Sensor device

Abstract

The present disclosure relates to a sensor device for an analyser apparatus configured to analyse parameters of medical fluid samples. The sensor device comprises: a measurement chamber defining an interior volume for receiving a fluid to be analysed; a chamber inlet and a chamber outlet, each respectively providing a respective fluid passage to the interior volume; a reference electrode arranged in fluid communication with the interior volume; and one or more ion-selective analyte sensors, wherein each of the analyte sensors comprises a sensor electrode and an ion-selective sensor membrane arranged between the interior volume and the sensor electrode. The sensor device further comprises a sulfur-reactive element arranged in fluid communication with the interior volume to thereby fluidly contact the fluid to be analysed when the interior volume receives the fluid to be analysed. The disclosure further relates to an analyser apparatus and use of a sulfur-reactive element.

Description

[0001] SENSOR DEVICE

[0002] TECHNICAL FIELD

[0003] The present invention relates to a sensor device for an analyser apparatus configured to analyse parameters of medical fluid samples, preferably configured to perform blood gas analysis. The invention further relates to an analyser apparatus, use of a sulfur-reactive element, and a method for manufacturing a sensor device.

[0004] BACKGROUND

[0005] Blood gas measurements can be used to provide information about respiratory and metabolic status of patients by measuring various parameters, such as concentration of electrolytes, in the blood of the patient.

[0006] Such blood gas measurements are typically performed by providing a blood sample to an analyser apparatus which performs the measurements. At least some measurements are performed in a sensor device comprising sensors and a measurement chamber defining an interior volume. A fluid to be analysed can then be provided to the interior volume, and measurements are performed by means of the sensors.

[0007] The measurement error of some measurements has been found to increase during use and / or over time. Conventionally, this issue has been solved simply by replacing the sensor device.

[0008] However, it would be far more desirable to reduce or eliminate this measurement error, thereby avoiding untimely and excessive replacement of the sensor device and ensuring maximal measurement accuracy throughout the lifetime of the sensor device.

[0009] SUMMARY

[0010] In the light of the above, it is desirable to provide a sensor device and an analyser apparatus which reduce or eliminate measurement error.

[0011] A first aspect of the present disclosure relates to a sensor device for an analyser apparatus configured to analyse parameters of medical fluid samples, the sensor device comprising : a measurement chamber defining an interior volume for receiving a fluid to be analysed; a chamber inlet and a chamber outlet, each respectively providing a respective fluid passage to the interior volume; a reference electrode arranged in fluid communication with the interior volume; and one or more ion-selective analyte sensors, wherein each of the analyte sensors comprises a sensor electrode and an ion-selective sensor membrane arranged between the interior volume and the sensor electrode, wherein each of the analyte sensors is configured to measure a difference in electric potential between the reference electrode and the analyte sensor across the fluid to be analysed when the interior volume receives the fluid to be analysed; wherein the sensor device further comprises: a sulfur- reactive element arranged in fluid communication with the interior volume to thereby fluidly contact the fluid to be analysed when the interior volume receives the fluid to be analysed.

[0012] Examples according to the present disclosure are directed at reducing or eliminating measurement error of the sensor device which arise during use over time.

[0013] The inventors have discovered that one source of measurement error arises at least partially due to build-up (e.g. precipitation) of sulfur from a sulfur-containing compound, for example in the form of as Ag?S, on the reference electrode. This gradually causes the reference electrode to stop functioning correctly as the relevant compound builds up, due to proper fluid communication with the fluid to be analysed being reduced.

[0014] Further investigation has established that the sulfur-containing compound may originate from anti-microbial rinse fluid used in the analyser apparatus and / or blood. The sulfur-containing compound may, for example, be methylisothiazolinone.

[0015] Moreover, the presence of blood residues in the interior volume has been found to worsen the problem, at least in some examples. This could be due to enhanced precipitation of sulfur on the reference electrode, and / or due to additional reactions of precipitated sulfur with proteins from the blood.

[0016] To reduce or eliminate precipitation of sulfur on the reference electrode, and thereby reduce or eliminate measurement errors of the sensor device related to the reference electrode, the present disclosure provides a sulfur-reactive element arranged in fluid communication with the interior volume and arranged to fluidly contact the fluid to be analysed when the interior volume receives the fluid to be analysed. The sulfur-reatove element can thereby fluidly contact the idling fluid or any fluid present in the interior volume.

[0017] As a result, any sulfur-containing compound in the interior volume may, at least partially, react with the sulfur-reactive element instead of contributing to precipitation on the reference electrode.

[0018] Thereby, precipitation of sulfur on the reference electrode may be reduced or eliminated. In turn, measurement errors may be reduced or eliminated, and untimely and excessive replacement of the sensor device may be avoided.

[0019] In sensor devices according to the present disclosure, the sensor device comprises a measurement chamber defining an interior volume for receiving a fluid to be analysed, such as a medical fluid sample, preferably a blood sample, the blood sample consisting of blood or the blood sample comprising blood dissolved in an analysis solution. The interior volume is also suitable for receiving other fluids, such as an idling liquid being present in the interior volume in between analysis of medical fluid samples. Such an idling liquid may consist of or comprise an anti-microbial rinse fluid, the anti-microbial rinse fluid typically comprising a sulfur-containing compound.

[0020] A chamber inlet and a chamber outlet each respectively provide a respective fluid passage to the interior volume from an exterior of the sensor device. This exterior of the sensor device can be an analysis apparatus. Medical fluid samples and idling liquid may thereby enter the interior volume via the chamber inlet and exit the interior volume via the chamber outlet.

[0021] In use, such liquids may be provided via an analyser apparatus, for example by means of a pump of the analyser apparatus.

