GB2108659A - Automatic sample preparation apparatus - Google Patents

Abstract

A sample preparation apparatus including a rotary head 40, a plurality of substantially vertical hollow columns 42 carried by the head, a rotary flow control valve 72, 102, a fluid conducting line 68 between the valve and the base of each column and a fluid conducting line 48 between the top of each column and the valve. It also includes a motor (50, not shown) for intermittently driving the head to rotate through a predetermined angular distance of 360 DIVIDED n degrees, and a circuit capable of accepting a pulse and on receipt thereof causing the head to make one rotary stepping movement through the predetermined angular distance. The pulses may be provided from a sample changer machine (12, not shown) in synchronism with the taking of the samples for transmission to columns 42. <IMAGE>

Description

SPECIFICATION Automatic sample preparation apparatus This invention relates to an automatic sample preparation apparatus.

Techniques exist for diagnostic screening, in which blood samples or other body fluids are taken one from each of a large number of persons being screened, and are analysed. Equipment exists for carrying out automatic analysis and recording of results but use of this equipment is often hindered by the fact that preparation of a large number of samples is tedious, expensive, and time-consuming. For example, where certain solvent extraction or column elution techniques are used to prepare samples, present day manual methods can prepare about 12 samples per working day.It would be highly desirable if greatly improved rates of sample preparation could be achieved and to the best of the present Applicant's knowledge and belief, the apparatus disclosed and claimed herein represents the first successful, practical and economic automatic apparatus whereby high rates of sample preparation can be obtained and which can operate unattended on a continuous basis (e.g. 24 hours/day).

According to one aspect of the present invention, there is provided sample preparation apparatus including a rotary head, a plurality of substantially vertical hollow columns carried by the head, a rotary flow control valve, a fluid conducting line between the valve and the base of each column, a fluid conducting line between the top of each column and the valve, a motor for intermittently driving the head to rotate through a predetermined angular distance of 360 11 degrees, and a circuit capable of accepting a pulse and on receipt thereof causing the head to make one rotary stepping movement through the predetermined angular distance.

According to another aspect of the present invention, there is provided a combination of a sample changer machine and an automatic elution apparatus, in which the latter has a rotary head carrying a plurality of elution columns, a rotary flow control valve controlling liquid flow to and from the columns and in which liquid flow connections and an operative connection are made between the sample changer and the control valve so that sequential samples taken from successive containers being processed by the sample changer machine are fed into successive elution columns.

In a preferred embodiment of the invention, the samples to be loaded and the elution solutions are presented to the apparatus using a multi-channel pump capable of variable flow rates.

The apparatus particularly disclosed and illustrated herein is designed to automatically prepare liquid samples by a discontinuous elution process using multi column indexing coupled to and synchronised with a sample changer machine or module. In operation, samples are taken individually from the sample changer machine and when each sample is taken the machine gives a signal output: The signal is used to start the rotation of the preparation unit each time a new sample is taken up. Up to 12 individual preprepared analytical columns may be mounted vertically in an indexing rotary head using conventional luer taper fittings. When the columns are assembled into the head and the apparatus is operating, the rotary head indexes on (e.g. 300 i.e. 360/120) in response to the signal output from the sample changer machine.Each indexing step is terminated preferably by an optoelectronic switch, to ensure repeated accuracy of the indexing movement. A precision-made flow control valve having a rotary valve member fixed to and moving with the column assembly controls flow of liquid to and from the columns in a desired sequence. In a preferred embodiment of the invention having 12 columns the valve member has 24 ports. While the valve member and head are stationary (between indexing steps) the flow to and from the columns may be effected for set time periods arranged by the operator, if desired.

The invention will be better understood from the following non-limiting description of examples thereof given with reference to the accompanying drawings in which: Figure 1 is a diagram illustrating the relationship between a sample changer machine and apparatus according to the invention; Figure 2 is a front elevation, partly in section, of apparatus according to the invention including a rotary head carrying 12 elution columns; Figure 3 is a diagram illustrating typical operations in six of the columns on the rotary head; and Figures 4A, 4B and 4C illustrate three possible modes of operation of apparatus according to the present invention.

In the figures of the drawings, like parts are represented by like reference numerals.

