Test setup comprising a test unit with a substrate

Abstract

Test apparatus comprising a test unit (1) with a substrate (2) and at least one test field provided on the surface of the substrate (2) and comprising at least one reagent, characterized in that at least one additional protective agent field (5) is provided on the surface of the substrate (2), which comprises a desiccant and / or an oxygen absorber.

Description

[0001] The present invention relates to a test device comprising a test unit with a substrate and at least one test field which is provided on the surface of the substrate and has at least one reagent.

[0002] Test devices of this type are particularly known as test strips and have been an important component in the field of rapid tests for decades. They allow for the rapid, simple, and semi-quantitative determination of various parameters with unknown concentrations in liquids. The analyte reacts with an indicator or reagent on a test field of the test strip, causing a color reaction or a color change. The reaction color can be evaluated using a color scale. The higher the concentration of the analyte in the tested liquid, the stronger the color reaction.

[0003] For ease of use, reactive test papers are applied as test fields to the strip-shaped substrate. This prevents user contact with the test solution. The test papers can be applied to the substrate using hot-melt glue or double-sided adhesive tape, for example. Multiple test fields on the substrate allow for simultaneous analysis of different parameters.

[0004] Test strips are used, among other things, in urine analysis, in the analysis of swimming pools, aquariums, and surface water. They are also used for the analysis of drinking and feed water, as well as in the analysis of process and wastewater.

[0005] Typically, several test strips are packaged in aluminum or plastic containers, and the containers are sealed with a stopper. A desiccant, such as a molecular sieve or silica gel, is placed in the stopper to protect against moisture. It is also possible to include a desiccant pouch inside the container. The desiccant protects moisture-sensitive test fields such as nitrate, nitrite, peroxide, etc. from moisture and thus from rapid aging. This allows for extended shelf lives of currently one year or more.

[0006] Alternatively, test strips are individually sealed, meaning they are wrapped in aluminum or paper foil. These test strips are typically packaged without a desiccant. This results in a shorter shelf life than test strips packaged in a can containing a desiccant.

[0007] The object of the invention is to further develop a test device of the type mentioned above so that it has improved durability.

[0008] This object is achieved in a test device of the type mentioned at the outset in that at least one protective agent field is additionally provided on the surface of the substrate, which field comprises a desiccant and / or an oxygen absorber.

[0009] The invention is therefore based on the idea of ​​providing an additional protective agent field on the substrate of the test unit itself, in addition to the existing test fields. It has been shown that this measure can significantly extend the shelf life of the test units, as moisture-sensitive and / or oxygen-sensitive test fields or reaction fields are protected from contact with moisture or oxygen, which are absorbed by the desiccant or oxygen absorber. The additional protective agent field can thus significantly increase the storage stability of the test units.

[0010] According to one embodiment of the invention, at least one protective agent field is provided on the surface of the substrate, which field comprises a desiccant, and another protective agent field is provided which comprises an oxygen absorber, and / or at least one protective agent field is provided on the surface of the substrate, which field comprises both a desiccant and an oxygen absorber. In other words, protective agent fields can be provided which comprise both a desiccant and an oxygen absorber. Likewise, protective agent fields can be provided which comprise exclusively a desiccant or exclusively an oxygen absorber. The respective selection depends on how much moisture is to be absorbed or how much oxygen is to be absorbed.

[0011] In a manner known per se, the substrate can be rod-shaped. In this case, the at least one test field and / or the at least one protective agent field can be provided circumferentially on the surface of the rod-shaped substrate.

[0012] Alternatively, the substrate can be strip-shaped, so that the test unit has the shape of a conventional test strip. In this case, the at least one test field is preferably provided on a top side and / or on a bottom side of the strip-shaped substrate, and the at least one protective agent field is provided on the top side and / or on the bottom side of the strip-shaped test field. In other words, the test fields can be provided on both the top side and the bottom side of the substrate. The same applies to the protective agent fields.

