensitive receiving tube 252 respectively arranged on both sides of the first arc-shaped slot; the sensor monitoring light path 253 emitted by the emitting tube 251 is located 1-2 mm above the upper surface of the first hydrophilic sieve plate 236.

[0058] Preferably, each support plate 2 includes a mounting plate 22 and a reinforcing plate 21. The reinforcing plate 21 is disposed on the upper end face of the mounting plate 22. Both sides of the reinforcing plate 21 are fixedly connected to the first fixing frame 24. Multiple first slots 221 and multiple second slots 211 are vertically through the front sidewalls of the mounting plate 22 and the reinforcing plate 21, respectively. In the vertical direction, the multiple first slots 221 and multiple second slots 211 correspond one-to-one and are coaxially fitted. The first slots 221 and the second slots 211 are connected to form a first arc slot. The inner diameter of the first slot 221 is larger than the outer diameter of the column head tube 231, and the inner diameter of the second slot 211 is tightly fitted with the outer diameter of the column head tube 231. When the extraction column 23 is installed in the first arc slot, the lower end face of the column head tube 231 is at the same horizontal plane as the lower end face of the mounting plate 22. The emitting tube 251 and the photosensitive receiving tube 252 are located on both sides of the first slot 221, respectively. The support plate 2 includes two independent components: a mounting plate 22 and a reinforcing plate 21. The mounting plate 22 can be made of a material with good toughness and self-lubricating properties, which can prevent the outer surface of the extraction column 23 from being worn during installation and extend the service life of the extraction column 23. The reinforcing plate 21 is made of a material with good rigidity, which can maintain the structural stability of the assembly of the mounting plate 22 and the reinforcing plate 21, improve the overall structural strength of the support plate 2, and prevent the mounting plate 22 from deforming during use.

[0059] like Figure 6 As shown, the column head tube 231 is detachably connected to the top of the packing tube 233 via the first connector 232. When the extraction column 23 is installed in the first arc-shaped groove, the lower end face of the column head tube 231 coincides with the lower end face of the support plate 2. The bottom of the packing tube 233 is detachably connected to an adapter tube 235 via a second connector 234. A second hydrophilic sieve plate 237 is provided inside the second connector 234. A small amount of the same fixed phase as that in the packing tube 233 is added to the upper surface of the first hydrophilic sieve plate 236. The first hydrophilic sieve plate 236 and the second hydrophilic sieve plate 237 are made of acid and alkali resistant and hydrophilic ultra-high molecular weight polyethylene or hydrophilic modified polytetrafluoroethylene.

[0060] The extraction column 23 has the function of automatically controlling or maintaining the liquid level, and the diameter and height of each component of the extraction column 23 can be flexibly adjusted as needed. The structure of the extraction column 23, from top to bottom, includes a column head tube 231, a first hydrophilic sieve plate 236, a first connector 232, a packing tube 233, a second hydrophilic sieve plate 237, a second connector 234, and an adapter tube 235, for a total of 7 components. The column head tube 231, packing tube 233, and adapter tube 235 are connected to the first connector 232 and the second connector 234 using a quick-insertion connection method: the outer diameter of the upper end of the first connector 232 is inserted into the inner diameter of the lower end of the column head tube 231, the lower end of the first connector 232 is inserted into the inner diameter of the upper end of the packing tube 233, the outer diameter of the upper end of the second connector 234 is inserted into the inner diameter of the lower end of the packing tube 233, and the outer diameter of the upper end of the adapter tube 235 is inserted into the inner diameter of the lower end of the second connector 234; the stationary phase for solid-phase extraction is filled in the packing tube 233, and the upper surfaces of the first and second connectors are respectively equipped with the first and second hydrophilic sieve plates; the column head tube 231 is made of transparent materials, such as PFA, FEP, quartz glass, or borosilicate glass. By changing the outer diameter of the lower end of the first connector 232 and the outer diameter of the upper end of the second connector 234, packing tubes 233 with different inner diameters can be matched. The length of the packing tube 233 can be flexibly adjusted according to the amount of solid-phase extraction packing used. The length of the adapter tube 235 can be adjusted so that the total length between the lower end face of the adapter tube 235 and the upper end face of the column head tube 231 remains constant, ensuring that the positions of the upper end face of the column head tube 231 and the lower end face of the adapter tube 235 remain unchanged within the instrument. Due to the hydrophilic effect of the first hydrophilic sieve plate 236, when the liquid level of the polar aqueous solution in the extraction column 23 drops to the surface of the first hydrophilic sieve plate 236, a strong surface tension is formed on the sieve plate surface, thereby preventing the aqueous solution in the extraction column 23 from continuing to drop. This gives the solid-phase extraction column 23 the function of automatically controlling and maintaining the liquid level of the aqueous solution, preventing further drop in liquid level, and avoiding air entering the packing tube 233 to form an air embolism. The extraction column 23 differs from existing extraction columns 23 in that it has the characteristic of automatically controlling and maintaining the solution in the extraction column 23 at the surface of the first hydrophilic sieve plate 236.

