A simple and portable vacuum assisted headspace solid phase microextraction device coupled to gas chromatography based on covalent organic framework/metal organic framework hybrid for simultaneous analysis of volatile and semi-volatile compounds in soil

Supramolecular Materials as Solid-Phase Microextraction Coatings in Environmental Analysis

Solid-phase microextraction (SPME) has been widely proposed for the extraction, clean-up, and preconcentration of analytes of environmental concern. Enrichment capabilities, preconcentration efficiency, sample throughput, and selectivity in extracting target compounds greatly depend on the materials used as SPME coatings. Supramolecular materials have emerged as promising porous coatings to be used for the extraction of target compounds due to their unique selectivity, three-dimensional framework, flexible design, and possibility to promote the interaction between the analytes and the coating by means of multiple oriented functional groups. The present review will cover the state of the art of the last 5 years related to SPME coatings based on metal organic frameworks (MOFs), covalent organic frameworks (COFs), and supramolecular macrocycles used for environmental applications.

Preparation of MIL-101(Cr)-NH2@TAPB-DVA-COF based membrane solid-phase extraction for efficient enrichment and sensitive determination of trace aromatic disinfection by-products in juice drinks

Aromatic disinfection by-products (DBPs) have garnered considerable interest in recent years for their potential carcinogenicity. However, efficient separation and enrichment of DBPs in complex samples is a challenge due to the extremely low content of aromatic DBPs and the complexity of sample matrices. In this study, a MIL-101(Cr)-NH2@TAPB-DVA-COF hybrid material was prepared as the enrichment medium of membrane solid-phase extraction (M-SPE) to efficiently determine trace emerging aromatic DBPs. This medium exhibited excellent enrichment capacity and selectivity for aromatic DBPs because of the strong hydrogen bonding, π-π stacking and hydrophobic interactions. An efficient analytical method for five aromatic DBPs in juice drinks was successfully established by use of this hybrid material as the enrichment medium for M-SPE in combination with liquid chromatography tandem mass spectrometry (LC-MS/MS). The limits of detection of the established method were from 0.50 to 3.00 ng/L. Moreover, the method had been successfully used in real juice drinks to determine trace five aromatic DBPs with the spiked recoveries ranging from 84.1% to 125%. The method possessed high analytical sensitivity and accuracy for these five aromatic DBPs in juice drinks with the aid of the efficient M-SPE technology proposed.

Discrimination and characterization of volatile organic compounds in Lonicerae Japonicae flos and Lonicerae flos using multivariate statistics combined with headspace gas chromatography-ion mobility spectrometry and headspace solid-phase microextraction gas chromatography-mass spectrometry techniques

RATIONALE

The volatile organic compounds (VOCs) of Lonicerae Japonicae flos (LJF) and Lonicera flos (LF) play a pivotal role in determining their sensory characteristics, medicinal properties, and subsequent impact on market pricing and consumer preferences. However, the differences and specificity of these VOCs remain obscure. Hence, it is crucial to conduct a comprehensive characterization of the VOCs in LJF and LF and pinpoint their potential differential VOCs.

METHODS

In this study, headspace gas chromatography-ion mobility spectrometry (HS-GC/IMS) and headspace solid-phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC/MS) were employed to comprehensively investigate the compositional characteristics and distinctions in VOCs between LJF and LF. Multivariate statistical analysis was used to identify candidate differential VOCs of LJF and LF samples.

RESULTS

A total of 54 and 88 VOCs were identified using HS-GC/IMS and HS-SPME-GC/MS analysis, respectively. Primary VOCs detected in LJF include leaf alcohol, (E)-2-hexen-1-ol dimer, 2-octyn-1-ol, and (E)-3-hexen-1-ol. Key VOCs prevalent in LF encompass farnesol, heptanoic acid, octanoic acid, and valeric acid. Multivariate statistical analysis indicates that compounds such as phenethyl alcohol and leaf alcohol were selected as potential VOCs for distinguishing between LJF and LF.

CONCLUSION

This research conducted a comprehensive analysis of the fundamental volatile components in both LJF and LF. It subsequently elucidated the distinctions and specificities within their respective VOC profiles. And this study enables differentiation between LJF and LF through the analysis of VOCs, offering valuable insights for enhancing the quality control of both LJF and LF.

Preparation and application of an imidazolium-based poly (ionic liquid) functionalized silica sorbent for solid-phase extraction of parabens from food samples

In this work, an imidazolium-based poly (ionic liquid) (poly(1-octyl-3-vinyl- imidazolium naphthalene sulfonate)) functionalized silica (poly(C8VIm+NapSO3-) @SiO2) was successfully prepared for the determination of parabens in food samples. The prepared poly(C8VIm+NapSO3-)@SiO2 was characterized by Fourier transform infrared spectrometry (FT-IR), X-ray photoelectron spectrogram (XPS) and Scanning electron microscopy (SEM). The simulation calculation results indicated that the suitable binding energies were between the polymeric ionic liquids and parabens, and the main interactions for extraction were hydrogen bonding, electrostatic and π-π stacking interactions. In addition, compared with commercial extraction materials, the prepared poly(C8VIm+NapSO3-)@SiO2 sorbent showed comparable or even better extraction performance towards parabens. The effective parameters were optimized by a combination of the univariate method and Box-Behnken design (BBD). Under the optimum conditions, coupled with high performance liquid chromatography (HPLC), wide linear ranges (1.0-800 μg L-1), good linearity (R2 ≥ 0.9997) and low limits of detection (0.1 μg L-1) were obtained. In addition, the intra-day and inter-day relative standard deviations (RSDs) were all lower than 6.3%. Moreover, the proposed method was successfully used for the determination of parabens in food samples and satisfactory recoveries in the range of 76.9-97.4% were obtained. The results indicated that the proposed method had good sensitivity, accuracy and precision for the detection of parabens in food samples.