[0022] Further, sensor devices according to the present disclosure comprise a reference electrode and one or more ion-selective analyte sensors. Together, the reference electrode and an ion- selective analyte sensor can measure a difference in electric potential between the reference electrode and the analyte sensor across a fluid to be analysed when the interior volume accommodates a fluid to be analysed, to, e.g., provide an indication of a concentration of an electrolyte in a blood sample. Each ion-selective analyte sensor comprises a sensor electrode and an ion-selective sensor membrane arranged between the interior volume and the sensor electrode. The ion-selective sensor membrane is configured to ensure that only one or more specific types of ions contribute to a measurement of the electric potential when measuring via the sensor electrode upon which the ion-selective sensor membrane is positioned. Thereby, the ion-selective analyte sensors can be selectively directed at measuring specific types of ions. An ion-selective sensor membrane is an ion-selective membrane positioned on an electrode to provide an ion-selective analyte sensor. Various types of ion-selective membranes are available.

[0023] An anti-microbial rinse fluid used may also be referred to as an anti-microbial agent. In typical examples, the anti-microbial agent comprises a sulfur-containing compound. Typically, the sulfur-containing compound has a molecular mass of less than 500 g / mol, preferably less than 250 g / mol. In addition to S, the sulfur-containing compound typically comprises carbon and hydrogen atoms and optionally one or more heteroatoms selected from N, O and P. In alternative examples, the sulfur containing compound is molecular sulfur. In preferred examples, the sulfur-containing compound is a heterocyclic compound, such as e.g. isothiazoline or a derivative thereof. Isothiazoline derivatives of interest include methylisothiazolinone (MIT), chloromethylisothiazolinone (CMIT), benzisothiazolinone (BIT), octylisothiazolinone (OIT), dichlorooctylisothiazolinone (DCOIT), and butylbenzisothiazolinone (BBIT), of which methylisothiazolinone (MIT) is of most interest.

[0024] In some examples, the sulfur- reactive element releases a sulfur-reactive agent into a fluid in the interior volume, for example a sulfur-reactive agent comprising, e.g., metal ions, to capture sulfur of the sulfur-containing compound. Such a sulfur-reactive agent may be dissolved in or suspended in a fluid in the interior volume. In some examples, the sulfur- containing compound reacts directly on a surface of the sulfur-reactive element without relying on a sulfur-reactive agent released into a fluid. In some examples, the sulfur- containing compound reacts both with a surface of the sulfur-reactive element and with a sulfur-reactive agent released into a fluid in the interior volume.

[0025] The sulfur-reactive element and / or the sulfur reactive agent released therefrom is able to at least partially bind the sulfur-containing compound. Binding may take place via the formation of bonds (such as covalent bonds) between the sulfur-reactive element and / or agent and the sulfur-containing compound. The sulfur-reactive element and / or agent may also bind the sulfur-containing compound in other ways, e.g. via ionic interactions (i.e. formation of ion pairs), metal-ligand interactions, or hydrogen bond formation. As an example, the sulfur-reactive element comprises Ag and the reference electrode is based on Ag ions dissolved in a reference electrode liquid of the reference electrode. In such an example, the sulfur-reactive element may ensure that at least some sulfur from antimicrobial rinse fluid and / or blood reacts with the sulfur-reactive element and dissolved Ag ions released therefrom, instead of reacting with the reference electrode or a surface area thereof.

[0026] Even though the sulfur-reactive element is arranged in fluid communication with the interior volume to thereby fluidly contact the fluid to be analysed when the interior volume receives the fluid to be analysed, the chemical action of the sulfur-reactive element may possibly occur while an anti-bacterial rinse fluid is present in the interior volume, and not while the fluid to be analysed is present. In other words, the sensor device may comprise a sulfurreactive element arranged in fluid communication with the interior volume to thereby fluidly contact the fluid to be analysed when the interior volume receives the fluid to be analysed to reduce precipitation of sulfur on the reference electrode when an anti-bacterial rinse fluid is present in the interior volume.

[0027] Sulfur-reactive element composition

[0028] In examples according to the present disclosure, the sulfur-reactive element comprises a metal.

[0029] In examples according to the present disclosure, the sulfur-reactive element comprises a metal salt, for example a metal chloride, such as e.g. AgCL

[0030] In examples according to the present disclosure, the metal of the sulfur-reactive element comprises a metal from groups 3-15, preferably from groups 3-12, more preferably Ag, Zn, Fe, Cu, Ni, Tl, Pb, Cd, Co, or Hg.

[0031] Generally, metals and metal salts are promising as they exhibit at least some reactivity with a sulfur-containing compound, and are thereby suitable as material for a sulfur-reactive element. Hereunder, metals from groups 3-15, and in particular from groups 3-12 of the periodic table of elements are suitable. An example of a preferable metal from groups 13-15 is Sn.

[0032] In case the sulfur-reactive element comprises a metal or a metal salt, the sulfur-reactive element preferably consists of at least 50 % by weight of the metal or metal salt, more preferably at least 60 % by weight, even more preferably at least 70 % by weight, such as at least 80 % by weight.

[0033] In examples according to the present disclosure, the sensor device further comprises one or more metabolite sensors arranged in fluid communication with the interior volume, wherein each of the metabolite sensors comprises a metabolite electrode, wherein the sulfur-reactive element and a portion of the one or more metabolite sensors are formed from the same material, for example wherein the sulfur-reactive element and the metabolite electrodes of the one or more metabolite sensors are formed from the same material.

