Fast and sensitive method to determine parabens by capillary electrophoresis using automatic reverse electrode polarity stacking mode: application to hair samples

Abstract

This paper describes a fast and sensitive method for the determination of methyl, ethyl, propyl, and butylparaben in hair samples by capillary electrophoresis using automatic reverse electrode polarity stacking mode. In the proposed method, solutions are injected using the flush command of the analysis software (940 mbar) and the polarity switching is carried out automatically immediately after the sample injection. The advantages compared with conventional stacking methods are the increased analytical frequency, repeatability, and inter-day precision. All analyses were performed in a fused silica capillary (50 cm, 41.5 cm in effective length, 50 μm i.d.), and the background electrolyte was composed of 20 mmol L(-1) sodium tetraborate in 10 % of methanol, pH 9.3. For the reverse polarity, -25 kV/35 s was applied followed by application of +30 kV for the electrophoretic run. Temperature was set at 20 °C, and all analytes were monitored at 297 nm. The method showed acceptable linearity (r (2) > 0.997) in the studied range of 0.1-5.0 mg L(-1), limits of detection below 0.017 mg L(-1), and inter-day, intra-day, and instrumental precision better than 6.2, 3.6, and 4.6 %, respectively. Considering parabens is widely used as a preservative in many products and the reported possibility of damage to the hair and also to human health caused by these compounds, the proposed method was applied to evaluate the adsorption of parabens in hair samples. The results indicate that there is a greater adsorption of methylparaben compared to the other parabens tested and also dyed hairs had a greater adsorption capacity for parabens than natural hairs.

A New Sensor for Methyl Paraben Using an Electrode Made of a Cellulose Nanocrystal–Reduced Graphene Oxide Nanocomposite

“…Cosmetic Directive 76/768/EEC annex VI limited the maximum level of parabens in cosmetics to 0.4% for one ester and 0.8% for a mixture of esters [4]. Conventional analytical methods such as gas chromatography (GC) [5], high-performance liquid chromatography (HPLC) [6], and capillary electrophoresis [7] are extensively used for paraben detection. However, the development of electrochemical sensors for paraben detection is attractive due to the possibility of simple, rapid, and in situ analysis compared with conventional analytical methods.…”

Development of a liquid chromatography/tandem mass spectrometry method for monitoring of long‐term exposure to parabens

“…Analytical methods have been reported for measuring and monitoring of parabens in biological samples, and they include the following: capillary electrophoresis, liquid chromatography–mass spectrometry and gas chromatography–mass spectrometry . Among these methods, parabens have generally been quantified using liquid chromatography–tandem mass spectrometry (LC/MS/MS) due to its high sensitivity and accuracy.…”

“…21,22 Importantly, hair samples may be useful in monitoring of long-term exposures due to the binding of chemicals to hair matrix which can allow for exposure determinations over the course of several months or even years, depending upon hair length. 21,23 Analytical methods have been reported for measuring and monitoring of parabens in biological samples, and they include the following: capillary electrophoresis, 24,25 liquid chromatography-mass spectrometry [26][27][28][29] and gas chromatography-mass spectrometry. 30 Among these methods, parabens have generally been quantified using liquid chromatography-tandem mass spectrometry (LC/MS/MS) due to its high sensitivity and accuracy.…”

Current trends in sample preparation for cosmetic analysis

“…To overcome the drawback, the more effective extraction methods are required. Although classical LLE and solid–liquid extraction (SLE) are broadly used in cosmetic analysis , the simpler, faster and greener procedures are being developed. Solvent extraction (SE) approach for isolating organic substances have turned into ultrasound‐assisted extraction (USAE) , accelerated SE , dispersive liquid–liquid microextraction (DLLME) , SPE , matrix solid‐phase dispersion (MSPD) , and SPME .…”