Method for simultaneously detecting seven small molecule peptides in cosmetics

Abstract

The invention relates to a method for simultaneously detecting seven small molecule peptides in cosmetics, and belongs to the technical field of analysis and detection. In order to solve the problem of non-solid addition of polypeptide content in cosmetics at present, the method comprises the following steps: S1, preparing mixed standard working solutions containing seven small molecule peptides and having different concentrations; s2, weighing a to-be-tested sample, and pretreating to obtain a to-be-tested sample solution for later use; s3, detecting the mixed standard working solution by using an ultra-high performance liquid chromatography-tandem mass spectrometer to obtain standard curves of the seven small molecule peptides; and S4, detecting the sample solution to be tested by using an ultra-high performance liquid chromatography-tandem mass spectrometer to obtain the contents of the seven small molecule peptides in the sample. The method provided by the invention is accurate and reliable in determination result, and provides technical support for product quality control and market supervision in the cosmetic industry.

Description

Technical Field

[0001] The present invention relates to the technical field of analysis and detection, and in particular to a method for simultaneously detecting seven small molecule peptides in cosmetics. Background Art

[0002] The biological activity of a polypeptide depends on its amino acid composition and sequence. Almost all physiological processes in the human body are regulated by polypeptides or proteins composed of specific amino acid sequences. Bioactive polypeptides have many biological effects, such as promoting cell division and differentiation, promoting epidermal healing, increasing the synthesis and secretion of extracellular matrix, and promoting the formation of skin capillary networks and small blood vessels. In recent years, polypeptides have been increasingly involved in the research and development and application of cosmetics, and due to different amino acid compositions, the roles they play in cosmetics are also different, mainly including moisturizing, repairing, anti-allergic, anti-oxidation, firming and anti-wrinkle, and inhibiting melanin production.

[0003] Peptides are compounds formed by α-amino acids linked together by peptide bonds and are intermediate products of protein hydrolysis. Compounds formed by the dehydration condensation of two amino acid molecules are called dipeptides. Similarly, there are tripeptides, tetrapeptides, pentapeptides, etc. Generally, those with more than 50 or 100 amino acids are proteins, those with 11-50 amino acids are polypeptides, and those with 2-10 amino acids are oligopeptides, that is, small molecule peptides. Due to the diversity of amino acid types and the high degree of freedom of spatial conformation of peptide chains, peptides have diverse biological effects. The development and application of active peptides has opened up a new field for personal care products.

[0004] At present, there are many problems with the addition of peptides in cosmetics: such as the determination of the amount of peptides in the cosmetic formula, how to adjust the ratio of different peptides to achieve the best synergistic effect; and the protection technology of peptide stability; in addition, due to the high price of peptide raw materials, some companies will conceptually add or even just claim that they will not be added to mislead consumers, causing economic losses to consumers. Therefore, it has become an urgent task to study and explore technologies that can detect small molecule peptides in cosmetics. By detecting small molecule peptides in cosmetics, it can not only provide quality control references for cosmetics manufacturers, but also provide necessary testing basis for quality supervision departments to regulate the industry. Summary of the invention

[0005] In order to solve the problem in the prior art that the addition of polypeptides in cosmetics is inconsistent with the actual situation, the present invention aims to provide a method for simultaneously detecting 7 small molecule peptides in cosmetics, which can accurately determine the contents of 7 small molecule peptides by simple operation, and provide important technical support for product research and development, product quality control and market supervision in the cosmetics industry.

[0006] The present invention achieves the above technical objectives by adopting the following technical solutions:

[0007] A method for simultaneously detecting seven small molecule peptides in cosmetics comprises the following steps:

[0008] S1: Prepare mixed standard working solutions containing 7 small molecule peptides at different concentrations;

[0009] S2: Weigh the sample to be tested and pre-treat it to obtain a solution of the sample to be tested for later use;

[0010] S3: The mixed standard working solution was tested by ultra-high performance liquid chromatography-tandem mass spectrometry to obtain standard curves of seven small molecule peptides;

[0011] S4: The test sample solution is detected by ultra-high performance liquid chromatography-tandem mass spectrometry to obtain the contents of 7 small molecule peptides in the test sample solution.

