Carboxylated graphene oxide/polyvinyl chloride as solid-phase extraction sorbent combined with ion chromatography for the determination of sulfonamides in cosmetics

Rapid determination of 111 anti-infective drugs possibly added in cosmetics using high-performance liquid chromatography-tandem mass spectrometry with scheduled multiple reaction monitoring

RATIONALE

Illegal addition of anti-infective drugs to cosmetics at low concentrations has been found. The illicit addition of anti-infective drugs encompasses a wide variety of medications. The current sample purification methods are inadequate to detect all these compounds. A sensitive, wide-coverage, and weak-matrix-effect measurement method needs to be established to address this issue.

METHODS

Samples were extracted using acetonitrile, diluted 25 times, and then analyzed using liquid chromatography-tandem mass spectrometry (LC-MS/MS) to detect 111 anti-infective drugs. The method was validated and assessed for matrix effect before being applied to cosmetic products.

RESULTS

The calibration curves for the analytes exhibited a strong correlation coefficient (r > 0.995). The limit of detection ranged from 0.006 to 0.6 mg/kg. Matrix effects were significantly improved after a 25-fold dilution. The method was successfully applied to various cosmetics. Two of 82 samples tested contained lincomycin and miconazole, respectively.

CONCLUSIONS

The developed method is quick and reliable to analyze anti-infective drugs in cosmetics, with potential for both qualitative and quantitative analyses. It is a valuable tool for cosmetic research and development, contributing to safer and more effective cosmetic products.

Diluting modulation-based two dimensional-liquid chromatography coupled with mass spectrometry for simultaneously determining multiclass prohibited substances in cosmetics

Developing efficient and comprehensive screening methods for prohibited substances in cosmetics is critical for ensuring the quality and safety of cosmetics used in everyday life. This study proposed a heart-cutting two-dimensional liquid chromatography-mass spectrometry (2D-LC-MS) method based on online diluting modulation for detecting multiclass prohibited substances in cosmetics. The 2D-LC-MS method combines HILIC and RPLC techniques. Compounds near the dead time that the first dimensional HILIC could not separate were transferred to the second dimensional RPLC by valve switch, achieving good separation with a wide range of polarities. Moreover, the online diluting modulation solved the problem of mobile phase incompatibility, realizing an excellent column-head focusing effect and reducing the loss of sensitivity. Besides, the first dimensional analysis did not restrict the flow rate of the second dimensional analysis owing to the diluting modulation. We demonstrated the 2D-LC-MS system by determining 126 prohibited substances in cosmetic products, including hormones, local anesthetics, anti-infectives, adrenergic agents, antihistamines, pesticides, and other chemicals. All correlation coefficients of the compounds were above 0.9950. The LODs and the LOQs ranged from 0.000259 ng/mL to 16.6 ng/mL and 0.000864 ng/mL to 55.3 ng/mL, respectively. The RSDs% for intra-day and inter-day precision were within 6% and 14%, respectively. Compared with conventional one-dimensional liquid chromatography methods, the established method expanded the analytical coverage of cosmetics-prohibited substances with reduced matrix effects for most compounds and improved sensitivity for polar analytes. The results indicated that the 2D-LC-MS method was a powerful tool for screening multiclass prohibited substances in cosmetics.

Superior adsorption performance of citrate modified graphene oxide as nano material for removal organic and inorganic pollutants from aqueous solution

This work addressed one step preparation method to form a novel nano material composite of graphene oxide nanosheet (GO) functionalized with low-cost tri-sodium citrate (C), using, teteraethylorthosilicate (TEOS) as a cross-linker. The prepared composite (GO–C) was characterized using various advanced techniques. Among these techniques, the TGA provided interesting information concerning the functionalization process. Within this process, the (–OH) groups that located at the GO-surface were consumed in the modification process which leads to increase the thermal stability of the resulted composite. Cationic organic methylene blue (MB) and crystal violet (CV), and inorganic copper (Cu²⁺) and cobalt (Co²⁺) pollutants were displayed as a model to assess their removal performance by the developed composite (GO–C) from aqueous solution, through batch technique. According to Langmuir isotherm the GO–C present an excellent adsorption capacity for MB (222.22 mg g⁻¹), CV (270.27 mg g⁻¹), Cu²⁺ (163.4 mg g⁻¹) and Co²⁺ (145.35 mg g⁻¹) which were more than the adsorption capacities found in literature. Additionally, the regenerated composite presents higher removal ability than the original composite.

