Quantitative liquid sample collection stick and use thereof

Abstract

To provide means of easily collecting a fixed amount of a sample solution without spilling dripping.SOLUTION: A stick provided herein is capable of collecting (adsorbing) a fixed amount of a liquid sample at a liquid collection part without dripping when taken out of the liquid sample, and quickly eluting the liquid sample into another solvent when the liquid collection part with the collected liquid sample is immersed in the solvent.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a stick for collecting a fixed amount of a liquid sample, and more particularly to a stick for collecting a fixed amount of a liquid sample having a liquid collection portion arranged on a support, and uses thereof.

[0002] In a laboratory, in order to accurately measure a very small amount of liquid sample, such as 100 μL, a certain amount of liquid is taken using a pipette and then all of the liquid is discharged from the pipette into a solvent. However, correct pipetting operation is required to perform such a process. Unlike researchers who are accustomed to using pipettes on a daily basis, such operations can be very difficult for those who are not accustomed to using pipettes, such as those working in primary industries such as agriculture and fishing, and those who process harvested products. However, in reality, there is no device that can measure a certain amount with a simple operation at processing sites. Summary of the Invention [Problem to be solved by the invention]

[0003] An object of the present invention is to provide a means for easily collecting a fixed amount of a sample solution without dripping. [Means for solving the problem]

[0004] The inventors have conducted extensive research into the configuration of a stick for easily collecting a fixed amount of sample, and have fabricated sticks in which a liquid collection part made of various fibers is arranged on a support of the stick. They have confirmed that when the liquid collection part of each of the sticks fabricated is immersed in a liquid sample and each stick is removed from the liquid sample after a predetermined time, a fixed amount of liquid sample can be collected (adsorbed) in the liquid collection part without dripping, and that when the liquid collection part of the stick from which the liquid sample has been collected is immersed in another solvent, the liquid sample can be quickly dissolved into the solvent, thereby completing the present invention.

[0005] That is, the present invention is as disclosed below. [1] A stick for collecting a fixed amount of a liquid sample, comprising a liquid collection portion disposed on a support. [2] A stick for collecting a fixed quantity of a liquid sample according to [1] above, characterized in that the liquid collection portion consists of a single-layered thin piece. [3] A stick for collecting a fixed quantity of a liquid sample according to [1] or [2] above, characterized in that the liquid collection portion is made of glass fiber. [4] The mass per unit area of ​​glass fiber is 70 to 80 g / m 2 The stick for collecting a fixed quantity of liquid samples according to [3] above, characterized in that: [5] The area of ​​the single-layered slice is 1 to 950 mm 2 The stick for collecting a fixed quantity of liquid samples according to [2] above, characterized in that: [6] The stick for collecting a quantitative amount of a liquid sample according to [2] above, wherein the thickness of the single-layered slice is 0.30 to 0.43 mm. [7] The stick for quantitatively collecting liquid samples according to [1] or [2] above, wherein the amount of liquid sample collected is 4.5 to 100 μg. [8] A stick for collecting a fixed quantity of a liquid sample according to [1] or [2] above, characterized in that the support is made of plastic.

[0006] The present invention is also as disclosed below. [9] A method for quantifying glutamic acid in a sample liquid, comprising: collecting a liquid sample using a stick for quantitatively collecting liquid samples described in any one of [1] to [8] above; and detecting glutamic acid in a test solution obtained by diluting the sample liquid. Effect of the Invention

[0007] According to the present invention, a liquid sample can be collected in a quantitative amount and the collected liquid sample can be completely dissolved in a solvent without special training on the usage procedure. [Brief description of the drawings]

[0008] [Figure 1] 1 shows a schematic diagram of a stick for collecting a fixed amount of liquid sample of the present invention. [Diagram 2] 1 shows an example of the procedure for collecting a liquid sample, commercially available "kelp soup" as a liquid sample, using the liquid sample collecting stick of the present invention for a quantitative amount of liquid sample, and conducting a dissolution test in water. (a) shows the liquid collecting part of the stick being immersed in the "kelp soup". (b) shows the liquid collecting part of the stick being pulled out of the "kelp soup", and then the entire liquid collecting part of the stick being immersed in pure water in a beaker and shaken while still holding the "kelp soup" collected in the liquid collecting part. (c) shows the stick being pulled out of the pure water in the beaker after visually checking whether or not there is any "kelp soup" remaining in the liquid collecting part of the stick. [Diagram 3] These are photographs of the liquid collection parts of the 12 types of materials that make up the liquid collection parts after they have been immersed in kelp soup for 3 seconds, after they have been shaken in water for 5 seconds, and after they have been shaken in water for 10 seconds. [Figure 4] 1 is a graph showing the relationship between the surface area of ​​a single-layered piece of glass fiber constituting a liquid collection portion and the absorbed weight of pure water. [Diagram 5] These are photographs of the liquid collection portion of a liquid sample collection stick, the liquid collection portion of which is made of glass fiber, after it has been immersed in various liquid foods for 3 seconds, after it has been shaken in water for 5 seconds, and after it has been shaken in water for 10 seconds. [Figure 6] This is an example of a color sample for L-glutamic acid test strips. [Figure 7] The degree of color development for each test solution on a test paper for determining the concentration of L-glutamic acid is shown. (1) shows the degree of color development for the control diluted test solution, (2) the diluted test solution prepared using the stick of the present invention, and (3) the diluted test solution for comparison. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] The liquid sample collection stick of the present invention is not particularly limited as long as it is a stick equipped with a liquid collection part arranged on a support, and the term "for collection of a fixed quantity" in the present invention means that it is used to collect a substantially constant, predetermined amount of sample by sampling. The range of the substantially constant, predetermined amount can be 90 to 110% of the weight collected by a liquid sample collection stick of the present invention.

