Evaluation of the QuEChERS and magnetic micro dispersive solid-phase extraction of brominated flame retardants in red fruits with determination by GC/MS

Assessing emerging and priority micropollutants in sewage sludge: environmental insights and analytical approaches

The application of sewage sludge (SS) in agriculture, as an alternative to manufactured fertilizers, is current practice worldwide. However, as wastewater is collected from households, industries, and hospitals, the resulting sludge could contaminate land with creeping levels of pharmaceuticals, pesticides, heavy metals, polycyclic aromatic hydrocarbons, and microplastics, among others. Thus, the sustainable management of SS requires the development of selective methods for the identification and quantification of pollutants, preventing ecological and/or health risks. This study presents a thorough evaluation of emerging and priority micropollutants in SS, through the lens of environmental insights, by developing and implementing an integrated analytical approach. A quick, easy, cheap, effective, rugged, and safe (QuEChERS) extraction method, coupled with gas chromatography and liquid chromatography, was optimized for the determination of 42 organic compounds. These include organophosphorus pesticides, organochlorine pesticides, pyrethroid pesticides, organophosphate ester flame retardants, polybrominated diphenyl ethers, polychlorinated biphenyls, and polycyclic aromatic hydrocarbons. The optimization of the dispersive-solid phase for clean-up, combined with the optimization of chromatographic parameters, ensured improved sensitivity. Method validation included assessments for recovery, reproducibility, limit of detection (LOD), and limit of quantification (LOQ). Recoveries ranged from 59.5 to 117%, while LODs ranged from 0.00700 to 0.271 µg g-1. Application of the method to seven SS samples from Portuguese wastewater treatment plants revealed the presence of sixteen compounds, including persistent organic pollutants. The quantification of α-endosulfan, an organochlorine pesticide, was consistently observed in all samples, with concentrations ranging from 0.110 to 0.571 µg g-1. Furthermore, the study encompasses the analysis of agronomic parameters, as well as the mineral and metal content in SS samples. The study demonstrates that the levels of heavy metals comply with legal limits. By conducting a comprehensive investigation into the presence of micropollutants in SS, this study contributes to a deeper understanding of the environmental and sustainable implications associated with SS management.

Research progress of applications for nano-materials in improved QuEChERS method

The quick, easy, cheap, effective, rugged, and safe (QuEChERS) approach is widely used in sample pretreatment in agricultural products, food, environment, etc. And nano-materials are widely used in QuEChERS method due to its small size and large specific surface area. In this review, we examine the typical applications of several commonly used nano-materials in improved QuEChERS method. These materials include multi-walled carbon nanotubes (MWCNTs) and their derivatives, magnetic nanoparticles (MNPs), metal organic frameworks (MOFs), covalent organic frameworks (COFs), graphene oxide (GO), lipid and protein adsorbent (LPAS), cucurbituril (CBs), and carbon nano-cages (CNCs), and so on. The strengths and weaknesses of each nano-material are presented, as well as the challenging aspects that need to be addressed in future research. By comparing the applications and the current technology development, this review suggests utilizing artificial intelligence (AI) to screen suitable combinations of purification agents and performing virtual simulation experiments to verify the reliability of this methodology. By doing so, we aim to accelerate the development of new products and decrease the cost of innovation. It also recommends designing smarter pretreatment instruments to enhance the convenience and automation of the sample pretreatment process and reduce the margin for human error.

Graphene-Type Materials for the Dispersive Solid-Phase Extraction Step in the QuEChERS Method for the Extraction of Brominated Flame Retardants from Capsicum Cultivars

A new application of graphene-type materials as an alternative cleanup sorbent in a quick, easy, cheap, effective, rugged, and safe (QuEChERS) procedure combined with GC-ECD/GC-MS/GC-MS/MS detection was successfully used for the simultaneous analysis of 12 brominated flame retardants in Capsicum cultivar samples. The chemical, structural, and morphological properties of the graphene-type materials were evaluated. The materials exhibited good adsorption capability of matrix interferents without compromising the extraction efficiency of target analytes when compared with other cleanups using commercial sorbents. Under optimal conditions, excellent recoveries were obtained, ranging from 90 to 108% with relative standard deviations of <14%. The developed method showed good linearity with a correlation coefficient above 0.9927, and the limits of quantification were in the range of 0.35-0.82 μg/kg. The developed QuEChERS procedure using reduced graphite oxide (rGO) combined with GC/MS was successfully applied in 20 samples, and the pentabromotoluene residues were quantified in two samples.

