Method for determining the platinum content in a cosmetic and mask base fabric

Abstract

The application belongs to the technical field of detection, and discloses a method for measuring the content of platinum in cosmetics and mask base cloth. The method comprises the following steps: immersing the sample to be measured in a mixed solution of nitric acid, hydrochloric acid and hydrogen peroxide in a container, performing microwave digestion treatment, transferring the digestion solution in the container to a colorimetric tube, washing the container with water, mixing the washing solution and the digestion solution, adding water to constant volume, obtaining a mother liquor, diluting the mother liquor to obtain a solution to be measured; preparing a platinum standard series solution and a blank solution, using an internal standard method, using an inductively coupled plasma mass spectrometer to detect the solution to be measured, the platinum standard series solution and the blank solution, obtaining the signal intensity of the internal standard element and the platinum element of the solution to be measured, and calculating the content of platinum in the sample to be measured according to a standard curve to complete the detection. The method is simple, rapid and easy to operate, can completely digest the cosmetics and mask base cloth, eliminate the influence of the matrix, has high repeatability and accuracy, and is suitable for measuring the content of platinum in cosmetics and mask base cloth.

Description

Technical Field

[0001] This invention belongs to the field of detection technology, specifically relating to a method for determining the platinum content in cosmetic and facial mask base fabrics. Background Technology

[0002] Platinum is a naturally occurring white precious metal element with the chemical symbol Pt, and its elemental form is commonly known as white gold. Platinum shone brightly in human civilization as early as 700 BC, and throughout its more than 2000-year history of use, it has always been considered one of the noblest metals. In today's society, platinum-containing substances have prominent applications in numerous fields, such as medicine, food and health, and cosmetics.

[0003] In the cosmetics industry, with rising living standards and increased social interaction, modern people are paying more and more attention to skincare. Platinum-themed "celebrity cosmetics," such as platinum masks and creams, leveraging the precious and rare properties of platinum, are gaining popularity, with manufacturers heavily promoting their "skincare benefits" in advertising. Platinum powder and colloidal platinum, raw materials used in top-tier cosmetics, possess strong antioxidant properties, preventing oxidation reactions and effectively removing free radicals in the body, thus delaying skin aging and moisturizing. They are typically added to cosmetics or mask bases to achieve antioxidant and anti-aging effects. However, some cosmetics bearing the name "platinum" contain extremely small amounts of platinum powder, and the actual effects of the powder do not match the product's claims, violating relevant regulations of the "Cosmetic Labeling Management Measures" and constituting exaggerated advertising.

[0004] There are currently no domestic standards or literature on the detection methods for platinum content in cosmetics and facial mask base fabrics. Summary of the Invention

[0005] In order to overcome the shortcomings of the existing technology, the purpose of this invention is to provide a method for determining the platinum content in cosmetic and facial mask base fabrics.

[0006] The purpose of this invention is to fill the gap in the technology for detecting platinum in cosmetic and facial mask base fabrics, and to provide a method for determining the platinum content in cosmetic and facial mask base fabrics using microwave digestion-inductively coupled plasma mass spectrometry (ICP-MS) detection technology.

[0007] To combat exaggerated advertising and address the lack of standardized supervision and enforcement, this invention provides a method for determining the platinum content in cosmetic and facial mask base fabrics. This method can provide a basis for cosmetic regulation.

[0008] The objective of this invention is achieved by at least one of the following technical solutions.

[0009] The method for determining the platinum content in cosmetic and facial mask base fabrics provided by this invention includes the following steps:

[0010] (1) Immerse the sample to be tested in a mixture of nitric acid, hydrochloric acid and hydrogen peroxide aqueous solution in a container (preferably a digestion vessel), seal the container (preferably a tightly sealed digestion vessel), and perform microwave digestion. After the container cools down, transfer the digestion solution in the container to a colorimetric tube, wash the container several times with water, combine the washing solution and the digestion solution, add water to make up to volume, obtain the mother liquor, dilute by the corresponding factor, and obtain the test solution.

