JPH0510940A - Analytical element - Google Patents

Abstract

PURPOSE:To reduce dispersion in analytical values and to obtain a multilayer analytical element of low cost by a method wherein the total quantity of an object of analysis, a substance similar to the object of analysis and an impediment of the object of analysis contained in the layer of the element is made to be a specified quantity or less. CONSTITUTION:In a multilayer analytical element having a reagent layer and a porous development layer provided on a substrate, the total quantity of an object of analysis, a substance similar to the object of analysis and an impediment of the object of analysis contained in the layer is controlled to be a quantity corresponding to 1/4 of a detection limit. The quantity corresponding to 1/4 of the detection limit is defined by [the quantity corresponding to 1/4 of the value of the detection limit] = 1/4X(the detection limit value)divided by (a specimen supply amount) divided by (the area of development by a specimen supply amount). As for a means for controlling the total quantity of the object of analysis, the substance similar to the object of analys and the impediment of the object of analysis in the layer, treatment by cation-exchange resin, anion-exchange resin or chelating resin, or a washing means by deionization water, can be mentioned.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an analytical element for metal ions and electrolytes.

[0002]

BACKGROUND OF THE INVENTION For example, analytical elements for measuring metal ions and electrolytes have been proposed. That is, a reagent layer containing a reagent that reacts with a metal ion or an electrolyte is provided on a support, and above it, an analytical element provided with a porous development layer composed of, for example, a filter paper raw material fiber substance and a binder resin. Proposed.

Incidentally, it has been pointed out that there are variations in the analysis values even though highly pure reagents and the like in the reagent layer are used.

[0004]

DISCLOSURE OF THE INVENTION As a result of intensive investigations on the above problems, the problem of variation is that the porous developed layer contains an analyte, an analogue of the analyte and an obstacle of the analyte, and We have noticed that these amounts are due to uncontrolled.

For example, when the analyte is an electrolyte such as sodium, potassium, chloro, or a metal ion such as calcium, magnesium, zinc, iron, copper, or inorganic phosphorus, the analyte itself is a reagent. It is contained not only in the layer but also in the porous expanded layer, and when the analyte is sodium ion, it contains an analyte analogue such as potassium ion or lithium ion, and the analyte is potassium ion. In the case where the analytes such as sodium ion and ammonium ion are included, or when the analyte is chlorion, the analytes such as bromide, iodide, nitrate and nitrite are included. Or, when the analyte is calcium ion, the ion of alkaline earth metal such as magnesium ion Such as an analyte analog or an interfering substance that reacts with the analyte such as oxalic acid or its salt and affects the analysis reaction, or when the analyte is magnesium ion It contains an analyte analogue such as an alkaline earth metal ion, or when the analyte is iron ion, it contains an analyte analogue such as copper ion, zinc ion, nickel ion, cobalt ion, or manganese ion. When the analyte is zinc ion, copper ion, iron ion, nickel ion, cobalt ion, manganese ion and similar analogues are included, or when the analyte is inorganic phosphorus, interference of ammonium etc. It has become clear that accurate measurements cannot be made if substances are included.

Therefore, the amount of the analyte, the analogue of the analyte and the obstacle of the analyte contained in each of the layers of the multilayer analytical element in which the reagent layer and the porous spreading layer are provided on the support are zero. Although preferable in terms of analysis accuracy, it is extremely difficult to reduce the amount of the analysis target substance, the analysis target analog, and the analysis target interference to zero, and the cost is high.

Therefore, as a result of further research, if the contents of the analyte, the analogue of the analyte and the interferent of the analyte are below a certain value, they are close to zero and the analysis value is close to zero. It was found that there was no difference and that the variation was very small. Moreover, in such a case,
The purification cost is much lower than that of the case of zero.

The present invention has been achieved on the basis of such knowledge, and an object of the present invention is to provide an analytical element having a small variation in analytical value and a low manufacturing cost. An object of the present invention is a multi-layer analytical element in which a reagent layer and a porous spreading layer are provided on a support, and an analyte, an analyte analogue and an analyte obstruction contained in the above layers. This is achieved by an analytical element in which the total amount is controlled to be equal to or less than 1/4 of the detection limit value.

