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

Abstract

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.

A facile online multi-gear capacitively coupled contactless conductivity detector for an automatic and wide range monitoring of high salt in HPLC

“…As a proof of concept, the LC with high salt gradient elution was chosen as the model process of two bactericides of 5-chloro-2-methyl-4-isothiazolin-3-one (CIT) and 2-methyl-4isothiazolin-3-one (MIT). 25 The experiments systemically validated the digital computation, theory, and model of M-C 4 D. In particular, the developed sensor was applied for the facile and automatic detection of wide salt gradient in LC, avoiding cumbersome manual switching of the detector head-stages. The M-C 4 D sensor has clear potential to automatic monitoring of high content electrolyte, buffer and aqueous-organic eluent in a biological or chemical process.…”

Determination of Methylisothiazolinone and Methylchloroisothiazolinone in personal care products by HPLC-DAD

“…Solid samples and liquid samples with high density or viscosity required ultrasonic extraction with different solvents before analysis [11]. In a previous study, sample matrices varied considerably medium water content, low water content and high water content [8]. Following that, shampoos, shower gel, cleanser, hand sanitizer (Group 1) are considered as high or medium water content whereas body cream and face cream are low ones (Group 2, Table 2).…”

“…Analysis of MI and MCI in cosmetics requires different analysis techniques and sample preparations. In terms of analysis techniques, many methods are used to analyze isothiazolinones namely GC-MS [5], HPLC-MS [6,7], HPLC-DAD [8].…”

“…Obviously, HPLC-MS method has identification capabilities for the determination of biocides and does not require derivatization, however; the instrument is expensive and requires internal standards with high cost. Both MI and MCI absorb UV lights with the maximum wavelength at 274nm [8]. Thus, the common analytical methodology to identify and quantify these preservatives in cosmetics is HPLC method with UV or diode-array detector (DAD) [8].…”

“…Both MI and MCI absorb UV lights with the maximum wavelength at 274nm [8]. Thus, the common analytical methodology to identify and quantify these preservatives in cosmetics is HPLC method with UV or diode-array detector (DAD) [8]. In terms of sample preparation, due to the complex structural complexities of cosmetic ingredients, a mixture of solvent as methanol: NaH 2 PO 4 [9], methanol:H 2 O [10], chloroform and then methanol [6] were used for extractions of MI and MCI in different types of cosmetics such as shampoos containing plant extracts [9], detergents [10] or eyeshadows and liquid lipsticks [6].…”