[0011] (2) Prepare a series of platinum standard solutions and a blank solution. Then, using the internal standard method, use an inductively coupled plasma mass spectrometer (ICP-MS) to detect the test solution, the series of platinum standard solutions and the blank solution in step (1). Obtain the internal standard element and the platinum element signal intensity of the platinum standard solutions, the blank solution and the test solution. Plot a standard curve based on the ratio of the mass spectrum signal intensity of the platinum element in the platinum standard solutions to the mass spectrum signal intensity of the internal standard element. Calculate the platinum content in the test sample based on the standard curve to complete the detection.

[0012] Preferably, in step (1), the container is washed with water several times. Water can be added to the container in small amounts multiple times to fully rinse the inner wall of the container and reduce errors.

[0013] Further, the mixture of nitric acid, hydrochloric acid, and hydrogen peroxide aqueous solution described in step (1) comprises, by volume parts:

[0014] 5-6 parts nitric acid;

[0015] 1-2 parts hydrochloric acid;

[0016] 1-2 parts of hydrogen peroxide aqueous solution.

[0017] Furthermore, the concentration of nitric acid in step (1) is 50% to 70%;

[0018] Furthermore, the concentration of hydrochloric acid in step (1) is 36% to 38%;

[0019] Further, the concentration of the hydrogen peroxide aqueous solution in step (1) is 20% to 35%;

[0020] Further, in step (1), the mass-to-volume ratio of the sample to be tested to the mixture of nitric acid, hydrochloric acid and hydrogen peroxide aqueous solution is 0.1-0.6g:7-10mL.

[0021] Preferably, when the sample to be tested in step (1) is a cosmetic, the mass-to-volume ratio of the sample to be tested and the mixture of nitric acid, hydrochloric acid and hydrogen peroxide aqueous solution is 0.5g:7-10mL.

[0022] Preferably, when the sample to be tested in step (1) is a mask base fabric, the mass-to-volume ratio of the sample to be tested and the mixture of nitric acid, hydrochloric acid and hydrogen peroxide aqueous solution is 0.25g:7-10mL.

[0023] Preferably, when the sample to be tested in step (1) is a mask base fabric, the mask base fabric needs to be squeezed dry and then air-dried naturally.

[0024] Further, the power of the microwave digestion process in step (1) is 1000-2000W, and the time of the microwave digestion process is 37-68min.

[0025] Preferably, the power of the microwave digestion process in step (1) is 1800W, and the time of the microwave digestion process is 52min.

[0026] Furthermore, the microwave digestion process includes three stages: In the first stage, the temperature is increased from room temperature to 110–130°C for 10–15 minutes, and then held at the specified temperature for 3–7 minutes; In the second stage, the temperature is increased from 110–130°C to 140–160°C for 3–7 minutes, and then held at the specified temperature for 3–7 minutes; In the third stage, the temperature is increased from 140–160°C to 180–200°C for 3–7 minutes, and then held at the specified temperature for 15–25 minutes.

[0027] Preferably, the microwave digestion process includes three stages: in the first stage, the temperature is increased from room temperature to 120°C over a period of 12 minutes, and then held at the specified temperature for 5 minutes; in the second stage, the temperature is increased from 120°C to 150°C over a period of 5 minutes, and then held at the specified temperature for 5 minutes; in the third stage, the temperature is increased from 150°C to 190°C over a period of 5 minutes, and then held at the specified temperature for 20 minutes.

[0028] Further, the concentration of the platinum standard series solutions in step (2) is a platinum ion solution of 0-100 μg / L.

[0029] Preferably, the preparation of the platinum standard series solutions in step (2) includes:

[0030] Take a standard solution containing platinum (Pt) (1000 μg / mL), and then use a mixed solution of nitric acid and hydrochloric acid (prepared by diluting 20 mL of 65% nitric acid and 5 mL of 37% hydrochloric acid with water to 1 L) to gradually dilute it into a series of platinum standard solutions with concentrations of 0, 1, 5, 10, 50, and 100 μg / L.