Figure 1 of the accompanying drawings illustrates a sample preparation apparatus 10 and a sample changer machine 12. The sample changer machine 12 is conventional and the details of its construction do not form part of the novelty of the present invention. A suitable such machine is that known as the "BEMAS sampler" available from Burkard Scientific (Sales) Limited P.O. Box 55, Uxbridge, Middlesex UB8 1 LA. The sample changer machine 12 has a support deck 14 upon which are carried a number of separate sample containers 16, connected together to form a chain. The machine also has a sampling head chain. The machine also has a sampling head generally indicated at 1 8 and consisting of a vertically reciprocal hollow probe or needle 20 carried by an arm 22 extending radially outwardly from a rotary shaft 24.In operation of this sample changer, the containers 1 6 are brought in turn by a rotary pick-up indexing mechanism to beneath the nozzle 20 and then a sample is taken from them by the nozzle 20 being lowered into the sample container and maintained therein for a predetermined period of time while a predetermined suction is applied. The base 26 of the sample changer includes appropriate control gear to effect a repetitive abstraction of samples from a series of containers which are sampled consecutively.

The abstracted samples are fed through a liquid line 28 to the apparatus 10, and the sample changer machine 1 2 is joined to the apparatus by an electrical cable 30. This cable carries a signal which emanates from the machine 12 each time a sample is taken; this signal is used to trigger rotation of the rotary head.

The sample preparation apparatus 10 includes a rotary head 40, a plurality of substantially vertical hollow columns 42 carried by the head, a rotary control valve 44, a fluid conducting line (not shown) from the valve to the base of each column, a fluid conducting line (shown at 48) from the top of each column to the valve 44, a motor 50 located in the base 52 of the apparatus 10 for intermittently driving the head 40 to rotate at intervals through successive angular amounts of 360 TI degrees and a circuit located in the base 52 and capable of accepting on electrical pulse from the sample changer machine 12 and upon receipt thereof causing the head 40 to make one rotary stepping movement.In a preferred embodiment of the invention, there are twelve columns located at 30O annular spacing around the vertical rotation axis 54 of the head 40.

The construction of the apparatus 10 will be better seen from Figure 2, showing the head and the valve in greater detail. The rotary head 40 is mounted on a shaft 60 and is made up of two parallel circular discs 62 and 64, the lower disc 64 being fixed to the shaft 60 and having a circumferential series of holes 66 therethrough to receive the lower ends of the columns. The lower ends of the columns have luer fittings thereon, so that a flexible plastics tube can readily be attached thereto. A screwed connection could be employed if larger columns were used in order to cater for the increased pressure. Such tubes are shown at 68 and are a tight push fit onto a spigot 70 extending outwardly in a radial direction from a rotary valve member 72 attached for rotation with the shaft 60. A drive pin 74 connects the disc 64 and the valve member 72.

The upper disc 62 is integral with a boss 78 and has a central hole therein through which the shaft 60 passes. Disc 62 is free to move up and down the shaft and is locked in position by a thumb screw 80. The disc can be readily removed to permit easy column replacement. However by undoing the screw 80 and lifting off the disc 62 and boss 78, the upper disc 62 can readily be removed when this is desired. Tube push-fit connections, one seen at 82, enable the liquid conducting tubes 48 to be disconnected from respective tubes, one seen at 84, which extend into each column seal 86.

Each column is made of material resistant to the elution solutions and resin or other particulate material 88, in line with conventional procedures in separation and sample preparation by elution techniques.

A pressure drive collar 90 and a locking screw 92 are included and encircle the shaft 60. The shaft 60 is driven and the drive is transmitted to the disc 64 via the pin 74 and via the collar 90 and its locking screw 92, the collar 90 being fixed to a boss 91 attached to the disc 64. The lower end of the collar 90 engages the upper end of a compression spring 94 whose lower end bears on a housing 73 of the valve member 72, so ensuring that its lower surface 72a at all times (except when the apparatus is disassembled) bears firmly against the upper surface 1 02a of the valve plate 102. More than one spring 94 may be provided if desired.

The rotary valve member 72 is constituted by a p.t.f.e. valve plate. The p.t.f.e. valve plate has a flat lower surface 72a which is in contact with the surface 1 02a as described. A stainless steel housing 73 partly encloses the valve member 72.

A support block 100 of PVC or other chemically resistant material is mounted on the base 52 (Figure 1) said base not being shown in Figure 2. Within a cylindrical recess in the support block 100 is located a stainless steel valve plate 102 having an accurately flat upper surface. This surface is in close engagement with an accurately flat lower surface of the rotary valve member 72 which may for example be made of p.t.f.e. The valve plate 102 is fixed and the valve member 72 rotates, relative movement occurring at the planar interface of these two parts. The plate and the valve member have corresponding ports opening at their respective planar faces, correspondingly arranged in two concentric circles with the ports being spaced circumferentially by an angular distance equal to 360 TI that is to say equal to one unit of indexing movement. Consequently when the head 40 rotates through one indexing step, a particular port in the valve block 102 is disconnected from the port in the valve member 72 with which it was formerly in communication, and is placed in communication with the next port of the valve block 72. Each of the fluid conducting lines 68 leads to one port in the valve member 72, these ports being arranged with their centres on one circle, and each of the fluid conducting lines 48 leads to a corresponding port in the valve block 72, these latter ports being arranged in a second or inner circular array.

