Trace determination of parabens in cosmetics and personal care products using fabric‐phase sorptive extraction and high‐performance liquid chromatography with UV detection

Magnetic polyimide nanocomposite for analysis of parabens in cooking wine by magnetic solid-phase extraction coupled with gas chromatography - Mass spectrometry

A magnetic polyimide (PI) nanocomposite has been synthesized by phase inversion of PI and simultaneous encapsulation of Fe3O4 nanoparticles. The Fe3O4/PI nanocomposite was characterized by a variety of characterization techniques, including infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, nitrogen adsorption-desorption isotherms, and vibrating sample magnetometry. The results showed that the prepared nanocomposite had a homogeneous structure, adequate specific surface area (76.1 m2/g) and high saturation magnetization (42.9 emu/g). Using parabens as model analytes, the performance of the Fe3O4/PI nanocomposite as an adsorbent for magnetic solid-phase extraction (MSPE) was evaluated. The extracted parabens were desorbed and determined by gas chromatography-mass spectrometry (GC-MS). The parameters affecting the extraction and desorption efficiency of parabens were optimized. Under the optimal conditions, the developed MSPE/GC-MS method was successfully applied to the determination of parabens in cooking wine. The MSPE/GC-MS method exhibited broad linearity (0.2-100 µg/L), low detection limits (0.04-0.05 µg/L), and satisfactory extraction recoveries (79.2 %-113.3 %) with relative standard deviations (RSDs) ranging from 0.7 % to 10.4 %. For real cooking wine samples, the spiked recoveries ranged from 91.7 % to 118.7 % with RSDs of 1.0 %-11.2 %. The results demonstrated that the Fe3O4/PI nanocomposite was an effective adsorbent, and this work provides a novel reference for the easy preparation of magnetic adsorbent materials.

A magnetic stir bar sorbent of metal organic frameworks, carbon foam decorated zinc oxide and cryogel to enrich and extract parabens and bisphenols from food samples

A porous composite magnetic stir bar adsorbent was fabricated for the extraction and enrichment of parabens and bisphenols from selected beverage samples. The adsorbent comprised a metal organic framework, carbon foam decorated zinc oxide and magnetic nanoparticles embedded in polyvinyl alcohol cryogel. The porous composite stir bar adsorbent could adsorb parabens and bisphenols via hydrogen bonding, π-π and hydrophobic interactions. In the best conditions, linearity was good from 5.0 to 200.0 µg/L for methyl paraben, ethyl paraben and bisphenol A and from 10.0 to 200.0 µg/L for bisphenol B and butyl paraben. Limits of detection ranged from 1.5 to 3.0 µg/L. The developed composite stir bar was successfully applied to extract and determine parabens and bisphenols in fruit juice, beer and milk. Recoveries ranged from 89.5 to 99.5 % with RSDs lower than 6 %. The developed sorbent and new methodology were evaluated in terms of its green character with satisfactory results.

Hybrid porous material supported in a cellulose acetate polymeric membrane for the direct immersion thin-film microextraction of parabens in water

A simple and sensitive direct immersion thin-film microextraction (DI-TFME) method based on MIL-101(Cr) modified with carbon nanofibers supported in cellulose acetate (CA-MIL-101(Cr)@CNFs) polymeric membrane was developed for the extraction and preconcentration of parabens in environmental water samples. A high-performance liquid chromatography-diode array detector (HPLC-DAD) was used for the determination and quantification of methylparaben (MP) and propylparaben (PP). The factors affecting the DI-TFME performance were investigated using central composite design (CCD). The linearity of the DI-TFME/HPLC-DAD method obtained under optimal conditions was 0.04-0.04-500 µg/L with a correlation coefficient (R2) greater than 0.99, respectively. The limits of detection (LOD) and quantification (LOQ) for methylparaben were 11 ng/L and 37 ng/L; for propylparaben, they were 13 ng/L and 43 ng/L, respectively. The enrichment factors were 93.7 and 123 for methylparaben and propylparaben. The intraday (repeatability) and interday (reproducibility) precisions expressed as relative standard deviations (%RSD) were less than 5%. Furthermore, the DI-TFME/HPLC-DAD method was validated using real water samples spiked with known concentrations of the analytes. The recoveries ranged from 91.5 to 99.8%, and intraday and interday trueness values were less than ±15%. The DI-TFME/HPLC-DAD approach was effectively used for the preconcentration and quantification of parabens in river water and wastewater samples.