[0034] By forming the sulfur-reactive element and a portion of one or more metabolite sensors from the same material, manufacturing of the sensor device is simplified, for example in comparison with a using different materials. Thereby, the production of a sulfur-reactive element in a sensor device may potentially be straightforwardly implemented into existing manufacturing methods.

[0035] Metabolite sensors may be configured to sense, e.g., glucose and / or lactate. Each of the metabolite sensors may comprise a metabolite sensor membrane arranged between the interior volume and the metabolite electrode. A metabolite sensor membrane is typically not ion-selective, but may be selective regarding one or more types of metabolites.

[0036] In contrast to the sulfur-reactive element, the one or more metabolite sensors may be covered by a metabolite sensor membrane. Thereby, the metabolite electrodes of the metabolite sensors may potentially not substantially contribute to binding sulfur, despite these metabolite electrodes potentially consisting of or comprising the same material as the sulfur-reactive element.

[0037] Reference electrode

[0038] In examples according to the present disclosure, the reference electrode comprises a reference electrode liquid and a diffusion-tight diaphragm arranged between the interior volume and the reference electrode liquid, the diffusion-tight diaphragm having a through- going orifice covered by a reference electrode membrane permitting diffusion of ions therethrough.

[0039] In examples according to the present disclosure, the reference electrode liquid comprises Ag ions, preferably Ag and Cl ions.

[0040] Sulfur-reactive element placement In examples according to the present disclosure, the measurement chamber has an inlet end and an outlet end, the chamber inlet being located at the inlet end and the chamber outlet being located at the outlet end, wherein the reference electrode and the sulfur-reactive element are both located at one end of the inlet end and the outlet end.

[0041] By locating both the reference electrode and the sulfur-reactive element at the same end of the measurement chamber, the precipitation of sulfur onto the reference electrode is advantageously minimized.

[0042] In examples according to the present disclosure, the sulfur-reactive element is located on a wall of the measurement chamber, preferably a wall of the measurement chamber opposite the reference electrode.

[0043] In examples according to the present disclosure, the sulfur-reactive element is located on the reference electrode membrane or the diffusion-tight diaphragm, for example around the through-going orifice.

[0044] By locating the sulfur-reactive element on a wall of the measurement chamber opposite to the reference electrode or onto a membrane or a diaphragm of the reference electrode, the sulfur-reactive element can be located near the reference electrode, and precipitation of sulfur onto the reference electrode can advantageously be minimized.

[0045] Further, by locating the sulfur-reactive element in close proximity to the reference electrode, the sulfur-reactive element may primarily react with the sulfur-containing compound where needed, and not in other sections of the sensor device or the analyser apparatus, thereby potentially avoiding an unnecessary reduction of, e.g., the rinsing capability of an antimicrobial rinse fluid comprising the sulfur-containing compound.

[0046] In examples according to the present disclosure, a distance from the sulfur-reactive element to the reference electrode, preferably to a conductive surface area of the reference electrode is at most 20 mm, for example at most 15 mm, for example at most 10 mm, for example at most 6.0 mm, for example at most 4.0 mm, for example at most 3.0 mm, such as at most 2.0 mm.

[0047] Accordingly, the sulfur-reactive element may primarily react with the sulfur-containing compound where needed, and not in other sections of the sensor device or the analyser apparatus. The distance from the reference electrode to the opposite wall of the measurement chamber may typically be in the order of 1 mm.

[0048] In examples according to the present disclosure, the chamber inlet and the chamber outlet define a flow direction from the chamber inlet to the chamber outlet, wherein the sulfurreactive element is located upstream of the reference electrode relative to the flow direction.

[0049] As an alternative to locating the sulfur-reactive element in the close proximity of the reference electrode, the sulfur-reactive element can be located remotely, for example if there are spatial constraints near the reference electrode. In such cases, locating the sulfurreactive element upstream of the reference electrode may ensure that precipitation of sulfur onto the reference electrode is minimized. As an example, the reference electrode may be located in the outlet end, while the sulfur-reactive element is located in the inlet end of the sensor device.

[0050] Sulfur-reactive element size

[0051] In examples according to the present disclosure, the reference electrode has an active electrode area defined by a conductive surface area of the reference electrode in communication with the interior volume, for example defined by the through-going orifice, wherein the sulfur-reactive element has an active sulfur-reactive area defined by a surface area of the sulfur-reactive element in communication with the interior volume, wherein the active sulfur-reactive area is greater than the active electrode area, for example at least two times greater, for example at least three times greater, such as at least five times greater than the active electrode surface area.

[0052] The provision of an active sulfur-reactive area which is greater than the active electrode area may advantageously ensure that precipitation of sulfur onto the reference electrode is minimized.

[0053] For a reference electrode comprising a diffusion-tight diaphragm having a through-going orifice covered by a reference electrode membrane permitting diffusion of ions therethrough, the area of the through-going orifice corresponds to the conductive surface area.

[0054] In examples according to the present disclosure, the active sulfur-reactive area is at least 0.1 mm2, for example at least 0.5 mm2, for example at least 1.0 mm2, such as at least 3.0 mm2. A certain minimum surface area of the active sulfur-reactive area of the sulfur-reactive element as exemplified above may advantageously ensure that precipitation of sulfur onto the reference electrode is minimized.

[0055] Analyser apparatus

[0056] A second aspect of the present disclosure relates to an analyser apparatus configured to analyse parameters of medical fluid samples, the analyser apparatus comprising : a sensor device, the sensor device comprising a measurement chamber defining an interior volume for receiving a fluid to be analysed, a chamber inlet and a chamber outlet each respectively providing a respective fluid passage to the interior volume, a reference electrode in fluid communication with the interior volume, and one or more ion-selective analyte sensors, wherein each of the analyte sensors comprises a sensor electrode and an ion-selective sensor membrane arranged between the interior volume and the sensor electrode; and a processing unit configured to measure a difference in electrical potential between the reference electrode and each of the analyte sensors across the fluid to be analysed when the interior volume receives the fluid to be analysed; wherein the analyser apparatus further comprises: a sulfur- reactive element arranged in fluid communication with the interior volume.

