Table of Content

22 February 2023, Volume 53 Issue 2 Previous Issue    Next Issue

Basic research

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Preparation of P/O/LC/W multiple emulsion Lv Yawen,Wang Jingwen,Ye Zhicheng,Shang Yazhuo,Liu Honglai 2023, 53 (2):  121-132.  doi: 10.3969/j.issn.1001-1803.2023.02.001 Abstract ( 369 )   HTML ( 28 )   PDF (5703KB) ( 419 )   A type of polyol-in-oil-in-liquid crystal-in-water （P/O/LC/W） multiple emulsion was prepared by two-step method with liquid crystal emulsifier and traditional emulsifier. The samples were characterized by microscopy. The effects of different liquid crystal emulsifiers, emulsification temperature and homogenization rate on the microstructure of P/O/LC/W multiple emulsion were studied. The steps of preparation process were as follows: The emulsification temperature was 60-75 ℃; the homogenization rate of polyol in oil was 7 000-8 400 r/min and homogenization time was ~6 min; the homogenization rate of polyol in oil in liquid crystal in water was 4 400-6 000 r/min and homogenization time was ~7 min. The emulsion was put at room temperature for 28 days, and multiple structures and liquid crystal structures could still be observed, and the liquid crystal became brighter. The components of the formula were glycerol （polyol phase）, squalane （oil phase）, P135 （hydrophobic emulsifier）, and IST-LC001 （liquid crystal emulsifier）. The ideal emulsion structure could thus be obtained. The formula was used to encapsulate active substances. Resveratrol was used as the target molecule for sustained-release experiment. The results of dialysis experiments in vitro showed that the P/O/LC/W multiple emulsion had a remarkable slow-release performance. The release ratio of target molecule was up to 83% after 10 h. When shikonin was used as the target molecule, it was proved that the P/O/LC/W multiple emulsion could mask the color of the target molecule. Compared with traditional emulsion, the color of P/O/LC/W multiple emulsion was lighter. Rheological measurement showed that the viscosity of the emulsion decreased with the increase of shear stress, indicative of positive thixotropy. Within the investigated range, the storage modulus of the emulsion was always higher than that of loss modulus, exhibiting elastic properties. The internal structure of the emulsion was stable and the emulsion could bring good skin feel to skin care products. The experimental results showed that, the P/O/LC/W multiple emulsion could not only solve the problems in application of insoluble functional ingredients in formulations, but also effectively deliver these active substances and achieve slow-release. The emulsion could also mask the color of introduced ingredients and improve the skin feel of products. The P/O/LC/W multiple emulsion has wide application value in the fields of medicine, food, cosmetics, etc. Figures and Tables | References | Related Articles | Metrics

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Preparation of Ca-SA/P（AM-AMPS） microsphere and their properties Xuan Yani,Tang Fan,Zhang Tao,Zhuang Liqi,Zhao Shicheng 2023, 53 (2):  133-139.  doi: 10.3969/j.issn.1001-1803.2023.02.002 Abstract ( 204 )   HTML ( 11 )   PDF (2380KB) ( 352 )   Polyacrylamide profile control agents have the problems of poor temperature resistance and rapid swelling at room temperature. Calcium alginate/Polyacrylamide （Ca-SA/P（AM-AMPS）） microspheres were prepared by cross-linking Ca2+ with sodium alginate （SA） on the surface of microspheres to improve their properties. FT-IR, SEM, TEM, Nano Sizer and Zeta-potential Tester were used to analyze the structure, morphology and properties of the microspheres. The results showed that the average particle size of Ca-SA/P（AM-AMPS） microspheres ranged from 47 nm to 92 nm at different SA mass fraction. When the mass fraction of SA was 8%, the swelling property of Ca-SA/P（AM-AMPS） microspheres was the best. The swelling property of Ca-SA/P（AM-AMPS） microspheres was 2.52 times at 20 ℃, which was 42% lower than that of P（AM-AMPS） microspheres. At 60 ℃, the swelling property of Ca-SA/P（AM-AMPS） microspheres was 3.35 times, 52% higher than P（AM-AMPS） microspheres. The results show that Ca-SA/P（AM-AMPS） microspheres swell slowly at room temperature, and swell quickly at high temperature with a larger swelling, which can better match the injection profile control process and achieve efficient profile control and oil displacement. Figures and Tables | References | Related Articles | Metrics

