Determination Of Methylparaben Research Articles

A novel sonication assisted dispersive liquid-liquid microextraction method for methylparaben in cosmetic samples using deep eutectic solvent

A simple, green and sensitive analytical methodology for extraction and determination of methylparaben (MP) in cosmetic samples, based on deep eutectic solvent-based sonication assisted dispersive liquid-liquid microextraction (DES-SA-DLLME) combined with UV–Vis spectrophotometry was optimized by using a central composite design (CCD). Herein, we prepared and tested six DES (as extraction solvent) for the selective extraction of MP. A mixture of 525 μL of DES-3 (consisting of a 1:2:3 M ratio mixture of proline, malic acid and water, respectively) and 390 μL THF (aprotic solvent) was used for the DES-SA-DLLME process. Under optimum conditions based on the CCD, the calibration graph showed high level of coefficient determination (R2:0.9978) for the MP in the range of 15–650 μg L−1. The limit of detection and enrichment factor were 4.5 μg L−1 and 148, respectively. The application of the DES-SA-DLLME method was investigated for the extraction and quantification of MP in selected cosmetic samples in micrograms per liter and quantitative analytical data were obtained (RSDs <3.8%). This method provides quantitative recoveries, less extraction time, and uses green solvents for the determination of trace MP in complex matrices.

Effective extraction of parabens from toothpaste by vortex-assisted liquid-phase microextraction based on low viscosity deep eutectic solvent

An efficient, green and reliable method, namely deep eutectic solvent-based vortex-assisted liquid-phase microextraction (DES-VALPME) was proposed for the rapid extraction and sensitive high performance liquid chromatography coupled with variable wavelength detector (HPLC-VWD) determination of methylparaben (MP), ethylparaben (EP), propylparaben (PP) and butylparaben (BP) in toothpaste samples as a proof-of-concept example of trace analysis of personal care and cosmetic products. Compared with traditional DES suffering from higher viscosity, a class of six low viscosity DESs were synthesized by simply dissolving quaternary ammonium salts (hydrogen bond acceptors, HBAs) in methanol or ethanol (hydrogen bond donors, HBDs) at ambient temperature. Initial studies indicated that the DES consisting of tetrabutylammonium chloride (TBAC) and ethanol at a molar ratio of 1:5 achieved the highest extraction efficiency for all target analytes. The influence of type, molar ratio and volume of DES, extraction temperature and vortex time on the extraction efficiency was investigated and optimized systematically. Under the selected conditions, the method displayed satisfactory linearity in the range of 0.05–10 μg/g (R2 ≥ 0.9995), acceptable recoveries for the real samples (varied from 79.4% to 108.6%), good precision (with relative standard deviation ≤ 5.2 %), as well as lower limits of detection (in the range of 0.01–0.02 μg/g). This study demonstrates that the separation and determination of PBs with the developed DES-VALPME-HPLC-VWD technique is simple, efficient, sensitive and inexpensive.

A New Approach for Histamine Functionalized Nanoparticles as Sorbent Phase for Bar Adsorptive Microextraction (BAµE) and Determination of Parabens in Water by HPLC-DAD

In this study, for the first time, histamine-functionalized magnetic nanoparticles (HIS-MNP) were used as sorbent phase combined with bar adsorptive microextraction (BAµE) for the determination of methylparaben (MP), ethylparaben (EP), propylparaben (PP), and butylparaben (BP) in water samples by high performance liquid chromatography coupled with diode array detection (HPLC-DAD). Extraction and desorption conditions, including desorption time and solvent, ionic strength effect and extraction time, were investigated. The extractions were performed for 90 min, 30% of NaCl and sample pH 5. Desorption was carried out using 250 μL of acetonitrile:methanol (25:75 v/v) for 30 min. The limits of detection (LODs) were of 1.5 μg L−1 and limits of quantification (LOQs) were 5.0 μg L−1 for all analytes. The intra-day precision ranged from 1% for EP, PP and BP to 3% for MP, EP, PP and BP. The inter-day precision ranged from 3% for EP to 18% for BP. The relative recoveries varied from 81 to 125%, and relative standard deviations (RSD) ranged between 1 and 16%.

