Phycocosmetics and Other Marine Cosmetics, Specific Cosmetics Formulated Using Marine Resources.

Marine resources exist in vast numbers and show enormous diversity. As a result, there are likely many possible applications for marine molecules of interest in the cosmetic industry, whether as excipients or additives, but especially as active substances. It is possible to obtain extracts from active substances; for example, quite a few algae species can be used in moisturizing or anti-ageing products. In the field of topical photoprotection, mycosporine-like amino acids and gadusol are important lines of enquiry that should not be overlooked. In the field of additives, the demonstration that certain seaweed (algae) extracts have antimicrobial properties suggests that they could provide alternatives to currently authorized preservatives. These promising leads must be explored, but it should be kept in mind that it is a long process to bring ingredients to market that are both effective and safe to use.

FPSE-HPLC-PDA analysis of seven paraben residues in human whole blood, plasma, and urine.

This work describes a new, fast and sensitive method for the simultaneous determination of seven paraben residues including methyl paraben (MPB), ethyl paraben (EPB), propyl paraben (PPB), isopropyl paraben (iPPB), butyl paraben (BPB), isobutyl paraben (iBPB) and benzyl paraben (BzPB) in human whole blood, plasma and urine. The analytes were extracted from the biological matrices by an innovative technique, fabric phase sorptive extraction (FPSE) and subsequently analyzed by high-performance liquid chromatography (HPLC) coupled with photo diode array detector (PDA). The separation was carried out with a Spherisorb C18 column using methanol and phosphate buffer as mobile phases. Ketoprofen was used as the internal standard (IS). The analytical method has been validated according to the International Guidelines in terms of calibration curves for each biological matrix, precision (intra and inter day), trueness, selectivity, LODs, LOQs and ruggedness. Subsequently, the performance of the analytical method was evaluated on real biological samples. The proposed innovative method allows simultaneous analysis of seven paraben residues in three different biological matrices, including whole blood, plasma and urine and therefore it is easily applicable to monitor these substances in different biological samples. Furthermore, extraction technique used in this work is fast, easy to use and in accordance with the modern green analytical chemistry (GAC) principles.

Miniaturized matrix solid-phase dispersion coupled with supramolecular solvent-based microextraction for the determination of paraben preservatives in cream samples.

An analytical method is presented for the determination of paraben preservatives in semisolid cream samples by matrix solid-phase dispersion combined with supramolecular solvent-based microextraction. Due to the oily and sticky nature of the sample matrix, parabens were first extracted from the samples by matrix solid-phase dispersion using silica as sorbent material with a clean-up performed with tetrahydrofuran in the elution step. The eluate (500 µL), 1-decanol (120 µL), and water (4.4 mL) were then mixed in a polyethylene pipette to form supramolecular solvent. Finally, the analytes in the supramolecular solvent were separated and determined by liquid chromatography with ultraviolet detection. Under optimal extraction conditions, the extraction recoveries of the studied compounds were obtained in the range of 63-83%. The limits of detection for the analytes were between 0.03 and 0.04 µg/g. The precision of the method varied between 4.0-6.7 (intraday) and 6.2-7.9% (interday). Finally, the optimized procedure was applied to the determination of the target preservatives in a variety of cream samples (diaper rash, skin allergy, face and hand moisturizing) with satisfactory recoveries (86-102%).

A stir foam composed of graphene oxide, poly(ethylene glycol) and natural latex for the extraction of preservatives and antioxidant.