Lecture of science and technology

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Properties of hair and scientific basis of hair care （Ⅱ） Spectroscopic techniques for hair characterization Chang Kuan,Ma Ling,Chen Timson,Wang Jing 2023, 53 (2):  140-148.  doi: 10.3969/j.issn.1001-1803.2023.02.003 Abstract ( 323 )   HTML ( 19 )   PDF (1926KB) ( 294 )   Most current research and development of hair care products have been focused on the evaluation of hair properties such as glossiness, combability, fluffiness, mechanical properties, etc. In contrast, the studies focused on the changes of hair at molecular level are few. With the development of modern spectroscopic techniques, infrared spectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopy and X-ray fluorescence spectroscopy have been widely used in hair related research, providing molecular-level explanations and scientific evidence for the composition difference of hair, the hair damage under different conditions and the mechanism of new hair care materials. In this review, the spectroscopic techniques commonly used for hair study were summarized. The sample preparation, characterization instruments and data analysis methods were introduced. Several cases of analyzing the structure-property relationships of hair based on spectroscopic characterization were also listed, aiming to provide a reference for the development of new hair care products and raw materials. Figures and Tables | References | Related Articles | Metrics

Development and application

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Preparation and evaluation of ceramide ⅢB phospholipid complex Song Guanjie,Wu Wenhai,Zhang Huirong,Wu Yuehang,Yi Fan,Li Li 2023, 53 (2):  149-156.  doi: 10.3969/j.issn.1001-1803.2023.02.004 Abstract ( 239 )   HTML ( 7 )   PDF (1724KB) ( 207 )   Using ceramide ⅢB （Cer ⅢB） and lecithin as raw materials and anhydrous ethanol as reaction solvent, ceramide ⅢB phospholipid complex （CerPC） was prepared by evaporative solvent method. By orthogonal experiment, CerPC was prepared and confirmed according to the following method. Cer ⅢB （20.0 mg/mL） and phospholipids was added in anhydrous ethanol in a molar ratio of 1∶6 and stirred for 1.0 h at 60 ℃. The formation of CerPC was confirmed by using Fourier transform infrared （FT IR） spectroscopy, differential scanning calorimetry （DSC）, and scanning electron microscopy （SEM）. Permeability and retention were analyzed by an in vitro diffusion test in a Franz diffusion cell with a Strat-M® membrane. Safety and irritation were analyzed by a chick embryo chorioallantois membrane （CAM） assay. The inhibition rate of CerPC on inflammatory factor COX-2 was determined by using a COX-2 inhibitor screening kit. The results show that the preparation method of the phospholipid complex designed in this study is safe and effective, and thus can be used as a drug delivery system for Cer ⅢB to improve its bioavailability and expand its application field. Figures and Tables | References | Related Articles | Metrics

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In chemico skin sensitisation: Amino acid Derivative Reactivity Assay （ADRA） transformation and validation Shen Li, Wang Xuemei, Zhang Huiwen, Suo Yaqiong, Wu Jing, Xing Shuxia 2023, 53 (2):  157-164.  doi: 10.3969/j.issn.1001-1803.2023.02.005 Abstract ( 359 )   HTML ( 10 )   PDF (1262KB) ( 287 )   A skin sensitizer refers to a substance that will lead to an allergic response following repeated skin contact as defined by the United Nations Globally Harmonized System of Classification and Labelling of Chemicals. The current knowledge of the chemical and biological mechanisms associated with skin sensitisation has been summarised as an Adverse Outcome Pathway （AOP） starting with a molecular initiating event through intermediate events to the adverse effect, namely allergic contact dermatitis. Using cysteine and lysine derivatives instead of skin tissue, simulating the reaction of skin proteins with compounds, classifying the substances by calculating the percentage of depletion value after the reaction of cysteine and lysine derivatives to distinguish skin sensitizers and desensitizers, this method is called Amino acid Derivative Reactivity Assay （ADRA）. In this study, ten known allergens were selected to explore the accuracy of the sensitivity evaluation of ADRA method, and verified accuracy by DPRA that several substances were randomly selected among the ten substances. The results show that the sensitivity determination results of 10 substances are consistent with the sensitivity of samples, and the accuracy of determination of ADRA sensitivity is good. Figures and Tables | References | Related Articles | Metrics