[0057] An analyser apparatus according to the second aspect of the present disclosure may generally provide the same or similar effects and advantages as provided by a sensor device according to the first aspect of the present disclosure. Accordingly, an analyser apparatus according to the second aspect may reduce or eliminate precipitation of sulfur on the reference electrode, and in turn, measurement errors may be reduced or eliminated and excessive replacement of the sensor device may be avoided.

[0058] The location of the sulfur-reactive element in the analyser apparatus is not restricted to the sensor device.

[0059] Instead, in some examples, the sulfur-reactive element is placed in a fluid conduit of the analyser apparatus externally from the sensor device. Yet, since such a fluid conduit can be arranged in fluid communication with the interior volume, such placement of the sulfurreactive element may still reduce precipitation of sulfur on the reference electrode.

[0060] In examples according to the present disclosure, the sensor device of the second aspect is a sensor device according to the first aspect or an example thereof.

[0061] Thereby, the sulfur-reactive element is located in the sensor device, for example on a wall of the measurement chamber. Here, the sulfur-reactive element is arranged in fluid communication with the interior volume to thereby fluidly contact the fluid to be analysed when the interior volume receives the fluid to be analysed.

[0062] In examples according to the present disclosure, the analyser apparatus further comprises a fluid conduit which is fluidly coupled with the chamber inlet for providing the fluid to be analysed or an anti-bacterial rinse fluid to the interior volume.

[0063] Such a fluid conduit may, for example, be a feed line or a fluid line of the analyser apparatus.

[0064] In examples according to the present disclosure, the sulfur-reactive element is located externally from the sensor device, for example in the fluid conduit of the analyser apparatus.

[0065] In examples according to the present disclosure, the sulfur-reactive element is located in the fluid conduit.

[0066] For example, the sulfur-reactive element may be located in the fluid conduit, the fluid conduit being upstream of the sensor device.

[0067] Thereby, precipitation of sulfur onto the reference electrode may be minimized.

[0068] Use

[0069] A third aspect of the present disclosure relates to use of a sulfur-reactive element to capture sulfur-containing compound in a sensor device, wherein the sensor device is for an analyser apparatus configured to analyse parameters of medical fluid samples, wherein the sensor device comprises: a measurement chamber defining an interior volume for receiving a fluid to be analysed; a chamber inlet and a chamber outlet each respectively providing a respective fluid passage to the interior volume; a reference electrode in fluid communication with the interior volume; and one or more ion-selective analyte sensors, wherein each of the analyte sensors comprises a sensor electrode and an ion-selective sensor membrane arranged between the interior volume and the sensor electrode, wherein the sensor device comprises the sulfur-reactive element, the sulfur-reactive element arranged in fluid communication with the interior volume to thereby capture the sulfur-containing compound in the interior volume.

[0070] Use according to the third aspect of the present disclosure may generally provide the same or similar effects and advantages as provided by a sensor device according to the first aspect of the present disclosure. Thereby, use according to the third aspect may reduce or eliminate precipitation of sulfur on the reference electrode, and in turn, measurement errors may be reduced or eliminated and excessive replacement of the sensor device may be avoided.

[0071] In examples according to the present disclosure, the sensor device of the third aspect is a sensor device according to the first aspect or an example thereof.

[0072] In examples according to the present disclosure, at least an anti-microbial rinse fluid chemically reacts with the sulfur-reactive element or metal ions released from the sulfurreactive element to capture the sulfur-containing compound.

[0073] In examples according to the present disclosure, at least an anti-microbial rinse fluid and / or blood residues chemically react with the sulfur-reactive element or metal ions released from the sulfur-reactive element to capture the sulfur-containing compound.

[0074] In examples according to the present disclosure, the sulfur-reactive element chemically reacts with methylisothiazolinone of the anti-microbial rinse fluid to capture the sulfur- containing compound.

[0075] In examples according to the present disclosure, the sulfur-reactive element chemically reacts with methylisothiazolinone of the anti-microbial rinse fluid and the blood residues to capture the sulfur-containing compound.

[0076] Manufacturing

[0077] A fourth aspect of the present disclosure relates to a method for manufacturing a sensor device according to the first aspect of the present disclosure or an example thereof, the method comprising a step of providing an electrode material onto different separate positions of a wall of the measurement chamber to manufacture the sulfur-reactive element and a portion of one or more metabolite sensors, for example one or more metabolite electrodes of the one or more metabolite sensors.

[0078] Hence, the sulfur-reactive element and a portion of one or more metabolite sensors can be manufactured using the same material, i.e., the electrode material, and, preferably, in a single manufacturing step, thereby simplifying the manufacturing process.

[0079] In examples according to the present disclosure, the step of providing electrode material is performed to concurrently manufacture the sulfur-reactive element and the portion of the one or more metabolite sensors, for example using any of inkjet printing, physical vapour deposition such as plasma sputtering, thick-film screen printing, chemical vapour deposition, and electrodeposition.

[0080] By utilizing any of the above-exemplified technologies, the electrode material can be applied onto separate regions of a substrate to thereby form the sulfur-reactive element and a portion of the one or more metabolite sensors. In the manufactured sensor device, this substrate may then constitute a wall of the measurement chamber.