[0010] The support is not particularly limited as long as it allows the liquid collection section to be placed thereon, but the material of the support is preferably a water-impermeable material, and non-porous materials are preferred in that they do not contribute to promoting the absorption of liquid samples. Examples of such materials include plastics such as polystyrene (PS), polypropylene (PP), polyvinyl chloride, and polycarbonate. The support can be made water-impermeable by laminating it with these materials, or a commercially available pre-cut backing sheet, which is a member for supporting and fixing the immunochromatographic strip, can also be used.

[0011] The liquid collection part is preferably one that does not dissolve in or react with the liquid sample, absorbs the liquid sample, and holds a predetermined amount of the absorbed liquid sample without dripping, and is also preferably one that can quickly release the liquid sample when immersed in a solvent that dissolves the liquid sample and shaken, and the material constituting the liquid collection part is preferably a porous material. The shape of the liquid collection part can be a single-layered flake, a cotton swab, a cylinder, a triangular prism, a square prism, or the like.

[0012] Examples of the porous material include glass fiber, cellulose fiber, etc., and the porous material can also be prepared using commercially available filter paper, nonwoven fabric, etc. The term "rapidly" means that the liquid sample collected in the liquid collection part is released from the liquid collection part into the pure water after being shaken in pure water for 10 seconds or more, preferably 5 seconds or more, so quickly that it can be visually determined that the liquid sample has been dissolved in the pure water, and this determination can be easily performed by using a colored liquid sample.

[0013] Examples of the glass fibers include known fibers such as borosilicate glass, quartz glass, soda-lime glass, and lead glass.

[0014] Examples of the cellulosic fibers include plant fibers, which are fibers whose main component is cellulose, extracted from plants such as wood and grass, and regenerated cellulose fibers, which are regenerated fibers made from cellulose as a raw material.

[0015] Examples of the filter paper include known filter papers such as silica filter paper, quartz filter paper, cellulose filter paper, ashless filter paper, and nitrocellulose filter paper.

[0016] Examples of the nonwoven fabric include known nonwoven fabrics such as PET (polyester) nonwoven fabric, PE (polyethylene) nonwoven fabric, PP (polypropylene) nonwoven fabric, PLA (polylactic acid) nonwoven fabric, and cellulose nonwoven fabric, as well as nonwoven fabrics made from regenerated fibers such as rayon and cupra, and natural fibers such as cotton.

[0017] When the liquid collection section is a monolayer flake, the method of arranging it on the support may include a method in which one side of a monolayer flake of the material constituting the liquid collection section is adhered to the surface of a flat support; a method in which one side of the first of two monolayer flakes is adhered to the surface of a flat support and one side of the second monolayer flake is adhered to the back surface of the support, and the two monolayer flakes are arranged on the support so as to sandwich the tip of the flat support; and the like. Examples of the shape of the monolayer flakes include monolayer flakes with a rectangular plane, bellows-shaped monolayer flakes, triangular and more polygonal shapes, but rectangular monolayer flakes are preferred in terms of storage convenience, cost, etc.

[0018] Examples of the method for adhering the liquid collection part to the support include a method of preparing an adhesive part by applying an organic solvent solution containing an adhesive base to the surface of the support on which the liquid collection part is to be placed, and adhering the liquid collection part to the surface of the support, and a method of adhering the liquid collection part by attaching a double-sided tape to the surface of the support. In addition, a method of adhering the liquid collection part by using a support having an adhesive part can be mentioned. Specifically, a method of adhering the liquid collection part by using a commercially available adhesive strip such as a precut backing sheet can be mentioned.

[0019] The position where the liquid collection part is arranged on the support (3) is not particularly limited, but when the stick (1) for collecting a fixed quantity of liquid samples of the present invention is used for a liquid sample, the liquid collection part (2) needs to be immersed under the liquid surface of the liquid sample, and it is preferable that the part from the upper end of the liquid collection part to the other end of the support in the longitudinal direction be a grip part (4) for supporting the stick of the present invention by hand, so that the liquid collection part is preferably arranged at one end of the support in the longitudinal direction. An example of a stick for collecting a fixed quantity of liquid samples in which a flat rectangular single-layered flake is arranged at one end of the support in the longitudinal direction is shown in Figure 1.

