SU1120169A1 - Automatic metering device for liquid chromatograph - Google Patents

Abstract

I, AUTOMATIC DISPENSER FOR LIQUID CHROMATOGRAPH, containing an input and sampling system, a control system, an aspirator, a conveyor with a sample vessel and a flushing system, and with an improved efficiency circuit separation of the exclusion of the transition and the economy of the pro- filled in the form of a manipulator mounted for rotation and. interaction with the sample introduction unit, with a capillary tube inside the manipulator for taking and entering the sample. 2. The dispenser according to Claim 1, of which is a shchi and with the fact that the lower end of the capillary tube is installed inside two telescopic tubes equipped with a spring and a bolt. 3. The dispenser according to claim 1, wherein the washing system is designed as a glass with an axial hole, in the lower part of which a spring-loaded cap is fitted eccentrically to the hole, equipped with a socket for setting the capillary end in the upper a portion of the side surface of the glass is provided with a liquid inlet for washing the capillary.

Description

1 The invention relates to the automatic dispensing of precise amounts of liquid into a stream under high pressure, and more specifically to the design of automatic sample dispensers for a high pressure liquid chromatograph. A known automatic sample dispenser containing a metering loop, a sampling tube, a vessel with a probe. Disadvantages of the dispenser are smearing the sample when it is washed out of the loop into the chromatograph column, there is too much sample to fill the loop, there is insufficient external washing of the sample needle and the relatively complex (and therefore unreliable) design of the sample vessels. Closest to the proposed technical entity is a liquid chromatograph shutter containing a manipulator connected to a sampling tube DG1, an aspirator, a sample inlet system for the column, and a control system. The system for entering the column contains a switchable loop valve. For flushing the extraction needle on the conveyor with the sample vessels, an additional liquid vessel is provided, washing the extraction tube and the metering loop. The sample is sucked into the loop with a syringe 2. Since the metering loop is connected to the extraction needle with a capillary of a certain length, the discharge required to fill the loop can cause evaporation of volatile samples. The disadvantages of the known dispenser are also excess sample when filling the loop, complex design of the sample vessels, insufficient external washing of the sampling needle and washing of the sample when it is washed out of the loop into the chromatograph column. The purpose of the invention is to increase the equipment efficiency of the separation, to eliminate the transition of traces of the previous sample to the next one and to save the sample. The goal is achieved by the fact that in an automatic metering device for a liquid chromatograph, which contains an injection and sampling system, a control system, a suction device, a conveyor with a sample vessel and a washing system, an injection system 92 and sampling is made in the form of a rotator-mounted manipulator. and interacting with the sample introduction unit, with a capillary tube inside the manipulator for taking and entering the sample. The lower end of the capillary tube is installed inside two telescopic tubes equipped with a spring and a bolt. The washing system is made in the form of a glass with an axial hole, in the lower part of which a spring-loaded bell is installed eccentrically to the hole, equipped with a socket for mounting the end of the capillary; 1 shows the dispenser, a general view; FIG. 2 shows the location of the input unit, the washing unit for the end of the capillary and the conveyor with vessels with respect to the axis of rotation of the manipulator; on fig.Z - node I on fig.I; figure 4 - node m in figure 1) figure 5 - position of the dispenser at the beginning of the cycle; Figure 6 shows the position of the manipulator after washing the needle; 7 - the same, before sampling; on Fig - then.zhe, when sampling; figure 9 - the same, after the selection of the prrba; figure 10 is the same, before washing the needle; in Fig. II - the same above the input node; on Fig - the same, before switching the valve of the sluice chamber of the input unit; on Fig the position of the dispenser when you enter the sample into the column; on Fig - position manipulator after entering the sample. An automatic liquid chromatograph metering device contains a manipulator I with a capillary 2 for sampling and sample introduction, an aspirator 3, a conveyor 4 with sample vessels 5, a sample introduction unit 6 into the column, a capillary end washing unit 7, a source 8 of liquid for washing (pump), actuator 9 of manipulator 1, actuator 10. the conveyor 4, the actuator 1I switching the input unit 6, the distributor 12 of the element flow from the pump 13, the pneumatic distributors 14 and 15, the control unit 16, the base 17. The manipulator torus 1 consists of the pneumatic cylinder 18 moving on the rod 19 in which the channels 20 and 21 for supplying compressed gas to different cavities of the cylinder 18. The rod 19, together with the cylinder 3, is mounted on the bearing 22 and provided with a stop 23 of the axis of movement. The cylinder 18 is connected via a bracket 24 to an outer tube 25 of a pair of telescopic tubes. A tube 26 is installed inside the tube 25, on the bottom of which a spring 27 is supported. The capillary tube 2 is attached to the tube 25 by means of a pressure nipple 28. A shutter 31 is attached to the outer tube 25 in the notch 29 on the axis 30 to fix the inner telescopic tube in the upper position. The spring 32 supports the shutter 31 in the fixation position of the inner tube. Part of the capillary 2 is coiled into the coil 33 to achieve flexibility when turning the manipulator 1 around the axis of the rod 19, as well as to place the sample in the capillary 2. The rod 19 together with the cylinder 18 is rotating around its axis 180, and the cylinder 18 is made moving on the rod 19 vertically, with the individual positions of the manipulator 1 being determined by limit switches (not shown). The rod 19 is connected to the pneumatic distributor 14. The suction device 3 consists of a cylinder 34, inside which is located a rod 35. The stroke length of the rod 35 is determined by the position of the micrometer screw 36. The rod 35 is held in its lower position by means of a spring 37 and is made moving upwards supply of compressed gas from distributor 15. The suction chamber 38 is connected to the eluent pump through distributor 12. Conveyor 4 consists of a disk 39, in slots 40 of which vessels 5 are located for the sample. The vessels 5 (Fig. 4) are spaced out of the body 41 and the cap 42, between which the washer 43 and the membrane 44 are located. Internal configuration; The