[0081] BRIEF DESCRIPTION OF THE DRAWINGS

[0082] Embodiments of the invention will now be further described by reference to the accompanying drawings, in which:

[0083] Fig. 1 illustrates a sensor device according to the present disclosure,

[0084] Fig. 2 illustrates a sulfur-reactive element located on a diffusion-tight diaphragm of a reference electrode according to the present disclosure,

[0085] Fig. 3 illustrates an analyser apparatus according to the present disclosure with various exemplary placements of a sulfur-reactive element, and

[0086] Fig. 4 illustrates experimental data indicative of performance of a reference electrode with and without the presence of a sulfur-reactive element. DETAILED DESCRIPTION

[0087] It should be understood that the detailed description and specific examples, while indicating embodiments of the disclosure, are given by way of illustration only, since various changes and modifications within the spirit and scope of the disclosure will become apparent to those skilled in the art from this detailed description.

[0088] Fig. 1 illustrates a sensor device 60 according to the present disclosure.

[0089] The sensor device 60 comprises a measurement chamber 2 defining an interior volume 82 for receiving a fluid to be analysed. A chamber inlet 6 and a chamber outlet 7 each provide a fluid passage to this interior volume 82 from an exterior of the sensor device.

[0090] Prior to insertion of the sensor device 60 into an analyser apparatus, the interior volume will typically be filled with a gas such as atmospheric air or an inert gas. When in use, a fluid to be analysed can be provided via the chamber inlet 6 from the exterior of the sensor device 60, for example via an analyser apparatus. The fluid to be analysed can leave the interior volume 82 via the chamber outlet 7. Further, the sensor device 60 may also receive other liquids during use, for example an idling liquid, such as an anti-bacterial rinse fluid, in between measurements.

[0091] The sensor device 60 further comprises a reference electrode 5 and ion-selective analyte sensors 39a-c. These are configured to measure a difference in electrical potential across a fluid to be analysed present in the interior volume 82. Each analyte sensor 39a-c comprises a respective sensor electrode 42a-c and a respective ion-selective sensor membrane 43a-c arranged between the interior volume and the respective sensor electrode.

[0092] The sensor device 60 of the present example comprises three ion-selective analyte sensors 39a-c. Of these, a first analyte sensor 39a comprises a first sensor electrode 42a and a first ion-selective sensor membrane 43a arranged between the interior volume 82 and the first sensor electrode 42a, a second analyte sensor 39b comprises a second sensor electrode 42b and a second ion-selective sensor membrane 43b arranged between the interior volume 82 and the second sensor electrode 42b, and a third analyte sensor 39c comprises a third sensor electrode 42c and a third ion-selective sensor membrane 43c arranged between the interior volume 82 and the third sensor electrode 42c.

[0093] Each of the ion-selective sensor membranes 43a-43c are configured to allow voltage measurement of a specific ion in a liquid medium, i.e., a specific electrolyte, for example Li+, Na+' K+' Ca2+, Mg2+, Cl’, HCO3’, NH4+, or a combination thereof. Such measurements may be performed by measuring a difference in electrical potential between the reference electrode 5 and a specific ion-selective analyte sensor 39a-c, for example by a potentiometric method. Thereby, an indication of an electrolyte ion concentration may be obtained.

[0094] In typical examples according to the present disclosure, measurements can be performed when the sensor device 60 is inserted into an analyser apparatus, which then performs the measurement via electrical communication with the reference electrode and one or more of the sensor electrodes 42a-c. The analyser apparatus may for example have a processing unit configured to conduct the measurement. However, in alternative examples, the measurement may also be performed by means of a processing unit in the sensor device 60. For example, a sensor device may comprise a measurement system configured to read out and / or gather signals between the reference electrode 5 and one or more of the analyte sensors 39a-c.

[0095] The sensor device 60 illustrated in Fig. 1 additionally comprises a sulfur-reactive element 81 arranged in fluid communication with the interior volume 82. Thereby, the sulfur- reactive element 81 is arranged to fluidly contact any fluid received by the interior volume 82, such as a fluid to be analysed, or an anti-bacterial rinse fluid. This is in contrast with the sensorelectrodes 42a-c which do not fluidly contact fluids received by the interior volume due to the presence of ion-selective sensor membranes 43a-c.

[0096] In the embodiment illustrated in Figure 1, the sulfur-reactive element 81 is located on a wall of the measurement chamber 2. This wall is located opposite to the reference electrode 5 (relative to the interior volume 82).

[0097] Further, both the reference electrode 5 and the sulfur-reactive element 81 are located at an outlet end of the measurement chamber 2, i.e., the end of the measurement chamber 2 at which the chamber outlet 7 is located.

[0098] In this particular example, both the sensor electrodes 42a-c and sulfur- reactive element 81 are formed primarily using Ag as material.

[0099] Due to the presence of the sulfur-reactive element 81, precipitation of sulfur onto the reference electrode is reduced.

[0100] For example, in between measurements, an anti-bacterial rinse fluid comprising methylisothiazolinone may be provided to the interior volume 82. In cases where the sensor device does not comprise a sulfur- reactive element, methylisothiazolinone or impurities from it can potentially cause precipitation of sulfur in the form of Ag?S on the reference electrode 5. However, when a sulfur-reactive element 81 is present, the methylisothiazolinone of the anti-microbial rinse fluid will tend to react with this sulfur-reactive element 81 instead of precipitating onto the reference electrode.

[0101] The illustrated sensor device 60 is suitable for insertion / engagement with an analyser apparatus. The sensor device 60 may thereby comprise an electrical device interface (not shown) for electrical communication with an electrical apparatus interface. In such examples, the reference electrode and the one or more analyte electrodes are electrically connected to the electrical device interface. Optionally, the sulfur-reactive element may also be electrically connected to such an electrical device interface, for example for the purpose of using the sulfur-reactive element for electrical grounding.

