Positive lists of cosmetic ingredients: Analytical methodology for regulatory and safety controls - A review

Decoding Cosmetic Complexities: A Comprehensive Guide to Matrix Composition and Pretreatment Technology

Despite advancements in analytical technologies, the complex nature of cosmetic matrices, coupled with the presence of diverse and trace unauthorized additives, hinders the application of these technologies in cosmetics analysis. This not only impedes effective regulation of cosmetics but also leads to the continual infiltration of illegal products into the market, posing serious health risks to consumers. The establishment of cosmetic regulations is often based on extensive scientific experiments, resulting in a certain degree of latency. Therefore, timely advancement in laboratory research is crucial to ensure the timely update and adaptability of regulations. A comprehensive understanding of the composition of cosmetic matrices and their pretreatment technologies is vital for enhancing the efficiency and accuracy of cosmetic detection. Drawing upon the China National Medical Products Administration's 2021 Cosmetic Classification Rules and Classification Catalogue, we streamline the wide array of cosmetics into four principal categories based on the following compositions: emulsified, liquid, powdered, and wax-based cosmetics. In this review, the characteristics, compositional elements, and physicochemical properties inherent to each category, as well as an extensive overview of the evolution of pretreatment methods for different categories, will be explored. Our objective is to provide a clear and comprehensive guide, equipping researchers with profound insights into the core compositions and pretreatment methods of cosmetics, which will in turn advance cosmetic analysis and improve detection and regulatory approaches in the industry.

Easy determination of benzophenone and its derivatives in sunscreen samples by direct-immersion solid-phase microextraction and gas chromatography-mass spectrometry

Benzophenones (BPs) absorb different sun radiation wavelengths, making them effective UVA and UVB filters, widely used in industry. In Europe, sunscreen products contain regulated amounts (6 % w/w) of benzophenone-3 (BP-3), usually combined with other filters like octocrylene. BPs are mutagens in UV radiation, and octocrylene may degrade into BPs, making their monitoring crucial. The present manuscript proposed a novel procedure based on liquid-liquid extraction followed by direct-immersion solid-phase microextraction (LLE-DI-SPME) to isolate and determine 10 BPs in sunscreen lotions with potential results. Parameters like extraction solvent, pH, adsorption, desorption time, stirring, sating effect, and presence of organic solvents were optimized and compared with different SPME fibers, being polyacrylate (PA) fiber the most effective. Detection and quantification were performed by gas chromatography-mass-spectrometry. Analytical parameters as limits of detection were 0.05-0.10 µg kg-1, while the linear range was 0.16 up to 2000 µg kg-1. In terms of recovery, the method ranged from 83 % to 103 %; the precision of the method was good in terms of relative standard deviation (RSD) from 3.2 % to 18.7 % and without a remarkable matrix effect (-15.06-8.45 %). Despite the complexity of the samples and the difficulty posed by the DI-SPME technique, the method proved robust. The proposed method successfully detected 10 BPs in 6 different sunscreen lotions. The total presence of BPs in sunscreens ranged from 165 to 931 mg kg-1, with BP-3 detected in all samples from 4.2 to 740 mg kg-1.

Advances on Hormones in Cosmetics: Illegal Addition Status, Sample Preparation, and Detection Technology

