GB2224847A

GB2224847A - Vessels with a plurality of cathodes for detection of micro-organisms

Info

Publication number: GB2224847A
Application number: GB8922929A
Authority: GB
Inventors: Martin Robert Ackland; Thomas Patrick Murphy
Original assignee: CMB Packaging UK Ltd; Metal Box PLC
Current assignee: Crown Packaging UK Ltd
Priority date: 1988-10-21
Filing date: 1989-10-11
Publication date: 1990-05-16
Also published as: GB8824729D0; GB8922929D0

Abstract

A vessel (10) for use in detection of microorganisms in a sample of a substance by electrochemical means contains one or more anode elements (14) and a plurality of cathode elements (11) spaced from one another to enable monitoring of conditions in different parts of the vessel to be effected. The cathode elements (11) may be spaced up the side of the vessel, or they may be spaced around its floor, e.g. with radial partitions separating the portions of the vessel containing each cathode element. <IMAGE>

Description

VESSELS FOR USE IN DETECTION OF MICRO-ORGANISMS This invention relates to vessels for use in detection of micro-organisms by electrochemical methods. Apparatus incorporating such vessels is described, for example, in our British Patent Specification No.2142433. The vessels described previously have been provided with two electrodes, generally of different metals, and detection of micro-organisms in a fluid sample in the vessels has been effected by measuring the changing potential between the electrodes which are in contact with the fluid sample. 'When the growth of the micro-organisms reaches a particular stage, the potential shows a marked change, e.a. a steep fall, and the time taken to reach this stage provides an indication of the number of micro-organisms originally present in the sample.

It is believed that different conditions can exist in different parts of the vessels, e.g. at different levels in the vessels, and that it could be advantageous to monitor such different conditions or indeed to create them.

Accordingly the present invention provides a vessel for use in detection of micro-organisms in a sample of a substance by electrochemical means, wherein a plurality of cathode elements are disposed in the vessel and spaced from one another.

The vessel may also contain a single anode element. For example, the cathode elements may be spaced up the wall of the vessel and the anode element disposed at the bottom of the vessel.

Alternatively, the cathode elements may be spaced up the vessel wall on one side of the cell and the anode element may be elongated and extend up the opposite side wall of the vessel.

In another embodiment of the invention, the cathode elements may be spaced up the vessel wall on one side of the vessel and a similar plurality of anode elements may be spaced from one another up the opposite side wall of the vessel.

In a further embodiment, the cathode elements are discs or buttons located in the floor of the vessel and spaced around its periphery.

In this case, the anode element may be a disc or button disposed in the centre of the vessel and radial partitions separate the portions of the vessl containing each cathode element while leaving each portion in contact with the anode.

The cathode elements will in general be all of a noble metal such as gold or platinum. Where the apparatus in which the vessel is to be used is designed to monitor a potential difference produced galvanically in the vessel, the anode element or elements is or are preferably of a metal such as aluminium which is well spaced from the noble metals in the electrochemical series and produces an easily measurable potential difference.

Alternatively, where the vessel is to be used in apparatus which is arranged to apply a potential to the electrodes, either in a potentiostatic or a galvanostatic mode, the cathode elements and the anode element or elements may all be of the same metal, preferably a corrosion resistant metal such as gold, platinum or one of the other noble metals, or stainless steel.

Specific embodiments of the invention will now be described by way of example and with reference to the accompanying drawings, in which: Figure 1 is a diagrammatic cross-section through a first embodiment of a vessel according to the invention, Figure 2 is a similar diagrammatic cross-section of a second embodiment, Figure 3 is a similar diagrammatic cross-section of a third embodiment, Figure 4 is a plan view of a fourth embodiment, and Figure 5 is a plan view of a fifth embodiment of the invention.

In the embodiment illustrated in Figure 1, the vessel 10 has a cylindrical metal body, in one side of which are fitted a series (six as shown) of cathode elements in the form of gold-plated pins 11, spaced from one another so as to lie at different levels. Each pin is insulated from the wall of the vessel 10 and provided with an external contact surface 12 for making contact with fixed contacts (not shown) in the apparatus. A single anode element 14 of aluminium or an aluminium alloy is secured in the bottom of the vessel 10 and again provided with an external contact surface 15 for contacting a fixed contact in the apparatus.

The embodiment shown in Figure 2 differs from that of Figure 1 only in that the anode element 141 is in this case elongated and extends up the opposite side wall of the vessel 10 from the cathode elements 11 and provides its external contact surface 151 on the outside of that side wall.

In the enbodiment of Figure 3, there is a plurality of anode elements 142 in the form of aluminium pins spaced from one another up the side wall of the vessel 10 opposite to the cathode elements 11, so as to provide a plurality of pairs of electrodes.

The cathode elements 11 are connected separately to the apparatus which monitors the potential difference between the cathode and anode elements, so that any one of the three vessels illustrated and described above can be used to monitor the conditions at different levels in the vessel. Alternatively, the cathode elements and anode elements may be the sane metal, e.g. platinum, and a potential may be applied between them either under potentiostatic conditions, in which case the current through the vessel is monitored, or under galvanostatic conditions, in which case the cathode potentials or the potential difference between cathode elements and anode elements are monitored, so as to monitor the conditions at different levels in the vessels.

In a further alternative, different conditions may be created at the different levels in the vessel by coating the cathode elements 11 with different antibodies or growth-enhancing materials.

In the embodiment of Figure 4, the anode element 143 is in the form of an aluminium disc or button 143 in the centre of the floor of the vessel 10, while the cathode elements are gold discs or buttons 111 located in the floor of the vessel and spaced around its periphery.

In the embodiment of Figure 5, the arrangement is similar to that of Figure 4 except that the portions 16 of the vessel 10 containing each of the cathode elements 111 are separated by radial partitions 17 which extend from the anode element 143 to the wall of the vessel 10.

Each portion 16 is thus in contact with one sector of the surface of the anode element but the portions 16 of the vessel are effectively separated from one another.

As an alternative to the use of such partitions a syrup or gel medium of high viscosity may be used to minimize transport of materials or cross-contamination between the cathode elements.

Claims

Claims:

1. A vessel for use in detection of micro-organisms in a sample of a substance by electrochemical means, wherein a plurality of cathode elements are disposed in the vessel and spaced from one another.

2. A vessel according to Claim 1, wherein the vessel also contains a single anode element.

3. A vessel according to Claim 2, wherein the cathode elements are spaced up the vessel wall and the anode element is disposed at the bottom of the vessel.

4. A vessel according to Claim 2, wherein the cathode elements are spaced up the vessel wall on one side of the vessel and the anode element is elongated and extends up the opposite side wall of the vessel.

5. A vessel according to Claim 1, wherein the cathode elements are spaced up the vessel wall on one side of the vessel and a similar plurality of anode elements are spaced from one another up the opposite side wall of the vessel.

6. A vessel according to claim 2 wherein the cathode elements are discs or buttons located in the floor of the vessel and spaced around its periphery.

7. A vessel according to claim 6 wherein the anode element is a disc or button disposed in the centre of the vessel and radial partitions separate the portions of the vessel containing each cathode element while leaving each portion in contact with the anode.

8. A vessel for use in detection of micro-organisms, substantially as hereinbefore described and as illustrated in Figure 1, Figure 2, Figure 3, Figure 4 or Figure 5 of the accompanying drawings.