Magnetic‐covalent organic polymer solid‐phase extraction coupled with high‐performance liquid chromatography for the sensitive determination of fluorescent whitening agents in cosmetics

Abstract

Magnetic solid-phase extraction is a powerful sample preparation tool. Combined with covalent organic polymers, this technique permits an excellent extraction performance. We present a sensitive, efficient, and easy operating magnetic- covalent organic polymer solid-phase extraction method. By using the magnetic covalent organic polymer nanoparticles yielded by a one-pot reaction, five fluorescent whitening agents were successfully preconcentrated and separated. The saturated extraction amounts of the magnetic covalent organic polymer nanoparticles for the five fluorescent whitening agents were in the range of 97-155 nmol/mg. Coupled with high-performance liquid chromatography, the limit of detection of the fluorescent whitening agent was improved by at least an order of magnitude compared to current literature records. Under the optimal conditions, the linear ranges of these five fluorescent whitening agents were up to 0.5-100 ng/L, the limit of detection was as low as 0.1 ng/L, and the recoveries were in the range of 78.2-105% with relative standard deviations lower than 5.5%. Meanwhile, a trace level of 7-diethylamino-4-methylcoumarin was found in a typical cosmetic sample by using this magnetic-covalent organic polymer solid-phase extraction method when coupling with high-performance liquid chromatography. Moreover, this sensitive, efficient, and easy operating sample preparation method can be extended to analysis of other analytes that have a π-π conjugated structure.

Identification of Fluorescent Brighteners as Another Emerging Class of Abundant, Ubiquitous Pollutants in the Indoor Environment

“…Most of these second-tier FBs are nonionic. In addition to detergents, their primary applications are in textiles and paper and plastic packaging, and they are even illegally added to cosmetics . However, they have never been the focus of indoor environmental studies.…”

“…In addition to detergents, their primary applications are in textiles and paper and plastic packaging, and they are even illegally added to cosmetics. 43 However, they have never been the focus of indoor environmental studies. Their relatively high concentrations together with all their DFs of 100% suggest that they are also frequently used in large quantities, but their emissions should be slower and less abundant in long-life polymeric and paper products relative to those of VBL, CXT, and FB 28/BA in frequently used detergents.…”

Covalent organic frameworks as multifunctional materials for chemical detection

“…Fourth, COFs are usually made of light elements, such as H, B, C, N, and O, which endow them with processability and feasibility to be integrated with the silica or metal fiber substrate in solid-phase microextraction or to form membranes. 350 COFs have been utilized as absorbents in dispersive microsolid-phase extraction, MSPE, and solid-phase microextraction for the detection of industrial chemicals, 351–376 pesticides and insecticides, 377–382 chemical warfare agents, 24 ions, 383 drug molecules, 384–390 and biomolecules 391,392 in safety inspection of water and food, environmental monitoring, and analysis of biological mixtures. In most cases, the detection is performed by coupling solid-phase extraction with HPLC, GC, MS, or chromatography–mass spectrometry combinations to enable quantitative analysis.…”

“…393 It is of great importance to monitor and control the amount of PAHs in the environment. A few detection methods that combine SPE 355,372 or MSPE 353,358,363,365 using COF-LZU1, 353 TpBD, 358,365,372 COF-SCU1, 355 and TpDA 363 with HPLC and GC have been established. The high extraction efficiency of these COFs can be usually attributed to strong π stacking and hydrophobic interactions between COFs and polycyclic aromatics.…”

Magnetic mesoporous polyimide composite for efficient extraction of Rhodamine B in food samples

“…In recent years, magnetic solid‐phase extraction (MSPE) has attracted more and more attention for its combination of the merits of dispersive LLE and SPE . Compared with traditional SPE methods, MSPE can offer higher adsorption capacity as a result of the extended contact area between sorbents and target analytes.…”