Application of Nanomaterials for Coping with Mycotoxin Contamination in Food Safety: From Detection to Control

Mycotoxins, which are toxic secondary metabolites produced by fungi, are harmful to humans. Mycotoxin-induced contamination has drawn attention worldwide. Consequently, the development of reliable and sensitive detection methods and high-efficiency control strategies for mycotoxins is important to safeguard food industry safety and public health. With the rapid development of nanotechnology, many novel nanomaterials that provide tremendous opportunities for greatly improving the detection and control performance of mycotoxins because of their unique properties have emerged. This review comprehensively summarizes recent trends in the application of nanomaterials for detecting mycotoxins (fluorescence, colorimetric, surface-enhanced Raman scattering, electrochemical, and point-of-care testing) and controlling mycotoxins (inhibition of fungal growth, mycotoxin absorption, and degradation). These detection methods possess the advantages of high sensitivity and selectivity, operational simplicity, and rapidity. With research attention on the control of mycotoxins and the gradual excavation of the properties of nanomaterials, nanomaterials are also employed for the inhibition of fungal growth, mycotoxin absorption, and mycotoxin degradation, and impressive controlling effects are obtained. This review is expected to provide the readers insight into this state-of-the-art area and a reference to design nanomaterials-based schemes for the detection and control of mycotoxins.

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.

Trace analysis of organophosphorus pesticide residues in fruit juices and vegetables by an electrochemically fabricated solid-phase microextraction fiber coated with a layer-by-layer graphenized graphite/graphene oxide/polyaniline nanocomposite

Herein, a solid-phase microextraction pencil lead fiber coated with a layer-by-layer graphenized graphite/graphene oxide/polyaniline nanocomposite (GG/GO/PANI) was fabricated by an in situ electrochemical technique for the trace analysis of organophosphorus pesticide residues in packed grape and apple juice and also fresh tomato samples. The effects of various parameters, including the type of desorption solvent, adsorption time, desorption time, pH, salt addition, and stirring rate, on the extraction efficiency of the studied pesticides were investigated and accordingly, these parameters were optimized. The proposed fiber demonstrated desirable linear ranges (0.01-300 μg L-1) with good correlation coefficients (R2 ≥ 0.996) as well as low limits of detection (0.003-0.03 μg L-1) for the studied pesticides. The relative standard deviations (n = 5) for the extraction of 50 μg L-1 of each analyte were less than 7 and 11.5% for inter and intra-day precisions, respectively. This fast, facile, and repeatable electrochemical fabrication method produced a porous and homogeneous coating. The proposed fiber demonstrated good extraction efficiency, high stability, and long life-time despite being low cost. The successful application of the proposed fiber for the trace determination of pesticides in complex food matrices was proven by the satisfactory relative recoveries of 80.7-116.5%.

Polyethylene glycol grafted with carboxylated graphene oxide as a novel interface modifier for polylactic acid/graphene nanocomposites

Strength and toughness are both of great importance for the application of polylactic acid (PLA). Unfortunately, these two properties are often contradictory. In this work, an effective and practical strategy is proposed by using carboxylated graphene oxide (GC) grafted with polyethylene glycol (PEG), i.e. GC-g-PEG. The synthesis procedure of GC-g-PEG is firstly optimized. Then, a series of PLA nanocomposites were prepared by the melt blending method via masterbatch. In comparison to that achieved over pure PLA, these nanocomposites are of higher crystallinity, thermal stability and mechanical strength. This is mainly attributed to well-tailored interface and good dispersion. Especially, while retaining the tensile strength of the original PLA, the elongation at break increases by seven times by adding 0.3 wt% GC-g-PEG.

Use of Nanomaterial-Based (Micro)Extraction Techniques for the Determination of Cosmetic-Related Compounds

The high consumer demand for cosmetic products has caused the authorities and the industry to require rigorous analytical controls to assure their safety and efficacy. Thus, the determination of prohibited compounds that could be present at trace level due to unintended causes is increasingly important. Furthermore, some cosmetic ingredients can be percutaneously absorbed, further metabolized and eventually excreted or bioaccumulated. Either the parent compound and/or their metabolites can cause adverse health effects even at trace level. Moreover, due to the increasing use of cosmetics, some of their ingredients have reached the environment, where they are accumulated causing harmful effects in the flora and fauna at trace levels. To this regard, the development of sensitive analytical methods to determine these cosmetic-related compounds either for cosmetic control, for percutaneous absorption studies or for environmental surveillance monitoring is of high interest. In this sense, (micro)extraction techniques based on nanomaterials as extraction phase have attracted attention during the last years, since they allow to reach the desired selectivity. The aim of this review is to provide a compilation of those nanomaterial-based (micro)extraction techniques for the determination of cosmetic-related compounds in cosmetic, biological and/or environmental samples spanning from the first attempt in 2010 to the present.