[0102] Additionally, the sensor device may optionally comprise other elements and corresponding interfaces for connecting these elements to an analyser apparatus. For example, the sensor device may comprise other sensor types, such as optical sensors, chemical sensors, and / or sensors utilizing other sensing technologies. Further, a sensor device may comprise heating element configured to be controlled by an analyser apparatus.

[0103] In an alternative example, a sensor device as illustrated in Fig. 1 additionally comprises one or more metabolite sensors, for example supplementing or replacing some of the illustrated ion-selective analyte sensors. Such a metabolite sensor may, for example, be positioned in the sensor device similarly to the positioning of the ion-selective analyte sensor at reference numeral 39c in Fig. 1.

[0104] Fig. 2 illustrates a sulfur-reactive element 81 located on a diffusion-tight diaphragm 52 of a reference electrode 5 according to the present disclosure. The illustration is provided as a cross-sectional view.

[0105] In some sensor devices according to the present disclosure, the reference electrode 5 comprises a reference electrode liquid 51 and a diffusion-tight diaphragm 52 arranged between the interior volume 82 of the sensor device and the reference electrode liquid as illustrated in Fig. 2. The diffusion-tight diaphragm 52 has a through-orifice 53 covered by a reference electrode membrane 55 permitting diffusion of ions therethrough. In this particular example, the reference electrode membrane 55 comprises two sub-membranes: a porous polycarbonate, polyester (PET) or polyimide (PI) membrane and a cellophane, polyurethane, cellulose acetate, or cellulose acetate butyrate membrane. The diffusion-tight diaphragm is formed of a polyester material. The reference electrode liquid is a saturated AgCI solution. The reference electrode 5 further comprises a reference electrode pin 54 in contact with the reference electrode liquid 51 for electrical contact when measuring the electric potential in a fluid to be analysed.

[0106] In the illustrated example, the sulfur-reactive element 81 is placed on the diffusion-tight diaphragm 52 next to the through-going orifice 53. The sulfur-reactive element 81 may for example be arranged as spots or as a ring around the through-going orifice 53.

[0107] Due to the placement directly adjacent the through-going orifice 53, precipitation of sulfur onto the reference electrode 5, specifically precipitation of sulfur at the through-going orifice 53, is efficiently reduced.

[0108] Note that the sulfur-reactive element 81 is not drawn to scale in Fig. 2. In some examples, the sulfur-reactive element is provided as a sheet, coating, or a layer of material, for example manufactured by sputtering. In some examples, the reference electrode membrane and / or the diffusion-tight diaphragm is manufactured as a composite reference electrode membrane and / or a composite diffusion-tight diaphragm in which the sulfur-reactive element is integrated.

[0109] Fig. 3 illustrates an analyser apparatus 1 according to the present disclosure with various exemplary placements of a sulfur-reactive element 81a-e.

[0110] The analyser apparatus 1 comprises an enclosure 40 configured to receive a sensor device 60, such as the sensor device illustrated in Fig. 1. The enclosure 40 is further configured to affix the sensor device within the analyser apparatus 1 and enable various communications between the sensor device and other components of the analyser apparatus, such as the processing unit 8 and the liquid handling system 20.

[0111] In the present illustration, reference numerals have been omitted from most elements of the sensor device to avoid obscuring the figure with unnecessary details. However, for the sake of understanding the functionality of the analyser apparatus 1, the elements of the sensor device 60 may be assumed to be the same as those described in relation to Fig. 1.

[0112] The analyser apparatus comprises a processing unit 8 in communication with the sensor device 60.

[0113] This processing unit 8 is configured to process measurements of a fluid to be analysed in the sensor device 60, such as measurements of electrical potential in the fluid to be analysed, using the reference electrode and the ion-selective analyte sensors of the sensor device 60. The processing unit 8 may comprise or communicate with a voltmeter for measuring electrical potential(s) between the reference electrode and one or more sensor electrodes.

[0114] The processing unit 8 may further be configured to control the liquid handling system 20, to perform analysis of measurements, to serve results from measurements and / or results from analysis of measurements to a user or an external device, to control other various components of the analyser apparatus 1, or any combination thereof. Other components of the analyser apparatus 1 may for example be valves, sensors (in or external to the sensor device 60), a temperature regulation unit, or some combination thereof.

[0115] The analyser apparatus 1 comprises a liquid handling system 20. The liquid handling system 20 comprises a pump 23 fluidly connected to the chamber outlet of the sensor device 60. The liquid handling system 20 further comprises a fluid selector arrangement 22 fluidly connected to the pump 23 and to the chamber inlet of the sensor device 60. The fluid selector arrangement 22, the sensor device 60, and the pump thereby form a fluid liquid circuit path through which the pump 23 may pump liquid.

[0116] The liquid handling system further comprises process liquid reservoirs 21 and a waste reservoir 24 fluidly connected to the fluid selector arrangement 22. The process liquid reservoirs 21 may comprise various individual reservoirs of process liquids, such as antibacterial rinse fluid, and liquids with known compositions for calibration and quality control purposes. The waste reservoir 24 is intended to receive fluid after it has been passed through the sensor device. The fluid selector arrangement 22 is configured to select a fluid from the process liquid reservoirs 21 based on a given process step. The fluid selector arrangement 22 may for example do so by controlling valves, based on a signal from the processing unit 8. Thereby, a relevant fluid can be transferred from the process liquid reservoirs 21 via the fluid selector arrangement 22 to the sensor device 60 using the pump 23, which also further transfers fluid into the waste reservoir 24.