[0020] When the liquid collection part is a monolayer flake, the length (vertical width) of the monolayer flake in the longitudinal direction of the support can be 1 to 19 mm, preferably 1.5 to 10 mm, more preferably 2 to 8 mm, and even more preferably 3 to 7 mm. When the monolayer flake is made of glass fiber and has a thickness of 0.43 mm, if the vertical width is 20 mm or more, there is a risk of liquid dripping. The length (horizontal width) of the monolayer flake in the lateral direction of the support is not particularly limited, but can be 1 to 50 mm, preferably 1.5 to 25 mm, more preferably 2 to 15 mm, and even more preferably 2 to 10 mm, for operational reasons.

[0021] The thickness of the single-layer flakes may be, for example, 0.1 to 1 mm, preferably 0.2 to 0.8 mm, more preferably 0.25 to 0.6 mm, and further preferably 0.3 to 0.5 mm.

[0022] Furthermore, the volume occupied by the single-layer flakes of the glass fiber is 0.1 to 950 mm 3 , preferably 0.45 to 200 mm 3 , more preferably 1.0 to 72 mm 3 , and more preferably 1.8 to 35 mm 3 Examples include:

[0023] The mass per unit area of ​​the single-layered flakes of the glass fibers is 30 to 120 g / m 2 and preferably 50 to 100 g / m 2 , more preferably 60 to 90 g / m 2 , and more preferably 70 to 80 g / m 2 Examples include:

[0024] As a method for preparing a liquid collection section for collecting a fixed amount of the above-mentioned liquid sample, when the liquid collection section is a monolayer flake, a method can be mentioned in which the liquid collection section is prepared by adhering a monolayer flake of a predetermined area and / or volume to the above-mentioned support.

[0025] The method for determining the amount of collection of the liquid collection part of the stick for collecting a fixed quantity of liquid samples of the present invention involves attaching a material constituting a liquid collection part with a different area and / or volume to the adhesive part at one end in the longitudinal direction of the support, producing a plurality of sticks (dry) for collecting a fixed quantity of liquid samples with different areas or volumes of the liquid collection part, measuring their weights, immersing the entire liquid collection part of each stick (dry) in pure water for 3 to 10 seconds and then removing it, removing excess pure water on the surface opposite the liquid collection part with a paper towel, measuring the weight of each stick (wet), and determining the weight of pure water absorbed by the liquid collection part by subtracting the weight of the stick (dry) from the weight of the stick (wet). Then, the relationship between the area and / or volume of the liquid collection portion and the measured weight of pure water collected is plotted on a graph, and if the calculated correlation coefficient is 0.99 or higher, it is determined that an approximately constant, predetermined amount of liquid sample can be collected by adjusting the area and / or volume of the liquid collection portion.Then, a stick capable of collecting an approximately constant, predetermined amount of liquid sample can be produced by using a liquid collection portion having the area or volume actually considered, or the area and volume of the material constituting the liquid collection portion can be calculated from the numerical values ​​on the straight line obtained from the graph, and a stick capable of collecting an approximately constant, predetermined amount of liquid sample can be produced.

[0026] The amount of liquid sample that can be collected by the liquid sample quantitative collection stick of the present invention can be 1 to 100 μg, for example, 2 to 70 μg is preferable, 3 to 50 μg is more preferable, and 4 to 40 μg is even more preferable.

[0027] The liquid sample in the present invention is preferably a non-viscous liquid food, and examples thereof include water, liquid soup base, white soup stock, soy sauce, sake, miso soup, milk, soy milk, non-viscous vegetable juice, etc. Examples of viscous liquid foods include foods that are clearly likely to remain in the liquid collection section of the stick of the present invention even when shaken in water for 5 seconds, and examples thereof include sukiyaki sauce, sauce, honey, olive oil, etc.

[0028] Examples of uses of the liquid sample quantitative collection stick of the present invention include measuring various components contained in a test solution prepared by using the liquid sample quantitative collection stick of the present invention to quantify a liquid sample and releasing it into a solvent. Specific examples of uses include determining the L-glutamic acid concentration in food or cell culture medium, determining the acidity of fruit juice, determining the glucose concentration in soft drinks, sake, etc., and determining whether a sample solution contains food allergens.

[0029] A method for preparing a test solution for a predetermined test using the liquid sample collection stick of the present invention is, for example, to attach the liquid sample collection stick of the present invention to the target liquid sample for a predetermined time, then remove the stick from the target liquid sample, immerse it in a predetermined amount of pure water or a suitable solvent, shake for 5 to 10 seconds, confirm that no liquid sample remains in the liquid collection section, and then remove the liquid sample collection stick from the pure water or a suitable solvent to prepare the test solution. If it is estimated that the concentration of the component to be tested is high in such a test solution, the prepared test solution can be diluted 10 times, 100 times, 1000 times, 10000 times, or more to prepare a diluted test solution for a predetermined test.