Owing to the rapid development of the cosmetic industry, cosmetic safety has become the focus of consumers' attention. However, in order to achieve the desired effects in the short term, the illegal addition of hormones in cosmetics has emerged frequently, which could induce skin problems and even skin cancer after long-term use. Therefore, it is of great significance to master the illegal addition in cosmetics and effectively detect the hormones that may exist in cosmetics. In this review, we analyze the illegally added hormone types, detection values, and cosmetic types, as well as discuss the hormone risks in cosmetics for human beings, according to the data in unqualified cosmetics in China from 2017 to 2022. Results showed that although the frequency of adding hormones in cosmetics has declined, hormones are still the main prohibited substances in illegal cosmetics, especially facial masks. Because of the complex composition and the low concentration of hormones in cosmetics, it is necessary to combine efficient sample preparation technology with instrumental analysis. In order to give the readers a comprehensive overview of hormone analytical technologies in cosmetics, we summarize the advanced sample preparation techniques and commonly used detection techniques of hormones in cosmetics in the last decade (2012-2022). We found that ultrasound-assisted extraction, solid phase extraction, and microextraction coupled with chromatographic analysis are still the most widely used analytical technologies for hormones in cosmetics. Through the investigation of market status, the summary of sample pretreatment and detection technologies, as well as the discussion of their development trends in the future, our purpose is to provide a reference for the supervision of illegal hormone residues in cosmetics.

The Impact of Communicating Sustainability and Ethical Behaviour of the Cosmetic Producers: Evidence from Thailand

Purpose—This study aims to demonstrate the antecedent factors of consumers’ cosmetics purchasing behaviour in the emerging market of Thailand from the perspective of sustainability. Specifically, the study aims to quantitatively analyse the impact of three hypothesised antecedents of consumer behaviour: product quality, communicating sustainability, and ethical business behaviour. Methodology—A quantitative methodology is applied in the study, which collects survey data from Thailand. This study focuses on two cosmetic brands in Thailand, a domestic brand and an international brand. The total 800-sample dataset was analysed using Structural Equation Modelling to validate a conceptual model with measurements of three antecedent factors: quality, ethical behaviour, and communication sustainability. Findings—It is found that ‘ethical behaviour of the producers had a non-significant impact for all samples and the ‘domestic brand’, whereas communicating sustainability had a significant impact in all sample cases. The proposed measurement scales present a practical and pioneering tool for assessing consumer responses and behaviour towards cosmetic brands. The set of scales will also help cosmetics marketers to appraise their strategic planning and monitor their progress toward creating and identifying consumer loyalty to cosmetics brands via producers’ ethical behaviour and CSR messaging. Originality—The global market and inter-stakeholder communications have greatly changed the way people perceive, behave towards, and react to business suppliers. The understanding of consumer brand loyalty in the cosmetics industry and the business strategies focused on the impact of communicating sustainability with ethical behaviour remain limited, especially in the context of the emerging market. This research contributes to filling this gap with empirical analyses.

Miniaturized Sample Preparation Methods to Simultaneously Determine the Levels of Glycols, Glycol Ethers and Their Acetates in Cosmetics

Two environmentally friendly methodologies based on ultrasound-assisted extraction (UAE) and micro-matrix solid-phase dispersion (µMSPD) followed by gas chromatography-mass spectrometry (GC-MS) analysis are proposed for the first time for the simultaneous analysis of 17 glycols, glycol ethers, and their acetates in cosmetics. These sample preparation approaches result in efficient and low-cost extraction while employing small amounts of sample, with a low consumption of reagents and organic solvents. The use of a highly polar column allows for the direct analysis of the obtained extracts by GC-MS without a previous derivatization step, drastically reducing the sample preparation time and residues and thus complying with green analytical chemistry (GAC) principles. Both the UAE and µMSPD methodologies were validated in terms of linearity, accuracy, and precision, providing satisfactory results. LODs were found to be lower than 0.75 µg g−1, allowing the determination of trace levels of the forbidden target compounds. Finally, the validated methodologies were applied to real cosmetics and personal care products, showing suitability, and providing a reliable and useful tool for cosmetics control laboratories.