In the present invention, the value is ¼ of the detection limit value.
The equivalent amount is [amount equivalent to 1/4 of the detection limit value] = 1/4 × (detection amount).
Limit value) / (Sample supply amount) / (Development by sample supply amount
Area) is a quantity defined by. Therefore, in the amount that is uniquely determined
Instead, the amount is determined by each measurement item. example
For example, the detection limit is 1 mg / dl and the sample supply is 10μ.
l, 10 μl of the spotted sample has a developed area of 1 c in diameter
circle of m (about 0.785 cm²) Of the detection limit
The amount corresponding to 1/4 of the value is 1.274 × 10 ^-Fourmg / c
m²= 1.274 mg / m²And less than this amount
There is a need.

As means for controlling the total amount of the analyte, the analogue of the analyte and the interferent of the analyte in the layer, treatment with a cation exchange resin, an anion exchange resin or a chelate resin, or deionization is carried out. A washing means with water can be used. In the case of the substance constituting the porous development layer, especially the filter paper raw material fiber, it is washed with deionized water, or, for example, after the ion exchange resin or chelate resin and the filter paper raw material fiber are mixed, they are separated using the difference in specific gravity. Means are used. The binder resin may be sufficiently washed with, for example, an acid aqueous solution and then washed with deionized water.

[0011]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited thereto. [Example 1] A layer having the following composition was provided on a transparent undercoated polyethylene terephthalate support having a thickness of 180 µm.

[Reagent Layer on Support] Deionized gelatin 15.5 g / m ² Triton X-100 (Rome & Haas Company nonionic surfactant) 1.2 g / m ² 3-cyclohexylaminopropanesulfonic acid 2.8 g / m ² 3,3′-bis [N, N-di (carboxymethyl) aminomethyl] -o-cresolphthalein (OCPC) 180 mg / m ² 8-hydroxyquinoline-5-sulfonic acid 1. 5 g / m ² Bis (vinylsulfonylmethyl) ether 350 mg / m ² Aqueous solution was adjusted to pH 11 with KOH.

[Adhesive layer on reagent layer] Vinylpyrrolidone-vinyl acetate copolymer (manufactured by BASF: copolymerization ratio 2 to 8) 1.5 g / m ² [Development layer on adhesive layer] Filter paper raw material fiber (Toyo Filter paper Co., Ltd. 40-100 mesh) 91.0 g / m ² styrene-glycidyl methacrylate copolymer (copolymerization ratio 2 to 8) 20.0 g / m ² butyl acrylate-acrylamide propane sulfonic acid copolymer (copolymerization ratio 1 to 1) 3.5 g / m ² Triton X-100 9.1 g / m ² However, the materials of the spreading layer and the adhesive layer were deionized. As a result, the total ion content (sum of alkaline earth metal ions such as calcium, magnesium, barium and strontium) was 0.25 mg / m ² .

On the other hand, as a comparative example, an analytical element was prepared using one that was not deionized. The total ion content in this case was 0.42 mg / m ² (Comparative analysis element 1)
Met. Further, an alkaline earth metal ion was added to prepare a sample having a total ion content of 3 mg / m ² (comparative analysis element 2). A calibration curve was prepared using human serum with a known calcium content for the above analytical element. For the measurement, Konica Dry Lab 80M (manufactured by Konica) was used, 10 μl of the sample was spotted on the spreading layer, followed by incubation at 37 ° C. for 7 minutes, and the reflection density was measured using light having a wavelength of 660 nm. It was

The measuring range of the analytical element of the present invention is 1 to 17 m.
g / dl, the comparative analysis element 1 was 1 to 17 mg / dl, and the comparative analysis element 2 was 1 to 15 mg / dl. And the total calcium concentration 1.8 mg / dl, 10.5 mg / dl
And 14.8 mg / dl serum were used to measure 10 times each, and the reproducibility was examined. The results are shown in Table 1.