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Hydrolysed zinc hyaluronan, a novel anti-acne candidate Chen Fan,Yang Jun,Yang Suping,Wu Yue 2023, 53 (2):  165-170.  doi: 10.3969/j.issn.1001-1803.2023.02.006 Abstract ( 335 )   HTML ( 22 )   PDF (2328KB) ( 388 )   In this study, the effects of hydrolysed zinc hyaluronan （HA-ZN） on lipid production and skin hydration were revealed. The HaCaT and SZ95 cell lines were applied to evaluate the toxicity and beneficial effect of hydrolysed zinc hyaluronan. Pro-acne agents, arachidonic acid was used to induce the lipid production of SZ95 and the effect of hydrolysed zinc hyaluronan was detected. At the same time, in vitro antibacterial experiment against acne-related bacteria and the expression of skin hydration involved proteins were estimated. At the identical concentration of zinc ion, hydrolysed zinc hyaluronan exhibits less toxicity than zinc chloride, suggesting a higher safe dosage of zinc ion. In addition, hydrolysed zinc hyaluronan possesses the ability of alleviating lipid production in SZ95, as well as inhibiting the growth of Propionibacterium acnes and Malassezia furfur in vitro. The expression of AQP3 and HAS2 is also augmented in hydrolysed zinc hyaluronan treated group. The results indicate that hydrolysed zinc hyaluronan might be a promising drug candidate against acne vulgaris, averting the side effects of existing drugs such as dry skin. Figures and Tables | References | Related Articles | Metrics

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Study on skin care efficacy of AIMP1 derived peptide Yang Xiufen,Ma Wenjun,Li Lei,Wang Peipei,Zheng Chunyang 2023, 53 (2):  171-179.  doi: 10.3969/j.issn.1001-1803.2023.02.007 Abstract ( 195 )   HTML ( 10 )   PDF (2188KB) ( 470 )   Advanced glycation end-products （AGEs） are produced during protein glycation and associated with skin ageing. The AIMP1 derived peptide （AdP） which is derived from aminoacyl tRNA synthase interacting multifunctional protein 1 may be used as an inhibitor of glycation. This study evaluated the potential anti-glycation effect of AdP and its application in cosmetic. Thirty valid subjects were selected as the research subjects, and non-invasive instruments were used to detect and record the water content, TEWL, R2, ITA°, wrinkle area/AOI area in the test group and the control group at 0, 4 and 8 weeks using corresponding products. The results show that the glycosylation reaction between BSA and glucose is inhibited by AdP, and the formation of protein carbonyl is reduced in a concentration-dependent manner. The applications of AdP in cosmetic has significant effects on improving the stratum corneum water content, the R2 value, the ITA° value, and the reducing the TEWL value and wrinkles. These findings suggest that AdP may serve as an inhibitor of glycation and provide new insights into its application. Figures and Tables | References | Related Articles | Metrics

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Process optimization of enzyme-catalyzed synthesis of monoglyceride and its antibacterial activity Li Xiaomin 2023, 53 (2):  180-186.  doi: 10.3969/j.issn.1001-1803.2023.02.008 Abstract ( 146 )   HTML ( 9 )   PDF (1344KB) ( 179 )   Lauric acid monoglyceride （GML） was synthesized, in which lauric acid and glycerol were used as raw materials, tert-butanol was used as the medium, and lipase was used to catalyze the reaction. Single-factor experiment was used to optimize the synthesis process of GML. The optimized conditions were as follows: The mass ratio of tert-butanol to glycerol was 1.5∶1, the amount of lipase was 12%, the reaction temperature was 70 ℃, the molar ratio of glycerol to lauric acid was 3∶1, and the reaction time was 1.5 h. The antibacterial test showed that GML had significant inhibitory effect against Escherichia coli, and the antibacterial effect was increased with the increase of mass concentration. The diameter of inhibition zone would not be further increased when the mass concentration of GML reached 16 mg/mL. The antibacterial effect and the half-life of bacteriostatic rate in the faintly acidic environment of pH 5.7 were both stronger than that in the neutral condition of pH 7.2, and the bacteriostatic rate of GML against Escherichia coli was still maintained at 3.9% in the environment of pH 5.7 at 72 h. Figures and Tables | References | Related Articles | Metrics