A stir foam composed of graphene oxide, poly(ethylene glycol) and natural latex (GO-PEG-NL) was prepared for use in micro-solid phase extraction sorbent of preservative agents and antioxidants from cosmetic products. The extracted analytes were quantified by GC-MS. Under the optimized conditions, the calibration plots are linear in the concentration ranges between 5.0 µg·L-1 to 1.0 mg·L-1 for benzoic acid, of 10.0 µg·L-1 to 1.0 mg·L-1 for 2-methyl-3-isothiazolinone (MI), and between 1.0 µg·L-1 and 1.0 mg·L-1 for both 3-tert-butyl-4-hydroxyanisole (BHA) and 2,6-di-tert-butyl-p-hydroxytoluene (BHT). The LODs are 1.0 µg·L-1 for benzoic acid, 5.0 µg·L-1 for MI and 0.5 µg·L-1 for both BHA and BHT. The stir-foam can be easily prepared, is inexpensive and well reproducible (RSDs <3%, for n = 6). It can be re-used for up to 12 times after which extraction efficiency has dropped to 90%. The method was successfully applied to the determination of preservatives and antioxidants in cosmetic samples. Recoveries from spiked samples ranged between 94.5 ± 2.1% and 99.8 ± 1.8%. Graphical abstract A stir foam was prepared from graphene oxide, poly(ethylene glycol) and natural latex (GO-PEG-NL) and is shown to be a most viable sorbent for the microextraction of trace amounts of preservative agents and antioxidants from cosmetic products.

Survival and detection of Bacillus cereus in the presence of Escherichia coli, Salmonella enteritidis, Staphylococcus aureus, Pseudomonas aeruginosa and Candida albicans after rechallenge in make-up removers.

OBJECTIVE: Pathogenic contamination of cosmetics intended to be applied on or around the eye area, including make-up removers, may lead to severe eye infections. To assess the efficacy of antimicrobial preservatives in these products, we investigated the survival and detection of Bacillus cereus F 4227A spiked into make-up removers, alone and in the presence of other relevant micro-organisms. METHODS: Four brands of make-up removers, A, B, C and D, were challenged three times (day 0, day 7 and day 14) using B. cereus, in pure and mixed cultures, at a final concentration of 5 log CFU per mL of Bacillus cereus or 6 log CFU per mL for other micro-organisms. Inoculated samples were diluted and spiral-plated after 30 min and 24 h of each challenge onto selective media for recovery of surviving micro-organisms: BACARA (B. cereus), MacConkey (E. coli), ChromID (P. aeruginosa), XLT4 (S. enteritidis), Baird Parker agar (Staph. aureus) and PDA+chlortetracycline HCL (C. albicans). RESULTS: The population of B. cereus spiked as a pure culture increased significantly from the first to the third challenge after 30-min exposure time, going from 0.73 to 2.59 in A, from 0.80 to 2.69 in B and from 0.80 to 1.67 log CFU per mL in C (P < 0.05). Likewise, the B. cereus population from the mixed cultures had a significantly higher survival count at the third challenge: from 0.12 log MPN per mL to 2.16 log CFU per mL in A, 0.57 to 2.27 log CFU per mL in B and from undetected (LOD = 0.48 log MPN) to 0.98 log CFU per mL in C, respectively. After challenges, Staph. aureus, C. albicans and P. aeruginosa increased in B; Staph. aureus and C. albicans in C; and E. coli and Staph. aureus in D. The growth of other bacteria types was unaffected by the number of challenges, but B. cereus population was detected with the third challenge. CONCLUSION: It is appropriate to assess the antimicrobial efficacy of preservatives using at least three challenges, especially for cosmetics that are subjected to repetitive contamination by users.

A multi-purpose tool for food inspection: Simultaneous determination of various classes of preservatives and biogenic amines in meat and fish products by LC-MS.

