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A rapid and simple analytical method based on liquid chromatography – ultraviolet detection has been developed and validated for the simultaneous determination of two high added-value cosmetic ingredients, honokiol and magnolol, in commercial cosmetic samples. These compounds from the Magnolia plant present demonstrated benefits for the skin, such as antioxidative and anti-inflammatory properties, besides of antimicrobial and antifungal capacity, which may lead to their possible use as alternative preservatives in cosmetic products. The proposed method has been successfully validated showing good linearity, limits of detection and quantification in the low µg mL−1 level (0.06 to 0.07 µg mL−1 and 0.19 to 0.24 µg mL−1, respectively) and good repeatability (relative standard deviation below 9%). The proposed method has been evaluated by analyzing a laboratory-made cosmetic sample containing known concentrations of the analytes, providing low relative errors (-6% for honokiol and −4% for magnolol) and quantitative recovery values (96 to 111%). Finally, the proposed analytical method has been applied to the determination of both analytes in eight commercial cosmetic samples with different properties, obtaining quantitative recovery values (93 to 115%) and thus showing that matrix effects are negligible. In summary, the results show that this firstly proposed method for honokiol and magnolol determination in cosmetic products is accurate and useful for the routinely quality control of these consumer products containing both ingredients. [ABSTRACT FROM AUTHOR]

Vitamin A (retinol) and some of its derivatives are a group of fat-soluble compounds used in cosmetic products as bioactive ingredients. Therefore, it is necessary to perform the quality control of final product to ensure their efficacy and safety. A simple and rapid method to determine retinol, retinal, retinyl acetate, retinyl propionate and retinyl palmitate in cosmetics is presented here. The method is based on vortex and/or ultrasound-assisted leaching of the analytes in ethanol followed by liquid chromatography with ultraviolet detection. The analytical performance of the method was evaluated. It has shown high levels of linearity, at least up to 100 µg mL−1; high precision with RSD values below 14% and high sensitivity with low MLODs ranging between 0.3 × 10−4 and 5.9 × 10−4 % w/w, which are enough to monitor these compounds in cosmetic products. The proposed method was successfully applied to seven commercial cosmetic samples to detect and quantify the target analytes, showing the method is suitable for its employment for quality control in cosmetic industries. Cosmetic samples were spiked at two levels of concentration and recovery values around 100% were obtained, showing no significant matrix effects and, therefore, external calibration was adequate for this determination. [ABSTRACT FROM AUTHOR]

2-Hydroxy-4-methoxybenzophenone (HMB), which is one of the most commonly used UV filters in sunscreen cosmetics to protect skin from the deleterious effects of the sun, can be percutaneously absorbed, further metabolized, and finally excreted or bioaccumulated. An analytical method for the sensitive determination of HMB and its three metabolites in both human urine and semen is developed. The presented analytical method is based on a solid-phase extraction (SPE) procedure to clean-up and preconcentrate the target analytes from the urine and semen samples followed by liquid chromatography–tandem mass spectrometry (LC-MS/MS) detection. The methodology was fully validated and the standard addition calibration method was used to quantify the target analytes in order to correct the matrix effects observed. Considering this approach, the accuracy of the method was evaluated and the recoveries ranged from 98% to 115% and from 86% to 111% in urine and semen samples, respectively, depending on the analyte. For urine samples, the limits of detection ranged between 0.027 and 0.103 ng mL and the repeatability of the method, expressed as relative standard deviation, was in the range of 7.2–9.2%, depending on the analyte. In the case of semen samples, the limits of detection ranged between 1 and 3 ng mL whereas the repeatability was in the range of 2.2–6.4%, depending on the analyte. The described SPE-LC-MS/MS method was satisfactorily applied to both urine and semen samples from a male volunteer who applied a sunscreen cosmetic product containing HMB. HMB and its metabolites were found and quantified in the low ng mL range in both urine and semen samples, although at a different extent. [ABSTRACT FROM AUTHOR]