[0012] As a further preferred embodiment of the above technical solution: in step S2, the step of weighing the sample to be tested and pre-treating it is as follows:

[0013] S11: Weigh the sample to be tested and place it in a centrifuge tube, and add a solution to dissolve it;

[0014] S12: subjecting the solution obtained in step S11 to ultrasonic and centrifugal treatment;

[0015] S13: After the centrifugal treatment in step S12, the solution is allowed to stand, and then the supernatant is aspirated and filtered to obtain a sample solution to be tested.

[0016] A further preferred implementation of the above scheme is: in step S11, the solution is any one of water, acetonitrile, trifluoroacetic acid aqueous solution or methanol.

[0017] A further preferred solution is: in step S12, the ultrasonic time is 30 to 60 minutes, the centrifugal speed is 6000 to 12000 r / min, and the centrifugal time is 5 to 10 minutes.

[0018] As a further preferred embodiment of the above technical solution: in step S2, the seven small molecule peptides are carnosine, copper peptide, glutathione, acetyl hexapeptide-8, palmitoyl pentapeptide-4, palmitoyl tripeptide-5, and palmitoyl tetrapeptide-7. The following is a brief description of the composition and function of the seven small molecule peptides:

[0019] Carnosine, whose scientific name is β-alanyl-L-histidine, is a dipeptide composed of two amino acids, β-alanine and L-histidine. Carnosine is an important type of neurotransmitter with important biological functions such as regulating enzyme activity and chelating heavy metals. It plays a unique role in the recovery of injured skin.

[0020] Glutathione is a tripeptide containing a γ-amide bond and a thiol group, composed of glutamic acid, cysteine ​​and glycine. As an important biologically active thiol substance in the body, glutathione plays a vital role in maintaining a suitable redox environment in the body. Clinically, glutathione can quickly improve the body's immunity, and has good effects in anti-oxidation, anti-radiation, scavenging free radicals, detoxification, and promoting iron absorption without side effects.

[0021] Copper peptide is a complex of glycyl histidyl lysine tripeptide and copper. Its aqueous solution is blue, so it is also called "blue copper peptide". Copper is one of the basic elements of the body. In terms of the function of skin tissue, it can assist in wound healing. Copper ions cannot enter the bottom layer of the skin alone. Therefore, through the blue copper peptide composed of glycine, lysine, histidine, etc., linked to a copper ion, copper can be introduced into the skin to exert its effect. Blue copper peptide can effectively promote the production of collagen and elastin and the antioxidant function. At the same time, it can penetrate deeper into the skin, promote self-repair ability, and exert anti-wrinkle effects.

[0022] Palmitoyl pentapeptide is the C-terminal fragment of collagen I, which can stimulate the proliferation of collagen, elastic fibers and hyaluronic acid, improve the skin's water content and water retention, increase skin thickness and reduce fine lines, and reverse the skin aging process by rebuilding from the inside out.

[0023] Palmitoyl Tetrapeptide is a peptide ingredient that can help promote collagen production and alleviate fine lines and wrinkles.

[0024] Acetyl hexapeptide achieves anti-wrinkle effects by inhibiting the release of acetylcholine and catecholamines, and is a mild and safe alternative to botulinum toxin.

[0025] Palmitoyl tripeptide can promote the synthesis of collagen and glucosamine in human fibroblasts, strengthen connective tissue, increase skin firmness, and promote cell activity. When added to cosmetics, it can not only replenish collagen for the skin, enhance its elasticity, and significantly reduce facial wrinkles, but also increase skin moisture content, restore smoothness and firmness, improve skin tone, and enhance radiance and transparency.