This paper describes an innovative fast and multipurpose method for the chemical inspection of meat and fish products by liquid chromatography-tandem mass spectrometry. Solid-liquid extraction and low temperature partitioning were applied to 17 analytes, which included large bacteriocins (3.5kDa) and small molecules (organic acids, heterocyclic compounds, polyene macrolides, alkyl esters of the p-hydroxybenzoic acid, aromatic, and aliphatic biogenic amines and polyamines). Chromatographic separation was achieved in 10min, using stationary phase of di-isopropyl-3-aminopropyl silane bound to hydroxylated silica. Method validation was in accordance to Commission Decision 657/2002/CE. Linear ranges were among 1.25-10.0mgkg-1 (natamycin and parabens), 2.50-10.0mgkg-1 (sorbate and nisin), 25.0-200mgkg-1 (biogenic amines, hexamethylenetetramine, benzoic and lactic acids), and 50.0-400mgkg-1 (citric acid). Expanded measurement uncertainty (U) was estimated by single laboratory validation combined to modeling in two calculation approaches: internal (U = 5%) and external standardization (U = 24%). Method applicability was checked on 89 real samples among raw, cooked, dry fermented and cured products, yielding acceptable recoveries. Many regulatory issues were revealed, corroborating the need for enhancement of the current analytical methods. This simple execution method dispenses the use of additional procedures of extraction and, therefore, reduces costs over time. It is suitable for routine analysis as a screening or confirmatory tool for both qualitative and quantitative results, replacing many time consuming analytical procedures.

Multidose Preservative Free Eyedrops by Selective Removal of Benzalkonium Chloride from Ocular Formulations.

PURPOSE: About 70% of eye drops contain benzalkonium chloride (BAK) to maintain sterility. BAK is an effective preservative but it can cause irritation and toxicity. We propose to mitigate ocular toxicity without compromising sterility by incorporating a filter into an eye drop bottle to selectively remove BAK during the process of drop instillation. METHODS: The filter is a packed bed of particles made from poly(2-hydroxyethyl methacrylate) (pHEMA), which is a common ophthalmic material. We showed that pHEMA particle prepared by using ethoxylated trimethylolpropane triacrylate as crosslinker can be incorporated into a modified eyedrop bottle tip to selectively remove the preservative as the formulation is squeezed out of the bottle. Hydraulic permeability of the plug is measured to determine the resistance to eye drop squeezing, and % removal of BAK and drugs are determined. RESULTS: The modified tip has a hydraulic permeability of about 2 Darcy, which allows eyedrops formulations to flow through without excessive resistance. The tip is designed such that the patients can create an eyedrop of solution of 1-10 cP viscosity in 4 s with a nominal pressure. During this short contact time, the packed particles removed nearly 100% of benzalkonium chloride (BAK) from a 15 mL, 0.012% BAK solution but have only minimal impact on the concentration of contained active components. CONCLUSION: Our novel design can eliminate the preservative induced toxicity from eye drops thereby impacting hundreds of millions of patients with chronic ophthalmic diseases like glaucoma and dry eyes.

Purification, structural features, antioxidant and moisture-preserving activities of an exopolysaccharide from Lachnum YM262.

A water-soluble exopolysaccharide, designated as LEP-2a, was isolated from Lachnum YM262 and purified by DEAE-Cellulose 52 and Sepharose CL-6B chromatographic columns. LEP-2a was a homogeneous polysaccharide, with a molecular weight of 1.52×105 Da. It was composed of mannose and galactose in a molar ratio of 20.6:1.0. Its structural features were investigated and elucidated by methylation analysis, periodate oxidation and Smith degradation, FT-IR and NMR spectroscopy. Based on obtained data, the backbone of LEP-2a consisted of 1,2-linked-α-d-mannose, 1,3-linked-α-d-mannose, 1,2,6-linked-α-d-mannose and 1,3-linked-ß-d-galactose and the side chains were attached to the backbone at O-6 position of 1,2,6-linked-α-d-mannose. In vitro antioxidant activity assay proved that LEP-2a possessed significant scavenging activities on superoxide, hydroxyl and DPPH radical. Furthermore, LEP-2a had strong in vitro moisture-absorption and -retention capacities as compared to chitosan and glycerol. These results suggested that LEP-2a might have a good potential to be applied as a multifunctional cosmetic additive in cosmetics.

Ultrasound-Assisted Surfactant-Enhanced Emulsification Micro-Extraction Followed by HPLC for Determination of Preservatives in Water, Beverages and Personal Care Products.

