A method for detecting boric acid and / or borate

Abstract

The invention discloses a method for detecting boric acid and / or borate, comprising the following steps: dissolving anhydrous acid in an anhydrous protonated solvent 1 to form a reagent A; dissolving curcumin in an anhydrous protonated solvent 2, then immersing filter paper, taking out and drying to obtain a turmeric test paper; mixing a sample to be tested with reagent A to obtain a mixture, dripping the mixture onto the turmeric test paper, and performing qualitative detection of boric acid and / or borate according to the color change of the turmeric test paper. The detection method of the invention is simple and convenient to operate, the color development process does not require operations such as heating or drying, the time is short, the result is easy to judge, the characteristic is good, no other equipment and conditions are required, it is suitable for on-site operation, and meets the needs of on-site rapid detection such as supervision departments, testing agencies and individuals.

Description

Technical Field

[0001] The present invention relates to the technical field of chemical analysis, and in particular to a method for detecting boric acid and / or borate. Background Art

[0002] Boric acid, with the chemical formula H3BO3, is a white powdery crystal or a triclinic flaky shiny crystal. Borates are a general term for salts related to boron trioxide, usually referring only to salts of orthoboric acid. The more commonly used borates include sodium tetraborate, commonly known as borax. Boric acid and borates are often used as topical fungicides, disinfectants, astringents and preservatives. They can be used as preservatives and antibacterial agents in cosmetics and are often used in products such as talcum powder.

[0003] Oral intake of boric acid and borates can cause acute poisoning, which is mainly manifested by gastrointestinal symptoms such as nausea, vomiting, abdominal pain, diarrhea, etc., followed by dehydration, shock, coma or acute renal failure, high fever, liver and kidney damage and convulsions, and severe cases can be fatal. Boric acid and borates are easily absorbed by damaged skin and cause poisoning, leading to nausea, diarrhea, cramps, erythema, cyanosis, circulatory organ failure, neurological disorders and other poisoning reactions. Boric acid and borates can cause chronic poisoning: long-term absorption of small amounts of this product through the gastrointestinal tract or skin can cause mild gastrointestinal symptoms, dermatitis, alopecia, and liver and kidney damage.

[0004] The "Technical Specifications for Safety of Cosmetics" (2015 edition) stipulates that boric acid and borates are prohibited in cosmetics for children under three years old, and there are requirements such as label precautions.

[0005] The "Technical Specifications for Safety of Cosmetics" stipulates the azomethine-H spectrophotometric detection method for boric acid and borates in cosmetics. This method is cumbersome to use, takes a long time to test, and has a short shelf life of the reagents, making it unsuitable for rapid and on-site testing requirements. Other detection methods for boric acid and borates include microcrystallization, colorimetric, titration, spectrophotometry, fluorescence, liquid chromatography, atomic absorption spectrophotometry, polarimetry, inductively coupled plasma atomic emission spectroscopy, and inductively coupled plasma mass spectrometry. The method of using reagents such as curcumin and oxalic acid to detect the element boron was first used in the agricultural field. After continuous improvement, the method of detecting boric acid and borates is widely used in food, soil, cosmetics and other fields by dissolving the treated boron in an aqueous solution, reacting it with curcumin, oxalic acid, sulfuric acid, etc., and then heating and drying to develop color. The curcumin colorimetric method is easy to operate, has good sensitivity and characteristic, and is suitable for the rapid screening of boric acid and borates. However, it also has problems such as cumbersome sample pretreatment, the need for heating and drying during the process, etc. There is room for further improvement in the rapid screening method for boric acid or borates in solid cosmetics. Summary of the invention

[0006] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides a method for detecting boric acid and / or borate, which can quickly perform qualitative detection on boric acid and / or borate and is simple to operate.

[0007] The technical solution adopted by the present invention is as follows:

[0008] A method for detecting boric acid and / or borate comprises the following steps:

[0009] The anhydrous acid is dissolved in the anhydrous protonated solvent 1 to form reagent A;

[0010] Dissolve curcumin in anhydrous protonated solvent 2, then immerse filter paper, take out and dry to obtain turmeric test paper;

[0011] The sample to be tested is mixed with the reagent A to obtain a mixture, and the mixture is dripped onto the turmeric test paper, and the boric acid and / or borate is qualitatively detected according to the color change of the turmeric test paper.

[0012] The method for detecting boric acid and borate according to the present invention has at least the following beneficial effects:

[0013] The present invention utilizes the color development reaction of boric acid (borates can also form boric acid under acidic conditions) and protonated curcumin to generate red rose red anthocyanin to quickly and qualitatively detect boric acid and borate. The detection method of the related art is generally carried out in an aqueous environment, curcumin is dissolved in an aqueous protonated solvent, then a turmeric test paper is prepared, and an aqueous acid solution is added for detection. The inventor found that the aqueous condition will greatly affect the protonation of curcumin, so the test paper needs to be heated and dried after the sample to be tested is added to make the red color appear, which is not only complicated and time-consuming, but also the protonated curcumin has thermal instability, and heating and drying will affect the accuracy of detection. Therefore, the detection method of the present invention is carried out under anhydrous conditions, which is not only conducive to the protonation of curcumin, but also does not need to be heated and dried, and the stability of the protonated curcumin is improved. When the mixture obtained by mixing the sample to be tested with the reagent A is added dropwise to the turmeric test paper, the color can be immediately developed without waiting, and the qualitative detection of boric acid and borate can be carried out quickly and accurately.