Extraction of Aloesin from Aloe vera Rind Using Alternative Green Solvents: Process Optimization and Biological Activity Assessment

Simple Summary

Aloesin is a bioactive constituent of Aloe spp. used primarily in cosmetic products. Its recovery from plant materials is affected by several variables that can compromise the process yield and profitability, which is why it is necessary to determine the best processing conditions. This study describes the design and optimization of a method for extraction of aloesin from Aloe vera rind, a leaf part often discarded as a by-product, using the response surface methodology. The effect of the variables time, temperature, solvent composition, and solid/liquid ratio were investigated. Green organic solvents (ethanol, propylene glycol, and glycerol) were used in aqueous mixtures. Aqueous propylene glycol was found to be the most promising solvent for aloesin recovery and a linear increase in extraction yields was verified with the increase in solid/liquid ratio. To assess the bioactivity of the extracts, their ability to inhibit lipid peroxidation and the fungal and bacterial growth, as well as their cytotoxic potential, was tested in vitro. Overall, it was possible to determine the best extraction conditions for aloesin and to better understand the antioxidant and antimicrobial properties of the aloesin-rich extracts, which may be produced and used by the industrial sector.

Abstract

Aloesin is an aromatic chromone with increasing applications in the cosmetic and health food industries. To optimize its extraction from the Aloe vera leaf rind, the independent variables time (10–210 min), temperature (25–95 °C) and organic solvent composition (0–100%, w/w) were combined in a central composite design coupled with response surface methodology. The solvents consisted of binary mixtures of water with ethanol, propylene glycol, or glycerol. The aloesin levels quantified in each extract were used as response for optimization. The theoretical models were fitted to the experimental data, statistically validated, and used to obtain the optimal extraction conditions. Then, a dose–response analysis of the solid/liquid ratio (S/L) was performed under the optimal conditions determined for each alcohol–water system and revealed that a linear improvement in extraction efficiency can be achieved by increasing the S/L ratio by up to 40 g/L. This analysis also allowed to experimentally validate the predictive models. Furthermore, the aloesin-rich extracts revealed antioxidant activity through thiobarbituric acid reactive substances (TBARS) formation inhibition, antimicrobial effects against bacterial and fungal strains, and no toxicity for PLP2 cells. Overall, this study provided optimal extraction conditions for the recovery of aloesin from Aloe vera rind through an eco-friendly extraction process and highlighted its bioactive potential.

Recent Advances in Sample Preparation for Cosmetics and Personal Care Products Analysis

The use of cosmetics and personal care products is increasing worldwide. Their high matrix complexity, together with the wide range of products currently marketed under different forms imply a challenge for their analysis, most of them requiring a sample pre-treatment step before analysis. Classical sample preparation methodologies involve large amounts of organic solvents as well as multiple steps resulting in large time consumption. Therefore, in recent years, the trends have been moved towards the development of simple, sustainable, and environmentally friendly methodologies in two ways: (i) the miniaturization of conventional procedures allowing a reduction in the consumption of solvents and reagents; and (ii) the development and application of sorbent- and liquid-based microextraction technologies to obtain a high analyte enrichment, avoiding or significantly reducing the use of organic solvents. This review provides an overview of analytical methodology during the last ten years, placing special emphasis on sample preparation to analyse cosmetics and personal care products. The use of liquid–liquid and solid–liquid extraction (LLE, SLE), ultrasound-assisted extraction (UAE), solid-phase extraction (SPE), pressurized liquid extraction (PLE), matrix solid-phase extraction (MSPD), and liquid- and sorbent-based microextraction techniques will be reviewed. The most recent advances and future trends including the development of new materials and green solvents will be also addressed.

An Overview of the Analytical Methods for the Determination of Organic Ultraviolet Filters in Cosmetic Products and Human Samples

UV filters are a group of compounds commonly used in different cosmetic products to absorb UV radiation. They are classified into a variety of chemical groups, such as benzophenones, salicylates, benzotriazoles, cinnamates, p-aminobenzoates, triazines, camphor derivatives, etc. Different tests have shown that some of these chemicals are absorbed through the skin and metabolised or bioaccumulated. These processes can cause negative health effects, including mutagenic and cancerogenic ones. Due to the absence of official monitoring protocols, there is an increased number of analytical methods that enable the determination of those compounds in cosmetic samples to ensure user safety, as well as in biological fluids and tissues samples, to obtain more information regarding their behaviour in the human body. This review aimed to show and discuss the published studies concerning analytical methods for the determination of organic UV filters in cosmetic and biological samples. It focused on sample preparation, analytical techniques, and analytical performance (limit of detection, accuracy, and repeatability).