An ultrasound-assisted surfactant-enhanced emulsification micro-extraction (UASEME) procedure has been developed for pre-concentration of benzoic acid (BA) and paraben preservatives, including methylparaben, ethylparaben, propylparaben and butylparaben, prior to high-performance liquid chromatography-ultraviolet (HPLC-UV) analysis. Separations were performed on a Lichrospher RP-18 endcapped 5 µm, using an isocratic mobile phase of 40% acetonitile, at a flow rate of 1 mL min-1 The selected UASEME conditions comprised the use of 10 mL sample extract, 125 µL 1-octanol as extraction solvent and 0.05 mmol L-1 Tween 20 as emulsifier, 0.5% sodium chloride, ultrasonication time of 6 min and centrifugation time of 10 min. Method performance demonstrated wide linear range between 0.5 and 7,000 µg L-1 (R2 > 0.9903) and limits of detection between 0.03 and 10 µg L-1, which providing the enrichment factors of 15-184. The method precision (relative standard deviation) was <7%. The developed UASEME coupled with HPLC-UV has been successfully applied to determine four paraben preservatives in various sample matrices such as water, beverages and personal care products. The recoveries in the range of 70-138.1% were obtained. However, BA could not be determined in real sample extracts.

Thinned stone fruits are a source of polyphenols and antioxidant compounds.

BACKGROUND: Thinned fruits are agricultural by-products that contain large quantities of interesting compounds due to their early maturity stage. In this work, the phenolic profile and the antioxidant activity of six thinned stone fruits (apricot, cherry, flat peach, peach, plum and nectarine) have been investigated, focussing on proanthocyanidins. RESULTS: Thinned nectarine had the highest content of total phenols [67.43 mg gallic acid equivalents (GAE) g-1 dry weight (DW)] and total flavonoids (56.97 mg CE g-1 DW) as well as the highest antioxidant activity measured by DPPH scavenging (133.30 mg [Trolox equivalents (TE) g-1 DW] and FRAP assay (30.42 mg TE g-1 DW). Proanthocyanidins were very abundant in these by-products, and the main phenolic group quantified in cherry (10.54 mg g-1 DW), flat peach (33.47 mg g-1 DW) and nectarine (59.89 mg g-1 DW), while hydroxycinnamic acids predominate in apricot, peach and plum (6.67, 22.04 and 23.75 mg g-1 DW, respectively). The low, mean degree of polymerisation of proanthocyanidins suggests that their bioavailability could be very high. CONCLUSIONS: This study shows that thinned stone fruit extracts might be used as antioxidants in foods or as a source of compounds with health-related benefits that can be used in the pharmaceutical, cosmetic and food industries. © 2016 Society of Chemical Industry.

Matrix solid-phase dispersion combined to liquid chromatography-tandem mass spectrometry for the determination of paraben preservatives in mollusks.

A method for the extraction and determination of seven parabens, esters of 4-hydroxybenzoic acid, widely used as preservatives in personal care products, pharmaceuticals, etc., and two chlorinated derivatives (mono- and di-chloro methyl paraben) from mollusk samples was developed by combining matrix solid-phase dispersion (MSPD) and liquid chromatography-tandem mass spectrometry. MSPD parameters, such as solvent, solid support and clean-up sorbent, were optimized. Besides, since blank problems were observed for some parabens, these were investigated and blanks were tackled by precleaning all sorbents prior to use. Under final conditions, 0.5g of freeze-dried mollusk were dispersed with 1.2g of silica and packed into a cartridge containing 3g of C18, as on-line clean-up sorbent. This cartridge was eluted with 10mL of acetonitrile, evaporated and reconstituted in methanol for analysis. In the validation stage, successful linearity (R(2)>0.999), recoveries (between 71 and 117% for most analytes), precision (RSD lower than 21%) and limits of detection and quantification (LOD and LOQ, lower than 0.4 and 1.4ngg(-1) dry weight respectively) levels were achieved. Finally, the new methodology was applied to mussel, clam and cockle samples. Methyl paraben was above the LOQ in five of the six samples (not found in one clam sample) at concentrations up to 7ngg(-1) dry weight. Ethyl paraben was found above the LOQ in mussel and cockle samples at a concentration level around 0.3ngg(-1). n-Propyl paraben was only above the LOQ in one mussel sample.

