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In the present study, we propose a novel method for the extraction of parabens in personal care products. A new, simple adsorptive material was obtained by combining metal‐organic frameworks and melamine sponges using the adhesive property of polyvinylidene fluoride. This new material, metal‐organic frameworks/melamine sponges, was found to be particularly suitable for solid‐phase extraction. The structural characteristics of metal‐organic frameworks/melamine sponges were first analyzed by scanning electron microscopy. Subsequently, solid‐phase extraction was performed on sample solutions, and the extracted substances were then analyzed by high‐performance liquid chromatography. Following optimization of important experimental conditions, excellent recovery rates were obtained. Our novel method was then applied to the extraction of four parabens (methylparahydroxybenzoates, ethylparahydroxybenzoates, propylparahydroxybenzoates, and butylparahydroxybenzoates) from real samples. The results yielded limits of detection of 0.26–0.41 ng/mL. The inter‐ and intra‐day recoveries were 104.0–109.7% and 91.2–98.1%, respectively (relative standard deviation, <13.8%). [ABSTRACT FROM AUTHOR]

In this study, several metal‐organic framework‐melamine foam columns were first developed and used as a laboratory‐made semi‐automatic solid phase extraction packed in syringe adsorber for the extraction of six triazine herbicides from vegetable oil samples coupled to high‐performance liquid chromatography‐tandem mass spectrometry. The metal‐organic framework‐foam columns were prepared using a simple approach by embedding the solid particles in melamine foam using polyvinylidene difluoride physical encapsulation. The method was applicable to a wide variety of metal‐organic framework materials, and the incorporated materials retained their unique properties. Key factors that affect the extraction efficiency, including the MIL‐101(Cr) amount, sample flow rate, type and volume of the eluting solvent, and flow rate of eluting solvent, were investigated. Under optimum conditions, the proposed method exhibited low limits of detection (0.017–0.096 ng/mL, S/N = 3) for six triazines. The relative standard deviations calculated for all herbicides ranged from 0.2 to 14.9%. This study demonstrated that the MIL‐101(Cr)‐foam column can be used as a high‐quality adsorption material for the detection of triazines in vegetable oils. [ABSTRACT FROM AUTHOR]

A novel vortex-assisted solid-phase extraction method based on MIL-68(Al)/Chitosan-melamine sponge column (or V-MIL-68(Al)/CS-SC-SPE) is presented in this paper. The MIL-68(Al)/Chitosan-sponge column was prepared by a simple infiltration method and a preparation process that does not consume organic solvents. Scanning electron microscopy was used to characterize the functionalized sponge columns, and the skeleton and pores of the melamine sponge were successfully modified with the coating material (MIL-68(Al) and chitosan). Chitosan was used successfully not only as an adsorption adjuvant material, but also as an adhesive in the preparation of MIL-68(Al)/CS coating sponge materials. The presented method was further combined with high performance liquid chromatography (HPLC) and used in the determination of trace parabens (including methyl-, ethyl-, propyl- and butyl-parabens) in environmental water samples. Several important factors that affect the extraction performance were investigated. Under the optimum conditions, the method was successfully used to detect the four kinds of parabens in different water samples (domestic water, lake water and river water). The limits of detection ranged between 0.21 and 0.50 ng/mL, and the relative standard deviations for all parabens were below 10.8%. Image 1 • The MIL-68(Al)/chitosan-sponge columns were prepared by a simple infiltration method. • The functionalized SCs were prepared without consuming organic solvents. • Chitosan not only acts as an adsorption adjuvant but also as an adhesive. • A vortex-assisted solid-phase extraction based on MIL-68(Al)/CS-SCs was proposed. • The method has excellent extraction performance (0.50 ng/mL) for parabens. [ABSTRACT FROM AUTHOR]

In the presented work, we proposed the use of polyvinylidene difluoride (PVDF) as a coupling agent to load MIL-101(Cr) and carboxylated multi-walled carbon nanotubes (MWCNTs) on the skeleton of melamine sponge (MeS) for the preparation of novel extraction media with high-efficiency. The morphology and structure of this composite were characterized by scanning electron microscopy (SEM) analyses. The obtained MIL-101(Cr)/MWCNTs functionalized MeS(MIL/M-MeS) cube was used as a sorbent for the solid-phase extraction (SPE) of six triazines (Atraton, Simetryne, Prometon, Ametryn, Propazine, and Prometryn) spiked corn samples. Several parameters that may affect the extraction efficiencies, including type and volume of extraction solvent, times of ultrasonic extraction, adsorption, and desorption; type and volume of desorption solvent, were optimized. This was followed by elution containing the herbicides, which were quantified using high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Under optimum conditions, the analytical method for the preparation of MIL/M-MeS cube produced satisfactory recoveries and repeatability. The LODs of the method when applied to spiked corn samples were in the range of 0.01–0.04 ng g−1 (LODs = 3δ/k). The relative intra- and inter-day recoveries ranged from 90.30 to 116.50% and 92.38–116.24%, respectively, and relative standard deviations ranged from 1.08 to 12.32% and 5.36–16.23%, respectively. The MIL-101(Cr)/MWCNTs functionalized MeS (MIL/M-MeS) cube material-based solid-phase extraction coupled with high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was applied to extract six triazines herbicides in corn. Satisfactory analytical performances were obtained. Image 1 • The prepared MOFs/MWCNTs functionalized melamine sponge was firstly used for the SPE. • Its high surface area facilitated the high adsorption capability of the triazines. • The method detection limits were less than 0.04 ng g−1 • The proposed method was applied for the analysis of triazines in corn. [ABSTRACT FROM AUTHOR]