Lightening Effect of Skin Lightening Cream Containing Piper betle L. Extract in Human Volunteers

Hyperpigmentation affects people globally with negative psychological impacts. Piper betle L. leaf (PBL) extract has many benefits including skin lightening which may reduce hyperpigmentation. The objective of this study was to develop an effective skin-lightening cream containing PBL with ideal characteristics. A formulation of base cream and PBL cream was prepared and characterized by centrifugation, particle size and zeta potential analysis, rheological profile studies and physical properties’ observation. In vivo studies on 30 human subjects tested the effects of base and PBL cream on skin-lightening, hydration, trans-epidermal water loss (TEWL) and elasticity through weekly tests 4 weeks in duration. Base and PBL creams had a non-Newtonian property with acceptable color, odor, texture, zeta potential, particle size and showed no phase separation. The in vivo study indicated a significant reduction in melanin content and an improvement in skin tone for PBL cream but not in base cream. TEWL and elasticity also showed significant reduction for both formulations, indicating a healthier skin barrier and supple skin with consistent use, although hydration fluctuated with no significant changes. The developed PBL cream showed significant results in the reduction in melanin content and improving skin tone, which shows the formulation can confer skin-lightening effect.

Multi-Target Strategy to Uncover Unexpected Compounds in Rinse-Off and Leave-On Cosmetics

The wide range and complexity of cosmetic formulations currently available on the market poses a challenge from an analytical point of view. In addition, during cosmetics manufacture, impurities coming from raw materials or formed by reaction of different organic compounds present in the formulation may be present. Their identification is mandatory to assure product quality and consumer health. In this work, micro-matrix solid-phase dispersion (μMSPD) is proposed as a multi-target sample preparation strategy to analyze a wide number of unexpected families of compounds including polycyclic aromatic hydrocarbons (PAHs), pesticides, plasticizers, nitrosamines, alkylphenols (APs), and alkylphenol ethoxylates (APEOs). Analytical determination was performed by gas chromatography-mass spectrometry (GC-MS) for the determination of 51 target compounds in a single run, whereas liquid chromatography tandem mass spectrometry (LC-MS/MS) was employed for the analysis of six APs and APEOs. Both methodologies were successfully validated in terms of linearity, accuracy, and precision in leave-on and rinse-off cosmetics. Limits of detection (LODs) were calculated in the low ng g⁻¹, showing their suitability to determine trace levels of impurities and banned compounds with different chemical natures, providing useful tools to cosmetic control laboratories and companies.

Deep eutectic solvent-based magnetic colloidal gel assisted magnetic solid-phase extraction: A simple and rapid method for the determination of sex hormones in cosmetic skin care toners

A simple rapid and efficient deep eutectic solvent-based magnetic colloidal gel (DES-MCG) assisted magnetic solid-phase extraction (MSPE) method followed by high performance liquid chromatography with a diode array detector (HPLC-DAD) was established for determination of four sex hormones (including ethinylestradiol, norgestrel, megestrol acetate and medroxyprogesterone acetate) in cosmetic skin care toners. The DES-MCG with the desirable advantages of high adsorbing ability was prepared by combining choline chloride/urea deep eutectic solvent and magnetic multiwalled carbon nanotubes (MMWCNTs). The synthesized DES-MCG was characterized using fourier transform infrared spectrometry (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and vibrating sample magnetometry (VSM). The cosmetic skin care toners were concentrated by a rotary evaporator and the obtained solutions were further purified by DES-MCG assisted magnetic solid-phase extraction. Response surface methodology (RSM) was applied for efficient optimization of the main variables in the extraction procedure. Under the optimized conditions, method detection limits and method quantitation limits were in the range of 1.2-6.6 ng mL^-1 and 4.4-26.6 ng mL^-1, respectively. The recoveries of the four sex hormones in different cosmetic skin care toners ranged from 80.1% to 118.8% and the precisions were no more than 0.35%. The developed method was successfully applied for the determination of sex hormones in cosmetic skin care toners.