Abstract: Recognition of the harmful effects of ultraviolet (UV) radiation on the skin has triggered development of organic chemicals (commonly referred as UV filters) that can absorb UV radiation and attenuate the negative effects of sunlight exposure. Depending on the properties and the intended degree of protection, a wide array of combinations is being marketed as delivering protection against most kinds of UV-induced skin damage. However, some UV filters have dermatological implications, so maximum applicable concentrations have been established. To monitor to what extent commercial products comply with the mandatory limits, several analytical methods have been used for their determination in cosmetics and related products. Further research on the efficacy of UV filters applied on the skin surface has brought to light a gradual attenuation of their UV-protective capacity that cannot solely be attributed to photo-induced decomposition. Investigations carried out to elucidate the reasons underlying this behaviour concluded that UV filters may be systematically absorbed through the skin surface or even released during bathing and washing activities. These observations gave rise to numerous studies aiming to investigate the magnitude and effects of skin penetration as well as accumulation in the water environment. Because of the need for more in-depth investigation into the behavior of UV filters, the initial demand for product certification has been extended to include reliable analytical methods to determine these substances at low concentration levels and in complex matrices (e.g., biological and environmental samples). Until now, most of the available methods, although designed to cover a large variety of substances, quantify them at only high-mg/L levels; however, recently, researchers have paid special attention to developing more sensitive procedures able to determine these substances in biological tissues and fluids or environmental samples at ng/L levels without matrix interferences. This article gives a comprehensive outline of the accumulated knowledge on UV-filter determination in biological and environmental samples and encourages further research in this new, challenging field of analytical, health and environmental science. [Copyright &y& Elsevier]

Liquid chromatography was used for the determination of the three most used water-soluble UV filters, benzophenone-4 (BZ4), terephthalylidene dicamphor sulfonic acid (TDS), and phenylbenzimidazole sulphonic acid (PBS), in aqueous sunscreen sprays. A C18 stationary phase and an isocratic mobile phase of EtOH–20 mM sodium acetate buffer of pH 4.6 (30:70, v/v) were used at a flow-rate of 0.5 ml min−1. Mobile phase was also used as solvent for samples and standards. UV detection was at 313 nm. The analytical run took 5.5 min. The limits of detection were 0.5, 0.9 and 2 μg ml−1 for BZ4, TDS and PBS, respectively. The proposed method does not involve highly toxic solvents. [Copyright &y& Elsevier]

Abstract: A new analytical method for the simultaneous determination of trace levels of seven prohibited N‐nitrosamines (N‐nitrosodimethylamine, N‐nitrosoethylmethylamine, N‐nitrosopyrrolidine, N‐nitrosodiethylamine, N‐nitrosopiperidine, N‐nitrosomorpholine, and N‐nitrosodiethanolamine) in cosmetic products has been developed. The method is based on vortex‐assisted reversed‐phase dispersive liquid–liquid microextraction, which allows the extraction of highly polar compounds, followed by liquid chromatography with mass spectrometry. The variables involved in the extraction process were studied to obtain the highest enrichment factor. Under the selected conditions, 75 μL of water as extraction solvent was added to 5 mL of n‐hexane sample solution and assisted by vortex mixing during 30 s to form the cloudy solution. The method was successfully validated showing good linearity (0.5–50 ng/mL), enrichment factors up to 65 depending on the target compound, limits of detection values of 1.8–50 ng/g, and good repeatability (RSD < 9.8%). Finally, the proposed method was applied to different cosmetic samples. Quantitative relative recovery values (80–113%) were obtained, thus showing that matrix effects were negligible. The achieved analytical features of the proposed method, besides of its simplicity and affordability, make it useful to perform the quality control of cosmetic products to ensure the safety of consumers. [ABSTRACT FROM AUTHOR]

An analytical method for the simultaneous determination of hydroxytyrosol and tyrosol in different types of olive extract raw materials and cosmetic cream samples has been developed. The determination was performed by liquid chromatography with UV spectrophotometric detection. Different chromatographic parameters, such as mobile phase pH and composition, oven temperature and different sample preparation variables were studied. The best chromatographic separation was obtained under the following conditions: C18 column set at 35 °C and isocratic elution of a mixture ethanol: 1% acetic acid solution at pH 5 (5:95, v/v) as mobile phase pumped at 1 mL min −1 . The detection wavelength was set at 280 nm and the total run time required for the chromatographic analysis was 10 min, except for cosmetic cream samples where 20 min runtime was required (including a cleaning step). The method was satisfactorily applied to 23 samples including solid, water-soluble and fat-soluble olive extracts and cosmetic cream samples containing hydroxytyrosol and tyrosol. Good recoveries (95–107%) and repeatability (1.1–3.6%) were obtained, besides of limits of detection values below the μg mL −1 level. These good analytical features, as well as its environmentally-friendly characteristics, make the presented method suitable to carry out both the control of the whole manufacture process of raw materials containing the target analytes and the quality control of the finished cosmetic products. [ABSTRACT FROM AUTHOR]