Vortex-assisted emulsification semimicroextraction for the analytical control of restricted ingredients in cosmetic products: determination of bronopol by liquid chromatography.

Vortex-assisted emulsification semimicroextraction is proposed as a one-step solution-extraction procedure for sample preparation in cosmetic products. The procedure allows rapid preparation based on dispersion of the sample in a mixture of 1 mL of n-hexane and 0.5 mL of ethanol, followed by the addition of 0.5 mL of water and centrifugation to obtain two separated phases. This procedure provides good sample clean-up with minimum dilution and is very useful for the determination of ingredients with restricted concentrations, such as bronopol. The procedure was applied to the determination of bronopol by liquid chromatography with UV detection. The best chromatographic separation was obtained by using a C18 column set at 40 °C and performing a stepwise elution with a mixture of ethanol/aqueous 1 % acetic acid solution as mobile phase pumped at 0.5 mL min(-1). The detection wavelength was set at 250 nm and the total run time required was 12 min. The method was successfully applied to 18 commercial cosmetic samples including creams, shampoos, and bath gels. Good recoveries and repeatability were obtained, with a limit of detection of 0.9 µg mL(-1), which makes the method suitable for the analytical control of cosmetic products. Moreover, it could be considered environmentally friendly, because water, ethanol, and only a low volume of n-hexane are used as solvents.

Antibacterial Effects of Cinnamon: From Farm to Food, Cosmetic and Pharmaceutical Industries.

Herbs and spices have been used since ancient times, because of their antimicrobial properties increasing the safety and shelf life of food products by acting against foodborne pathogens and spoilage bacteria. Plants have historically been used in traditional medicine as sources of natural antimicrobial substances for the treatment of infectious disease. Therefore, much attention has been paid to medicinal plants as a source of alternative antimicrobial strategies. Moreover, due to the growing demand for preservative-free cosmetics, herbal extracts with antimicrobial activity have recently been used in the cosmetic industry to reduce the risk of allergies connected to the presence of methylparabens. Some species belonging to the genus Cinnamomum, commonly used as spices, contain many antibacterial compounds. This paper reviews the literature published over the last five years regarding the antibacterial effects of cinnamon. In addition, a brief summary of the history, traditional uses, phytochemical constituents, and clinical impact of cinnamon is provided.

Halogen bonding and pharmaceutical cocrystals: the case of a widely used preservative.

3-Iodo-2-propynyl-N-butylcarbamate (IPBC) is an iodinated antimicrobial product used globally as a preservative, fungicide, and algaecide. IPBC is difficult to obtain in pure form as well as to handle in industrial products because it tends to be sticky and clumpy. Here, we describe the preparation of four pharmaceutical cocrystals involving IPBC. The obtained cocrystals have been characterized by X-ray diffraction, solution and solid-state NMR, IR, and DSC analyses. In all the described cases the halogen bond (XB) is the key interaction responsible for the self-assembly of the pharmaceutical cocrystals thanks to the involvement of the 1-iodoalkyne moiety of IPBC, which functions as a very reliable XB-donor, with both neutral and anionic XB-acceptors. Most of the obtained cocrystals have improved properties with respect to the source API, in terms, e.g., of thermal stability. The cocrystal involving the GRAS excipient CaCl2 has superior powder flow characteristics compared to the pure IPBC, representing a promising solution to the handling issues related to the manufacturing of products containing IPBC.

Advanced oxidation kinetics and mechanism of preservative propylparaben degradation in aqueous suspension of TiO2 and risk assessment of its degradation products.