[0030] For example, when the specified test is a test for determining the concentration of L-glutamic acid, a method for preparing a test solution may include immersing the stick of the present invention in, for example, miso soup, which is the target liquid sample, for 3 seconds, then removing the stick from the miso soup, and then, while still holding the miso soup collected in the liquid collection portion, immersing the entire liquid collection portion of the stick in pure water in a beaker, shaking for 10 seconds, confirming that no miso soup remains in the liquid collection portion, and diluting the pure water in the beaker as necessary to prepare a diluted test solution.

[0031] The diluted test solution prepared above can be used to soak test paper for measuring the concentration of L-glutamic acid, such as Glutamic Acid Test Paper (manufactured by Tsukuba Food Evaluation Center Co., Ltd.), and the degree of color development of the test paper can be determined by referring to the attached color sample (sample used to determine concentration) shown in Figure 6.

[0032] In determining the acidity of fruits, a fixed amount of fruit juice collected using the stick of the present invention can be diluted in an appropriate solvent and used as a diluted solution in an acidity meter.

[0033] The present invention will be described in more detail below with reference to examples, but the technical scope of the present invention is not limited to these examples. EXAMPLES

[0034] [Example 1] [Preparation of sticks for quantitative collection of liquid samples] (Material for liquid collection) The 12 types of fiber materials shown in Table 1 below were each cut into fiber fragments measuring 5 mm in length and 7 mm in width. A precut backing sheet (GL187 Lohmann (G&L)) was used as a support, which has an adhesive (sheet) part made by bonding an acrylic adhesive to a white polystyrene base material that is widely used as a member for supporting immunochromatographic strips. The precut backing sheet was cut to a length of 60 mm and a width of 7 mm, and each of the fiber fragments was attached to the adhesive part measuring 5 mm in length and 7 mm in width at one end of the longitudinal direction of the precut backing sheet to prepare 12 types of sticks for quantitative collection of liquid samples. A schematic diagram of the stick for quantitative collection of liquid samples is shown in Figure 1.

[0035] [Table 1]

[0036] (Dissolution test in water) The liquid collection parts of the 12 types of liquid sample collection sticks with pieces of each of the above materials attached were immersed in their entirety in commercially available "Kombu Tsuyu" (manufactured by Yamasa Shoyu Co., Ltd.) for 3 seconds (Figure 2(a)), and then each of the above sticks was removed from the "Kombu Tsuyu". The state in which the liquid collection parts had absorbed the "Kombu Tsuyu" was visually observed. Then, while still holding the "Kombu Tsuyu" collected in the liquid collection parts, the entire liquid collection parts of each liquid sample collection stick were immersed in 20 mL of pure water in a beaker and shaken for 5 and / or 10 seconds (Figure 2(b)). It was visually confirmed whether or not there was any kombu Tsuyu remaining in each liquid collection part, and each liquid sample collection stick was removed (Figure 2(c)). The results are shown in Figure 3.

[0037] (Results and Discussion) (1) After the glass fiber A was immersed in kelp soup for 3 seconds, the kelp soup was evenly absorbed into the fiber, and after it was immersed in water and shaken for 5 seconds, no soup remained. Therefore, it was confirmed that all the soup was dissolved into the water by simply shaking for the short period of 5 seconds. (2) After immersing cellulose fiber nonwoven fabric 1 in kelp soup for 3 seconds, the kelp soup was evenly absorbed into the fibers. However, after immersing it in water and shaking for 5 seconds, the soup remained. After shaking for 10 seconds, no soup remained, so it was confirmed that the kelp soup can be dissolved in water by shaking for 10 seconds, although it takes longer than glass fiber. (3) After immersing cellulose fiber nonwoven fabric 2 (E) and cellulose-PET laminate (F) in kelp soup for 3 seconds, the kelp soup was uniformly absorbed into the fibers. However, after immersing in water and shaking for 5 seconds, some soup remained. After shaking for 10 seconds, it was confirmed that a small amount of soup remained. (4) After immersing the glass fiber filter paper 1 (B), the PET nonwoven fabric 1 (G), the PET nonwoven fabric 2 (H), the cellulose filter paper (J), and the silica filter paper (L) in kelp soup for 3 seconds, the kelp soup was excessively on the fiber surface and could not be absorbed uniformly throughout the fiber. In addition, the soup remained even after shaking in water for 10 seconds. (5) In the case of the glass fiber filter paper 2 (C) and the cellulose fiber pad (K), after immersion in kelp soup for 3 seconds, the kelp soup was evenly absorbed into the fibers, but the soup remained even after shaking in water for 10 seconds. (6) In the case of PET nonwoven fabric 3 in I, even after immersion in kelp soup for 3 seconds, the liquid was merely on the surface of the fibers and did not soak into the fibers.

[0038] From the above results shown in Figure 3, it was determined that all materials except for A, glass fiber, and D, cellulose fiber nonwoven fabric 1, were unsuitable as sticks for quantitative collection of liquid samples. A, glass fiber, was selected as the most suitable material for accurately collecting the collected liquid sample and completely dissolving it in the solvent in a short time.