Highlights: [•] A reliable LC-UV method to determine fat-soluble UV filters in cosmetics is presented. [•] Commercial samples are analyzed with excellent recoveries. [•] Excellent accordance is also obtained in the analysis of different home-made samples. [•] The environmentally-friendly characteristics make it suitable for routine analysis. [•] The good analytical features make it also suitable for candidate reference method. [Copyright &y& Elsevier]

An analytical method for the determination of traces of formaldehyde in cosmetic products containing formaldehyde-releasing preservatives has been developed. The method is based on reversed-phase dispersive liquid–liquid microextraction (RP-DLLME), that allows the extraction of highly polar compounds, followed by liquid chromatography–ultraviolet/visible (LC–UV/vis) determination with post-column derivatization. The variables involved in the RP-DLLME process were studied to provide the best enrichment factors. Under the selected conditions, a mixture of 500 μL of acetonitrile (disperser solvent) and 50 μL of water (extraction solvent) was rapidly injected into 5 mL of toluene sample solution. The extracts were injected into the LC–UV/vis system using phosphate buffer 6 mmol L −1 at pH 2 as mobile phase. After chromatographic separation, the eluate merged with a flow stream of pentane-2,4-dione in ammonium acetate solution as derivatizing reagent and passed throughout a post-column reactor at 85 °C in order to derivatize formaldehyde into 3,5-diacetyl-1,4-dihydrolutidine, according to Hantzsch reaction, which was finally measured spectrophotometrically at 407 nm. The method was successfully validated showing good linearity, an enrichment factor of 86 ± 2, limits of detection and quantification of 0.7 and 2.3 ng mL −1 , respectively, and good repeatability (RSD < 9.2%). Finally, the proposed analytical method was applied to the determination of formaldehyde in different commercial cosmetic samples containing formaldehyde-releasing preservatives, such as bronopol, diazolidinyl urea, imidazolidinyl urea, and DMDM hydantoin, with good relative recovery values (91–113%) thus showing that matrix effects were negligible. The good analytical features of the proposed method besides of its simplicity and affordability, make it useful to carry out the quality control of cosmetic products containing formaldehyde-releasing preservatives. [ABSTRACT FROM AUTHOR]

A new analytical method for the determination of N-nitrosodiethanolamine (NDELA), a very harmful compound not allowed in cosmetic products, is presented. The method is based on a new approach of dispersive liquid–liquid microextraction (DLLME) useful for extraction of highly polar compounds, called reversed-phase DLLME (RP-DLLME), followed by liquid chromatography–ultraviolet/visible (LC-UV/Vis) determination. The variables involved in the RP-DLLME process were studied to provide the best enrichment factors. Under the optimized conditions, a mixture of 750 µL of acetone (disperser solvent) and 125 µL of water (extraction solvent) was rapidly injected into 5 mL of toluene sample solution. The extracts were injected into the LC-UV/Vis system using ammonium acetate 0.02 M as mobile phase. After chromatographic separation, the eluate passed throughout a photolysis unit in order to convert NDELA to nitrite, and then it was merged with a flow stream of Griess Reagent and passed throughout a post-column reactor at 50 °C to derivatize nitrite into an azo-dye, which was finally measured spectrophotometrically at 540 nm. The method was successfully validated showing good linearity, an enrichment factor of 31.5±0.9, limits of detection and quantification of 1.1 and 3.6 ng mL −1 , respectively, and a good repeatability (RSD <8%). Finally, the proposed analytical method was applied to the determination of NDELA in commercial cosmetic samples of different nature, specifically three lipophilic creams and a hydrophilic shower gel, with good relative recovery values (87 – 117%) thus showing that matrix effects are negligible. These results were compared with those obtained by applying the ISO 10130 official method, which uses the same detection approach. It was concluded that a great improvement in the sensitivity was achieved, whereas the use of organochlorine solvents is avoided and therefore it can be considered as a greener approach. [ABSTRACT FROM AUTHOR]

An analytical method for the simultaneous determination of phenethyl alcohol, methylpropanediol, phenylpropanol, caprylyl glycol, and ethylhexylglycerin, which are used as alternative preservatives in cosmetic products, has been developed. The method is based on liquid chromatography with UV spectrophotometric detection after chromophoric derivatization with benzoyl chloride and vortex-assisted liquid–liquid semimicroextraction. Different chromatographic parameters, derivatization conditions, and sample preparation variables were studied. Under optimized conditions, the limits of detection values for the analytes ranged from 0.02 to 0.06 µg mL −1 . The method was validated with good recovery values (84–118%) and precision values (3.9–9.5%). It was successfully applied to 10 commercially available cosmetic samples. The good analytical features of the proposed method besides of its environmentally-friendly characteristics, make it useful to carry out the quality control of cosmetic products containing the target compounds as preservative agents. [ABSTRACT FROM AUTHOR]