[0014] In some embodiments of the present invention, the anhydrous acid is anhydrous hydrogen chloride.

[0015] Acidic environment is conducive to the complexation reaction between boric acid and protonated curcumin, but not all acidic environments can be used for the detection method of the present invention. For example, the presence of oxalic acid will make the product less stable and less sensitive, sulfuric acid is oxidizing and dehydrating, and is not suitable for use on test paper; phosphoric acid is not strong enough and will affect the judgment of the color development of curcumin test paper.

[0016] In some embodiments of the present invention, the anhydrous protonated solvent 1 and the anhydrous protonated solvent 2 are independently anhydrous alcohol solvents, independently including at least one of anhydrous methanol and anhydrous ethanol, and the anhydrous protonated solvent 1 and the anhydrous protonated solvent 2 may be the same or different.

[0017] The detection method of the present invention requires that the anhydrous protonated solvent used can dissolve anhydrous hydrogen chloride, boric acid and borate, so that the color reaction can proceed normally; and the anhydrous protonated solvent must be liquid at room temperature and have room temperature volatility, so that the color reaction is more sensitive and does not affect the color judgment. More suitable are anhydrous alcohol solvents such as anhydrous methanol and anhydrous ethanol preferred in this method. In addition, the color change product rose red anthocyanin generated during the detection process is soluble in alcohol solvents, but insoluble in water or non-protonated solvents, so the selection of anhydrous alcohol solvents can improve the sensitivity of detection.

[0018] In some embodiments of the present invention, the mass ratio of the anhydrous hydrogen chloride to the anhydrous protonated solvent 1 is 0.1-30:100.

[0019] In some embodiments of the present invention, the drying method for obtaining the turmeric test paper is natural drying.

[0020] In some embodiments of the present invention, the ratio of the sample to be tested to the reagent A is 10-100 mg: 0.05-0.5 mL. Generally, the volume of 1 drop of liquid is about 0.05 mL. In actual operation, the test can be performed according to the ratio of 10-100 mg of the sample to be tested and 1-10 drops of the reagent A.

[0021] In some embodiments of the present invention, the sample to be tested is an anhydrous sample, preferably an anhydrous solid powder sample. The detection method of the present invention can directly detect solid samples without any pre-treatment of the sample to be tested, which simplifies the operation and saves detection time. At the same time, the reagent A and the turmeric test paper of the present invention are both water-free, and the water-free sample to be tested reacts quickly with protonated curcumin under anhydrous solvent conditions, thereby improving the sensitivity of detection, eliminating the process of heating and drying, and accelerating the detection speed.

[0022] In some embodiments of the present invention, the sample to be tested is an anhydrous solid powder cosmetic.

[0023] In some embodiments of the present invention, the qualitative detection of boric acid and / or borate according to the color change of the turmeric test paper is specifically that if the turmeric test paper appears red, it is judged that the sample to be tested contains boric acid and / or borate, and the darker the red color, the higher the content of boric acid and / or borate in the sample to be tested.

[0024] In some embodiments of the present invention, the detection method further includes the steps of: adding the mixture obtained by mixing the sample to be tested with reagent A to a turmeric test paper, and at the same time, adding the reagent A to the turmeric test paper as a blank, and comparing the test paper to which the mixture is added with the blank; if the test paper to which the mixture is added appears red compared to the blank, it is determined that the sample to be tested contains boric acid and / or borate; if the test paper to which the mixture is added does not appear red compared to the blank, it is determined that the sample to be tested does not contain boric acid and borate.

[0025] In some embodiments of the present invention, after the mixture obtained by mixing the sample to be tested with reagent A is added dropwise to the turmeric test paper, a comparison and judgment can be made after waiting for 0 to 5 minutes. Generally, the color of the mixture can be immediately developed after being added dropwise to the turmeric test paper, and the judgment can be made without waiting.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] The detection method of the present invention is simple and convenient to operate, does not require operations such as heating or drying, takes a short time, and the results are easy to judge. It has good characteristics and does not require other equipment and conditions. It is suitable for on-site operation and meets the needs of supervisory departments, testing institutions, individuals and the like for on-site rapid detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 Schematic diagram of the detection process (A) and the detection results of Examples 1 to 3 of the present invention (B). DETAILED DESCRIPTION

[0029] The technical solution of the present invention is further described in detail below in conjunction with specific embodiments.

[0030] Take a solid powdered cosmetic that does not contain boric acid and borate as a negative sample (the solid powdered cosmetic is sampled by the national cosmetics supervision and is tested by the statutory method to determine that it does not contain boric acid or borate); add anhydrous boric acid to the negative sample, and mix to prepare a boric acid sample with a boric acid mass concentration of 1 mg / g or 10 mg / g; add sodium tetraborate to the negative sample, and mix to prepare a borate sample with a boric acid mass concentration of 10 mg / g.