Development of a new strategy for the synthesis of graphene oxide-alumina nanocomposite as an efficient adsorbent for dispersive solid-phase extraction of parabens

The present study investigates the synthesis and application of the graphene oxide-alumina nanocomposite as a new adsorbent for the dispersive solid-phase extraction of three parabens and their determination using high-performance liquid chromatography-ultraviolet detection. The characterization of the synthesized material was accomplished and its size, morphology, chemical composition, porosity, and thermal stability were studied. Application of the proposed strategy for the synthesis of the nanocomposite resulted in the incorporation of Al₂ O₃ nanoparticles into graphene oxide nanosheets, further resulting in the exfoliation of graphene oxide nanosheets increasing their surface area. An orthogonal rotatable central composite design was used to optimize the extraction. Under the optimum conditions, the analytical performance of the method showed a suitable linear dynamic range (0.2-100.0 μg/L), reasonable limits of detection (0.03-0.05 μg/L), and preconcentration factors ranging from 128 to 173. Finally, the new validated method was applied for the determination of parabens in some real samples including wastewater, cream, toothpaste, and juice samples with satisfactory recoveries (88%-109%), and relative standard deviations less than 8.7% (n = 3). Results demonstrated that inserting alumina nanoparticles into graphene oxide nanosheets improved the extraction efficiency of parabens, as polar acidic compounds, by providing additional efficient interactions including hydrogen bonding, dipole-dipole, and Brønsted and Lewis acid-base interactions.

Parabens and Menopause-Related Health Outcomes in Midlife Women: A Pilot Study

Background: Parabens are antimicrobial agents prevalently found in daily-use products that can interfere with the endocrine and reproductive systems. In this study, we examined the cross-sectional associations of parabens with hot flashes, hormone concentrations, and ovarian volume in a subsample of 101 nonsmoking, non-Hispanic 45- to 54-year-old women from the Midlife Women's Health Study. Materials and Methods: Women self-reported their hot flash history and underwent a transvaginal ultrasound to measure ovarian volume. Participants provided blood for quantification of serum hormones (by enzyme-linked immunosorbent assay or radioimmunoassay) and urine samples for measurements of urinary paraben biomarker levels (by high-performance liquid chromatography negative-ion electrospray ionization-tandem mass spectrometry). Linear or logistic regression models evaluated associations of specific gravity-adjusted paraben biomarker concentrations with hot flashes, hormone concentrations, and ovarian volume. Results: We observed marginal associations of propylparaben, methylparaben, and ∑parabens biomarkers (molar sum of four parabens) with hot flashes and follicle-stimulating hormone (FSH) concentrations, and of these paraben biomarkers and ethylparaben with ovarian volume. For example, women tended to have 32% (95% confidence intervals [CI]: 0.9 to 1.81), 40% (95% CI: 1.0 to 1.95), and 40% (95% CI: 0.98 to 2.01) higher odds of having recent, monthly, and mild hot flashes, respectively, for every two-fold increase in ∑parabens. Similarly, women tended to have 14.54% (95% CI: -0.10 to 31.32) higher FSH concentrations, but 5.67% (95% CI: -12.54 to 1.75) reduced ovarian volume for every two-fold increase in ∑parabens Conclusions: Overall, our preliminary findings suggest that urinary paraben biomarkers may be associated with menopause-related outcomes in midlife women. Additional studies in larger and diverse populations are needed to expand on these findings.