Abstract: A user-friendly and inexpensive ionic liquid-based single-drop microextraction (IL-SDME) procedure has been developed to preconcentrate trace amounts of six typical UV filters extensively used in cosmetic products (i.e., 2-hydroxy-4-methoxybenzophenone, isoamyl 4-methoxycinnamate, 3-(4′-methylbenzylidene)camphor, 2-ethylhexyl 2-cyano-3,3-diphenylacrylate, 2-ethylhexyl 4-dimethylaminobenzoate and 2-ethylhexyl 4-methoxycinnamate) from surface water samples prior to analysis by liquid chromatography-ultraviolet spectrophotometry detection (LC-UV). A two-stage multivariate optimization approach was developed by means of a Plackett–Burman design for screening and selecting the significant variables involved in the SDME procedure, which were later optimized by means of a circumscribed central composite design. The studied variables were drop volume, sample volume, agitation speed, ionic strength, extraction time and ethanol quantity. Owing to particularities, ionic liquid type and pH of the sample were optimized separately. Under optimized experimental conditions (i.e., 10μL of 1-hexyl-3-methylimidazolium hexafluorophosphate, 20mL of sample containing 1% (v/v) ethanol and NaCl free adjusted to pH 2, 37min extraction time and 1300rpm agitation speed) enrichment factors up to ca. 100-fold were obtained depending on the target analyte. The method gave good levels of repeatability with relative standard deviations varying between 2.8 and 8.8% (n =6). Limits of detection were found in the low μgL−1 range, varying between 0.06 and 3.0μgL−1 depending on the target analyte. Recovery studies from different types of surface water samples collected during the winter period, which were analysed and confirmed free of all target analytes, ranged between 92 and 115%, showing that the matrix had a negligible effect upon extraction. Finally, the proposed method was applied to the analysis of different water samples (taken from two beaches, two swimming pools and a river) collected during the summer period. [Copyright &y& Elsevier]

Abstract: 2-Hydroxy-4-methoxybenzophenone and 2-hydroxy-4-methoxybenzophenone-5-sulphonic acid, commonly known as benzophenone-3 (BZ3) and benzophenone-4 (BZ4), respectively, are substances widely used as UV filters in cosmetic products in order to absorb UV radiation and protect human skin from direct exposure to the deleterious wavelengths of sunlight. As with other UV filters, there is evidence of their percutaneous absorption. This work describes an analytical method developed to determine trace levels of free BZ3 and BZ4 in human urine. The methodology is based on a solid-phase extraction (SPE) procedure for clean-up and pre-concentration, followed by the monitoring of the UV filters by liquid chromatography–ultraviolet spectrophotometry detection (LC–UV). In order to improve not only the sensitivity and selectivity, but also the precision of the method, the principle of sequential injection analysis was used to automate the SPE process and to transfer the eluates from the SPE to the LC system. The application of a six-channel valve as an interface for the switching arrangements successfully allowed the on-line connection of SPE sample processing with LC analysis. The SPE process for BZ3 and BZ4 was performed using octadecyl (C18) and diethylaminopropyl (DEA) modified silica microcolumns, respectively, in which the analytes were retained and eluted selectively. Due to the matrix effects, the determination was based on standard addition quantification and was fully validated. The relative standard deviations of the results were 13% and 6% for BZ3 and BZ4, respectively, whereas the limits of detection were 60 and 30ngmL−1, respectively. The method was satisfactorily applied to determine BZ3 and BZ4 in urine from volunteers that had applied a sunscreen cosmetic containing both UV filters. [Copyright &y& Elsevier]

• A new method to determine eight B vitamins in cosmetic products is presented. • It is simple and affordable for their simultaneous determination. • Simple LC-UV instrumentation, suitable for routine analysis, is used. • The method is environmentally-friendly according to the Green Chemistry principles. B vitamins are a group of compounds with beneficious properties for dermatologic care, and therefore they are included in the cosmetic formulations as high added-value ingredients. In this paper, an analytical method for the simultaneous determination of eight water-soluble B vitamins in cosmetic products is reported for the first time. This method is based on liquid chromatography with ultraviolet detection (LC-UV) analysis after simple water leaching of the analytes from the cosmetic matrix. No organic solvents are required, beyond the ethanol used in the chromatographic mobile phase. The proposed method has been successfully validated showing good linearity, limits of detection in the low μg mL−1 range (from 0.14 to 0.43 μg mL−1) and good repeatability (relative standard deviation below 11 %). The accuracy of the method has been proven by the analysis of laboratory-made samples (i.e., a cream and a gel) with known concentrations of the analytes, providing low relative errors (below 12 %). Finally, the method has been successfully applied to four commercial cosmetic samples of different formulations without significant matrix effects. The results obtained and the environmentally friendly features of the method showed its usefulness for carrying out both pre- and in-market quality control of final cosmetic products. [ABSTRACT FROM AUTHOR]