[0026] As a further preferred embodiment of the above technical solution: in step S2, the steps of preparing the mixed standard working solution are as follows:

[0027] S21: single standard stock solutions of carnosine, copper peptide, glutathione, acetyl hexapeptide-8, palmitoyl pentapeptide-4, palmitoyl tripeptide-5, and palmitoyl tetrapeptide-7 were prepared using a mixed solvent;

[0028] S22: Take each single standard stock solution and dilute it with a mixed solvent to prepare a mixed standard intermediate solution;

[0029] S23: Pipette the mixed standard intermediate solution into multiple volumetric flasks respectively, make up to volume with the mixed solvent, and prepare mixed standard working solutions of different concentrations.

[0030] A further preferred implementation of the above scheme is: in step S21 to step S23, the volume ratio of the mixed solvent is water: methanol: acetic acid = 60-80: 30-50: 10-20.

[0031] A further preferred implementation of the above scheme is: in step S21, the concentration of each single standard stock solution is 1000 mg / L;

[0032] In step S22, the concentration of the mixed standard intermediate solution is 1.0 mg / L;

[0033] In step S23, the mixed standard working solutions with different concentrations are 0.5 μg / L, 1 μg / L, 10 μg / L, 20 μg / L, 50 μg / L, and 100 μg / L, respectively.

[0034] 9. The method for simultaneously detecting seven small molecule peptides in cosmetics according to claim 1, characterized in that in step S3, the chromatographic column used in ultra-high performance liquid chromatography is:

[0035] Chromatographic column: Waters BEH C18, 3 mm × 100 mm, 1.7 μm;

[0036] The mobile phases were: phase A: 0.1% trifluoroacetic acid aqueous solution, phase B: 0.1% trifluoroacetic acid acetonitrile solution; injection volume: 5 μL; flow rate: 0.3 mL / min; column temperature: 40°C; gradient elution.

[0037] As a further preferred embodiment of the above technical solution: in step S3, the mass spectrometry conditions used in ultra-high performance liquid chromatography are:

[0038] Ion source: ESI+, ion source temperature: 500°C, capillary voltage: 5500 V, curtain gas pressure: 30 psi, nebulizer gas pressure: 55 psi, auxiliary gas pressure: 55 psi, multiple reaction monitoring mode was used.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] 1. The method of the present invention improves the extraction rate of 7 small molecule peptides by optimizing the extraction solvent and extraction method of sample pretreatment, and provides an effective detection means for the qualitative and quantitative detection of small molecule peptides in cosmetics. The method is simple to operate, fast to separate, accurate and reliable in measurement results, and has a high recovery rate, which makes up for the defects of existing detection methods.

[0041] 2. The detection method of the present invention can simultaneously measure 7 small molecule peptides in cosmetics, and can be used for cosmetics with various matrix types. It can not only provide a quality control reference for cosmetics manufacturers, but also provide the necessary detection basis for quality supervision departments to regulate the industry and protect the rights and interests of consumers. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required in the embodiments are briefly introduced below.

[0043] Figure 1 is a standard curve diagram of carnosine of the present invention;

[0044] Figure 2 is a standard curve diagram of glutathione of the present invention;

[0045] Figure 3 is a standard curve diagram of the copper peptide of the present invention;

[0046] Figure 4 This is a standard curve diagram of palmitoyl tripeptide-5 of the present invention;

[0047] Figure 5 This is a standard curve diagram of palmitoyl pentapeptide-4 of the present invention;

[0048] Figure 6 This is a standard curve diagram of palmitoyl tetrapeptide-7 of the present invention;

[0049] Figure 7 is a standard curve diagram of acetyl hexapeptide-8 of the present invention;

[0050] Figure 8 The standard spectra of carnosine, glutathione and copper peptide of the present invention; wherein: 1 represents carnosine, 2 represents glutathione, and 3 represents copper peptide;

[0051] Fig. 9 It is the standard spectrum of palmitoyl tripeptide-5, palmitoyl pentapeptide-4 and acetyl hexapeptide-8 of the present invention; wherein: 4 represents palmitoyl tripeptide-5, 5 represents palmitoyl pentapeptide-4, and 6 represents acetyl hexapeptide-8;

[0052] Fig.10 7 is the standard spectrum of acetyl hexapeptide-8 of the present invention, and 7 represents acetyl hexapeptide-8. DETAILED DESCRIPTION

[0053] In order to make the purpose, technical scheme and advantages of the present invention clearer, the technical scheme in the embodiments will be described clearly and completely in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments, not all of the embodiments. For ordinary technicians in this field, other embodiments can be obtained without creative work.