[0039] [Example 2] [Test to confirm the amount of liquid collected using liquid collection parts with different areas] (Preparation of sticks for quantitative collection of liquid samples) The above glass fiber A, having a length of 5 mm and a width of 300 mm, was attached to the adhesive part at one end of the longitudinal direction of the precut backing sheet. Then, the width was cut to 5 mm by using a guillotine cutter for immunochromatography (compact cutter NF-300ICG (manufactured by Nippon Engineering Co., Ltd.) 1.5mm (area 7.5mm 2 , volume 3.225mm 3 ), 3.0mm (area 15.0mm 2 , volume 6.45mm 3 ), 4.0mm (area 20.0mm 2 , volume 8.6mm 3 ), 5.0mm (area 25.0mm 2 , volume 10.75mm 3 ), 6.0mm (area 30.0mm 2 , volume 12.9mm 3 ), 7.0mm (area 35.0mm 2 , volume 15.05mm 3 ), 8.0mm (area 40.0mm2 , volume 17.2mm 3 ), and 10.0mm (Area 50.0mm 2 , volume 21.5mm 3 ) and eight types of liquid collection sticks with liquid collection areas of different glass fiber areas were produced.

[0040] The eight types of sticks with different areas were tested using three sticks per type. The weight of each liquid sample quantitative collection stick was measured in advance using a precision electronic balance, and was taken as the stick (dry) weight. The entire liquid collection part of each liquid sample quantitative collection stick to which the glass fiber was attached was immersed in 20 mL of pure water in a beaker for 3 seconds, then removed, and the excess pure water on the opposite side of the support to the side on which the glass fiber was placed was removed with a paper towel, after which the weight was measured using a precision electronic balance, and was taken as the stick (immersed) weight. The value obtained by subtracting the stick (dry) weight from the stick (immersed) weight was calculated, and the average value of the three sticks was taken as the weight of pure water absorbed by the glass fiber of each area. The width, area, and measured weight of pure water of the glass fiber A mentioned above are shown in Table 2, and the relationship between the area of ​​the glass fiber A mentioned above and the measured weight of the collected pure water is shown in the graph of Figure 4.

[0041] [Table 2]

[0042] (Results and Discussion) As is clear from Table 2 and the graph in Figure 4, there is a high correlation between the area of ​​the glass fiber in the liquid collection section and the amount of pure water absorbed, and the calculated correlation coefficient was 0.9949, indicating a good correlation. In addition, the glass fiber that collected the pure water was able to retain a constant amount of pure water without dripping.

[0043] From the above results, it became clear that by adjusting the area of ​​the glass fiber, it was possible to quantitatively collect a liquid in the range of 4.5μg to 33μg, and it was shown that even a small amount in the range of 4.5μg to 10μg could be accurately collected. 2 It was confirmed that a glass fiber of 5.0 mm length × 3.0 mm width (area 15.0 mm) can hold approximately 20 ug (= 20 uL) of pure water. 2 ) was confirmed to be able to hold approximately 10ug (=10uL) of pure water.

[0044] [Example 3] [Test to confirm the amount of harvested material depending on the immersion time] (Preparation of sticks for quantitative collection of liquid samples) Since there was a risk that the above precut backing sheet would absorb moisture if it was immersed in water for a long period of time, we decided to use a polypropylene plate (thickness 1 mm, model number PPN-050501 (manufactured by AS ONE Corporation)) as a support for our study. The above polypropylene plate was cut to a size of 7 mm wide and 60 mm long to prepare a polypropylene support, and a double-sided tape with the release liner on one side removed was attached to one end of the polypropylene support in the longitudinal direction, and the other release liner was then peeled off to form the adhesive part of the support. 2 ) above A glass fiber, and a length of 5 mm x width of 10 mm (area 50 mm 2 The glass fiber A of each of the above was attached to the adhesive portion, and two types of liquid collecting sticks having liquid collecting portions with different glass fiber areas were prepared.

[0045] The above two types of sticks with different areas were tested for different immersion times. The weight of each stick for collecting a fixed amount of liquid samples was measured in advance using a precision electronic balance, and this was taken as the stick (dry) weight. 20 mL of pure water was placed in a glass beaker, and the entire liquid collection part of each stick for collecting a fixed amount of liquid samples was immersed in the pure water for 3 seconds, 10 seconds, 1 minute, or 3 minutes, then removed. After removing excess pure water from the side opposite the glass fiber with a paper towel, the weight of the stick for collecting a fixed amount of liquid samples was measured using a precision electronic balance, and this was taken as the stick (immersed) weight. The stick (immersed) weight was subtracted from the stick (dry) weight, and the average of the two sticks was taken as the weight of pure water absorbed by the glass fiber. Area 25 mm 2 The results for glass fiber are shown in Table 3. 2 The results for the glass fibers are shown in Table 4.