Table 1 Calcium concentration 1.8 mg / dl 10.5 mg / dl 14.8 mg / dl Inventive average value 1.82 10.45 14.77 Analysis element SD 0.043 0.163 0.315 CV 2 .4% 1.6% 2.1% Comparative analysis average 1.96 10.71 14.26 Element 1 SD 0.089 0.172 0.334 CV 4.7% 1.6% 2.3% Comparison Analysis average value 1.93 10.43 15.24 Element 2 SD 0.098 0.211 0.796 CV 5.1% 2.0% 5.2% As is apparent from Table 1, the analytical element of the present invention. Shows good reproducibility over the entire measurement range. However, in the comparative analysis element 1, the coefficient of variation CV in the lower limit region of the measurement range is twice as large as that of the present invention, and the reproducibility is poor, and in the comparative analysis element 2, the measurement is performed in the comparative analysis element 2. The coefficient of variation CV is not less than twice as large as that of the present invention not only in the lower limit region of the range but also in the upper limit region thereof, and reproducibility is remarkably poor. That is, the total amount of the analyte, the analogue of the analyte, and the interferent of the analyte contained in the layers of the multilayer analytical element in which the reagent layer and the porous spreading layer are provided on the support is 1/4 of the detection limit value. The analytical element controlled to an amount equal to or less than is extremely reproducible and can perform accurate measurement.

Example 2 A transparent undercoating having a thickness of 18
A layer having the following composition was provided on a 0 μm polyethylene terephthalate support. [Support on the reagent layer] deionized gelatin 10.0 g / m ² glutaric acid 4.0 g / m ² Triton X-100 0.6g / m ² alkanol XC (DuPont, anionic surfactant) 0.6 g / m ² dioctyl phenyl phosphate 3.0 g / m ² 3- (2-pyridyl) -5,6-bis (4-sulfophenyl) -1,2,4 - triazine, disodium salt 0.3 g / m ² KOH Adjust to pH 4.0.

[Barrier layer on reagent layer] Deionized gelatin 5.0 g / m ² Triton X-100 0.6 g / m ² Bis (vinylsulfonylmethyl) ether 0.45 g / m ² [Reducing layer on barrier layer ] Poly (vinylpyrrolidone) (BASF Corp., Kollidon K-90) 6.0 g / m ² Ascorbic acid palmitate 1.0 g / m ² Neocuproine 0.45 g / m ² [Development layer on reducing layer] Filter paper raw material fiber (Toyo Roshi Kaisha Ltd. 40 mesh or more) 91.0 g / m ² Triton X-100 9.1 g / m ² Styrene-glycidyl methacrylate copolymer (copolymerization ratio 9: 1) 23.0 g / m ² However, the above each layer of material, iron ions, copper ions, cobalt ions, osmium ion, the total content of 9.55μg / m ² deionized punished as to become the following rubidium ions It was carried out. The total ion content of these is 8.06 μg /
It was m ² .

On the other hand, as a comparative example, a comparative analysis element was prepared without deionization. The total ion content in this case was 15.6 μg / m ² . Various human sera with known total iron ion concentrations were prepared for the above-mentioned analytical element, 10 μl of the sample was spotted on the developed layer of each analytical element, and incubated at 37 ° C. for 7 minutes using Konica Dry Lab 80M. After that, reflection density measurement was performed using a filter of 546 nm, and a calibration curve of each analytical element was created from the result.

The measuring range of the analytical element of the present invention and the comparative analytical element was 30 μg / dl to 600 μg / dl.
Furthermore, the total iron ion concentration is 45 μg / dl, 251 μg
The simultaneous reproducibility was calculated by determining the iron ion concentration using a calibration curve prepared by measuring 10 times using human serum of dl / dl and 583 μg / dl, and the results are shown in Table 2.

Table 2 Total iron ion concentration 45 μg / dl 251 μg / dl 583 μg / dl Average value for the present invention 47.2 253.0 581.6 Analytical element SD 5.31 8.96 16.33 CV 11.3% 3 0.5% 2.8% Comparative analysis average value 48.6 255.1 584.3 element SD 8.86 9.43 18.18 CV 18.2% 3.7% 3.1% It can be seen that the analytical element of the invention has better simultaneous reproducibility near the detection limit value than the comparative analytical element.

Claims (1)

Claim: What is claimed is: 1. A multilayer analytical element comprising a support and a reagent layer and a porous spreading layer provided on the support, wherein the analyte, the analogue of the analyte, and the analysis contained in the layer. An analysis element in which the total amount of target obstacles is controlled to be equal to or less than 1/4 of the detection limit value.