The absolute kinetic rate constants of propylparaben (PPB) in water with different free radicals were investigated, and it was found that both hydroxyl radicals (HO(•)) and hydrated electrons could rapidly react with PPB. The advanced oxidation kinetics and mechanisms of PPB were investigated using photocatalytic process as a model technology, and the degradation was found to be a pseudo-first-order model. Oxidative species, particularly HO(•), were the most important reactive oxygen species mediating photocatalytic degradation of PPB, and PPB degradation was found to be significantly affected by pH because it was controlled by the radical reaction mechanism and was postulated to occur primarily via HO(•)-addition or H-abstraction reactions on the basis of pulse radiolysis measurements and observed reaction products. To investigate potential risk of PPB to humans and aqueous organisms, the estrogenic assays and bioassays were performed using 100 µM PPB solution degraded by photocatalysis at specific intervals. The estrogenic activity decreased as PPB was degraded, while the acute toxicity at three trophic levels first increased slowly and then decreased rapidly as the total organic carbon decreased during photocatalytic degradation.

Determination of isothiazolinone preservatives in cosmetics and household products by matrix solid-phase dispersion followed by high-performance liquid chromatography-tandem mass spectrometry.

In this work, the development of a new efficient methodology applying, for the first time, matrix solid phase dispersion (MSPD) for the determination of sensitizer isothiazolinone biocides in cosmetics and household products - 2-methyl-3-isothiazolinone (MI), 5-chloro-2-methyl-3-isothiazolinone (CMI), 1,2-benzisothiazolinone (BzI) and 2-octyl-3-isothiazolinone (OI) - is described. The main factors affecting the MSPD extraction procedure, the dispersive phase and the elution solvent, are assessed and optimized through a multicategorical experimental design, using a real cosmetic sample. The most suitable extraction conditions comprise the use of 2g of florisil as dispersive phase and 5 mL of methanol as elution solvent. Subsequently, the extract is readily analyzed by HPLC-MS/MS without any further clean-up or concentration steps. Method performance was evaluated demonstrating to have a broad linear range (R(2)>0.9980) and limits of detection (LOD) and quantification (LOQ) at the low nanogram per gram level, which are well below the required limits for UE regulation compliance. Satisfactory recoveries above 80%, except for MI (mean values close to 60%), were obtained. In all cases, the method precision (% RSD) was lower than 7%, making this low cost extraction method reliable for routine control. The validated methodology was finally applied to the analysis of a wide variety of cosmetics and household products. Most of the real samples analyzed have been shown to comply with the current European Cosmetic Regulation, although the results obtained for some rinse-off cosmetics (e.g. baby care products) revealed high isothiazolinone content.

The constituents of essential oil: antimicrobial and antioxidant activity of Micromeria congesta Boiss. & Hausskn. ex Boiss. from East Anatolia.

The chemical composition, antimicrobial activity, total phenol content, total antioxidant activity, and total oxidant status of the essential oil from Micromeria congesta Boiss. & Hausskn. ex Boiss. were investigated. Steam distillation was used to obtain the essential oil, and the chemical analyses were performed by gas chromatography-mass spectrometry. The antimicrobial activity was tested by an agar disc diffusion method against the tested microorganisms: Bacillus subtilis NRRL B-744, Bacillus cereus NRRL B-3711, Staphylococcus aureus ATCC 12598, S. aureus ATCC 25923, S. aureus ATCC 25933, Escherichia coli 0157H7, E. coli ATCC25922, Micrococcus luteus NRLL B-4375, Enterococcus faecalis ATCC 19433, Proteus vulgaris RSKK 96026, and Yersinia enterecolitica RSKK 1501. The major compounds found in volatiles of M. congesta were piperitone oxide, linalool oxide, veratrole, pulegone, dihydro carvone, naphthalene, iso-menthone, para-menthone, and cyclohexanone. Compared to that of reference antibiotics, the antibacterial activity of the essential oil is considered as significant. Results showed that M. congesta has the potential for being used in food and medicine depending on its antioxidant and antibacterial activity.