[0031] Furthermore, the internal standard element used in the internal standard method described in step (2) is one of Re, Rh, Bi and Tb; the concentration of the internal standard element is 20-200 μg / L.

[0032] Preferably, Re in step (2) is 185 Re.

[0033] Preferably, Rh in step (2) is 103 Rh.

[0034] Preferably, Bi in step (2) is 209 Bi.

[0035] Preferably, Tb in step (2) is 159 Tb.

[0036] Preferably, when the internal standard element used in the internal standard method in step (2) is Re or Rh, the concentration of the internal standard element is 20 μg / L.

[0037] Preferably, when the internal standard element used in the internal standard method in step (2) is Bi or Tb, the concentration of the internal standard element is 200 μg / L.

[0038] Preferably, the solvent of the internal standard element solution used in the internal standard method in step (2) is a nitric acid solution (prepared by diluting 20 mL of 65% nitric acid with water to 1 L).

[0039] Further, the standard curve in step (2) is obtained by measuring the standard solution using an inductively coupled plasma mass spectrometer, and plotting the standard curve based on the ratio of the mass spectrometry signal intensity of the analyte element to its internal standard element and the corresponding element concentration. The linear correlation coefficient of the standard curve is between 0.995 and 1.000.

[0040] Further, step (2), which involves calculating the platinum content in the sample based on the standard curve, includes:

[0041] The concentration of platinum in the test solution and blank solution is obtained by using a standard curve, and then the content of platinum in the test sample is calculated according to formula (1); where formula (1) is shown below;

[0042]

[0043] X represents the platinum content in the sample to be tested, expressed in milligrams per kilogram (mg / kg).

[0044] C represents the concentration of platinum in the solution being tested, expressed in micrograms per liter (μg / L).

[0045] C0 represents the concentration of platinum in the blank solution, expressed in micrograms per liter (μg / L).

[0046] V represents the final volume of the solution to be tested, in milliliters (mL);

[0047] m is the mass of the sample to be tested, in grams (g);

[0048] F represents the dilution factor of the solution to be tested.

[0049] Preferably, the analytical conditions for the inductively coupled plasma mass spectrometer (ICP-MS) in step (2) are as follows:

[0050] 1) RF power: 1550W;

[0051] 2) Internal standard element: Rhenium ( 185 Re) or bismuth 209 Bi) or terbium ( 159 Tb) or rhodium 103 Rh);

[0052] 3) Internal standard addition method: Online three-way connection;

[0053] 4) Carrier gas flow rate: 0.99 mL / min;

[0054] 5) Atomization chamber temperature: 2℃;

[0055] 6) Sampling depth: 9mm;

[0056] 7) Sampling method: Fully quantitative;

[0057] 8) Number of scans: 50;

[0058] 9) Number of measurements: 3;

[0059] 10) The colliding gas is He, and the flow rate is 4.3 mL / min;

[0060] 11) Monitoring quality number: 195 Pt.

[0061] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0062] The method for determining the platinum content in cosmetic and facial mask base fabrics provided by this invention involves microwave digestion using nitric acid, hydrochloric acid, and hydrogen peroxide aqueous solution during the pretreatment stage, followed by ICP-MS detection. This method is simple, rapid, and easy to operate, ensuring complete digestion of the cosmetic and facial mask base fabrics, eliminating matrix influences, and exhibiting high repeatability and accuracy. It is suitable for determining the platinum content in cosmetic and facial mask base fabrics. This invention fills the technical gap in the determination of platinum content in cosmetic and facial mask base fabrics using microwave digestion-inductively coupled plasma mass spectrometry, providing technical support for cosmetic regulation. Attached Figure Description

[0063] Figure 1 A schematic diagram of the standard curve provided for an embodiment of the present invention. Detailed Implementation

[0064] The following examples further illustrate specific implementations of the present invention, but the implementation and protection of the present invention are not limited thereto. It should be noted that any processes not specifically described below are those that can be implemented or understood by those skilled in the art by referring to existing technology. Reagents or instruments whose manufacturers are not specified are considered to be conventional products that can be purchased commercially.