Effect of Trust in Domain-Specific Information of Safety, Brand Loyalty, and Perceived Value for Cosmetics on Purchase Intentions in Mobile E-Commerce Context

In 2016, the safety issues of humidifier disinfectants and some other safety incidents in personal cares caused chemical phobia syndrome in the Korean society. This series of events has created a trend for cosmetic consumers to undermine brand confidence and to self-check the safety of commercial cosmetic formulations through mobile apps. The purpose of this study is to examine the influence of trust in domain specific information on the safety rating of cosmetic ingredients on the perceived value and the purchase intention of the cosmetics. The results of structural equation modeling showed that involvement of skin safety (ISS) had a positive effect on trust in domain specific information on safety (TDSI) and brand loyalty (BL). TDSI showed a positive effect on the perceived safety value (PFV) and the perceived social value (PSV), and BL had a positive effect on the PSV. ISS, TDSI, and PSV had a positive effect on the purchase intention (PI) of green-grade cosmetics (GGC). As hypothesized, BL had an adverse effect on PI of GGC. Given the results, utilizing the signal of the domain specific information may be recommended to new entrants to the cosmetic business or manufacturers with relatively weak brand power.

Vacuum-assisted sorbent extraction: An analytical methodology for the determination of ultraviolet filters in environmental samples

Vacuum-assisted sorbent extraction (VASE) has been applied in combination with gas chromatography-mass spectrometry for the determination of UV filters in water samples. VASE is a variant of headspace extraction which was developed in conjunction with the sorbent pen (SP) technology. This technique combines the advantages of both stir-bar assisted extraction and headspace solid-phase microextraction. The SP traps allowed both reduced pressure in-vial extraction and direct thermal desorption via a unique gas chromatographic injection port. The main parameters that affect the performance of VASE, including both extraction and desorption conditions, were extensively optimized. Under optimum conditions, extraction required 10 mL of sample within 40 mL vials, pH 3.5, ~30 s of air-evacuation, 14 h incubation at 70 °C, stirring at 200 rpm, and a final water management step conducted at ~ -17 °C for 15 min. Optimal thermal desorption required preheating at 260 °C for 2 min followed by desorption at 300 °C for 2 min. The beneficial effect of reduced-pressure extraction was demonstrated by comparing the UV filter extraction time profiles collected using VASE to an analogous atmospheric pressure procedure, resulting in up to a 3-fold improvement under optimized conditions. The VASE methodology enabled simultaneous extractions using different SPs without compromising the method reproducibility, which increases the overall sample throughput. The method was characterized by low limits of detection, from 0.5 to 80 ng L^-1, and adequate reproducibility, with inter-SP and inter-day relative standard deviation lower than 14%. Tap and lake water was successfully analyzed with the proposed methodology, resulting in relative recoveries of spiked samples ranging between 70.0 and 120%.

Miniaturized Matrix Solid-Phase Dispersion for the Analysis of Ultraviolet Filters and Other Cosmetic Ingredients in Personal Care Products

A method based on micro-matrix solid-phase dispersion (μ-MSPD) followed by gas-chromatography tandem mass spectrometry (GC–MS/MS) was developed to analyze UV filters in personal care products. It is the first time that MSPD is employed to extract UV filters from cosmetics samples. This technique provides efficient and low-cost extractions, and allows performing extraction and clean-up in one step, which is one of their main advantages. The amount of sample employed was only 0.1 g and the extraction procedure was performed preparing the sample-sorbent column in a glass Pasteur pipette instead of the classic plastic columns in order to avoid plastizicer contamination. Factors affecting the process such as type of sorbent, and amount and type of elution solvent were studied by a factorial design. The method was validated and extended to other families of cosmetic ingredients such as fragrance allergens, preservatives, plasticizers and synthetic musks, including a total of 78 target analytes. Recovery studies in real sample at several concentration levels were also performed. Finally, the green extraction methodology was applied to the analysis of real cosmetic samples of different nature.