A Novel HPLC Method for Simultaneous Determination of Methyl, Ethyl, n-propyl, Isopropyl, n-butyl, Isobutyl and Benzyl Paraben in Pharmaceuticals and Cosmetics.

The alkyl esters of p-hydroxybenzoic acid at the C-4 position, "the parabens," including methyl, ethyl, propyl, and butyl, are widely used as antimicrobial preservatives in foods, cosmetics, and pharmaceuticals. Official regulations on the use of these compounds make their analysis essential for the estimation of their exposure. On this basis, the presented study was realized to develop a simple, selective and cheap high-performance liquid chromatographic method for the quantitative determination of methylparaben, ethylparaben (EP), n-propyl paraben (NPP), isopropyl paraben (IPP), n-butyl paraben (NBP), isobutyl paraben (IBP) and benzyl paraben (BP) in pharmaceuticals and cosmetic products. The chromatographic separation of the analytes was achieved under flow rate gradient elution conditions using a C18-bonded core-shell silica particle column (2.6 μm particle size, 150 × 3.0 mm from Phenomenex Co.). The samples were injected into the system as aliquots of 1.0 μL, and the compounds were detected by using a photodiode array detector set at 254 nm wavelength. With this technique, seven paraben derivatives can be determined in the concentration range of 250-2000 ng/mL. The recovery of the method is in the range of 99.95-13.84%, and the RSD is at a maximum value of 3.95%. The proposed method was fully validated and successfully applied to different pharmaceutical and cosmetic samples (n=16), including syrups, suspensions, oral sprays, gels, etc. At least one paraben derivative was detected in six samples and was determined quantitatively. The maximum amount of a paraben derivative found in the analyzed samples was 321.7 ng/mL, which was MP. To the best of our knowledge, this is the first LC method, which is applicable both on pharmaceutical and cosmetic samples.

Determination of methylparaben in some cosmetics and pharmaceutics using liquid-liquid extraction and spectrophotometric technique

Parabens are compounds often added to cosmetics and pharmaceutics as preservatives for fungi and bacterial growth, but, recent studies have linked these compounds to several adverse side-effects such as cancer, miscarriage and infertility. The extraction of methyl paraben from (hand cream, body lotion, blusher, body cream, and bath foam) was studied using liquid-liquid extraction with ethyl acetate as a solvent, and double beam UV-spectrophotometer at wave length 282 nm. Calibrations are linear (correlation coefficient r>0.997) and the limit of detection was 2.358 μg/mL The concentrations of methyl paraben for the selected cosmetic samples were ranged from 0.077% to 0.451%.

Simultaneous Determination Of Six Parabens In Cosmetics By A New High Performance Liquid Chromatography Method With Fluorescence Detection

In this study, a new high performance liquid chromatography method with fluorescence detection was developed and validated for the simultaneous determination of methyl paraben, ethyl paraben, propyl paraben, isopropyl paraben, butyl paraben and benzyl paraben in cosmetics. Separations were achieved using a C18 guard column (2.1 Ч 10 mm, 3 µm) and a C18 analytical column (2.1 Ч 150 mm, 3 µm). Isocratic elution was applied with a mobile phase consisting of 45 % aqueous o-phosphoric acid solution (0.08 %) and 55 % methanol/water mixture (90 : 10 v/v). The excitation and the emission wavelengths were 254 and 310 nm, respectively. Column temperature was fixed at 40 єC. The linear range was 0.50-10.00 μg/mL for all of the parabens. Limits of detection and quantification were in the range of 0.29-0.32 μg/mL and 0.88-0.97 μg/ mL, respectively. Precision and accuracy values were calculated by analysis results of standard solutions at 0.50, 2.50 and 10.00 μg/mL. The developed and validated method was applied for simultaneous quantitative determination of six paraben species in cosmetic tonic and micellar water samples successfully.