[0065] Example 1

[0066] (1) Sample and sample blank treatment:

[0067] Weigh out two 0.5g samples of platinum-containing cream and two 0.25g samples of platinum-containing facial mask base fabric (squeezed dry and air-dried), and place them in four microwave digestion vessels. Add 5mL of nitric acid (65% by mass), 1mL of hydrochloric acid (37% by mass), and 2mL of hydrogen peroxide aqueous solution (30% by mass) to each vessel, ensuring the samples are fully submerged. Seal and tighten the caps, and microwave digest according to the set program. After the four digestion vessels have cooled, transfer the four digests to four 50mL colorimetric tubes. Wash the containers several times with water, combine the washings, and dilute with water to the 50mL mark on each tube to obtain four mother solutions. Dilute these mother solutions by the appropriate factor (5-fold dilution) to obtain four sample solutions.

[0068] The microwave digestion procedure is as follows: microwave power 1800W.

[0069] Stage 1: Temperature reaches 120℃, heat for 12 minutes, hold for 5 minutes;

[0070] Second stage: Temperature up to 150℃, heat for 5 minutes, hold for 5 minutes;

[0071] Three stages: Temperature reaches 190℃, heat for 5 minutes, and hold for 20 minutes;

[0072] Sample blank treatment: Prepare a sample blank solution according to the above sample treatment process; no sample is added during the preparation of the sample blank solution, and the remaining operations are the same as those for the preparation of the sample solution.

[0073] (2) Preparation of standard solutions and plotting of standard working curves:

[0074] Preparation of standard solutions: Take a platinum (Pt) single-element standard solution (1000 μg / mL) and dilute it stepwise with a mixed solution of nitric acid and hydrochloric acid (prepared by diluting 20 mL of 65% nitric acid and 5 mL of 37% hydrochloric acid with water to 1 L) to obtain platinum series standard solutions with concentrations of 0, 1, 5, 10, 50, and 100 μg / L. At the same time, take a mixed solution of nitric acid and hydrochloric acid (prepared by diluting 20 mL of 65% nitric acid and 5 mL of 37% hydrochloric acid with water to 1 L) as a reagent blank (i.e., 0 μg / L) for later use.

[0075] Plotting the standard working curve: Take the above-mentioned platinum standard series solutions, and use an online three-way valve to add an internal standard containing 20 μg / L of [unspecified substance]. 185 Re and 103 Rh, containing 200 μg / L 209 Bihe 159 Tb (prepared by diluting 20 mL of 65% nitric acid solution with water to a final volume of 1 L) was measured by inductively coupled plasma mass spectrometry under the following test conditions:

[0076] 1) RF power: 1550W;

[0077] 2) Internal standard element: Bismuth ( 209 Bi);

[0078] 3) Internal standard addition method: Online three-way connection;

[0079] 4) Carrier gas flow rate: 0.99 mL / min;

[0080] 5) Atomization chamber temperature: 2℃;

[0081] 6) Sampling depth: 9mm;

[0082] 7) Sampling method: Fully quantitative;

[0083] 8) Number of scans: 50;

[0084] 9) Number of measurements: 3;

[0085] 10) The colliding gas is He, and the flow rate is 4.3 mL / min;

[0086] 11) Monitoring quality number:195 Pt.

[0087] A standard curve is plotted based on the ratio of the mass spectrometry signal intensity of the analyte to its internal standard and the corresponding elemental concentration (refer to...). Figure 1 As shown in the figure, the linear equation of the standard curve of platinum is: y = 0.0013x + 0.00001, the correlation coefficient R = 1.0000, and the method detection limit is 0.006 μg / L.