Microwave-assisted dispersive liquid-liquid microextraction coupling to solidification of floating organic droplet for colorants analysis in selected cosmetics by liquid chromatography

A convenient and rapid method was developed for determination of fourteen colorants in selected cosmetics based on microwave-assisted dispersive liquid-liquid microextraction (MA-DLLME) using solidification of the floating organic droplet (SFOD) as a clean-up step followed by high-performance liquid chromatography diode array detection (HPLC-DAD). DLLME was performed in a microwave device for reducing manual operations and facilitating rapid extraction equilibrium, resulting in high sample throughput and good extraction efficiency. Matrix effects could be effectively eliminated by SFOD technique. Various parameters affecting the extraction efficiency were optimized by multi-response surface methodology. The limits of detection and quantification were 0.25-3.2 mg kg^-1 and 0.85-11.0 mg kg^-1, respectively. The recoveries ranged from 90.2% to 106.1% with relative standard deviations of 0.30-3.1%. The method was successfully applied to the analysis of cosmetics, in which all the colorants could be quantified, and their median values ranged from 4.94 to 591 mg kg^-1 for seventy-two lipsticks, and from 7.70 to 1.73 × 10³ mg kg^-1 for fifty eye shadows, respectively. The proposed protocol could achieve batch preparation of samples and avoid measurement errors from the obvious volume reduction of the recovered extract, and it could serve as a powerful tool for high-throughput analysis of multiple colorants in complex samples.

Extreme cosmetics and borderline products: an analytical-based survey of European regulation compliance

The cosmetic industry currently focuses on products with magnified or exaggerated effects or extremely long-lasting characteristics. There are also a number of related commercial products for which the regulatory framework is far from clear; they are called 'borderline', and the European authorities only recommend which regulations they need to comply with. In any case, all these products must be safe under reasonable conditions of use in accordance with the applicable laws in force in the European Union (EU) framework. In this context, adequate analytical methodology is needed to evaluate the degree of compliance. Ultrasound Assisted Extraction (UAE) procedures for the analysis of 70 cosmetic ingredients have therefore been developed in this work. Moreover, for cosmetics with plastic applicators, a Supported-UAE (Sup-UAE) method was also opportunely optimized to check if a partial transfer of plasticizers to the cosmetics-and thereby to the consumers-could happen. In a survey of 50 commercial products (30 'extreme' and 20 'borderline'), the methods afforded mean recoveries of about 100% and RSD values lower than 5% for UAE and 10% for Sup-UAE, and with detection limits far below the legal requirements, for all the target compounds, thereby demonstrating their analytical suitability. Results are discussed in detail for phthalates, fragrances (musks and allergens) and some frequent preservatives. Additionally, a labelling study was performed to check if the consumer is correctly and fully informed. Graphical abstract ᅟ.

Analysis of Dyes in Cosmetics: Challenges and Recent Developments

Colour plays a decisive role in the marketing of a cosmetic product. Among thousands of substances used to colour, synthetic dyes are the most widespread in the industry. Their potential secondary effects on human health and different regulatory requirements for their use between the main world markets make analytical control necessary to guarantee the safety of a cosmetic product. However, methodologies for the determination of dyes in cosmetics are scarce with respect to those reported for other cosmetic ingredients such as preservatives or ultraviolet UV filters. In addition, most of the existing methods just consider a part of the total of dyes regulated. On the other hand, many methods have been developed for matrices different than cosmetics such as foodstuff, beverages or wastewater. The current paper reviews the recent developments in analytical methodologies for the control of synthetic dyes in cosmetics proposed in the international scientific literature in the last 10 years (2008–2018). A trend towards the use of miniaturized extraction techniques is evidenced. Due to the hydrophilic nature of dyes, liquid chromatography is the most usual choice in combination with absorbance detectors and, more recently, with mass spectrometry.