Reviews

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Analysis on the “Technical Guidelines for the Development and Drafting of Supplementary Test Methods for Cosmetics” Xue Jing, Yang Qingyun, Huang Baobin 2023, 53 (2):  187-192.  doi: 10.3969/j.issn.1001-1803.2023.02.009 Abstract ( 156 )   HTML ( 6 )   PDF (995KB) ( 231 )   In order to standardize the development of supplementary testing methods for cosmetics, in April 2021, National Medical Products Administration issued the “Technical Guidelines for the Development and Drafting of Supplementary Testing Methods for Cosmetics”. In this paper, regulations and requirements of the technical guide are analyzed in detail, the legal basis, development scope, main development direction, requirements for method text editing and method validation are arranged, and the project application and technical requirements for method development are focused on in combination with the “Guidelines for the Development of Supplementary Test Methods for Drugs”. In the end, it provides reference for the relevant personnel of drug inspection institutions to develop supplementary testing methods for cosmetics, and some targeted suggestions are put forward. Figures and Tables | References | Related Articles | Metrics

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Research status of cosmetic soothing efficacy evaluation Tan Qidan, Bi Yongxian, Liu Lei, Hu Xueqing, Dai Xiaoyan 2023, 53 (2):  193-201.  doi: 10.3969/j.issn.1001-1803.2023.02.010 Abstract ( 881 )   HTML ( 24 )   PDF (1051KB) ( 372 )   In recent years, with the continuous development of the global economy and the gradual improvement of the living standards of residents, consumers have higher and higher requirements on the quantity, quality, safety and efficacy of cosmetics. At the same time, the proportion of people with sensitive skin is gradually increasing due to air pollution, ultraviolet radiation, work and life pressure, irregular diet and rest, and long-term wearing of masks during the epidemic. Compared with normal skin, sensitive skin is more prone to skin irritation and other problems, while soothing cosmetics can help improve the skin tension, dryness, redness, burning, tingling, itching, scale and other adverse skin conditions caused by internal and external factors. China’s current laws and regulations, the Evaluation Criteria for Cosmetic Efficacy claims, clearly require that cosmetics with efficacy claims such as anti wrinkle, firming and soothing should be evaluated for efficacy claims. However, at present, there is no scientific and effective method system related to the evaluation of soothing efficacy at home and abroad, and there is no standard evaluation method for reference in the industry. It is not conducive to the development of raw materials, formulation development and efficacy evaluation of soothing cosmetics, and it is difficult to protect the rights and interests of consumers. Starting from the causes of sensitive skin, this paper expounds the formation mechanism of sensitive skin caused by the impairment of skin barrier function, skin immune inflammatory reaction, skin nerve reaction and their mutual promotion and accumulation, which provides a certain theoretical basis for the development of soothing raw materials and cosmetic products with the functions of repairing skin barrier function, inhibiting skin inflammatory reaction and calming nerves. On this basis, the evaluation methods of the soothing efficacy of cosmetics in different dimensions such as human body, animal, 3D skin model, cell, biochemistry and physicochemistry are also investigated, aiming to provide scientific basis and theoretical support for the establishment and improvement of the soothing efficacy evaluation system. It helps to continuously improve the cosmetics regulatory system that conforms to China’s national conditions and is in line with international standards, protect the rights and interests of consumers, and promote the sustainable and healthy development of China’s cosmetics industry. References | Related Articles | Metrics

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Application of 3D printing technology in cosmetics Liufu Chunqiao,Zeng Shaofeng,Zhou Baixian,Zhang Wenfang,Yang Fan,Song Fenglan 2023, 53 (2):  202-209.  doi: 10.3969/j.issn.1001-1803.2023.02.011 Abstract ( 322 )   HTML ( 13 )   PDF (1649KB) ( 340 )   With the rapid development of science and technology, a lot of advanced techniques have come one after another. As the representative of new era technology, 3D printing technology is known as the “core technology of the third industrial revolution”, which has the characteristics of high precision, personalization and intelligence. It is widely used in many fields such as machinery industry, construction industry, food processing industry, medical education and many other fields. In recent years, personalized customization products have set off a boom in the market. As an effective means of rapid prototyping and personalized customization, 3D printing technology combines with the development of cosmetics can not only realize effective precise skin care and personalized customization products, but also meet the needs of various skin care cosmetics. By exploring the development status of 3D printing in the field of cosmetics industry, this essay further introduces the application and advantages of 3D printing technology in personalized skin care products, cosmetics molds and customized makeup, in order to provide ideas for the development of precision skin management and intelligent makeup in the future. Figures and Tables | References | Related Articles | Metrics