Determination of Bisphenol A by High-Performance Liquid Chromatography Based on Graphene Magnetic Dispersion Solid Phase Extraction

Bisphenol A (BPA), as one of the environmental endocrine disruptors, is extensively existing and threatening to human health. To evaluate the environmental exposure level and protect human from the hazard of BPA, a precise and sensitive method is established. In this work, Graphene@ Fe3O4 (G@Fe3O4) is prepared by chemical coprecipitation method as magnetic dispersion solid phase extraction (MDSPE) material. The rapid and specific detection method of BPA is carried out by high-performance liquid chromatography (HPLC). Properties of G@Fe3O4 are identified by the fourier infrared spectrum and scanning electron microscopy. Conditions of solid phase extraction are optimized. Under the optimal extraction conditions, G@Fe3O4 has perfect enrichment effect on BPA. There is a good linear relationship in the range of 5.0~1000.0 μg/L with the correlation coefficient of 0.9997. The detection limit is 0.1 μg/L. This method is applied to water samples successfully, and recoveries of BPA are between 88.19% and 99.56% (RSDs < 3.00%). G@Fe3O4 was synthesized, which was used to extract BPA in water samples before HPLC analysis, and has shown perfect extraction ability toward BPA, which indicates that the determination method of BPA by HPLC based on graphene MDSPE is faster and more precise.

Magnetic metal organic framework for pre-concentration of ampicillin from cow milk samples

The aim of this study is a present of a simple solvothermal synthesis approach to preparation of Cu-based magnetic metal organic framework (MMOF) and subsequently its application as sorbent for ultrasound assisted magnetic solid phase extraction (UAMSPE) of ampicillin (AMP) from cow milk samples prior to high performance liquid chromatography-Ultraviolet (HPLC-UV) determination. Characteristics of prepared MMOF were fully investigated by different techniques which showed the exclusive properties of proposed sorbent in terms of proper functionality, desirable magnetic property and also high specific surface area. Different influential factors on extraction recovery including sorbent dosage, ultrasonic time, washing solvent volume and eluent solvent volume were assessed using central composite design (CCD) based response surface methodology (RSM) as an operative and powerful optimization tool. This is the first report for determination of AMP using MMOF. The proposed method addressed some drawbacks of other methods and sorbents for determination of AMP. The presented method decreases the extraction time (4 min) and also enhances adsorption capacity (250 mg/g). Moreover, the magnetic property of presented sorbent (15 emu/g) accelerates the extraction process which does not need filtration, centrifuge and precipitation procedures. Under the optimized conditions, the proposed method is applicable for linear range of 1.0–5000.0 μg/L with detection limit of 0.29 μg/L, satisfactory recoveries (≥95.0%) and acceptable repeatability (RSD less than 4.0%). The present study indicates highly promising perspectives of MMOF for highly effective analysis of AMP in complicated matrices.

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MMOF was prepared and used for the first time for determination of ampicillin from cow milk samples.

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The extraction method was convenient, rapid and the MMOF can be used more than 8 times.

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The MMOF have high specific surface area (300.0 m²/g) and high adsorption capacity (250.5 mg g⁻¹).

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The separation time was only 5 min, which was much shorter than other reported.

Application of affinity microspheres for effective SPE cleanup before the determination of sulfamerazine by HPLC

This paper describes the application of poly (ethylene glycol dimethacrylate-N-methacryloyl-L-tryptophane methyl ester) [p(EGDMA-MATrp)] microspheres as an affinity sorbent for the SPE (solid phase extraction) cleanup of sulfamerazine (SMR) from food samples of animal origin before high performance liquid chromatography (HPLC) analysis. The microspheres were prepared by suspension polymerization of ethylene glycol dimethacrylate (EGDMA) and N-methacryloyl-L-tryptophane methyl ester (MATrp) as a crosslinker and a monomer, respectively. Various parameters affecting the SPE cleanup efficiency of the p(EGDMA-MATrp) microspheres (contact time, pH, initial SMR concentration, ionic strength etc.) were optimized. Under the optimized conditions, maximum adsorption capacity was found to be 8.55 ± 0.44 mg/g sorbent at pH 5.0. 90% of the adsorbed SMR was desorbed by using ACN:MeOH (5:5) mixture as a desorption agent. Applicability of the microspheres for the SPE cleanup of SMR residues in the food samples such as egg and milk with HPLC was also determined. It was demonstrated that the prepared p(EGDMA-MATrp) microspheres could be repeatedly applied for SPE cleanup of sulfamerazine before chromatographic analysis. Also, the recoveries of SMR in milk and egg samples were reasonably satisfactory and in the range of 71 to 90%.