A simple solvent collection technique for a dispersive liquid-liquid microextraction of parabens from aqueous samples using low-density organic solvent.

A simple technique for the collection of an extraction solvent lighter than water after dispersive liquid-liquid microextraction combined with high-performance liquid chromatography with ultraviolet detection was developed for the determination of four paraben preservatives in aqueous samples. After the extraction procedure, low-density organic solvent together with some little aqueous phase was separated by using a disposable glass Pasteur pipette. Next, the flow of the aqueous phase was stopped by successive dipping the capillary tip of the pipette into anhydrous Na(2)SO(4). The upper organic layer was then removed simply with a microsyringe and injected into the high-performance liquid chromatography system. Experimental parameters that affect the extraction efficiency were investigated and optimized. Under optimal extraction conditions, the extraction recoveries ranged from 25 to 86%. Good linearity with coefficients with the square of correlation coefficients ranging from 0.9984 to 0.9998 was observed in the concentration range of 0.001-0.5 µg/mL. The relative standard deviations ranged from 4.1 to 9.3% (n = 5) for all compounds. The limits of detection ranged from 0.021 to 0.046 ng/mL. The method was successfully applied for the determination of parabens in tap water and fruit juice samples and good recoveries (61-108%) were achieved for spiked samples.

Large volume sample stacking with EOF and sweeping in CE for determination of common preservatives in cosmetic products by chemometric experimental design.

This study proposes a capillary electrophoresis method incorporating large volume sample stacking, EOF and sweeping for detection of common preservatives used in cosmetic products. The method was developed using chemometric experimental design (fractional factorial design and central composite design) to determine multiple separation variables by efficient steps. The samples were loaded by hydrodynamic injection (10 psi, 90 s), and separated by phosphate buffer (50 mM, pH 3) containing 30% methanol and 80 mM SDS at -20 kV. During method validation, calibration curves were found to be linear over a range of 5-100 µg/mL for butyl paraben and isobutyl paraben; 0.05-10 µg/mL for ethyl paraben; 0.2-50 µg/mL for dehydroacetic acid; 0.5-70 µg/mL for methyl paraben; 5-350 µg/mL for sorbic acid; 0.02-450 µg/mL for p-hydroxybenzoic acid and 0.05-10 µg/mL for salicylic acid and benzoic acid. The analytes were analysed simultaneously and their detection limits (S/N = 3) were down to 0.005-2 µg/mL. The analysis method was successfully used for detection of preservatives used in commercial cosmetics.

Analysis of multi-class preservatives in leave-on and rinse-off cosmetics by matrix solid-phase dispersion.

Matrix solid-phase extraction has been successfully applied for the determination of multi-class preservatives in a wide variety of cosmetic samples including rinse-off and leave-on products. After extraction, derivatization with acetic anhydride, and gas chromatography-mass spectrometry analysis were performed. Optimization studies were done on real non-spiked and spiked leave-on and rinse-off cosmetic samples. The selection of the most suitable extraction conditions was made using statistical tools such as ANOVA, as well as factorial experimental designs. The final optimized conditions were common for both groups of cosmetics and included the dispersion of the sample with Florisil (1:4), and the elution of the MSPD column with 5 mL of hexane/acetone (1:1). After derivatization, the extract was analyzed without any further clean-up or concentration step. Accuracy, precision, linearity and detection limits were evaluated to assess the performance of the proposed method. The recovery studies on leave-on and rinse-off cosmetics gave satisfactory values (>78% for all analytes in all the samples) with an average relative standard deviation value of 4.2%. The quantification limits were well below those set by the international cosmetic regulations, making this multi-component analytical method suitable for routine control. The analysis of a broad range of cosmetics including body milk, moisturizing creams, anti-stretch marks creams, hand creams, deodorant, shampoos, liquid soaps, makeup, sun milk, hand soaps, among others, demonstrated the high use of most of the target preservatives, especially butylated hydroxytoluene, methylparaben, propylparaben, and butylparaben.