Characterization and determination of Benvitimod, an unknown risk substance in cosmetics, using nuclear magnetic resonance spectroscopy and HPLC-MS/MS

Ultra-high performance liquid chromatography-tandem high-resolution mass spectrometry, combined with preparative chromatography and nuclear magnetic resonance spectroscopy, a new method for identifying unknown risk substances structure in cosmetics has been established. Moreover, HPLC-MS/MS was developed for the determination of benvitimod in cosmetics. The sample was collected in Ultra-high performance liquid chromatography-tandem high-resolution mass spectrometry, the molecular formula of the unknown was obtained as C₁₇ H₁₈ O₂ . After preparative chromatography enrichment and purification, the enriched compound was scanned by nuclear magnetic resonance spectroscopy, and the chemical structure of the unknown was confirmed as benvitimod. Subsequently, the separation was determined in multiple reaction monitoring mode. The results showed that the linearity of benvitimod was good in the range of 1∼100 μg/L with the correlation coefficient r² >0.999; the limit of detection and quantification were 0.02 mg/kg and 0.067 mg/kg; the precision and stability were good; the average recoveries were 104.2%, 108.2% and 108.7% for low, medium and high spiked concentrations. Forty batches of cosmetics were screened, of which two batches were detected with illegal addition of benvitimod at 2.48 g/kg and 3.13 g/kg. The method effectively solved the loopholes in regulation and provided a research basis for the qualitative identification of structurally unknown compounds in cosmetics. This article is protected by copyright. All rights reserved.

An in vitro assessment for human skin exposure to parabens using magnetic solid phase extraction coupled with HPLC

Skin contact was a significant source of human exposure to parabens during the use of personal care products. In this study, a novel and simple in vitro evaluation method for human skin exposure to parabens was established for the first time. Firstly, magnetic porous carbon (MPC) derived from discarded cigarette butts was prepared as an adsorbent of magnetic solid-phase extraction (MSPE), which provided a fast and efficient sample preparation method with satisfactory extraction performance for parabens in cosmetics and was easy to couple with high performance liquid chromatography. Secondly, the extraction conditions were optimized including the etching ratio of KOH, amount of MPC, extraction time, pH, salt concentration, desorption solvent volume and desorption time. Under the optimized conditions, the limits of detection were between 0.25 and 0.34 ng mL^-1 and the spiked recoveries were in the range of 85.8-112.6%. Thirdly, the developed method was successfully employed to determine five typical parabens in real unspiked cosmetic samples, and two parabens were detected at a relatively high level. Then, the developed method was applied to in vitro assays. The absorbable dose of parabens in cream was investigated and in vitro experiments were further designed with agarose-simulated skin to demonstrate the penetration ability of parabens. In conclusion, these results indicated that parabens did have the risk of entering the body through the skin and the exposure was preferably no more than 3 h with skin contact.

Extraction of parabens by melamine sponge with determination by high-performance liquid chromatography

In the present study, we propose a novel method for the extraction of parabens in personal care products. A new, simple adsorptive material was obtained by combining metal-organic frameworks and melamine sponges using the adhesive property of polyvinylidene fluoride. This new material, metal-organic frameworks/melamine sponges, was found to be particularly suitable for solid-phase extraction. The structural characteristics of metal-organic frameworks/melamine sponges were first analyzed by scanning electron microscopy. Subsequently, solid-phase extraction was performed on sample solutions, and the extracted substances were then analyzed by high-performance liquid chromatography. Following optimization of important experimental conditions, excellent recovery rates were obtained. Our novel method was then applied to the extraction of four parabens (methylparahydroxybenzoates, ethylparahydroxybenzoates, propylparahydroxybenzoates, and butylparahydroxybenzoates) from real samples. The results yielded LODs of 0.26-0.41 ng/mL. The inter- and intra-day recoveries were 104.0-109.7% and 91.2-98.1%, respectively (relative standard deviation, <13.8%).

Strategies to improve the challenges of classic dispersive liquid-liquid microextraction for determination of the parabens in personal care products-One step closer to green analytical chemistry