[0013] The protective agent fields can be of any size. If the test fields are of a uniform size, it has proven useful for the protective agent field(s) to also be of a corresponding size. In principle, however, the size of at least one protective agent field can be freely selected.

[0014] The same applies to the positioning of the test fields of the at least one protective agent field. One embodiment of the invention is characterized in that at least one test field, in particular all test fields, and at least one protective agent field, in particular all protective agent fields, are provided on the upper side of the strip-shaped substrate.

[0015] In a manner known per se, the desiccant can be a molecular sieve and / or silica gel.

[0016] In a further embodiment of the invention, it can be provided that the additional protective agent field is also applied during the production process of the test units, i.e., the attachment of the test fields to the substrate. Accordingly, a further embodiment of the test devices is characterized in that the protective agent field is applied to the substrate together with the at least one test field in a single operation.

[0017] According to one embodiment of the invention, it is provided that each test unit is individually housed in a package, in particular sealed in an aluminum or paper foil as packaging.

[0018] Alternatively, the packaging may comprise a can, a bag, or a vial. In this case, several test units are contained within the packaging, with a desiccant reservoir being provided in particular.

[0019] It is essential that, according to the invention, the test units are each housed in the respective packaging without the protective agent field being covered, for example, by an adhesive strip, thus protecting them against unwanted moisture contact. Accordingly, the test unit is housed in the packaging with the protective agent field(s) exposed.

[0020] Preferably, the packaging can be a can sealed with a stopper, and a desiccant, in particular a molecular sieve or silica gel, is housed in the stopper. A desiccant bag can also be housed in the packaging. However, due to the protective agent fields provided on the substrates of the test units, additional desiccant in the packaging can be omitted.

[0021] In a manner known per se, several test fields can be provided on the substrate, each containing different reagents.

[0022] For further developments of the invention, reference is made to the following exemplary embodiment of the invention with reference to the accompanying drawing. The drawing shows Fig. 1 a test unit designed as a test strip of a test device according to the present invention in front view.

[0023] In the Fig. Figure 1 shows a test strip representing a test unit 1 of a test device according to the present invention. The test unit 1 comprises a strip-shaped substrate 2. Two test fields 3, 4 are provided on the upper side of the test strip, each containing different reagents and changing color when they come into contact with a given analyte.

[0024] The reagents in test fields 3, 4 are sensitive to moisture. To protect them from unwanted contact with moisture and thus increase their durability, a protective agent field 5 containing a desiccant such as a molecular sieve or silica gel is additionally provided on the top side of substrate 1. If protection against oxygen is also desired because some of the reagents are sensitive to oxygen, protective agent field 5 can also contain an oxygen absorber (= oxygen absorber or oxygen scavenger), or another protective agent field containing an oxygen absorber can be provided on substrate 1.

[0025] Not shown is that the test device comprises, in addition to the test unit 1, a package in which the test unit 1 can be stored. The package can be, for example, an aluminum or paper foil in which the test unit 1 is sealed. Alternatively, the packaging can comprise a can, a bag, or a vial in which several test units 1 are then packaged.