[0054] Unless otherwise defined, all technical and scientific terms used in the present invention have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The experimental methods in the following examples where specific conditions are not specified are usually carried out under conventional conditions or under conditions recommended by the manufacturer. The various commonly used chemical reagents used in the examples are all commercially available products.

[0055] Reference Figure 1-10 The present invention provides a method for simultaneously detecting seven small molecule peptides in cosmetics, comprising the following steps:

[0056] S1: Prepare mixed standard working solutions containing 7 small molecule peptides at different concentrations;

[0057] S2: Weigh the sample to be tested and pre-treat it to obtain a solution of the sample to be tested for later use;

[0058] S3: The mixed standard working solution was tested by ultra-high performance liquid chromatography-tandem mass spectrometry to obtain standard curves of seven small molecule peptides;

[0059] S4: The test sample solution is detected by ultra-high performance liquid chromatography-tandem mass spectrometry to obtain the contents of 7 small molecule peptides in the test sample solution.

[0060] In step S2, the process of weighing the sample to be tested and pre-treating it is as follows:

[0061] Weigh 0.2-5g (accurate value 0.01g) of the test sample and place it in a 10-50mL centrifuge tube, add 10-25mL of solution to dissolve the test sample, then ultrasonicate for 30-60min, and centrifuge at a speed of 6000-12000r / min for 5-10min. After centrifugation, let it stand, absorb the supernatant, and filter it through a 0.22μm microporous filter membrane to obtain a test sample solution.

[0062] In an embodiment of the present invention, the solution used is any one of water, acetonitrile, trifluoroacetic acid aqueous solution or methanol.

[0063] The 7 small molecule peptides in the present invention are carnosine, copper peptide, glutathione, acetyl hexapeptide-8, palmitoyl pentapeptide-4, palmitoyl tripeptide-5, and palmitoyl tetrapeptide-7.

[0064] In step S2, the steps for preparing the mixed standard working solution are as follows:

[0065] 1) Accurately weigh 10.0 mg of carnosine, copper peptide, glutathione, acetyl hexapeptide-8, palmitoyl pentapeptide-4, palmitoyl tripeptide-5, and palmitoyl tetrapeptide-7 respectively and place them in a 10 mL volumetric flask, add a mixed solvent to the volumetric flask in proportion to dissolve and dilute to the set scale to prepare a single standard stock solution with a concentration of 1000 mg / L;

[0066] 2) Accurately pipette 100 μL of a single standard stock solution into a 100 mL volumetric flask, dilute to volume with a mixed solvent (water: methanol: acetic acid = 60:30:10, volume ratio) to prepare a mixed standard intermediate solution with a concentration of 1.0 mg / L;

[0067] 3) Pipette 0.005, 0.01, 0.1, 0.2, 0.5, and 1.0 mL of the mixed standard intermediate solution into a 10 mL volumetric flask, dilute to volume with the mixed solvent, and prepare mixed standard working solutions of different concentrations, whose concentrations are 0.5 μg / L, 1 μg / L, 10 μg / L, 20 μg / L, 50 μg / L, and 100 μg / L, respectively.

[0068] In an embodiment of the present invention, the mixed solvent is water, methanol and acetic acid mixed in proportion, and the volume ratio is water: methanol: acetic acid = 60-80: 30-50: 10-20, preferably water: methanol: acetic acid = 60: 30: 10.