[0046] [Table 3]

[0047] [Table 4]

[0048] (Results and Discussion) Glass fiber area 25mm 2 The glass fiber did not show a significant increase in the absorbed weight of pure water from 3 seconds to 3 minutes, and the weight after 3 minutes of immersion was in the range of 101% to 104% compared to the weight after 3 seconds, confirming that after the glass fiber absorbs a certain amount, it does not absorb any more. 2 The same tendency was observed, ranging from 102% to 103% of the weight at 3 seconds. From these results, it was confirmed that the stick with glass fibers arranged thereon can collect a substantially constant amount of liquid regardless of the time of immersion in the liquid when it is immersed for more than 3 seconds, and that a specified volume of sample can be accurately collected by simply immersing it in the liquid sample for 3 seconds or more.

[0049] [Example 4] [Comparison of the amount of liquid food sampled using a liquid sample stick and a pipette] A comparison was made between sampling the liquid foods listed in Table 5 below using a pipette and sampling using a liquid sample stick.

[0050] [Table 5]

[0051] (Preparation of sticks for quantitative collection of liquid samples) The glass fiber A having a length of 5 mm and a width of 300 mm was attached to the adhesive part at one end of the precut backing sheet in the longitudinal direction. Then, the width was cut to 3.0 mm (area 15.0 mm) using the immunochromatography guillotine cutter. 2 ), 6.0mm (area 30.0mm 2 ), and 9.0 mm (area 45.0 mm 2 ) and 3 different types of liquid collection sticks with liquid collection areas of different glass fiber areas were produced.

[0052] The above three types of sticks with different surface areas were used for the test, with three sticks per type. The weight of each liquid sample quantitative collection stick was measured in advance with a precision electronic balance. 20 mL of pure water was placed in a glass beaker, and the entire liquid collection part of each liquid sample quantitative collection stick with the glass fiber attached was immersed in each liquid food for 3 seconds, then removed, and the excess pure water on the side opposite the glass fiber was removed with a paper towel, after which the weight of the liquid sample quantitative collection stick was measured with a precision electronic balance while still in the glass beaker containing pure water. The change in the weight of the entire beaker was recorded, and the weight calculated by subtracting the weight of the liquid collection stick before collection was used as the weight of the liquid food collected by the liquid sample quantitative collection stick. Three sticks were measured for each stick, and the average value of the three was calculated, and this was used as the weight collected by each liquid sample quantitative collection stick.

[0053] (Collecting liquid with a pipette) When liquid foods were collected using a pipette, a glass beaker containing 20 mL of pure water was placed on a precision electronic balance and the weight was measured. A precision-calibrated micropipette (Finnpipette, for 5 μL to 20 μL (manufactured by Thermo Scientific)) was set to 10 μL, 20 μL, or 30 μL, and a tip (123R-755CS (WATSON)) was attached to collect the commercially available liquid foods shown in Table 5, and the entire amount was pushed out and added to the beaker containing pure water. The change in the weight of the entire beaker at that time was recorded, and the increased weight was taken as the weight collected by the pipette. Each measurement was repeated three times and the average value was calculated.

[0054] The weights collected using the liquid sample stick and the weights collected using the pipette were compared, and the ratios to the weight collected using the pipette were calculated. The results are shown in Tables 6 to 8.

[0055] [Table 6]

[0056] [Table 7]

[0057] [Table 8]

[0058] 1) As is clear from Table 6, the pipette is 10 μL and the area of ​​the glass fiber is 15.0 mm 2 When the collected weight was compared with that of a liquid sample collection stick for quantitative liquid sampling, the collected weight by the stick was in the range of 93.8 to 109.6% of the collected weight by the pipette, within ±10%.

[0059] 2) As is clear from Table 7, the pipette is 20 μL and the area of ​​the glass fiber is 30.0 mm 2When the collected weight was compared with that of a liquid sample collection stick for quantitative liquid sampling, the collected weight by the stick was in the range of 97.9 to 109.4% of the collected weight by the pipette, within ±10%.

[0060] 3) As is clear from Table 8, the pipette is 30 μL and the area of ​​the glass fiber is 45.0 mm 2 When the collected weight was compared with that of a liquid sample collection stick with a fixed quantity of liquid samples, the collected weight by the stick was 90.5-106.5% of the collected weight by a pipette, both within ±10%. From the above results, the collected weight of the liquid sample collection stick with glass fiber almost coincides with the collected weight by a pipette, and it is clear that the liquid sample collection stick of the present invention can collect liquid food samples with almost the same quantitative accuracy as a pipette.

[0061] [Example 5] [Examination of the amount of liquid food to be collected] A study was conducted on viscous liquid foods.

[0062] (Preparation of sticks for quantitative collection of liquid samples) The above glass fiber A, measuring 5 mm in length and 300 mm in width, was attached to the adhesive part at one end of the precut backing sheet in the longitudinal direction. Then, the above immunochromatographic guillotine cutter was used to cut the width to 6.0 mm (area 30.0 mm 2 ) to prepare the liquid collection area, and a liquid sample collection stick capable of collecting 20 μL was produced.