[0031] Example 1

[0032] Take 5 g of dry hydrogen chloride and dissolve it in 100 g of anhydrous methanol to obtain reagent A with a mass concentration of 5%.

[0033] Take 20 mg of 1 mg / g boric acid sample into a test tube, add 2 drops of reagent A, and shake to obtain a mixture. Pipette 1 drop of the mixture onto one end of the turmeric test paper, and at the same time, add 1 drop of reagent A onto the other end of the turmeric test paper as a blank. After adding the mixture, the turmeric test paper immediately shows the following Figure 1 Results shown.

[0034] from Figure 1 It can be seen that after adding reagent A, the turmeric test paper did not turn red, but after adding the mixture, the turmeric test paper immediately turned light red, indicating that this detection method can quickly detect boric acid and determine whether the sample to be tested contains boric acid.

[0035] Example 2

[0036] Take 2 g of dry hydrogen chloride and dissolve it in 100 g of anhydrous ethanol to obtain reagent A with a mass concentration of 2%.

[0037] Take 40 mg of 10 mg / g boric acid sample into a test tube, add 3 drops of reagent A, and shake to obtain a mixture. Pipette 1 drop of the mixture and add it to one end of the turmeric test paper. At the same time, add 1 drop of reagent A to the other end of the turmeric test paper as a blank. After adding the mixture, the turmeric test paper immediately shows the following Figure 1 Results shown.

[0038] from Figure 1 It can be seen that the turmeric test paper does not turn red after the reagent A is added, while the turmeric test paper immediately turns red after the mixture is added. At the same time, compared with Example 1, the red color of this embodiment becomes deeper, which should be related to the concentration of boric acid, reflecting that the detection method of the present invention can quickly compare the concentration of boric acid in different samples to be tested according to the depth of red, and the deeper the red color, the higher the concentration of boric acid.

[0039] Example 3

[0040] Take 13 g of dry hydrogen chloride and dissolve it in 100 g of anhydrous methanol to obtain reagent A with a mass concentration of 13%.

[0041] Take 80 mg of negative sample into a test tube, add 8 drops of reagent A, and shake to obtain a mixture. Pipette 1 drop of the mixture and add it to one end of the turmeric test paper. At the same time, add 1 drop of reagent A to the other end of the turmeric test paper as a blank. After adding the mixture, the turmeric test paper immediately shows the following Figure 1 The results shown ( Figure 1 Example 3-1).

[0042] Separately, take 80 mg of 10 mg / g borate sample into a test tube, add 8 drops of reagent A, and shake to obtain a mixture. Pipette 1 drop of the mixture onto one end of the turmeric test paper, and at the same time, add 1 drop of reagent A onto the other end of the turmeric test paper as a blank. After adding the mixture, the turmeric test paper immediately shows the following Figure 1 The results shown ( Figure 1 Example 3-2).

[0043] from Figure 1It can be seen that after adding the negative sample, the turmeric test paper did not show any red color like the blank, but after adding the borate sample, the turmeric test paper immediately turned red, indicating that this detection method can quickly detect borates and determine whether the sample to be tested contains borates.

[0044] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A method for detecting boric acid and / or borate, characterized in that: The steps include: The anhydrous acid is dissolved in the anhydrous protonated solvent 1 to form reagent A; The curcumin is dissolved in an anhydrous protonated solvent 2, and then immersed in filter paper, taken out and dried to obtain a turmeric test paper; the sample to be tested is mixed with the reagent A to obtain a mixture, and the mixture is dripped onto the turmeric test paper, and the boric acid and / or borate are qualitatively detected according to the color change of the turmeric test paper; the anhydrous acid is anhydrous hydrogen chloride; the anhydrous protonated solvent 1 and the anhydrous protonated solvent 2 are independently anhydrous alcohol solvents.

2. The detection method according to claim 1, characterized in that: The anhydrous protonated solvent 1 and the anhydrous protonated solvent 2 independently include at least one of anhydrous methanol and anhydrous ethanol.

3. The detection method according to claim 1, characterized in that: The mass ratio of the anhydrous hydrogen chloride to the anhydrous protonated solvent 1 is 0.1-30:

100.

4. The detection method according to claim 1, characterized in that: The dosage ratio of the sample to be tested to reagent A is 10-100 mg: 0.05-0.5 mL.

5. The detection method according to claim 1, characterized in that: The sample to be tested is an anhydrous sample.

6. The detection method according to claim 5, characterized in that: The sample to be tested is an anhydrous solid powder sample.

7. The detection method according to claim 6, characterized in that: The sample to be tested is an anhydrous solid powder cosmetic.

8. The detection method according to any one of claims 1 to 7, characterized in that: The boric acid and / or borate is qualitatively detected according to the color change of the turmeric test paper. Specifically, if the turmeric test paper appears red, it is judged that the sample to be tested contains boric acid and / or borate, and the darker the red color, the higher the content of boric acid and / or borate in the sample to be tested.

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