The role of graphene oxide and graphene oxide-based nanomaterials in the removal of pharmaceuticals from aqueous media: a review

In this review paper, the ill effects of pharmaceuticals (PhAs) on the environment and their adsorption on graphene oxide (GO) and graphene oxide-based (GO-based) nanomaterials have been summarised and discussed. The adsorption of prominent PhAs discussed herein includes beta-blockers (atenolol and propranolol), antibiotics (tetracycline, ciprofloxacin and sulfamethoxazole), pharmaceutically active compounds (carbamazepine) and analgesics such as diclofenac. The adsorption of PhAs strictly depends upon the experimental conditions such as pH, adsorbent and adsorbate concentrations, temperature, ionic strength, etc. To understand the adsorption mechanism and feasibility of the adsorption process, the adsorption isotherms, thermodynamics and kinetic studies were also considered. Except for some cases, GO and its derivatives show excellent adsorption capacities for PhAs, which is crucial for their applications in the environmental pollution cleanup.

Graphene oxide adsorbent based dispersive solid phase extraction coupled with multi-pretreatment clean-up for analysis of trace aflatoxins in traditional proprietary Chinese medicines

Graphene oxide (GO)-based dispersive solid phase extraction (D-SPE) method combined with multi-step preparation has been proposed for the evaluation of trace aflatoxins in proprietary Chinese medicines (PCM). After being extracted by methanol, the sample was purified based on multi-step preparation, including dehydration with MgSO₄/NaCl and cleanup with neutral alumina. Then GO was used as an adsorbent in D-SPE method for further preconcentration of aflatoxins prior to high performance liquid chromatography-fluorescence detection. The selected conditions were investigated. The Box-Behnken design (BBD) was used to optimize factors affecting adsorption procedure. Under the optimized conditions, good linear relationships had been achieved with the correlation coefficient (R²) varying from 0.9904 to 0.9990. The LODs and LOQs were ranging from 0.020 to 0.041ng/mL and 0.061 to 0.125ng/mL, respectively. The results of the recoveries were 74.0-102.7% for the four aflatoxins, while the precisions from 1.8% to 7.2% were obtained, which indicated that the method was suitable for the analysis of aflatoxins in PCM.

Functionalization of magnetic hollow porous oval shape NiFe2O4 as a highly selective sorbent for the simultaneous determination of five heavy metals in real samples

In this study, a functionalized magnetic hollow porous oval-shape NiFe2O4 (MHPO-NiFe2O4) was designed by a facile synthesis procedure, and employed as magnetic solid phase extraction (MSPE) material to extract several heavy metal ions. As-prepared MHPO-NiFe2O4 exhibited superior adsorption capacities of 20.17, 16.64, 16.82, 9.69 and 16.58mgg-1, for Cu(II), Cd(II), Cr(III), Co(II) and Zn(II), and was then used to detect these heavy metals elements in real samples by combining with inductively coupled plasma optical emission spectroscopy (ICP-OES). The possible mechanism of the enrichment of heavy metals ions on MHPO-NiFe2O4 was proposed, which involved the dominant adsorption and desorption. The detection limits were as low as 0.015, 0.13, 0.062, 0.035 and 0.46μgL-1 for Cu(II), Cd(II), Cr(III), Co(II) and Zn(II), respectively. A good repeatability was obtained with the relative standard deviation (RSD) of 3.87%. Moreover, the method was successfully utilized for the analysis of five heavy metals in real samples (cabbage, lettuce, apple, seawater), with satisfactory recoveries in the range of 92-108%.

Current trends in sample preparation for cosmetic analysis

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

Application of an optimized modified stir bar with ZnS nanoparticles loaded on activated carbon for preconcentration of carbofuran and propoxur insecticides in water samples and their HPLC determination

In this study, the stir bar was coated with the ZnS-NPs loaded on activated carbon (ZnS-AC) as well as [EMIM][PF₆] ionic liquid using sol gel technique was used for stir bar sorptive extraction (SBSE) of carbofuran and propoxur.