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Preparation of SiO2 antireflective coatings by sol-gel method Jing Ximing,Sheng Yonggang 2023, 53 (2):  210-219.  doi: 10.3969/j.issn.1001-1803.2023.02.012 Abstract ( 190 )   HTML ( 18 )   PDF (1435KB) ( 445 )   Antireflection film （antireflective coating） has been widely used in military applications, daily life, industry, etc., especially in high-energy laser systems （one of the most important technologies for inertial confinement fusion）. In this paper, the optical principle of antireflective coating was analyzed, and the characteristics of its common manufacturing material silica （SiO2） were introduced. The principle and unique advantages of the antireflective coating prepared by the sol-gel method were described. The process of sol-gel plating antireflective coating was described. The precursor SiO2 sol was prepared by reaction, and then the antireflective coating was made by dip coating, spin coating, spraying, and coating. Various chemical reactions in the precursor sol were analyzed. The effects of various factors of reactions on the SiO2 material and the antireflective coating prepared from it were analyzed. Finally, the new research progress in the preparation of antireflective coatings by sol-gel method was reviewed, such as adding additives to the sol, modifying the materials to be coated, and combining with other methods to prepare the antireflective coatings. The antireflective coatings prepared by those methods not only enhance the optical properties of the film but also have functions such as self-cleaning function. Their wide applications in a variety of cutting-edge fields of technology, e.g., in photovoltaic industry, LED lighting, etc., were also prospected. Figures and Tables | References | Related Articles | Metrics

Analytical methods and testing

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Determination of sodium lauroyl glycinate by HPLC-ELSD Zhuo Wenshan, Feng Shunqing, Tang Jianfeng 2023, 53 (2):  220-225.  doi: 10.3969/j.issn.1001-1803.2023.02.013 Abstract ( 201 )   HTML ( 9 )   PDF (1382KB) ( 193 )   A method for rapid quantitative analysis of sodium lauroyl glycinate （SLG） was established by using a reversed-phase HPLC combined with evaporative light scattering detection （ELSD） without complex pre-treatment. HPLC-ELSD was equipped with Thermo Scientific Acclaim Surfactant Plus column （250 mm×4.6 mm, 5 μm）. Acetonitrile-0.1 mol/L ammonium acetate aqueous solution （the pH was adjusted to 5.4 by acetic acid） was used as the mobile phase for gradient elution and the parameters in ELSD were optimized as follows: Evaporation temperature was 75 ℃; nebulization temperature was 85 ℃; N2 flow rate was 0.9 L/min. The facial cleanser samples were extracted by mixed solvent of 80% acetonitrile-20% water and the amount of SLG was determined. The results showed that, in the range of 10-200 mg/L, the logarithm of the response value of ELSD was linearly related to the logarithm of the concentration of SLG with the correlation coefficients greater than 0.999, and the detection limit was 3 mg/L. The relative standard deviation of facial cleansing sample in 24 h was less than 1.5%, and the relative standard deviation in parallel samples was less than 2.0%. The average spike recoveries varied from 90.9% to 100.4% with standard addition. The developed HPLC-ELSD method could rapidly determine the content of SLG in facial cleansers with the advantages of simple operation, high accuracy and good reproducibility, and it was suitable for determination of other N-acylamino acid surfactants. Figures and Tables | References | Related Articles | Metrics

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Determination of 16 coumarin compounds in commonly cosmetics plant extract raw materials by UPLC-MS/MS Zhang Yanping, Zhou Zongzhou, Huang Wanfeng, Chen Yihua, Zhang Min, He Zuomin 2023, 53 (2):  226-232.  doi: 10.3969/j.issn.1001-1803.2023.02.014 Abstract ( 164 )   HTML ( 4 )   PDF (1162KB) ( 154 )   An analytical method based on UPLC-MS/MS for the determination of 16 coumarin compounds in commonly cosmetics plant extract raw materials was established. The study aimed to evaluate the safety of plant extract as raw materials for cosmetics and to provide theoretical basis for regulating the application of plant extract in cosmetics. The separation was performed on a Waters ACQUITY HPLC BEH C18 column. Acetonitrile and 0.1% formic acid were used as mobile phases with gradient elution at a flow rate of 0.30 mL/min. A triple quadrupole mass spectrometer operating in positive electrospray ionization mode with multiple reaction monitoring was used. The results of 16 coumarin compounds show good linear relationships within their own rangers, the correlation coefficients （r） are above 0.995, and the mean recoveries at three spiked levels range from 85.7% to 108.6, with the relative standards of 1.5%-5.8%. The limits of detections （LODS） for the 16 coumarin compounds range from 0.3 μg/kg to 28.0 μg/kg. The limits of quantitation （LOQS） range from 1.0 μg/kg to 93.0 μg/kg. Coumarin compounds are detected in 4 of the 14 batches of plant extracts collected. The method not only is convenient, rapid, sensitive and accurate, but also can be used for the qualitative screening and quantitative determination of 16 coumarin compounds in cosmetics plant extract raw materials, which provides a way to explore the material basis of allergenic risk of the plant extract raw materials. It is suggested to pay attention to the safety risk of allergenic components from the plant extract raw materials, to establish the product quality and use specification of the plant extract raw materials. Figures and Tables | References | Related Articles | Metrics