[0063] (Collection of various liquid foods) The area of ​​the liquid collection section is 30.0 mm 2The weight of the 20μL liquid sample collection stick was measured in advance with a precision electronic balance and used as the stick (dry) weight. The entire liquid collection part of each liquid sample collection stick with the glass fiber attached was immersed in each liquid food shown in Table 9 for 3 seconds, then removed. The excess liquid food on the side opposite the glass fiber was removed with a paper towel, and the weight was measured with a precision electronic balance and used as the stick (immersed) weight. The value obtained by subtracting the stick (dry) weight from the stick (immersed) weight was averaged for the two sticks and used as the weight of pure water absorbed by the glass fiber. The weight collected with the pipette and the weight collected with the liquid sample collection stick were compared, and the ratio to the pipette was calculated. The results are shown in Table 10.

[0064] [Table 9]

[0065] [Table 10]

[0066] (Results and Discussion) In the comparison of non-viscous vegetable juice (A), milk (B), and soy milk (C), the difference in the collected amount between the pipette and the liquid sample collection stick was within ±10%, so the collected amount was almost the same, and it was determined that the liquid sample collection stick can collect a fixed amount of food equivalent to the pipette for non-viscous liquid foods. On the other hand, for viscous foods D to I, neither the pipette nor the liquid sample collection stick could collect a fixed amount of food accurately. In other words, in the case of the pipette, the amount collected varied greatly depending on the operation method, as food adhered to the tip or food remained on the tip during dissolution. In addition, with the liquid sample collection stick, excess food was attached to the surface of the glass fiber, significantly increasing the amount collected. From the above results, it was revealed that the liquid sample collection stick equipped with glass fiber can collect non-viscous liquid foods with a quantitative accuracy almost the same as that of the pipette.

[0067] [Example 6] [Investigation of the time to shake the stick in the solvent after collecting the liquid (dissolution time)] (Preparation of sticks for quantitative collection of liquid samples) The above glass fiber A, measuring 5 mm in length and 300 mm in width, was attached to the adhesive part at one end of the precut backing sheet in the longitudinal direction. Then, the above immunochromatographic guillotine cutter was used to cut the width to 6.0 mm (area 30.0 mm 2 ) to prepare the liquid collection area, and a liquid sample collection stick capable of collecting 20 μL was produced.

[0068] (Collection of various liquid foods) The liquid collection portion of the liquid sample collection stick capable of collecting 20 μL was immersed in each liquid food shown in Table 11 for 3 seconds, and then each stick was removed from each food. Then, while holding each liquid food collected in the liquid collection portion, the liquid collection portion of each liquid sample collection stick was immersed in 20 mL of pure water in a beaker and shaken for 5 to 10 seconds. Each liquid collection portion was visually checked for any remaining food, and each liquid sample collection stick with no remaining food in the liquid collection portion was removed from the pure water. The results are shown in Figure 5.

[0069] [Table 11]

[0070] (Results and Discussion) In the case of sukiyaki sauce B, a lot of the sauce remained on the glass fiber after shaking for 5 seconds, but none remained on the glass fiber after shaking for 10 seconds. This is thought to be because sukiyaki sauce contains a large amount of additives such as sugar, and it took time for the sauce absorbed by the glass fiber to dissolve into the water. A vegetable juice and C soy sauce also remained slightly on the glass fiber after 5 seconds, but none remained on the glass fiber after shaking for 10 seconds. D white soup stock did not remain on the glass fiber after either 5 or 10 seconds.

[0071] From the above results, it was considered that the components contained in food are diverse, and that in order to dissolve the liquid absorbed by the glass fiber in a solvent such as water, it is appropriate to shake the food in the solvent for more than 10 seconds.

[0072] [Example 7] [Study on glutamic acid test strips for liquid foods] (Preparation of sticks for quantitative collection of liquid samples) The above glass fiber A, measuring 5 mm in length and 300 mm in width, was attached to the adhesive part at one end of the precut backing sheet in the longitudinal direction. Then, the above immunochromatographic guillotine cutter was used to cut the width to 6.0 mm (area 30.0 mm 2 ) to prepare the liquid collection area, and a liquid sample collection stick capable of collecting 20 μL was produced.

[0073] The cellulose filter paper used in Example 1, J, was used as the liquid collection part, and the area of ​​the filter paper was 72 mm2, which is capable of absorbing 20 μL. 2 A comparative stick was prepared by attaching a piece of cellulose filter paper (length 10 mm, width 7.2 mm) to the adhesive part at one end in the longitudinal direction of the precut backing sheet.

[0074] (Verification using glutamic acid test strips) 20 μL of "Kombu Tsuyu" was collected with a micropipette, dissolved in 20 mL of pure water, and diluted 1000-fold to obtain (1) the control diluted test solution. In addition, the liquid sample quantitative collection stick capable of collecting 20 μL and the comparison stick were each immersed in commercially available "Kombu Tsuyu" (manufactured by Yamasa Shoyu Co., Ltd.) for 3 seconds, and then each of the sticks was removed from the "Kombu Tsuyu". Then, while holding the "Kombu Tsuyu" collected in the liquid collection part, the entire liquid collection part of each stick was immersed in 20 mL of pure water in a beaker, shaken for 10 seconds, and after confirming that no kombu Tsuyu remained in the liquid collection part, both sticks were removed. The "Kombu Tsuyu" prepared using the liquid sample quantitative collection stick was diluted 1000-fold to obtain (2) the diluted test solution. The "Kombu Tsuyu" prepared using the comparison stick was diluted 1000-fold to obtain (3) the diluted comparison test solution.