[0069] In step S3, the prepared mixed standard working solutions of different concentrations are injected into an ultra-high performance liquid chromatography-tandem quadrupole mass spectrometer for determination, and the standard curves of the seven small molecule peptides are drawn with the concentration as the abscissa and the peak area as the ordinate, as shown in FIG. Figure 1-7 As shown, the corresponding linear regression equation and its correlation coefficient were obtained, and then the detection limit was calculated using a 3-fold signal-to-noise ratio (S / N=3). The results are shown in Table 1. The results show that the 7 small molecule peptides have good linearity within the corresponding linear range, and each correlation coefficient is above 0.996.

[0070] Table 1 Linear regression equations and detection limits of 7 small molecule peptides

[0071]

[0072] The conditions of the ultra-high performance liquid chromatography tandem quadrupole mass spectrometer used in the present invention are as follows:

[0073] 1) Liquid chromatography conditions

[0074] Chromatographic column: Waters BEH C18, 3 mm × 100 mm, 1.7 μm;

[0075] Injection volume: 5 μL; flow rate: 0.3 mL / min; column temperature: 40 °C;

[0076] The mobile phases were: phase A: 0.1% trifluoroacetic acid aqueous solution, phase B: 0.1% trifluoroacetic acid acetonitrile solution; gradient elution, the gradient elution ratio is shown in Table 2 below.

[0077] Table 2 Gradient elution ratio

[0078] Time / min Phase A / % Phase B / % 0 98 2 1 98 2 4 35 65 5.5 5 95 7 5 95 7.1 98 2 10 98 2

[0079] 2) Mass spectrometry conditions

[0080] Ion source: ESI+, ion source temperature: 500°C, capillary voltage: 5500 V, curtain gas pressure: 30 psi, nebulizer gas pressure: 55 psi, auxiliary gas pressure: 55 psi, multiple reaction monitoring mode was adopted, and other mass spectrometry parameters are shown in Table 3 below.

[0081] Table 3 Mass spectrometry parameters of 7 small molecule peptides

[0082]

[0083]

[0084] Furthermore, the following spike recovery experiments were performed using the mixed standard working solution:

[0085] Weigh 0.2-5g (accurate to 0.01g) of blank sample and place it in a 10-50mL centrifuge tube, add a mixed standard working solution containing 7 small molecule peptides, so that the concentrations of the 7 small molecule peptides are as shown in Table 4, add 10-25mL solution to dissolve, then ultrasonicate for 30-60min, and centrifuge at a speed of 6000-12000r / min for 5-10min. After centrifugation, let it stand, absorb the supernatant, pass through a 0.22μm microporous filter membrane, and obtain a blank sample solution. Under the optimized conditions, parallel measurements were performed 6 times, and the spiked recovery and relative standard deviation (RSD) of the blank sample were calculated. The measurement results are shown in Table 4.

[0086] Table 4 Recovery and precision of spiked blank sample solution

[0087]

[0088]

[0089] From the results in Table 4, it can be seen that the spiked recoveries of the seven small molecule peptides are between 99.3% and 105.6%, and the RSD (precision) is between 1.0% and 4.0%, which meets the requirements for the determination of the contents of the seven small molecule peptides in cosmetics.

[0090] In step S4, the sample solutions to be tested are the cosmetic samples in Examples 1 to 3 respectively. It should be understood that the samples listed in Examples 1 to 3 below are only exemplary and are not intended to limit the scope of protection of the present invention.

[0091] Embodiment 1:

[0092] The sample solution to be tested is a solution prepared from cosmetic sample 1 (matrix type: cream matrix), and a spike addition experiment is performed on the solution to determine the spike addition recovery rate.