Single drop microextraction in a 96-well plate format: A step toward automated and high-throughput analysis

In this study, an innovative and high-throughput parallel-single-drop microextraction (Pa-SDME) using the [P6,6,6,14+]2[MnCl42−] magnetic ionic liquid (MIL) as extraction phase is demonstrated, for the first time, in the determination of methylparaben, ethylparaben, propylparaben, bisphenol A, butylparaben, benzophenone and triclocarban from environmental aqueous samples. This experimental setup comprised of a 96-well plate system containing a set of magnetic pins which aided in stabilizing the MIL drops and enabled the simultaneous extraction of up to 96 samples. Using this low-cost experimental apparatus, the sample throughput was lower than 1 min per sample. This novel approach exhibits a number of advantages over classical SDME approaches, particularly in maintaining a stable solvent microdrop and facilitating high-throughput analysis. Experimental conditions were carefully optimized using one-factor-at-a-time and multivariate designs. The optimal conditions employed 5.38 ± 0.55 mg (n = 10) of MIL, a sample volume of 1.5 mL at pH 6, and dilution in 20 μL of acetonitrile. The analytical parameters of merit were determined under the optimized conditions and highly satisfactory results were achieved, with LODs ranging from 1.5 to 3 μg L−1 and coefficients of determination higher than 0.994. Intraday and interday precision ranged from 0.6 to 21.3% (n = 3) and 10.4–20.2% (n = 9), respectively, with analyte relative recovery in three aqueous samples ranging between 63% and 126%.

Exploiting green sorbents in rotating-disk sorptive extraction for the determination of parabens by high-performance liquid chromatography with tandem electrospray ionization triple quadrupole mass spectrometry.

In this study, the viability of applying cork and montmorillonite clay modified with ionic liquid as biosorbents in the rotating-disk sorptive extraction technique was investigated. Specifically, this was aimed at the determination of methyl paraben, ethyl paraben, propyl paraben, and isobutyl paraben, with separation/determination by high-performance liquid chromatography coupled with mass spectrometry. The optimization of the method for both biosorbents was performed using multivariate procedures. The extraction efficiencies for the target compounds in aqueous matrices were compared to those obtained using the commercial sorbent Octadecil Silano-C18. The optimum extraction conditions for both natural sorbents were the use of an ammonia solution (pH 10) as desorption solvent and an extraction time of 30min. The proposed methods show limits of quantification of 0.8μg/L for cork, 3.0μg/L for montmorillonite clay and 6.0μg/L for Octadecil Silano-C18. The relative recoveries from river water and tap water samples ranged from 80.3 to 118.7% and 80.0 to 119.9% for cork and montmorillonite clay modified with ionic liquid, respectively. Relative standard deviations were obtained for intra- and interday precisions of <15% and <19% for cork and <19% and <17% for montmorillonite clay modified with ionic liquid.

Electrochemical oxidation and determination of methylparaben at overoxidized polypyrrole film modified a boron-doped diamond electrode

Electrochemical oxidation of methylparaben (MP) is studied on an overoxidized polypyrrole (OPPy)-modified boron-doped diamond electrode using the cyclic voltammetry (CV) and square wave voltammetry (SWV) techniques. The OPPy-modified BDD electrode displays the catalytic activity of electrooxidation of methylparaben. The modification of BDD electrode surface results in higher values of recorded oxidation currents of the methylparaben than on a bare BDD electrode. The diffusion character of recorded current is determined on the basis of the relation between the current and the scan rate. The linear relationship between methylparaben oxidation peak current is obtained in the range 1.57 × 10− 6–2.06 × 10− 5 mol L− 1. A new voltammetric procedure is proposed to quantify methylparaben in cosmetic products using an overoxidized polypyrrole (OPPy)-modified BDD electrode. The results are compared to the HPLC technique described in the literature as the reference method.