[0117] The analyser apparatus 1 also comprises two feed lines 12a-b, through which a user may provide a liquid sample. The connection from the inlet of the sensor device 60 to the fluid selector arrangement 22 further constitutes a third feed line 12c. Thereby, three feed lines 12a-c are available for supplying a fluid to the sensor device 60.

[0118] As described in relation to Figs. 1 and 2, a sulfur-reactive element may be located within the sensor device 60. However, alternatively, the sulfur-reactive element may also be located externally from the sensor device 60 within the analyser apparatus 1. Fig 3 illustrates various exemplary placements of such a sulfur-reactive element. The figure illustrates a first sulfur- reactive element 81a located on a wall of the measurement chamber 2 of the sensor device as also illustrated in Fig. 1. A second sulfur-reactive element 81b is located in a fluid line 15a between the feed lines 12a-12c and the chamber inlet of the sensor device 60. A third sulfur-reactive element 81c is located in a feed line 12a which provides fluid communication with the sensor device from an external source, for example through which a user may provide a liquid sample. A fourth sulfur-reactive element 81d is located in a feed line 12c fluidly connecting the fluid selector arrangement 22 to the chamber inlet of the sensor device 60. A fifth sulfur-reactive element 81e is located in a fluid line 15b between the process liquid reservoirs 21 and the fluid selector arrangement 22.

[0119] The several sulfur-reactive elements 81a-e are all illustrated primarily for the purpose of clarifying exemplary locations rather than for the purpose of limitation. In typical examples, an analyser apparatus 1 comprises just one, or potentially a few sulfur reactive elements 81a-e, for example directed at a specific section of the analyser apparatus 1.

[0120] Fig. 4 illustrates experimental data indicative of performance of a reference electrode with and without the presence of a sulfur-reactive element.

[0121] Sensor devices as schematically illustrated in Fig. 1 were used in an analyser apparatus as schematically illustrated in Fig. 3. Five sensor devices with a sulfur-reactive element formed by Ag / AgCI, and five sensor devices without a sulfur-reactive element were tested. Each sensor device was subjected to 1200 samples over 28 days. In between samples, antibacterial rinse fluid was transferred to the interior volume of the sensor device.

[0122] During the measurement period, the reliability of the reference electrode was tested, providing a value in potentiometric units indicative of the functionality of the reference electrode. A greater value is indicative of reduced functionality. If the value is greater than 1 potentiometric unit in two consecutive measurements, the sensor device is disposed.

[0123] In Fig. 4, the left-hand panel shows the results from sensor devices without a sulfur- reactive element, and the right-hand panel shows the results from sensor device with a sulfurreactive element. The horizontal axis provides the number of days in which a given sensor device has been in the analyser apparatus. The vertical axis provides the value indicative of the functionality of the reference electrode in potentiometric units.

[0124] Each different type of symbol plotted in the panels correspond to specific sensor device and is plotted together with a respective trend line. A comparison between the left-hand panel and the right-hand panel evidently exhibits that the functionality of sensor devices, specifically the functionality of the reference electrode, declines significantly during the measurement period for the sensor devices in which a sulfurreactive element is absent. For several of these devices, the value indicative of functionality of the reference electrode rises to 0.8-1.0 after 15 to 28 days, which indicates a reduced functionality. In contrast, for sensor devices comprising a sulfur-reactive element, almost all measurements of the value indicative of the functionality of the reference electrode lie significantly below 0.8 within the measurement period.

[0125] Accordingly, the provision of a sulfur-reactive element can reduce measurement errors and avoid untimely and excessive replacement of the sensor device.

[0126] Various versions and elements of the invention have been exemplified for the purpose of clarification rather than limitation. Well-known details of methods and systems have been omitted to not obscure the content of the disclosure with redundancy. Various elements and features of the invention and this disclosure may be combined in any way possible within the scope of the claims.

[0127] List of figure references:

[0128] 1 analyser apparatus

[0129] 2 measurement chamber

[0130] 5 reference electrode

[0131] 6 chamber inlet

[0132] 7 chamber outlet

[0133] 8 processing unit

[0134] 12 feed line

[0135] 15 fluid line

[0136] 20 liquid handling system

[0137] 21 process liquid reservoirs

[0138] 22 fluid selector arrangement

[0139] 23 pump

[0140] 24 waste reservoir

[0141] 39 ion-selective analyte sensor

[0142] 40 enclosure

[0143] 42 sensor electrode

[0144] 43 ion-selective sensor membrane

[0145] 51 reference electrode liquid

[0146] 52 diffusion-tight diaphragm

[0147] 53 through-going orifice 54 reference electrode pin

[0148] 55 reference electrode membrane

[0149] 60 sensor device

[0150] 81 sulfur-reactive element 82 interior volume

Claims

CLAIMS1. A sensor device (60) for an analyser apparatus (1) configured to analyse parameters of medical fluid samples, the sensor device (60) comprising : a measurement chamber (2) defining an interior volume (82) for receiving a fluid to be analysed; a chamber inlet (6) and a chamber outlet (7), each respectively providing a respective fluid passage to the interior volume (82); a reference electrode (5) arranged in fluid communication with the interior volume (82); and one or more ion-selective analyte sensors (39a, 39b, 39c), wherein each of the analyte sensors (39a, 39b, 39c) comprises a sensor electrode (42a, 42b, 42c) and an ion-selective sensor membrane (43a, 43b, 43c) arranged between the interior volume (82) and the sensor electrode (42a, 42b, 42c), wherein each of the analyte sensors (39a, 39b, 39c) is configured to measure a difference in electric potential between the reference electrode (5) and the analyte sensor (39a, 39b, 39c) across the fluid to be analysed when the interior volume (82) receives the fluid to be analysed; wherein the sensor device (60) further comprises: a sulfur- reactive element (81) arranged in fluid communication with the interior volume (82) to thereby fluidly contact the fluid to be analysed when the interior volume (82) receives the fluid to be analysed.