Gas flow-assisted dispersive liquid-phase microextraction based on deep eutectic solvent was used to determine parabens in personal care products such as mouthwash, lidocaine gel, aloe vera gel, and skin tonic. A homemade extraction device was innovated, in which by passing the stream of gas bubbles through the deep eutectic solvent a thin layer of the extraction phase is coated on the surface of the bubbles. The extraction is finally achieved when the bubbles are going up through the sample. The single-factor experiments and response surface methodology were applied to optimize the independent variables. The linear range of the method was 0.5 to 1000 µg L^-1, the coefficient of determination for the goal analytes was higher than 0.9989, the instrumental limit of detections were in the range 0.2-0.3 μg L^-1, and the instrumental limit of quantifications were in the range 0.5-1.1 μg L^-1, the relative standard deviations were <5.2% for repeatability and <11.2% for intermediate precision, and the enrichment factors were 66 to 87 obtained under the optimized conditions. A spiking approach by means of standard material was used to estimate accuracy. The relative recoveries were in the range 95.8-105.2%. By using mentioned strategies, the organic waste and energy consumption reduced, toxic reagents replaced with safer ones, and operator safety enhanced. Accordingly, these benefits have been simultaneously attained and, the proposed method was one step closer to automation and sustainable analytical chemistry.

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.

Microextraction by packed sorbent optimized by statistical design of experiment as an approach to increase the sensitivity and selectivity of HPLC-UV determination of parabens in cosmetics

A new approach to the quantitative analysis of parabens (PBs) in cosmetics, based on microextraction by packed sorbent (MEPS) followed by HPLC-UV detection is proposed. The development of optimal conditions for the sample preparation step was carried out in two stages. The potentially important factors that could influence the extraction were screened using the Plackett-Burman design approach, as a result of which, three statistically significant factors were selected from the nine studied. Thereafter, the selected variables were optimized by response surface methodology using a Central Composite Design. Under optimal conditions, the linear ranges for PBs analysis in cosmetic samples were 0.05-4 μg/mL with excellent precision. Limits of detection (LOD) of PBs in cosmetic samples were 2-5 ng/mL, and the extraction recovery ranged from 89 to 105 %. By comparing the chromatograms of the diluted shampoo sample before and after MEPS, the benefits of developed approach were shown. Then it was applied to the analysis of PBs in commercial hair cosmetic products: parabens were determined in all samples in which they were indicated on the package and in 1 of 12 samples labeled "paraben-free". Finally, the proposed method was compared with other analytical HPLC-UV methods with various sample pretreatment techniques for PBs analysis in cosmetics described in recent articles. Its sensitivity turned out to be one of the highest, while it is express, automated, meets the principles of green chemistry.

Simultaneous Determination of Isothiazolinones and Parabens in Cosmetic Products Using Solid-Phase Extraction and Ultra-High Performance Liquid Chromatography/Diode Array Detector

Isothiazolinones methylisothiazolinone (MI) and methylchloroisothiazolinone (MCI), and parabens methylparaben (MP), ethylparaben (EP), propylparaben (PP) and butylparaben (BP) are the most common synthetic preservatives. They are all known to be potential skin allergens that lead to contact dermatitis. Thus, the identification of these unsafe chemicals in cosmetic products is of high importance. In the present study, solid-phase extraction (SPE) based on HyperSep reversed-phase C8/benzene sulfonic acid ion exchanger (HyperSep C8/BSAIE) and Sep-Pak C18 sorbents, and ultra-high performance liquid chromatography/diode array detector (UHPLC/DAD) were optimized for the simultaneous determination of MI, MCI, MP, EP, PP and BP in cosmetic products. HyperSep C8/BSAIE and UHPLC/DAD with the eluting solvent mixture (acetonitrile/methanol, 2:1, v/v) and detection wavelength (255 nm) were found to be the optimal conditions, respectively. The method illustrates the excellent linearity range (0.008–20 μg/mL) with coefficient of determination (R², 0.997–0.999), limits of detection (LOD, 0.001–0.002 μg/mL), precision in terms of relative standard deviation (RSD < 3%, intra-day and <6%, inter-day) when examining a standard mixture at low (0.07 µg/mL), medium (3 µg/mL) and high (15 µg/mL) concentrations. A total of 31 cosmetic samples were studied, achieving concentrations (MI, not detected (nd)-0.89 µg/g), (MCI, nd-0.62 µg/g), (MP, nd-6.53 µg/g), (EP, nd-0.90 µg/g), (PP, nd-9.69 µg/g) and (BP, nd-17.80 µg/g). Recovery values ranged from 92.33 to 101.43% depending on the types of sample. To our knowledge, this is the first specific method which covers the theme and describes background amounts of such preservatives in cosmetics.