[0026] The protective agent field 5 can be attached to the substrate 2 during the production process of the test unit 1. The protective agent field 5 can thus be combined with one or more parameters. The table below lists seven parameters that were stored under stress conditions with and without a desiccant. For this purpose, test units / test strips were produced with a corresponding test field with and without a protective agent field and individually sealed in aluminum foil. For the parameter nitrate (entry 1), the test field was already discolored in the dry state after stress storage (without protective agent field), so that an unambiguous assignment after immersion in test solutions was no longer possible. A similar result was observed for the parameters nitrite and leukocytes (entries 2 and 3). Both test parameters showed an incorrect color in the dry state after stress storage and a false positive color reaction in a negative test solution.The blood test pad also showed an off-color after storage and a weakened color reaction in the positive test solution (entry 4). The parameters nitrite, leukocytes, blood, density, and pH are frequently determined in urine analysis. The increased stability of individually sealed test strips due to the protective pad increases user-friendliness and the reliability of the analysis results. All parameters were unremarkable both in the dry state and after immersion in test solutions when sealed with a protective pad according to the invention. entry parameter Test strips without protective agent field Test strip with protective agent field 1 nitrate Incorrect color when dry; no clear assignment to the value on the color scale No color errors when dry; correct assignment to the value on the color scale 2 nitrite False color when dry; false positive reaction No color errors when dry; correct assignment to the value on the color scale 3 Leukocytes False color when dry; false positive reaction No color errors when dry; correct assignment to the value on the color scale 4 blood Discoloration when dry; weakened reaction No color errors when dry; correct assignment to the value on the color scale 5 density Incorrect color when dry; no clear assignment to the value on the color scale No color errors when dry; correct assignment to the value on the color scale 5 pH Incorrect color when dry; no clear assignment to the value on the color scale No color errors when dry; correct assignment to the value on the color scale 6 Glycol Incorrect color when dry; no clear assignment to the value on the color scale No color errors when dry; correct assignment to the value on the color scale 7 copper Incorrect color when dry; no clear assignment to the value on the color scale No color errors when dry; correct assignment to the value on the color scale List of reference symbols 1 test unit 2 Substrat 3 Test field 4 Test field 5 Protective agent field

Claims

[1] Test device comprising a test unit (1) with a substrate (2) and at least one test field which is provided on the surface of the substrate (2) and has at least one reagent, characterized by that at least one protective agent field (5) is additionally provided on the surface of the substrate (2), which field comprises a desiccant and / or an oxygen absorber. [2] Test device according to claim 1, characterized by that at least one protective agent field (5) is provided on the surface of the substrate (2), which field comprises a desiccant, and a further protective agent field (5) is provided, which field comprises an oxygen absorber, and / or that at least one protective agent field (5) is provided on the surface of the substrate (2), which field comprises both a desiccant and an oxygen absorber. [3] Test device according to claim 1 or 2, characterized by that the substrate (2) is rod-shaped. [4] Test device according to claim 3, characterized by that the at least one test field (3, 4) and / or that the at least one protective agent field (5) is provided circumferentially on the surface of the rod-shaped substrate (2). [5] Test device according to claim 1 or 2, characterized by that the substrate (2) is strip-shaped. [6] Test device according to claim 5, characterized by that at least one test field (3, 4) is provided on an upper side and / or an underside of the strip-shaped substrate (2), and that at least one protective agent field (5) is provided on the upper side and / or on the underside of the strip-shaped test field. [7] Test device according to claim 6, characterized by that at least one test field (3, 4) and at least one protective agent field (5) are provided on the upper side of the strip-shaped substrate (2). [8] Test device according to one of the preceding claims, characterized bythat the desiccant is a molecular sieve and / or silica gel. [9] Test device according to one of the preceding claims, characterized by that the at least one protective agent field (5) is applied to the substrate (2) together with the at least one test field (3, 4) in one operation. [10] Test device according to one of the preceding claims, characterized by that it further comprises a packaging and the test unit (1) with exposed protective agent field (5) or with exposed protective agent fields (5) is accommodated in the packaging. [11] Test device according to claim 10, characterized by that the test unit (1) is individually housed in a package, in particular sealed in an aluminum or paper foil as packaging. [12] Test device according to claim 10, characterized bythat the packaging comprises a can or a bag or a vial and several test units (1) are packed in the packaging, wherein, in particular, a desiccant depot is additionally provided in the packaging. [13] Test device according to claim 12, characterized by that the packaging is a can closed with a stopper and a desiccant, in particular a molecular sieve or silica gel, is housed in the stopper. [14] Test device according to claim 12, characterized by that the packaging contains a bag of desiccant. [15] Test device according to one of the preceding claims, characterized by that several test fields are provided on the substrate (2), each containing different reagents.

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