JPS59120843A - Examination paper for measuring specific gravity - Google Patents

Abstract

PURPOSE:To simply and accurately measure the specific gravity of urine by using a refractive index-urine specific gravity conversion table, by a method wherein synthetic resin paper having specific communication porous structure is impregnated with urine to be examined and light reflectivity or light permeability changed by the penetration of urine is calculated to calculate the refractive index of urine. CONSTITUTION:Synthetic resin paper having a porous structure communicated from the surface to the interior thereof of which the pore void is 0.1-10mum, the void ratio is 50vol% or more and the range of the refractive index is 1.35-1.59 is prepared from polypropylene, styrene resin or polycarbonate. This paper is cut into a predetermined dimension and adhered to a support 2 comprising synthetic resin as examination paper 1. This examination paper 1 is immersed in urine to be examined and, after moisture is lightly shaken off, the reflectivity or the permeability of the examination paper 1 is measured by a spectrophotometer using a tungsten lamp 3 as a light source. For example, reflectivity is measured by an apparatus having an integration sphere 8 and a detector 9 while a refractive index is calculated from reflectivity and the specific gravity of urine is calculated from a specific gravity-refractive index conversion table preliminarily calculated from urine with known specific gravity.

Description

[Detailed description of the invention] The present invention relates to a specific gravity test strip.

Urine specific gravity has traditionally been tested in clinical tests. The Baume method using a float and the gravimetric method using a specific gravity bottle are commonly used to measure urine specific gravity. However, when these methods are used, it is troublesome to clean the float and pycnometer after use, resulting in a feeling of uncleanness.For this reason, recently test strips coated with polymer [lyte] have been used. has been done. In this method, hydrogen ions released from a polymer electrolyte in response to the ion concentration of solutes in urine react with a pH indicator, resulting in a color change, and the specific gravity of the bed is tested based on the color tone.

If you use test strips like this, the measurement time will be short.
This method has advantages over the gravimetric method and the like in that it does not require correction due to temperature. However, such test strips reflect only the degree of ionic substances in urine, and do not reflect urea, which is the main component in urine.
Since the concentration of glucose is not relevant, the apparent specific gravity does not change even if the concentration of urea or glucose changes, so there is a drawback that the measured value does not correspond to the actual urine specific gravity.

The present invention was made with the aim of eliminating such drawbacks, and its gist is that it is made of a synthetic resin material having a porous structure that communicates from the surface to the inside, and has cough pores 9i, m.
The pores forming the structure are 01 to 10 μm, the porosity is 50 μm or more, and the refractive index is in the range of 135 to 1.59.

Next, the test paper for measuring specific gravity of the present invention will be explained in more detail.

The test strip in the present invention is made of a film-like synthetic lintel having a porous structure that communicates from the surface to the inside. Suitable synthetic resins include, for example, polyolefin resins, styrene resins, vinyl chloride resins, vinyl acetate resins, (meth)acrylic acid resins, polyamide plum fat, polycarbonate plum fat, and the like. The pores forming the porous structure are preferably larger than the wavelength of the spectrophotometric needle used for measurement and have a size of 0.1 to 10 μm so as to increase the light reflectance per unit area. The porosity of the synthetic resin material is preferably Ic, 50 vol or more, so that it can be sufficiently impregnated with urine. The refractive index of the synthetic plum fat H is 20°C
The range of 1.34 to 1.59 is preferable. The synthetic resin material preferably does not contain colorants, fillers, stabilizers, etc. that absorb or reflect light.

When measuring the specific gravity of urine using a test strip, the test strip is impregnated with urine. Urine penetrates into the pores of the test strip by capillary action and fills the pores. Before urine is dropped, air is trapped in the pores, so the difference in refractive index between the synthetic resin that forms the test strip and the air is large, so the test strip reflects light (although it is opaque, it does not absorb urine). When it permeates, the difference in refractive index with the synthetic resin becomes smaller, making the test strip nearly transparent.Therefore, by measuring the transmittance or reflectance of this test strip with a spectrophotometer, you can determine the specific gravity of the urine. Yes, when the pores are filled with urine and a spectrophotometer is used to shine light onto the test paper, the light is reflected at the interface between the urine and the synthetic wax.
This reflection becomes larger as the difference in refractive index between the two becomes larger. Therefore, when the specific gravity of urine increases, the refractive index of urine becomes high, and the reflectance and transmission become correspondingly high.