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Analysis of microbial contamination of cosmetics and identification of contaminated bacteria in Guangxi from 2018 to 2020 Wang Tao, Tan Huimin, Zhu Bin 2023, 53 (2):  233-238.  doi: 10.3969/j.issn.1001-1803.2023.02.015 Abstract ( 146 )   HTML ( 5 )   PDF (1282KB) ( 281 )   According to the “Technical Specification for Safety of Cosmetics” （2015 edition）, the cosmetics are tested for microbial indicators. The contaminated bacteria are identified by malDI-TOF-MS and 16S rRNA sequencing technology, and the homology of the contaminated strains is compared and analyzed to investigate the microbial contamination of cosmetics in Guangxi. The results show that the homology of the same bacterial strain （Pluralibacter gergoviae） from three batches of mask of the same manufacturer is high after comparison and analysis. A total of 1 521 batches are qualified among 1 538 batches of cosmetics with the pass rate of 98.9% during 2018 to 2020. Among them, the qualified rate of aerobic bacterial count is 99.0%, the qualified rate of mold and yeast is 99.9%, the qualified rate of Pseudomonas aeruginosa is 99.9%, and the qualified rate of Staphylococcus aureus and heat-resistant coliform is 100.0%. The samples of contaminated microorganisms are mainly facial mask, skin care, toothpaste, hair care, and skin care products for infants. The unqualified samples are 10 batches of facial mask, 4 batches of skin care, 2 batches of toothpaste and 1 batch of hair care. The work indicates that the contaminated microorganisms are exceeded the standard in some cosmetics, and the conditioned pathogens above the standards （such as Burkholderia cepacia complex，BCC and Pluralibacter gergoviae） are detected in some samples. Although the qualified rate of microbial indicators in cosmetics is increasing year by year, microbial contamination still needs to be paid attention to. Figures and Tables | References | Related Articles | Metrics

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Determination of 16 preservatives of benzoates and parabens in cosmetics by GC-MS Lü Wen, Zhang Jingya, Hu Bei, Liu Hong, Huang Wei 2023, 53 (2):  239-244.  doi: 10.3969/j.issn.1001-1803.2023.02.016 Abstract ( 167 )   HTML ( 6 )   PDF (1226KB) ( 185 )   A method for the determination of benzoate and paraben preservatives in cosmetics by gas chromatography-mass spectrometry （GC-MS） was established. The sample was extracted by saturated sodium chloride and ethyl acetate, then the supernatant was fixed to volume with acetonitrile after centrifugation. The extracted solution was separated by the chromatographic column of HP-5ms （30 m×250 μm×0.25 μm）. The determination was carried out under the mode of selected ion monitoring （SIM） and the external standard method was used for quantitative determination. All the 16 preservatives show good linearity in the corresponding range, the LOD and LOQ of benzoates are 0.3 μg/g and 1 μg/g, respectively, and the LOD and LOQ of parabens are 0.6 μg/g and 2 μg/g, respectively. Three types of cosmetics are selected to verify the accuracy and precision of the method at two levels. The average spiked recoveries of the 16 preservatives are 85.4%-113.8%, and the corresponding relative standard deviations （RSDs, n=6） ≤10.9%. The use frequency of methylparaben and propylparaben in 50 baby cosmetics are 50% and 36%, respectively, and the maximum contents are lower than the limit of relevant requirements. Figures and Tables | References | Related Articles | Metrics