Determination of Parabens in Polish River and Lake Water as a Function of Season

ABSTRACTA method for the determination of methylparaben, ethylparaben, propylparaben, butylparaben, and benzylparaben is reported. A polymeric cartridge containing ultra-pure polystyrene cross-linked with 50% divinylbenzene and 50% poly(methyl methacrylate) was employed for the isolation of parabens from water samples. The extracted samples were analyzed by high-performance liquid chromatography coupled with tandem mass spectrometry. The limits of detection for the method were from 0.3 to 2.9 ng L−1 that allowed the determination of parabens in river and lake water samples with suitable precision and accuracy. There was high variability in the results depending on time of sample collection. The highest concentrations were obtained for samples collected in July – up to 466 ng L−1 of methylparaben and 144 ng L−1 of propylparaben.

Automated Flow Injection Chromatography for the Rapid Assay of Parabens in Hygiene Wipes

ABSTRACTA fully automated flow injection chromatography (FIC) instrument and method are reported for the determination of methylparaben and propylparaben. The system consisted of a computer-controlled MilliGAT precision pump, a six–way injection valve, a peristaltic pump, a monolithic column, and an ultraviolet absorbance detector. The mobile phase composition, flow rate, and sample volume were optimized. The method was fully validated; the calibration plots were linear from 1.0 × 10−6 to 5.0 × 10−5 mol L−1 for both parabens. The limits of detection were 1.0 × 10−7 mol L−1 for methylparaben and 3.0 × 10−7 mol L−1 for propylparaben. The recoveries for both parabens were 97% and the interlaboratory reproducibility was 2.4% for methylpareben and 4.1% for propylparaben at 1.0 × 10−5 mol L−1. The method was employed for the determination of methylparaben and propylparaben in hygiene wipes.

A novel method based on electrochemical approaches and multivariate calibrations for study and determination of methylparaben in the presence of unexpected interference in cosmetics

The use of multivariate voltammetric calibration for the simultaneous determination of two preservatives (methylparaben (MP) and propylparaben (PP)) in cosmetics is reported. At first, electrochemical studies of MP and PP were done by cyclic voltammetry (CV), chronocoulometry (CHC) and linear sweep voltammetry (LSV) techniques. Then central composite rotatable design (CCRD) and response surface methodology (RSM) were used for simultaneous optimization of effective parameters on voltammetric responses of the two analytes. The optimum values of pH, scan rate, step potential and pulse height were 7.0, 0.062Vs−1, 0.009V and 0.07V, respectively. After optimization, the resolution of the two multicomponent mixtures has been accomplished by partial least squares (PLS) for voltammmetric studies of them at the surface of a glassy carbon electrode. Finally, the proposed method was found to be applicable for routine analysis (recovery tests) of the preservatives in a cosmetic product.

A new strategy for enhancing electrochemical sensing from MWCNTs modified electrode with Langmuir-Blodgett film and used in determination of methylparaben

A new type of voltammetric sensor, Langmuir-Blodgett (LB) film of multi-walled carbon nanotubes (MWCNTs) perpendicularly modified glassy carbon electrode (GCE), was prepared and applied in determination of methylparaben. Based on the excellent electrochemical property of vertical MWCNTs on the GCE (MWCNTs-LB/GCE), a sensitive voltammetric method for determination of methylparaben was erected with liner range from 1×10−6molL−1 to 8×10−5molL−1 and detection limit of 4×10−7molL−1. The electrochemical characters of MWCNTs-LB/GCE were investigated in detail and the reaction mechanism of methylparaben was discussed. Meanwhile, cosmetic samples were analyzed using proposed method and the results obtained were well satisfactory.