By the way, the clinically significant range of urine specific gravity is 1. o o
.

~1.040, which is converted to the refractive index of urine (!
: Within the range of L a s to 1,35. However, if a test paper with a refractive index within the range of 1.33 to 1.35 is used, it will apparently show the same value as the refractive index of the floor, so it cannot be used.

Therefore, the test paper according to the present invention has a 1.35 to 1,59
Use test strips with a refractive index of

Next, a method of measuring urine specific gravity using the above test strip will be explained.

Test paper 1 is synthesized as shown in Figure 1! It is supported by a support 2 made of M resin, celluloid, paper, etc. Holding the support 2, dip this test strip 1 into 4* urine to impregnate the holes in the test strip with urine. Next, this test strip 1 is placed in a spectrophotometer, the reflectance or transmittance of the test strip is measured using the tungsten lamp 3 as a light source, and the urine specific gravity is determined from a urine specific gravity-refractive index conversion table.

Aperture with 4L heat source absorption filter 5 attached, 6
Optical lens, 7 cane interference filter, shy sphere, 9L
It is a photodetector.

According to the test paper for specific gravity measurement of the present invention, there is no need to use a float or a pycnometer as in conventional measurement methods, and the porous structure of the synthetic bath fat material is filled with the object to be measured such as urine. The specific gravity can be determined simply by measuring the reflectance or transmittance of the test paper.

Example 1 A polyethylene porous film (average pore FJE o, s μm) with a thickness of 50 μm and a refractive index of 1.51 at 25° C.
F@Xl0IB was cut and fixed to approximately the center of a transparent film support made of polyethylene glycostyrene using an adhesive to obtain a test paper. Next, as a urine mock test solution, urea and sodium chloride, which are the main components of urine, were dissolved in distilled water to prepare the following test solution.

The test solution (11 distillation 7 only, with a refractive index of 1.3390 at 25°C (2 fl)) contains urea 2LO1 sodium chloride 1.21
7d, 1 is dissolved and the refractive index at 25°C is 1.34.
59 things (3) (1) Urine X'Os Sodium chloride 2, a
The refractive index at 25°C is 1.3 when y/d and e are dissolved.
511 Soak a test paper in these test solutions, lightly drain the water, and measure the absorbance of test solutions (1), (2), and (3) using a spectrophotometer. Test solution (2), (
Figure 3 shows the results of plotting the absorbance difference with 3) and the refractive index. , the refractive index in the clinically relevant range of urine is 13
3 to 1.35, but there was a positive correlation between the refractive index and the change in polarity -1 (difference in absorbance) almost within that range.

In addition, absorption, luminous intensity difference: Absorbance of test solution (1) - test solution (1), (
2) and (3).

Example 2 A polypropylene porous film with a refractive index of 1.49 and a thickness of 50 pm was used.The absorbance of the sample was measured using the same treatment, test solution, and equipment as in Example 1. The difference in absorbance between 1::rfefo and the ST solution 2.3 was 0.11 and 0.21, respectively, and a good positive correlation with the refractive index was obtained.

Comparative Example The absorbance was measured using the same treatment, test solution, and equipment as in Comparative Example, except that a porous polystyrene film with a refractive index of 1.59 and a thickness of 50 μm was used. As a result, the absorbance of test solution 1 was The absorbance difference between the two and the liquid 2.3 was 10, 12, and 0,06, respectively, so a good correlation with the refractive index could not be obtained.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an example of the test paper for measuring specific gravity of the present invention;
FIG. 2 is a front view showing an example of specific gravity measurement mode, and FIG. 3 is a graph showing the relationship between refractive index and absorbance in Example 1. Patent Applicant Sekisui Chemical Co., Ltd. Representative Kirin Fujinuma 1 fig.

Claims (1)

[Claims] 1. Made of synthetic resin H having a porous structure communicating from the surface to the inside, the pores forming the porous structure are 01 to 1.
A test paper for measuring specific gravity, which has a diameter of 0.071 m, a porosity of 5.0 m or more, and a refractive index of 1.35 to 1.59.