case 41 of the vessel 5 is made in the form of two cylinders arranged eccentrically relative to each other in such a way that the axis of the lower, smaller cylinder is shifted relative to the axis of the vessel. All details of the vessel 5 are made of chemically resistant material. The vessels 5 are supported in the sockets 40 by the springs 45. The conveyor 4 receives rotation from the actuator 10. The sample introduction unit 6 consists of a body 46, in which a rotating flap 47 is located. A seal 49-4 is installed between the flap 47 and the rim 48. Channel the column passes through the valve 47, the seal 49, the seal 50 and the cap 51. The valve 47 receives rotation from the actuator 11. The washing unit 7 for washing the end of the capillary 2 (FIG. 3) consists of a housing 52, in which there is a slot (hole) 53, the diameter of which is by some value greater than the diameter of the end of the capillary 2. In The lower part of the housing 52 is a cap 54, which is spring-loaded by a spring 55, which in turn rests in the socket 56. The cap 54 is provided with a socket for the end of the end of the capillary 2 and an orifice 57. A channel 58 is provided for supplying flushing fluid from the source 8, which can use, for example, a diaphragm pump driven by an electromagnet. Drives 9-11 can be electromechanical or pneumatic. The conveyor 4, the input unit 6 and the washing unit 7 in a plane perpendicular to the axis of the rod I9 of the manipulator I are arranged as shown in Fig. 2. A plate 59 with an aperture 60 is located above the conveyor 4. In Fig. 5, a release element 61 of the shutter 31 is shown. In Fig. 1, reference numeral 62 denotes the line element, reference numeral 63 denotes the line of compressed gas and position 64 of the electric control line. Automatic metering device for liquid chromatograph works as follows. At the beginning of the operating cycle, the manipulator I is in the position when the end of the capillary in the industrial unit 7 (Fig. 5). The chromatograph was at this time washing the column or elution of the previous sample. After a command from the control unit 16, the distribution is switched, the body 15 and the element are displaced from the aspirator 3, and hence from the capillary 2. The amount of the eluent being forced out, i.e. and the sample to be taken is installed at the start of operation with a micrometer screw 36. Then the pump 8 is turned on and the end of the capillary 2 is washed in the eluent stream in some other solvent which dissolves possible traces of the sample. Since the opening 53 in the housing 52 is only slightly larger than the diameter of the capillary 2, a high linear velocity flow is obtained and, therefore, efficient washing. Even before the end of the washing, the manipulator 1, at the command of the block 16, switches the distributor 14 to move upwards. In this way, the socket in the cap 54 is also flushed. Since the release member 61 holds the shutter 31 in the off position, the inner telescopic tube 26 under the influence of the spring 27 as the manipulator 1 moves upwards is pushed up until it rests against the protrusion of the outer tube 25. After reaching the position (Fig. 6), the manipulator 1 is turned by means of the actuator 9 by 90 to a position above the conveyor 4 (Fig. 7). Thereafter, by switching the distributor 14, the manipulator 1 is deflated downward. The end of the capillary 2 passes through the hole 60 in the plate 59 and through the membrane 44 into the sample vessel. The telescopic Tpy6ka 26 rests on the plate 59 and moves inside the tube 25 until it is fixed in the extended position by the shutter 3I. The telescopic tubes 25 and 26 accurately determine the location of the end of the capillary 2 and prevent it from bending. At the end of the downward movement (phn.4) of the capillary 2, the end of the latter rests on the cone-shaped bottom of the vessel 5 and, if necessary, the vessel moves downwards. The axis of the lower cylinder of the vessel body 41 with a cone-shaped bottom is displaced relative to the axis of the main cylinder by a certain amount. This ensures that, in the lower position, the hole in the end of capillary 2 does not close. The use of vessels with an internal configuration of eccentric cylinders with a smaller diameter allows the same vessel to be used for large quantities of sample as well as for microscopic quantities ( 510 µl. When the manipulator 1 reaches the lower extreme position, the distributor 13 is switched and the rod 35 of the aspirator 3 is moved back by the action of the spring 37, soaking up the sample in the capillary p 2. The inner diameter of the capillary 2 is chosen such that the prescribed maximum dose is placed only a few centimeters from the end of the capillary 2. At the same time, the vacuum required for the sample to be drawn is at a slight 696 and does not cause evaporation of volatile samples. After that, the distributor 14 switches the manipulator 1 up. the tube 26 is fixed by the shutter 31 in the retracted position, then a bare capillary tube 2 comes out of the vessel. This prevents the trace of the sample from reaching the bottom of the tube 26, especially the walls of the lower opening for the passage of capillary 2. Paul The output of the manipulator I after sampling is shown in Fig.9. Now the manipulator 2 is turned with the help of the actuator 9 back B to the position in which the end of the capillary 2 remains above the washing unit 7 (Fig. 10). By switching the distributor I4, the manipulator I goes down and the end of the capillary 2 passes into the washing unit 7. In the lower position, the release member 61 moves the shutter. 31, when the downward movement is stopped, the pump 8 is supplied with the washing liquid. The capillary end 2 is supported in the socket in the cap 54, which prevents the sample from washing out from the end of capillary 2. Manipulator I moves up only after turning off the flow from pump 8. When you move manipulator 1 up, the telescopic tube 26 moves out under the influence of spring 27 from the outside. At the end of the operation, the manipulator 1 takes the position shown in Fig. 6. After this, the actuator 9 turns the manipulator 1 into a position in which the end of the capillary 2 remains above the channel of the input unit 6 (Fig. 11) .. By switching the distributor 14, the manipulator 1 moves down to the position shown in Fig. 12. The end of the capillary 2 passes through the opening in the seal 49, and then the downward movement stops. To ensure tightness, the opening in the seal 49 is selected such that the capillary tube 2 is very tight. The telescope tubes 26 and 25 prevent the bending of the capillary 2 at this time. With the next operation, the valve 47 of the input unit is turned by means of the actuator 11 to a position in which a straight channel is formed in the column. Then the manipulator 1 moves down to failure (Fig. 13). The telescopic tube 26, which rests on the cap 51, moves