[0093] The specific operation process of the spiked recovery rate of the test sample solution is as follows:

[0094] Weigh 0.2 g of the sample (tested to contain no 7 small molecule peptides) and put it into a 50 mL centrifuge tube, accurately add the above-mentioned mixed standard working solution containing 7 small molecule peptides, add 10 mL of acetonitrile to dissolve the sample to be tested, ultrasonically treat for 30 minutes, centrifuge at 6000 r / min for 10 minutes, and after centrifugation, aspirate the supernatant, pass through a 0.22 μm microporous filter membrane, test 6 times, and calculate the spike recovery rate and relative standard deviation (precision / RSD), as shown in Table 5.

[0095] Table 5 Recovery and precision of spiked cream matrix samples

[0096]

[0097]

[0098] Embodiment 2:

[0099] The sample solution to be tested is a solution prepared from cosmetic sample 2 (matrix type: emulsion matrix), and a spike addition experiment is performed on the solution to determine the spike addition recovery rate.

[0100] The specific operation process of the spiked recovery rate of the test sample solution is as follows:

[0101] Weigh 2 g of the sample to be tested (tested to contain no 7 small molecule peptides) and put it into a 50 mL centrifuge tube, accurately add the above-mentioned mixed standard working solution containing 7 small molecule peptides, add 10 mL of acetonitrile to dissolve the sample to be tested, ultrasonically treat for 30 minutes, centrifuge at 6000 r / min for 10 minutes, aspirate the supernatant after centrifugation, pass through a 0.22 μm microporous filter membrane, test 6 times, calculate the spike recovery rate and relative standard deviation (precision / RSD), as shown in Table 6 below.

[0102] Table 6 Recovery and precision of spiked samples in latex matrix

[0103]

[0104]

[0105] Embodiment 3:

[0106] The sample solution to be tested is a solution prepared from cosmetic sample 3 (matrix type: water matrix), and a spike addition experiment is performed on the solution to determine the spike addition recovery rate.

[0107] The specific operation process of the spiked recovery rate of the test sample solution is as follows:

[0108] Weigh 5 g of the sample to be tested (tested to contain no 7 small molecule peptides) and put it into a 50 mL centrifuge tube, accurately add the above-mentioned mixed standard working solution containing 7 small molecule peptides, add 10 mL of acetonitrile to dissolve the sample to be tested, ultrasonically treat for 30 minutes, centrifuge at 6000 r / min for 10 minutes, aspirate the supernatant after centrifugation, pass through a 0.22 μm microporous filter membrane, test 6 times, calculate the spike recovery rate and relative standard deviation (precision / RSD), as shown in Table 7 below.

[0109] Table 7 Recovery and precision of spiked samples in water-based matrix

[0110]

[0111]

[0112] Embodiment 4:

[0113] The detection method of the present invention was used to determine 7 small molecule peptides in 30 batches of common cosmetics (matrix types: 10 batches of creams, 10 batches of oil-based matrices, and 10 batches of water-based matrices).

[0114] The test results showed that among 30 batches of ordinary cosmetics, 6 batches of carnosine were detected, with a content of 0.031%-0.122%; 13 batches of copper peptides were detected, with a content of 0.013%-0.205%; 3 batches of acetyl hexapeptide-8 were detected, with a content of 0.023%-0.092%; 2 batches were labeled with palmitoyl tetrapeptide-7 and 1 batch was labeled with palmitoyl tripeptide-5, but the actual results did not detect them, which should attract the attention of relevant departments to strengthen the supervision and management of the cosmetics industry.

[0115] It should be clear that the above detailed description of the embodiments of the present invention provided in the accompanying drawings is only used to further illustrate the present invention and is not intended to limit the scope of the invention claimed for protection, but only represents selected embodiments of the present invention. Based on the embodiments of the present invention, some non-essential improvements and adjustments made by ordinary technicians in this field according to the above content of the present invention belong to the protection scope of the present invention.

Claims

1. A method for simultaneously detecting 7 small molecule peptides in cosmetics, characterized in that: The following steps are involved: S1: Prepare mixed standard working solutions containing 7 small molecule peptides at different concentrations; S2: Weigh the sample to be tested and pre-treat it to obtain a solution of the sample to be tested for later use; S3: The mixed standard working solution was tested by ultra-high performance liquid chromatography-tandem mass spectrometry to obtain standard curves of seven small molecule peptides; S4: The test sample solution is detected by ultra-high performance liquid chromatography-tandem mass spectrometry to obtain the contents of 7 small molecule peptides in the test sample solution.