[0061] At the same time, a small amount of the same fixed phase as that in the packing tube 233 is added to the upper surface of the first hydrophilic sieve plate 236, so that a thin covering layer is formed on the upper surface of the first hydrophilic sieve plate 236. The thickness of the covering layer is 1-2 mm. The small amount of fixed phase here keeps the surface of the first hydrophilic sieve plate 236 wet, prevents the upper surface of the first hydrophilic sieve plate 236 from being exposed to the air and prevents air from seeping into the surface of the first hydrophilic sieve plate 236 to form an air embolism.

[0062] When the extraction column 23 is installed in the first arc-shaped groove, the upper end of the column head 231 is first horizontally pushed into the first arc-shaped groove. Then, the extraction column 23 is moved upwards as a whole until the lower end face of the column head 231 is at the same level as the lower end face of the support plate 2. This ensures that the installation positions of multiple extraction columns 23 are consistent, and that the sensor monitoring optical path 253 is located exactly 1-2 mm above the upper surface of the first hydrophilic sieve plate 236 inside the extraction column 23. This solves the problem of inconsistent liquid levels inside the existing extraction columns 23. Preferably, but not limited to, such as Figure 1 and Figure 2 As shown, a collimation mechanism is provided between the solid phase extraction column 23 array unit and the collection tube device. The collimation mechanism includes a second fixing frame 33 located below the adapter tube 235. The second fixing frame 33 is provided with multiple collimation plates 31. Multiple second arc grooves are evenly arranged along the length direction on the front side wall of each collimation plate 31. Each second arc groove is vertically arranged and penetrates the collimation plate 31. A collimation tube 32 is vertically installed in each second arc groove. The bottom end of the adapter tube 235 is located inside the collimation tube 32, and the bottom end of the collimation tube 32 is located at the top of the collection tube.

[0063] In the vertical direction, the second arc-shaped slot is matched with the first arc-shaped slot in a one-to-one relationship, and the axis of the second arc-shaped slot coincides with the axis of the first arc-shaped slot.

[0064] The collimation tube 32 in the collimation mechanism is used to connect the adapter tube 235 and the collection tube, keeping the outlet of the adapter tube 235 positioned at the designated location of the collection tube device below. The inner diameter of the collimation tube 32 is larger than the outer diameter of the adapter tube 235 of the extraction column 23, facilitating the insertion of the adapter tube 235 into the collimation tube 32; the collimation tube 32 is fixed on the collimation plate 31 to ensure that the collimation tube 32 is in a vertical state; the second arc-shaped slot hole allows for easy disassembly of the collimation tube 32, facilitating cleaning of the collimation tube 32.

[0065] This solid-phase extraction instrument can operate in two modes: the first mode is for processing batch samples, and the second mode is for performing elution curve operations on a few specified extraction columns located in the middle of the extraction column array.

[0066] When this solid phase extraction instrument is used in the first working mode, multiple rows or all of the extraction columns 23 can be installed to perform parallel solid phase extraction operations on multiple samples. At this time, a large collection tube rack 45 is installed below the extraction column array to collect the elution components of each sample (i.e. each extraction column).

[0067] When this solid phase extraction instrument is used in the second working mode, the elution curve operation is specified for several extraction columns located in the middle of the extraction column array. At this time, a small collection tube rack 47 is installed below the extraction column array to collect each eluent in sequence at specified volume intervals (such as 1.0 or 0.5 mL).

[0068] In summary, the controllable liquid level parallel automatic solid phase extraction instrument of the present invention has a controllable liquid level in the extraction column 23, can monitor the liquid level in the extraction column 23, and can process samples simultaneously and in parallel in all extraction columns 23. It can realize two working modes, namely batch sample processing and extraction column 23 elution curve condition study, on the same set of equipment, thereby improving sample processing efficiency and reliability.

Claims

1. A controllable liquid level parallel automatic solid phase extraction instrument, characterized in that, The system includes a liquid addition system electrically connected to a control system, a solid-phase extraction column array unit, and a collection tube device; the solid-phase extraction column array unit is located below the liquid addition system, and the collection tube device is located below the solid-phase extraction column array unit; the liquid addition system includes a liquid addition tube for adding reagents to the solid-phase extraction column array unit. The solid phase extraction column array unit includes a first fixing frame, on which multiple support plates are arranged. Each support plate is provided with multiple extraction columns and multiple sensors electrically connected to the control system. The sensors are matched one-to-one with the extraction columns and are used to monitor the liquid level of the solution in the extraction column. Each extraction column includes a vertically arranged packing tube, the inside of which is filled with a solid phase extraction stationary phase. A column head tube is detachably connected to the top of the packing tube, and a first hydrophilic sieve plate is provided inside the column head tube. The same stationary phase as that in the packing tube is added to the upper surface of the first hydrophilic sieve plate. The collection tube device includes a collection tube frame movement mechanism electrically connected to the control system. The collection tube frame movement mechanism is provided with multiple collection tubes, which are located below the extraction column.