[0088] (3) Determination of sample solution and sample blank:

[0089] The sample solution and blank solution were measured separately, and the platinum content was calculated based on the standard curve plotted above.

[0090] The calculation of the platinum content is performed according to formula (1); where formula (1) is shown below;

[0091]

[0092] X represents the platinum content in the sample solution or blank sample solution, in mg / kg.

[0093] C represents the concentration of platinum in the sample solution, in μg / L;

[0094] C0 represents the concentration of platinum in the blank sample solution, in μg / L.

[0095] V is the final volume of the sample solution, in mL;

[0096] m is the mass of the sample, in grams;

[0097] F is the dilution factor of the sample solution.

[0098] Comparative Example 1

[0099] Two 0.5g samples of platinum-containing cream and two 0.25g samples of platinum-containing facial mask base fabric (squeezed dry and air-dried) were weighed and placed in four microwave digestion vessels. 7mL of nitric acid (65% by mass) was added to each of the four microwave digestion vessels. All other treatments were the same as in Example 1.

[0100] Comparative Example 2

[0101] Weigh out two 0.5g samples of platinum-containing cream and two 0.25g samples of platinum-containing facial mask base fabric (squeezed dry and air-dried), and place them in four microwave digestion vessels. Add 5mL of nitric acid (65% by mass) and 2mL of hydrogen peroxide aqueous solution (30% by mass) to each of the four microwave digestion vessels. All other treatments are the same as in Example 1.

[0102] Comparative Example 3

[0103] Two 0.5g samples of platinum-containing cream and two 0.25g samples of platinum-containing facial mask base fabric (squeezed dry and air-dried) were weighed and placed in four microwave digestion vessels. 5mL of nitric acid (65% by mass) and 2mL of hydrochloric acid (37% by mass) were added to each of the four microwave digestion vessels. All other treatments were the same as in Example 1.

[0104] Comparative Example 4

[0105] Two 0.5g samples of platinum-containing cream and two 0.25g samples of platinum-containing facial mask base fabric (squeezed dry and air-dried) were weighed and placed in four microwave digestion vessels. 6mL of hydrochloric acid (37% by mass) and 2mL of nitric acid (65% by mass) were added to each of the four microwave digestion vessels. All other treatments were the same as in Example 1.

[0106] The detection results of Example 1 and Comparative Examples 1-4 were compared, and Table 1 is obtained.

[0107] Table 1. Detection results of Example 1 and Comparative Examples 1-4

[0108]

[0109] As shown in Table 1, the platinum content was low when only nitric acid or nitric acid plus hydrogen peroxide aqueous solution was used for digestion with the sample. After adding hydrochloric acid, platinum could be completely digested from the cosmetic matrix and mask base fabric. Therefore, the nitric acid, hydrochloric acid and hydrogen peroxide aqueous solution digestion system was selected.

[0110] Example 2 Recovery rate determination

[0111] Referring to the method in Example 1, various types of base cosmetics (liquid, emulsion, cream, powder, and mask liquid) and mask base fabrics were spiked with a platinum standard solution for recovery. The spiked recovery concentration was 30 μg / L, and the recovery rate was calculated. The experimental results are shown in Table 2.

[0112] Table 2 Results of Recovery Rate Measurement

[0113] liquid 99.8 lotion 99.9 Cream 98.4 powder 108.0 Facial Mask Liquid 97.7 Mask base fabric 90.6

[0114] As shown in Table 2, the method for determining the platinum content in cosmetics and mask base fabrics provided by this invention has a recovery rate of 90.6%-108.0% for various types of base cosmetics (liquid, emulsion, cream, powder, and mask liquid) and mask base fabrics, indicating good recovery rate and high accuracy.

[0115] The above embodiments are merely preferred embodiments of the present invention and are only used to explain the present invention, not to limit the present invention. Any changes, substitutions, modifications, etc., made by those skilled in the art without departing from the spirit and essence of the present invention should be within the protection scope of the present invention.