Abstract: Benzophenone-3 (BZ3), one of the compounds most commonly used as UV filter in cosmetic products, can be absorbed through the skin into the human body, since it can be found at trace levels in urine from users of cosmetic products that contain BZ3. Moreover, different undesirable effects have been attributed to this compound. Thus, sensitive analytical methods to monitor urinary excretion of this compound should be developed. This paper presents a selective and sensitive methodology for BZ3 determination at ultratrace levels in human urine samples. The methodology is based on a novel microextraction technique, known as single-drop microextraction (SDME). An ionic liquid (IL) has been used as extractant phase instead of an organic solvent. After the microextraction process, the extractant phase was injected into a liquid chromatography system. The variables of interest in the SDME process were optimized using a multivariate optimization approach. A Plackett–Burman design for screening and a circumscribed central composite design for optimizing the significant variables were applied. Ionic strength, extraction time, stirring speed, pH, ionic liquid type, drop volume and sample volume were the variables studied. The optimum experimental conditions found were: sodium chloride concentration, 13% (w/v); extraction time, 25min; stirring speed, 900rpm; pH, 2; ionic liquid type, 1-hexyl-3-methylimidazolium hexafluorophosphate ([C6MIM][PF6]); drop volume, 5μL; and sample volume, 10mL. The proposed method requires a standard addition calibration approach, and it has been successfully employed to determine free BZ3 in urine samples coming from human volunteers who applied a sunscreen cosmetic containing this UV filter. The limit of detection was in the order of 1.3ngmL−1 and repeatability of the method, expressed as relative standard deviation, was 6% (n =8). [Copyright &y& Elsevier]

• A method for determining acrylamide in cosmetics is presented for the first time. • The method allows an effective liquid phase-based microextraction of acrylamide. • Trace levels of carcinogenic acrylamide can be determined by this method. • Trace amounts of acrylamide have been found in both lipophilic and hydrophilic samples. According to the European Regulation on cosmetic products, the presence of acrylamide in these consumer products is not allowed due to its mutagenic and potentially carcinogenic effects. Despite this ban, acrylamide might be present in those cosmetic products containing acrylamide-based polymers. However, there is no analytical method for its determination in this type of matrices. Based on this, the development of analytical methods for the determination of acrylamide in cosmetic products is required to guarantee consumer safety. In this work, an analytical method for determining traces of prohibited acrylamide in cosmetic products is presented for the first time. The method is based on dispersive liquid-liquid microextraction (DLLME), followed by liquid chromatography–ultraviolet (LC-UV) detection. A previous derivatization of acrylamide with 2-naphthalenethiol was performed to obtain a more lipophilic compound, and therefore, more extractable in the DLLME step, in addition to the bathochromic displacement of the measurement wavelength. The main variables involved in both derivatization and DLLME step were studied to provide the best enrichment factors. Under the optimized conditions, 6.5 mL of aqueous sample solution was cleaned-up from lipophilic matrix components by liquid-liquid extraction (LLE) using 3.5 mL of hexane. Then, 5 mL were taken and subjected to microwave derivatization with a mixture of 250 μL of 2-naphthalenethiol (0.5 mg mL−1) and 250 μL of di-sodium tetraborate (4 mg mL−1). Afterwards, it was subjected to DLLME by injecting a mixture of 250 µL of acetone (as disperser solvent) and 80 µL of chloroform (as extraction solvent). The extracts were evaporated to dryness, reconstituted in mobile phase and injected into the LC-UV system. The method was successfully validated showing good linearity (from 10 ng mL−1 to 20 µg mL−1), an enrichment factor of 103 ± 2, instrumental limits of detection and quantification of 3.0 and 9.8 ng mL−1, which, according to sample treatment, correspond to 0.7 and 2.4 µg kg−1 in the sample, respectively, and a good repeatability (RSD < 14%). Finally, the proposed analytical method was applied to the determination of acrylamide in commercial cosmetic samples of different nature with good relative recovery values (85 – 112%), which shows that the matrix effect is negligible. This method could help the cosmetic industry to control the cosmetic products containing potential acrylamide-releasing ingredients. [ABSTRACT FROM AUTHOR]