Novel two wavelength spectrophotometric methods for simultaneous determination of binary mixtures with severely overlapping spectra

This work presents the application of different spectrophotometric techniques based on two wavelengths for the determination of severely overlapped spectral components in a binary mixture without prior separation. Four novel spectrophotometric methods were developed namely: induced dual wavelength method (IDW), dual wavelength resolution technique (DWRT), advanced amplitude modulation method (AAM) and induced amplitude modulation method (IAM). The results of the novel methods were compared to that of three well-established methods which were: dual wavelength method (DW), Vierordt’s method (VD) and bivariate method (BV). The developed methods were applied for the analysis of the binary mixture of hydrocortisone acetate (HCA) and fusidic acid (FSA) formulated as topical cream accompanied by the determination of methyl paraben and propyl paraben present as preservatives. The specificity of the novel methods was investigated by analyzing laboratory prepared mixtures and the combined dosage form. The methods were validated as per ICH guidelines where accuracy, repeatability, inter-day precision and robustness were found to be within the acceptable limits. The results obtained from the proposed methods were statistically compared with official ones where no significant difference was observed. No difference was observed between the obtained results when compared to the reported HPLC method, which proved that the developed methods could be alternative to HPLC techniques in quality control laboratories.

Determination of Methylparaben by Square Wave Voltammetry at Boron-Doped Diamond Electrode

Parabens have been widely used as preservative in personal care products, foods and drugs. However, due to their endocrine disruption and carcinogenic possible action, the quantification of these pollutants in several matrices is necessary. In this way, the present work has as objective, the development of an electroanalytical methodology using square-wave technique. The target molecule is the methylparaben (MePa), which will be determined using the boron-doped diamond electrode (BDD) as the work electrode. Several operating conditions and voltammetric parameters were studied seeking greater efficiency of the technique. Under chosen conditions, the measurements were realized in an electrochemical cell containing Ag/AgCl as the reference system and a platinum foil as auxiliary electrode. Several electrolyte solutions were tested and the best results were obtained in 0.2 molL-1 phosphate buffer (pH 7.5). In such electrochemical cell, MePa showed a well-defined square wave voltammetric peak at a potential around 0.8 V, whose peak currents are linearly proportional to the MePa concentration in the electrolyte. Adequate linearity (0.9986), as shown in figure 1, in the range of 0.5 to 30 mgL-1, with limit of detection and quantification of 0.103 mgL-1 and 0.344 mgL-1, respectively, was found. The method was validated for the determination of MePa in a creek water sample, with low pollution content, obtained in Sao Carlos – SP county (S 21 59.670’ / W 047 54.183’). Spiked solutions of such water samples added to the buffer solution, showed recovery range between 68.40% a 106.15%, with a relative standard deviation (RSD) less than 6.8% (n=3). The method seemed to be sensitive to MePa and can be used for detection in others water samples. In future, we intended to use this method for detection of methylparaben in cosmetics creams.Figure 1. Method calibration curve for determination of MePa. Concentrations: 0.5, 0.75, 1.0, 5.0, 10.0, 15.0, 20.0, 25.0, 30.0 mgL-1.

Simultaneous determination of seven preservatives in cosmetics by dispersive liquid–liquid microextraction coupled with high performance capillary electrophoresis

A simple, rapid, inexpensive and efficient method based on dispersive liquid–liquid microextraction (DLLME) coupled with high performance capillary electrophoresis (HPCE) has been developed for the extraction and determination of methylparaben (MP), ethylparaben (EP), propylparaben (PP), butylparaben (BP), sorbic acid (SOA), benzoic acid (BA), and salicylic acid (SA) in cosmetic products. A dispersive solution composed of 50 μL trichloromethane and 0.45 mL isopropyl alcohol was used to extract the target analytes from acidified sample solution quantitatively in the DLLME procedure. A suitable amount of lower layer was transferred into a vial and evaporated to dryness under nitrogen gas. The residue was reconstituted in methanol–water (20:80, v/v) solution, and separated using bare fused-silica capillary (50 μm i.d., 50 cm of total length, and 41 cm effective length) and detected at 230 nm. Urobenzoic acid was used as the internal standard. The calibration curves were linear in the range of 0.05 to 5.0 μg mL−1 for MP and SA, and 0.025 to 5.0 μg mL−1 for the rest with the coefficients of correlation ranging from 0.9978 to 0.9995. The limits of detection were in the range of 0.200–0.375 mg kg−1 with enrichment factors ranging from 41 to 133 for all target analytes. Recoveries of the method were in the range of 71.1–112.6%, with the intraday RSDs and interday RSDs in the range of 2.22–4.51% and 3.05–4.89%, respectively. This method has been successfully applied for analysis of the preservatives in different samples of cosmetic.