Claims

1. A method for determining the platinum content in the base fabric of cosmetics and facial masks, characterized in that, Includes the following steps: (1) Immerse the sample to be tested in a mixture of nitric acid, hydrochloric acid and hydrogen peroxide aqueous solution in a container and perform microwave digestion. Then transfer the digestion solution in the container to a colorimetric tube, wash the container with water, mix the washing solution and digestion solution, add water to make up to volume, obtain the mother liquor, dilute, and obtain the test solution. (2) Prepare a series of platinum standard solutions and blank solutions. Then, using the internal standard method, use an inductively coupled plasma mass spectrometer to detect the test solution, the platinum standard solutions and blank solutions described in step (1), obtain the internal standard element and platinum element signal intensity of the test solution, and calculate the platinum content in the test sample according to the standard curve to complete the detection. The mixture of nitric acid, hydrochloric acid, and hydrogen peroxide aqueous solution in step (1) comprises, by volume,: 5-6 parts nitric acid; 1-2 parts hydrochloric acid; 1-2 parts of hydrogen peroxide aqueous solution; The mass-to-volume ratio of the sample to be tested to the aqueous solution of nitric acid, hydrochloric acid and hydrogen peroxide is 0.1-0.6 g : 7-10 mL; The microwave digestion process comprises three stages: In the first stage, the temperature is increased from room temperature to 110-130°C over a period of 10-15 minutes, and then held at the specified temperature for 3-7 minutes; In the second stage, the temperature is increased from 110-130°C to 140-160°C over a period of 3-7 minutes, and then held at the specified temperature for 3-7 minutes; In the third stage, the temperature is increased from 140-160°C to 180-200°C over a period of 3-7 minutes, and then held at the specified temperature for 15-25 minutes.

2. The method for determining the platinum content in the base fabric of cosmetics and facial masks according to claim 1, characterized in that, The mass percentage concentration of nitric acid in step (1) is 50%~70%; the mass percentage concentration of hydrochloric acid in step (1) is 36%~38%; the mass percentage concentration of hydrogen peroxide aqueous solution in step (1) is 20%~35%.

3. The method for determining the platinum content in the base fabric of cosmetics and facial masks according to claim 1, characterized in that, The power of the microwave digestion process in step (1) is 1000~2000W, and the time of the microwave digestion process is 37~68min.

4. The method for determining the platinum content in the base fabric of cosmetics and facial masks according to claim 1, characterized in that, The platinum standard series solutions mentioned in step (2) are platinum ion solutions with a concentration of 0-100 μg / L.

5. The method for determining the platinum content in the base fabric of cosmetics and facial masks according to claim 1, characterized in that, The internal standard element used in step (2) of the internal standard method is one of Re, Rh, Bi and Tb; the concentration of the internal standard element is 20-200 μg / L.

6. The method for determining the platinum content in the base fabric of cosmetics and facial masks according to claim 1, characterized in that, The standard curve in step (2) is obtained by measuring the standard solution using an inductively coupled plasma mass spectrometer and plotting the standard curve based on the ratio of the mass spectrometry signal intensity of the analyte to its internal standard and the corresponding element concentration. The linear correlation coefficient of the standard curve is between 0.995 and 1.

000.

7. The method for determining the platinum content in the base fabric of cosmetics and facial masks according to any one of claims 1-6, characterized in that, Step (2) involves calculating the platinum content in the sample based on the standard curve, including: The concentration of platinum in the test solution and blank solution is obtained by using a standard curve, and then the content of platinum in the test sample is calculated according to formula (1); where formula (1) is as follows; （1）； X represents the platinum content in the sample to be tested, in mg / kg. C represents the concentration of platinum in the solution being tested, in μg / L. C0 represents the concentration of platinum in the blank solution, in μg / L. V is the final volume of the solution to be tested, in mL; m is the mass of the sample to be tested, in grams; F represents the dilution factor of the solution to be tested.

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