In the valve plate 102 there are two concentric circular arrays of ports corresponding to those on the lower planar surface of the valve member 72, and from these ports, fluid conducting lines lead to any desired destination to remove liquid expelled from the columns, two such lines being shown at 106 and 108. The inlet lines 110, 112 leading to the outer circular array of ports on the valve plate 102 are connected to spigot pipes 1 14, 1 6. These are suitable for the push-fit connection of plastics liquid conducting tubes, and the spigot pipes are mounted on a vertical support plate 118. In this way an operator can readily manually make different connections in accordance with a desired programme of elution, washing, etcetera.

That is to say, the support plate 1 18 would, in the case of a rotary head having twelve columns, have twenty four spigots 114. These twenty four spigots would be for the attachment of an in-flow line and an out-flow line in respect of each of the twelve possible column positions. By way of a simple example, a six-stage elution operation is illustrated in Figure 3. The numbers 1-6 represent six out of the twelve possible column positions, the other six positions are not used in this particular example or, as an alternative, the other six positions may be operated in an exactly similar way to the way about to be described.

During the rotation of the rotary head, the individual columns pass in turn from position 1 to position 2 to positions 3, 4, 5 and 6. As illustrated in Figure 3, when a given column is position 1, it is regenerated by washing out to waste of any residue material from a previous cycle of stages and by converting the packing material to the correct chemical form. When this column reaches position 2 it is equilibriated to the correct chemical and physical form to accept the sample, by appropriate feeding of a selected fluid. When the same column reaches position 3, it is loaded with a sample which is a multi-component sample, and is represented by symbois 1 30-136 of which 1 34 represents the particles or molecules of the particular fraction to be separated out.This sample is loaded into the column by being fed along the in-flow line of the pair of lines corresponding to position number 3.

When the same column reaches position 4 and then 5, a washing step is carried out at each position by feeding washing liquid along the inflow lines appropriate to positions 4 and 5 and connecting the out-flow lines appropriate to the said positions to waste. When the column reaches position 6, the elution step is carried out and the desired fraction 1 34 is taken via the out-flow line of column position 6 to a suitable collection vessel 138. The same column then passes to column position 1 whereupon the six step cycle, involving six indexing movements of the rotary head, starts again. Any number of these separated fractions may be collected and the collections can be made from any of the outlet positions.

Figure 3 illustrates the out-flow as taking place from the bottom of the columns and the in-flow being fed into the top of the columns, but this arrangement is illustrated purely by way of example and in practice it is preferred that the flow direction should be upwardly through the columns, that is to say the in-flow is at the base along line 68 of Figure 2 and the out-flow from the top of the columns, along lines 48 of Figure 2.

Figure 4A illustrates the continuous production of a pure fraction from a single bulk sample. The bulk sample is contained in a vessel 180 and any suitable indexing timer is used to index the rotary column head to make successive indexing steps.

A series of small fractions are processed one after another in a 6-step processing schedule and the end product is fed into a receiving vessel 1 82. A multi-channel pump 184 is used.

Figure 4B illustrates a different mode of operation, namely automatic fractionation of samples for discrete techniques. A series of sample contained in containers 140, 142, 144 etcetera are passed through the sample preparation apparatus and are respectively collected in a series of collection containers 150, 152, 1 54 etcetera. In this mode of operation, the timing signal pulse emanating from the sample changer machine 12 is used not only to index on the rotation of the rotary column head but also to index on the movement of the individual containers in a fraction collector machine 1 56.

Figure 4C illustrates another possible mode of operation of the apparatus according to the invention. In this case there is a fuliy automatic combined sample preparation by fractionation, and then an analysis or detection step is carried out on each one of a series of successive samples.

The fraction resulting from the elution column 6 is fed along a line 1 60 into a reaction manifold 1 62 through which are also fed suitable reagents via lines 164, 166 and 168. The reagents are fed by a pump 170 which may be the same pump as the pump 1 72 enbodied in the sample preparation apparatus 10. Such a pump would have multiple parallel liquid pathways therethrough.