Development and Application of Ultra Performance Liquid Chromatography Method to the Quantification of the Biotransformation of Methyl Paraben in Eisenia foetida

AbstractA simple and quick ultra performance liquid chromatography method (UPLC) has been developed for determination of methyl paraben (MP) and its major metabolites p‐hydroxybenzoic acid (pHBA) and phenol (Phe), following its biotransformations in Eisenia foetida. After different exposure time to paper contact test, the presence of methyl paraben and his biotransformation products in adult earthworms was monitored. Determination of its metabolites was achieved with a BEH (bridged ethane‐silicon hybrid) C18 column (2.1×50 mm i.d., 1.7 µm particle size), using methanol/water/phosphoric acid as mobile phase, under a gradient elution program, and a PDA (photo‐diode array) detection (quantification with MaxPlot in the range 210–400 nm). The absorption of MP did not exceed 30% and in the first 4–6 h after exposure only minute amounts of pHBA and Phe were detected in the worm homogenates. After 48 h of exposures, almost 70% of absorbed MP was already metabolized to Phe and around 20% could be found as pHBA.

Determination of methylparaben, propylparaben, triamcinolone acetonide and its degradation product in a topical cream by RP-HPLC.

A novel reversed-phase high-performance liquid chromatographic (RP-HPLC) method was developed and validated for the determination of active component triamcinolone acetonide, its degradation product triamcinolone (occurring in formulation after long-term stability tests) and two preservatives presented in the cream-methylparaben and propylparaben, using hydrocortisone as an internal standard. The chromatographic separation was performed on a Supelco Discovery C18 column; the mobile phase for separation of all compounds consists of a mixture of acetonitrile and water (40:60 v/v). The analysis time was less than 9 min, at a flow rate of 0.6 mL min(-1) and detection at 240 nm. The method was found to be applicable for routine analysis (stability tests, homogeneity) in the pharmaceutical product topical cream Triamcinolon cream 0.1%.

Determination of methylparaben, propylparaben, clotrimazole and its degradation products in topical cream by RP-HPLC

Reversed-phase, high-performance liquid chromatographic (RP-HPLC) methods with UV detection were developed and validated for determination of compounds in a topical cream. The first method describes determination of the active component clotrimazole and two preservatives present in the cream; methylparaben and propylparaben. The second method describes determination of two degradation products of clotrimazole, imidazole and (2-chlorophenyl) diphenylmethanol, in a topical cream after long-term stability tests. Chromatographic separation was on a Purospher RP-18e column; the mobile phase in Method1 for separation of clotrimazole, methylparaben and propylparaben comprises acetonitrile and water (70:30 v/v). For determination of degradations products-imidazole and (2-chlorophenyl) diphenylmethanol—the optimum composition of mobile phase in Method2 was acetonitrile and water (75:25 v/v) apparent pH* 2.7. Analysis time was <10 min for both methods. The methods were found to be applicable for routine analysis of the active compound clotrimazole, preservatives and degradation products in the pharmaceutical product: topical cream 1% Clotrimazol Cream.

Liquid chromatographic determination of methylparaben and propylparaben in nortriptyline hydrochloride oil-water microemulsions

A reversed-phase LC method using UV detection has been developed and validated for the analysis of methylparaben and propylparaben in nortriptyline hydrochloride oil-water (o-w) microemulsions. The precision and accuracy of the method was excellent with RSD values of 4.53% and 2.13% respectively for methylparaben, and 3.69% and 2.06% respectively for propylparaben. The linearity established was 50–150% of theoretical concentrations of each product in dosage form, withr 2 0.9940 for methylparaben and 0.9956 for propylparaben. Recoveries of all products from spiked placebos were >95%, with detection limits 0.86 µg · mL−1 for methylparaben, and 0.06 µg · mL−1 for propylparaben. The method was successfully used for determining both compounds in nortriptyline o-w microemulsions.