[0075] The above three types of diluted test solutions were tested using glutamic acid test paper (manufactured by Tsukuba Food Evaluation Center Co., Ltd.), and the concentration of L-glutamic acid was determined by referring to the degree of color development of the test paper and the attached color sample (sample used for concentration determination) shown in Figure 6. The results are shown in Figure 7.

[0076] As is clear from Figure 7, the degree of color development was similar between the control diluted test solution (1) and the diluted test solution (2), and the concentration determined by the color sample was also consistent at 30 mg / L. On the other hand, the diluted comparison test solution (3) was lightly colored, and the concentration determined by the color sample was also low at 15 mg / L. Therefore, when cellulose filter paper was used, it was thought that the entire amount could not be dissolved in 20 mL of pure water, and kelp soup remained in the filter paper.

[0077] From the above results, it was revealed that the liquid sample collection stick of the present invention, which uses the above-mentioned glass fiber as the liquid collection part, can accurately measure 20 μL and can easily dissolve in a solvent such as pure water. By using such a stick, it was possible to develop a stick that can easily collect a fixed amount and dissolve in a solvent without using a device such as a pipette, which is difficult to operate.

[0078] [Example 7] [Drip confirmation test using liquid collection parts with different areas] (Preparation of sticks for quantitative collection of liquid samples) The above glass fibers A, each with a different glass fiber area, were attached to the adhesive part at one end of the longitudinal direction of the precut backing sheet in 25 different combinations of five different sizes (vertical widths of 5mm, 10mm, 20mm, 30mm, and 50mm) and five different sizes (horizontal widths of 5mm, 10mm, 20mm, 30mm, and 50mm), to produce 25 types of liquid collection sticks, each with a liquid collection part with a different glass fiber area.

[0079] The test was carried out using sukiyaki sauce (manufactured by Ebara Foods Industries, Inc.), which is known to have a large amount of dissolved sugar and other ingredients. Using 25 types of sticks with different areas of the liquid collection part, the entire liquid collection part of each liquid sample collection stick with the glass fiber attached was immersed in sukiyaki sauce in a test tube for 5 seconds and then removed, and the retention of the sukiyaki sauce was visually confirmed. The length, width, area, and visual retention of the sauce of the above glass fiber A are shown in Table 12.

[0080] [Table 12]

[0081] (Results and Discussion) As is clear from Table 12, when the glass fiber of the liquid collection part is 20 mm or more in length, the sukiyaki sauce flows under the glass fiber due to its weight and accumulates, and when it is 30 mm or more, the glass fiber cannot hold the sauce and drips, so it was found that the length is preferably less than 20 mm. Also, when the length is 10 mm or less, it was possible to collect the sauce evenly even if the width was 50 mm, so it was thought that the width size does not have a significant effect on dripping. However, when considering the container to put the sample in when collecting the liquid, for example, when a 1.5 mL microtube (manufactured by AS ONE Co., Ltd.) or a 15 mL centrifuge tube (manufactured by AGC Technoglass Co., Ltd.) is used as a container for holding a small amount of liquid, the liquid collection stick can be made to have a width size that fits into the inner diameter of these containers, and since the inner diameter of a 1.5 mL microtube is about 11 mm and that of a 15 mL centrifuge tube is about 15 mm, the width of the glass fiber can be made 10 mm or less. [Explanation of symbols]

[0082] 1 Liquid sample stick 2 Liquid sampling section 3 Support 4 Grip part

Claims

1. A stick for collecting a fixed amount of a liquid sample, comprising a liquid collection portion disposed on a support.

2. 2. The stick for collecting a fixed quantity of a liquid sample according to claim 1, wherein the liquid collection portion is made of a single-layered thin piece.

3. 3. The stick for collecting a fixed quantity of a liquid sample according to claim 1 or 2, wherein the liquid collecting portion is made of glass fiber.

4. The mass of glass fiber per unit area is 70 to 80 g / m ２ 4. The stick for collecting a fixed amount of liquid sample according to claim 3,

5. The area of ​​the single-layered flakes is 1 to 950 mm ２ 3. The stick for collecting a fixed amount of liquid sample according to claim 2,

6. 3. The liquid sample collection stick according to claim 2, wherein the thickness of the single-layered slice is 0.30 to 0.43 mm.

7. 3. The liquid sample collection stick according to claim 1, wherein the amount of liquid sample collected is 4.5 to 100 μg.

8. 3. A stick for collecting a fixed quantity of liquid samples according to claim 1 or 2, characterized in that the support is made of plastic.

9. A method for quantifying glutamic acid in a sample liquid, comprising: collecting a liquid sample using a liquid sample quantitative collection stick according to any one of claims 1 to 8; and detecting glutamic acid in a test solution obtained by diluting the sample liquid.

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