Once the fraction has been appropriately treated by the reagents, for example to bring up the colour representative of the compound or material being detected, it is passed into a detector 1 74 which measures and records the result of the test. A continuous graphic recorder 1 76 is connected to the detector 1 74 and records, e.g. on a moving strip of graph paper, the test results. In this way there is automatically obtained a continuous record giving the results of tests carried out successively on a large number of samples, each of which has been automatically concentrated or fractionated by being passed through the apparatus 10.

The following are among the useful and advantageous operational features of the apparatus particularly disclosed and illustrated herein.

1. Accurately synchronized changes of column eluting fluids, of sample loading and of a fraction collecting may be carried out.

2. By using a single highly accurate adjustable timer, to initiate the column rotation, changes in the processing schedule may readily be made.

3. The sample preparation apparatus has at least three separate modes of operation and can be integrated into continuous flow detection as well as into discrete detection methods.

4. The apparatus has wide application and versatility; the following parameters can be varied without difficulty or complexity to achieve optimum separation of various desired fractions at a maximum separation rate: a. the type, structure and particle size of the column packing material.

b. the diameter and length of the columns. On a standard unit four sizes of columns allows packing volumes 0.2 to 10 millilitres.

c. the flow rate of the eluting solutions. A standard pump unit allows flow rates of from 0.015 to 3.9 millilitres per minute.

d. the period of time for which a given column remains at one station of the elution cycle may readily be varied. It may for example be varied from 10 to 900 seconds.

e. there may be up to twelve changes including sampling of elution and regeneration solution per analytical cycle.

f. not all of the twelve columns need be connected to eluting solutions but can be allowed to idle through unused stations. For this, a simple programme or schedule of liquid supply and removal connection would be employed.

g. the direction of liquid flow through the columns can easily be reversed, so that a strongly retained material does not have to travel the whole length of the column, thus speeding regeneration.

h. the column material is freshly regenerated just prior to use on a fresh sample so ensuring the best dynamic flow conditions for sample binding and separation.

i. apparatus functions at low back pressures so minimizing the problems of leaky connections and avoiding the need to use expensive liquid-tight connectors.

In an alternative embodiments, electromagnetically controlled liquid valves could be used for controlling the feeding of liquids to columns, in place of the rotary valve 72, 102 described in connection with Figure 2.

Claims (12)

Claims

1. A sample preparation apparatus including a rotary head, a plurality of substantially vertical hollow columns carried by the head, a rotary flow control valve, a fluid conducting line between the valve and the base of each column, a fluid conducting line between the top of each column and the valve, a motor for intermittently driving the head to rotate through a predetermined angular distance of 360 TI degrees, and a circuit capable of accepting a pulse on and receipt thereof causing the head to make one rotary stepping movement through the predetermined angular distance.

2. A combination of a sample changer machine and an automatic elution apparatus, in which the latter has a rotary head carrying a plurality of elution columns, a rotary flow control valve controlling liquid flow to and from the columns and in which liquid flow connections and an operative connection are made between the sample changer and the control valve so that sequential samples taken from successive containers being processed by the sample changer machine are fed into successive elution columns.

3. Apparatus according to claim 1 or a combination according to claim 2 including a multi-channel pump capable of variable flow rates.

4. Apparatus according to claim 1 or a combination according to claim 2 in which individual columns are supported by a pair of parallel discs supported on a common shaft.

5. Apparatus according to claim 1, 3 or 4 or a combination according to claim 2, 3 or 4 in which the columns are a push fit into leurfittings carried by the lower disc.

6. Apparatus according to claim 1, 3, 4 or 5 or a combination according to claim 2, 3, 4 or 5 in which the rotary flow control valve is formed by a multi-port fixed valve plate co-operating with a multiport rotary valve member.

7. Apparatus or a combination according to claim 6 in which the valve plate and the valve member have their ports located in circular array on respective flat confronting surfaces.

8. A sample preparation apparatus substantially as herein described with reference to and as illustrated in Figure 2 of the accompanying drawings.

9. A combination of a sample changer machine and an automatic elution apparatus substantially as herein described with reference to and as illustrated in Figure 1 of the accompanying drawings.

1 0. A sample preparation apparatus substantially as herein described with reference to and as illustrated in Figure 4A of the accompanying drawings.

11. A sample preparation apparatus substantially as herein described with reference to and as illustrated in Figure 4B of the accompanying drawings.

12. A sample preparation apparatus substantially as herein described with reference to and as illustrated in Figure 4C of the accompanying drawings.