2. A method for simultaneously detecting seven small molecule peptides in cosmetics according to claim 1, characterized in that: In step S2, the steps of weighing the sample to be tested and pre-treating it are as follows: S11: Weigh the sample to be tested and place it in a centrifuge tube, and add the solution to dissolve it; S12: subjecting the solution obtained in step S11 to ultrasonic and centrifugal treatment; S13: After the centrifugal treatment in step S12, the solution is allowed to stand, and then the supernatant is aspirated and filtered to obtain a sample solution to be tested.

3. A method for simultaneously detecting seven small molecule peptides in cosmetics according to claim 2, characterized in that: In step S11, the solution is any one of water, acetonitrile, trifluoroacetic acid aqueous solution or methanol.

4. A method for simultaneously detecting seven small molecule peptides in cosmetics according to claim 2, characterized in that: In step S12, the ultrasonic time is 30-60 min, the centrifugal speed is 6000-12000 r / min, and the centrifugal time is 5-10 min.

5. The method for simultaneously detecting seven small molecule peptides in cosmetics according to claim 1, characterized in that: In step S2, the seven small molecule peptides are carnosine, copper peptide, glutathione, acetyl hexapeptide-8, palmitoyl pentapeptide-4, palmitoyl tripeptide-5, and palmitoyl tetrapeptide-7.

6. The method for simultaneously detecting seven small molecule peptides in cosmetics according to claim 1, characterized in that: In step S2, the steps for preparing the mixed standard working solution are as follows: S21: using mixed solvents to prepare single standard stock solutions of carnosine, copper peptide, glutathione, acetyl hexapeptide-8, palmitoyl pentapeptide-4, palmitoyl tripeptide-5, and palmitoyl tetrapeptide-7; S22: Take each single standard stock solution and dilute it with a mixed solvent to prepare a mixed standard intermediate solution; S23: Pipette the mixed standard intermediate solution into multiple volumetric flasks respectively, make up to volume with the mixed solvent, and prepare mixed standard working solutions of different concentrations.

7. A method for simultaneously detecting seven small molecule peptides in cosmetics according to claim 6, characterized in that: In step S21 to step S23, the volume ratio of the mixed solvent is water: methanol: acetic acid = 60~80: 30~50: 10~20.

8. The method for simultaneously detecting seven small molecule peptides in cosmetics according to claim 7, characterized in that: In step S21, the concentration of each single standard stock solution is 1000 mg / L; In step S22, the concentration of the mixed standard intermediate solution is 1.0 mg / L; In step S23, the mixed standard working solutions with different concentrations are 0.5 μg / L, 1 μg / L, 10 μg / L, 20 μg / L, 50 μg / L, and 100 μg / L, respectively.

9. The method for simultaneously detecting seven small molecule peptides in cosmetics according to claim 1, characterized in that: In step S3, the chromatographic column used in ultra-high performance liquid chromatography is: Chromatographic column: Waters BEH C18, 3 mm × 100 mm, 1.7 μm; The mobile phases were: phase A: 0.1% trifluoroacetic acid aqueous solution, phase B: 0.1% trifluoroacetic acid acetonitrile solution; injection volume: 5 μL; flow rate: 0.3 mL / min; column temperature: 40°C; gradient elution.

10. According to the method for simultaneously detecting seven small molecule peptides in cosmetics according to claim 9, in step S3, the mass spectrometry conditions used by ultra-high performance liquid chromatography are: Ion source: ESI+, ion source temperature: 500°C, capillary voltage: 5500 V, curtain gas pressure: 30 psi, nebulizer gas pressure: 55 psi, auxiliary gas pressure: 55 psi, multiple reaction monitoring mode was used.

Images