Cosmetics Preservation: A Review on Present Strategies

Cosmetics, like any product containing water and organic/inorganic compounds, require preservation against microbial contamination to guarantee consumer’s safety and to increase their shelf-life. The microbiological safety has as main goal of consumer protection against potentially pathogenic microorganisms, together with the product’s preservation resulting from biological and physicochemical deterioration. This is ensured by chemical, physical, or physicochemical strategies. The most common strategy is based on the application of antimicrobial agents, either by using synthetic or natural compounds, or even multifunctional ingredients. Current validation of a preservation system follow the application of good manufacturing practices (GMPs), the control of the raw material, and the verification of the preservative effect by suitable methodologies, including the challenge test. Among the preservatives described in the positive lists of regulations, there are parabens, isothiasolinone, organic acids, formaldehyde releasers, triclosan, and chlorhexidine. These chemical agents have different mechanisms of antimicrobial action, depending on their chemical structure and functional group’s reactivity. Preservatives act on several cell targets; however, they might present toxic effects to the consumer. Indeed, their use at high concentrations is more effective from the preservation viewpoint being, however, toxic for the consumer, whereas at low concentrations microbial resistance can develop.

Miniaturized matrix solid-phase dispersion followed by liquid chromatography-tandem mass spectrometry for the quantification of synthetic dyes in cosmetics and foodstuffs used or consumed by children

Miniaturized matrix solid-phase dispersion (MSPD) followed by liquid chromatography tandem mass spectrometry (LC-MS/MS) has been proposed for the simultaneous analysis of different classes of synthetic dyes in confectionery and cosmetics intended for or mostly consumed by children. Selected compounds include most of the permitted dyes as food additives as well as some of the most frequently used to color cosmetic products in accordance with the respective European directives. MSPD procedure was optimized by means of experimental design, allowing an effective, rapid and simple extraction of dyes with low sample and reagents consumption (0.1g of sample and 2mL of elution solvent). LC-MS/MS was optimized for good resolution, selectivity and sensitivity using a low ionic strength mobile phase (3mM NH₄Ac-methanol). Method performance was demonstrated in real samples showing good linearity (R≥0.9928) and intra- and inter-day precision (%RSD≤15%). Method LODs were ≤0.952μgg^-1 and ≤0.476μgg^-1 for confectionery and cosmetic samples, respectively. Recoveries of compounds from nine different matrices were quantitative. The validated method was successfully applied to 24 commercial samples (14 cosmetics and 10 foods) in which 9 of the selected dyes were found at concentrations up to 989μgg^-1, exceeding in some cases the regulated maximum permitted limits. A non-permitted dye, Acid Orange 7, was found in one candy.

Current trends in sample preparation for cosmetic analysis

The widespread applications of cosmetics in modern life make their analysis particularly important from a safety point of view. There is a wide variety of restricted ingredients and prohibited substances that primarily influence the safety of cosmetics. Sample preparation for cosmetic analysis is a crucial step as the complex matrices may seriously interfere with the determination of target analytes. In this review, some new developments (2010-2016) in sample preparation techniques for cosmetic analysis, including liquid-phase microextraction, solid-phase microextraction, matrix solid-phase dispersion, pressurized liquid extraction, cloud point extraction, ultrasound-assisted extraction, and microwave digestion, are presented. Furthermore, the research and progress in sample preparation techniques and their applications in the separation and purification of allowed ingredients and prohibited substances are reviewed.