2. A sensor device (60) according to claim 1, wherein the sulfur-reactive element (81) comprises a metal.

3. A sensor device (60) according to claim 2, wherein the sulfur-reactive element (81) comprises a metal salt, for example a metal chloride, such as e.g. AgCL4. A sensor device (60) according to any one of claims 2 or 3, wherein the metal of the sulfur-reactive element (81) comprises a metal from groups 3-15, preferably from groups 3- 12, more preferably Ag, Zn, Fe, Cu, Ni, Tl, Pb, Cd, Co, or Hg.

5. A sensor device (60) according to any of the preceding claims, wherein the reference electrode (5) comprises a reference electrode liquid (51) and a diffusion-tight diaphragm (52) arranged between the interior volume (82) and the reference electrode liquid (51), the diffusion-tight diaphragm (52) having a through-going orifice (53) covered by a reference electrode membrane (55) permitting diffusion of ions therethrough.

6. A sensor device (60) according to any of the preceding claims, wherein the measurement chamber (2) has an inlet end and an outlet end, the chamber inlet (6) being located at the inlet end and the chamber outlet being located at the outlet end, wherein the reference electrode (5) and the sulfur-reactive element (81) are both located at one end of the inlet end and the outlet end.

7. A sensor device (60) according to any of the preceding claims, wherein the sulfur-reactive element (81) is located on a wall of the measurement chamber (2), preferably a wall of the measurement chamber (2) opposite to the reference electrode (5).

8. A sensor device (60) according to any claims 5-6, wherein the sulfur-reactive element (81) is located on the reference electrode membrane (55) or the diffusion-tight diaphragm (52), for example around the through-going orifice (53).

9. A sensor device (60) according to any of the preceding claims, wherein the reference electrode (5) has an active electrode area defined by a conductive surface area of the reference electrode (5) in communication with the interior volume (82), for example defined by the through-going orifice (53), wherein the sulfur-reactive element (81) has an active sulfur-reactive area defined by a surface area of the sulfur-reactive element (81) in communication with the interior volume (82), wherein the active sulfur-reactive area is greater than the active electrode area, for example at least two times greater, for example at least three times greater, such as at least five times greater than the active electrode surface area.

10. A sensor device (60) according to any of the preceding claims, wherein the active sulfurreactive area is at least 0.1 mm2, for example at least 0.5 mm2, for example at least 1.0 mm2, such as at least 3.0 mm2.

11. An analyser apparatus (1) configured to analyse parameters of medical fluid samples, the analyser apparatus (1) comprising : a sensor device (60), the sensor device (60) comprising a measurement chamber (2) defining an interior volume (82) for receiving a fluid to be analysed, a chamber inlet (6) and a chamber outlet (7) each respectively providing a respective fluid passage to the interior volume (82), a reference electrode (5) in fluid communication with the interior volume (82), and one or more ion-selective analyte sensors (39a, 39b, 39c), wherein each of the analyte sensors (39a, 39b, 39c) comprises a sensor electrode (42a, 42b, 42c) and an ion-selective sensor membrane (43a, 43b, 43c) arranged between the interior volume (82) and the sensor electrode (42a, 42b, 42c); and a processing unit (8) configured to measure a difference in electrical potential between the reference electrode (5) and each of the analyte sensors (39a, 39b, 39c) across the fluid to be analysed when the interior volume (82) receives the fluid to be analysed; wherein the analyser apparatus (1) further comprises: a sulfur-reactive element (81) arranged in fluid communication with the interior volume (82).

12. Use of a sulfur-reactive element (81) to capture a sulfur-containing compound in a sensor device (60), wherein the sensor device (60) is for an analyser apparatus (1) configured to analyse parameters of medical fluid samples, wherein the sensor device (60) comprises: a measurement chamber (2) defining an interior volume (82) for receiving a fluid to be analysed; a chamber inlet (6) and a chamber outlet (7) each respectively providing a respective fluid passage to the interior volume (82); a reference electrode (5) in fluid communication with the interior volume (82); and one or more ion-selective analyte sensors (39a, 39b, 39c), wherein each of the analyte sensors (39a, 39b, 39c) comprises a sensor electrode (42a, 42b, 42c) and an ion-selective sensor membrane (43a, 43b, 43c) arranged between the interior volume (82) and the sensor electrode (42a, 42b, 42c), wherein the sensor device (60) comprises the sulfur-reactive element (81), the sulfur-reactive element (81) arranged in fluid communication with the interior volume (82) to thereby capture the sulfur-containing compound in the interior volume (82).

13. Use according to claim 12, wherein at least an anti-microbial rinse fluid chemically reacts with the sulfur-reactive element (81) or metal ions released from the sulfur-reactive element (81) to capture the sulfur-containing compound.

14. A method for manufacturing a sensor device (60) according to any of claims 1-10, the method comprising a step of providing an electrode material onto different separate positions of a wall of the measurement chamber (2) to manufacture the sulfur-reactive element (81) and a portion of one or more metabolite sensors, for example one or more metabolite electrodes of the one or more metabolite sensors.

15. A method according to claim 14, wherein the step of providing electrode material is performed to concurrently manufacture the sulfur-reactive element (81) and the portion of the one or more metabolite sensors, for example using any of inkjet printing, physical vapour deposition such as plasma sputtering, thick-film screen printing, chemical vapour deposition, and electrodeposition.

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