, 7

inside the tube 25 and fixing it with the syringe 3. The next operation is to change the distributor 12 and the eluent passes through the aspirator chamber 38, the helix 33 and the capillary 2, washing the sample into the column. Spiral 3 of the capillary 2 is provided to prevent the sample from moving into the chamber 38 of the aspirator 3 under the influence of the head in the column. If, under the pressure of eluent, the elasticity of the suction system of the sample moves in the capillary toward the intake side of body 3, then it remains in the capillary tube 2 (in the helix 33 But since the capillary is chosen to be small in diameter, then the sample is moved There is no noticeable erosion in one direction or another. The column is attached to the input unit 6 so that the end of the capillary 2 reaches the sorbent layer. Thus, the method of sample introduction is provided, ensuring the best efficiency of the column. Duration of sample washing out of the capillary 2 It limits a control unit 16 and depending on podachi.nasosa 13 and can be reconfigured. After washing valve 14 chaets Swap-in position shown in Figure 1.

Then by switching the distributor 14, the manipulator I moves upward until the end of the capillary 2 comes out of the flap 47 and switches it. After that, the manipulator 1 rises up to the full in order to fail.

The life shown in FIG. 14. Since the inner tube 26 is fixed in the tube 25, a bare capillary tube 2 comes out of the input unit 6.

5 This prevents traces of the sample from entering the lower part of the tube 26, especially the walls of the lower opening for the passage of the capillary 2. Now the manipulator 1 is turned at

o the aid of the actuator 9 to the position above the washing unit 7 is lowered down and the end of the capillary 2 is washed, as described at the beginning of the cycle. This one cycle of automatic

5, the dispenser is finished and it remains in the waiting position until the end of the next cycle. At the beginning of the next cycle, the actuator 10 rotates the conveyor 4 by one step. Washing the capillary 2 of taking and entering the sample three times during the cycle completely prevents traces of the previous sample from entering the next one, both in the sample vessels and in the column (in the input unit) ..

The use of the proposed device will significantly improve the hardware efficiency of the disaggregation (there is no extra-column erosion of the sample in a loop-type metering device, as is the case with all known automatic dispensers), to eliminate the transfer of traces of the previous sample to the next one and to increase the sample saving.

5 of a very small amount and a sampled sample is completely introduced into the chromatograph column.

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Claims (3)

1. AUTOMATIC DISPENSER FOR A LIQUID CHROMATOGRAPH, containing a sampling input and sampling system, a control system, a suction device, a conveyor with sample vessels and a washing system, so that in order to increase the separation efficiency of the apparatus / exclusion transition and saving pro: would | the system of input and sampling you. it is complete in the form of a manipulator installed with the possibility of rotation and interaction with the sample inlet node, while a capillary tube is placed inside the manipulator for sampling and introducing the sample. 2. The dispenser according to claim 1, with respect to the fact that the lower end of the capillary tube is installed inside two telescopic tubes equipped with a spring and a shutter. 3. Dispenser πό p. 1, characterized in that the rinsing system * is made in the form of a cup with an axial hole, in the lower part of which an eccentric hole has a spring-loaded cap equipped with a socket for installing the end of the capillary, an opening is made in the upper part of the side surface of the glass fluid supply for washing the capillary. iU „..1120169 I I20169