2. The controllable liquid level parallel automatic solid phase extraction instrument according to claim 1, characterized in that, The column head tube is a transparent tube; multiple first arc-shaped slots are evenly spaced along the length of the front sidewall of each support plate, each first arc-shaped slot is vertically arranged and penetrates the support plate, and an extraction column is installed in each first arc-shaped slot, the diameter of the column head tube matching the inner diameter of the first arc-shaped slot; each sensor includes an emitting tube and a photosensitive receiving tube respectively arranged on both sides of the first arc-shaped slot; the sensor monitoring light path emitted by the emitting tube is 1~2mm higher than the upper surface of the first hydrophilic sieve plate.

3. The controllable liquid level parallel automatic solid phase extraction instrument according to claim 2, characterized in that, The column head tube is detachably connected to the top of the packing tube via a first connector. When the extraction column is installed in the first arc groove, the lower end face of the column head tube coincides with the lower end face of the support plate. The bottom of the packing tube is detachably connected to an adapter tube via a second connector, and a second hydrophilic sieve plate is provided inside the second connector.

4. The controllable liquid level parallel automatic solid phase extraction instrument according to claim 3, characterized in that, The first and second hydrophilic sieve plates are made of acid and alkali resistant and hydrophilic ultra-high molecular weight polyethylene or hydrophilic modified polytetrafluoroethylene.

5. The controllable liquid level parallel automatic solid phase extraction instrument according to claim 4, characterized in that, A collimation mechanism is provided between the solid-phase extraction column array unit and the collection tube device. The collimation mechanism includes a second fixing frame located below the adapter tube. The second fixing frame is provided with multiple collimation plates. Each collimation plate has multiple second arc-shaped slots evenly spaced along its length on its front sidewall. Each second arc-shaped slot is vertically arranged and penetrates the collimation plate. A collimation tube is vertically installed in each second arc-shaped slot. The bottom end of the adapter tube is located inside the collimation tube, and the bottom end of the collimation tube is located at the top of the collection tube. In the vertical direction, the second arc-shaped slot and the first arc-shaped slot are matched one-to-one, and the axis of the second arc-shaped slot coincides with the axis of the first arc-shaped slot.

6. The controllable liquid level parallel automatic solid phase extraction instrument according to claim 5, characterized in that, The collection tube rack motion mechanism includes a first motion mechanism, a second motion mechanism, and a drive component electrically connected to the control system. The first motion mechanism includes two horizontally spaced first slide rails, each of which has a first slider slidably mounted on it. The upper surfaces of the two first sliders are fixedly connected to a first sliding plate. The second motion mechanism includes two horizontally spaced second slide rails, which are fixedly mounted on the first slide plate and move back and forth synchronously with the first slide plate; a second slide plate is mounted on the two second slide rails, and the second slide plate can move back and forth along the slide grooves on the two second slide rails; a collection tube rack is provided on the second slide plate. The first motion mechanism and the second motion mechanism move in directions perpendicular to each other, and the driving member is used to drive the first motion mechanism and the second motion mechanism to move.

7. The controllable liquid level parallel automatic solid phase extraction instrument according to claim 6, characterized in that, The collection tube rack includes a large collection tube rack detachably connected to the second slide rail and a small collection tube rack detachably connected to the second slide plate; multiple large collection tubes are arranged in an array on the large collection tube rack; multiple small collection tubes are arranged in an array on the small collection tube rack; the large collection tube rack and the small collection tube rack are not installed in the instrument at the same time: when the instrument is used in the first working mode, the large collection tube rack is installed; when the instrument is used in the rinsing curve mode, the small collection tube rack is installed.

8. The controllable liquid level parallel automatic solid phase extraction instrument according to claim 2, characterized in that, Each of the support plates includes a mounting plate and a reinforcing plate. The reinforcing plate is disposed on the upper end face of the mounting plate, and both sides of the reinforcing plate are fixedly connected to the first fixing frame. Multiple first slots and multiple second slots are vertically through the front sidewalls of the mounting plate and the reinforcing plate, respectively. In the vertical direction, the multiple first slots and multiple second slots correspond one-to-one and are coaxially fitted. The first slots and second slots are connected to form a first arc-shaped slot. The inner diameter of the first slot is larger than the outer diameter of the column head tube, and the inner diameter of the second slot is tightly fitted with the outer diameter of the column head tube. When the extraction column is installed in the first arc-shaped slot, the lower end face of the column head tube of the extraction column is on the same plane as the lower end face of the mounting plate. The emitting tube and the photosensitive receiving tube are respectively located on both sides of the first slot.

9. The controllable liquid level parallel automatic solid phase extraction instrument according to claim 2, characterized in that, The liquid addition tube adds reagents to the solid phase extraction column array unit through a three-dimensional motion mechanism.

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