Multiple Organic Contaminants Determination Including Multiclass of Pesticides, Polychlorinated Biphenyls, and Brominated Flame Retardants in Portuguese Kiwano Fruits by Gas Chromatography

Global production of exotic fruits has been growing steadily over the past decade and expanded beyond the originating countries. The consumption of exotic and new fruits, such as kiwano, has increased due to their beneficial properties for human health. However, these fruits are scarcely studied in terms of chemical safety. As there are no studies on the presence of multiple contaminants in kiwano, an optimized analytical method based on the QuEChERS for the evaluation of 30 multiple contaminants (18 pesticides, 5 polychlorinated biphenyls (PCB), 7 brominated flame retardants) was developed and validated. Under the optimal conditions, satisfactory extraction efficiency was obtained with recoveries ranging from 90% to 122%, excellent sensitivity, with a quantification limit in the range of 0.6 to 7.4 µg kg^-1, and good linearity ranging from 0.991 to 0.999. The relative standard deviation for precision studies was less than 15%. The assessment of the matrix effects showed enhancement for all the target compounds. The developed method was validated by analyzing samples collected from Douro Region. PCB 101 was found in trace concentration (5.1 µg kg^-1). The study highlights the relevance of including other organic contaminants in monitoring studies in food samples in addition to pesticides.

Performance comparison between solid phase extraction and magnetic carbon nanotubes facilitated dispersive-micro solid phase extractions (Mag-CNTs/d-µSPE) of a cyanide metabolite in biological samples using GC–MS

Dispersive-micro solid phase extraction (d-µSPE) has gained increasing attention due to its convenience, effectiveness, and flexibility for sorbent selection. Among a various selection of materials, magnetic carbon nanotubes (Mag-CNTs) is a promising d-µSPE sorbent with excellent separation efficiency in addition to its high surface area and adsorption capability. In this work, two different surface-modified Mag-CNTs, Mag-CNTs-COOH and Mag-CNTs-SO3H, were developed to facilitate d-µSPE (Mag-CNTs/d-µSPE). The cyanide metabolite, 2-aminothiazoline-4-carboxylic acid (ATCA), was selected to evaluate their extraction performance using gas chromatography–mass spectrometry (GC–MS) analysis. The Mag-CNTs-COOH enabled a one-step derivatization/desorption approach in the workflow; therefore, a better overall performance was achieved. Compared to the Mag-CNTs-SO3H/d-µSPE and SPE workflow, the one-step desorption/derivatization approach improved the overall extraction efficiency and reduced solvent consumption and waste production. Both Mag-CNTs/d-µSPE workflows were validated according to ANSI/ASB 036 guidelines and showed excellent analytical performances. The limit of detection (LOD) and limit of quantitation (LOQ) of ATCA in synthetic urine were 5 and 10 ng/mL, respectively, and that in bovine blood were achieved at 10 and 60 ng/mL. The SPE method’s LOD and LOQ were also determined at 1 and 25 ng/mL in bovine blood samples. The Mag-CNTs/d-µSPE methods demonstrated great potential to extract polar and ionic metabolites from biological matrices. The extraction processes of ATCA described in this work can provide an easier-to-adopt procedure for potential routine forensic testing of the stable biomarker in cyanide poisoning cases, particularly for those cases where the cyanide detection window has passed.

Preparation of Polyacrylonitrile/Ni-MOF electrospun nanofiber as an efficient fiber coating material for headspace solid-phase microextraction of diazinon and chlorpyrifos followed by CD-IMS analysis

Herein, an electrospun polyacrylonitrile/nickel-based metal-organic framework nanocomposite (PAN/Ni-MOF) coating on a stainless steel wire was synthesized and employed as a novel nanosorbent for headspace solid-phase microextraction (HS-SPME) of organophosphorus pesticides (OPPs), diazinon (DIZ), and chlorpyrifos (CPS) from the diverse aqueous media followed by corona discharge ion mobility spectrometry (CD-IMS). Under the optimum experimental conditions, the calibration plots were linear in the range of 1.0-250.0 ng mL^-1 for DIZ and 0.5-300.0 ng mL^-1 for CPS with r² > 0.999. The detection limits (S/N = 3) were 0.3 and 0.2 ng mL^-1 for DIZ and CPS, respectively. The intra-day relative standard deviations (RSDs%) (n = 5) at the concentration levels of 20.0, 40.0, and 100.0 ng mL^-1 were ≤ 5.2%. To investigate the extraction efficiency, PAN/Ni-MOF was employed to analyze various juice samples, including orange, apple, and grape juices, and in three water samples where it led to good recoveries ranged between 87% and 98%.

Greenness of magnetic nanomaterials in miniaturized extraction techniques: A review

Green analytical chemistry principles should be followed, as much as possible, and particularly during the development of analytical sample preparation methods. In the past few years, outstanding materials such as ionic liquids, metal-organic frameworks, carbonaceous materials, molecularly imprinted materials, and many others, have been introduced in a wide variety of miniaturized techniques in order to reduce the amount of solvents and sorbents required during the analytical sample preparation step while pursuing more efficient extraction methods. Among them, magnetic nanomaterials (MNMs) have gained special attention due to their versatile properties. Mainly, their ability to be separated from the sample matrix using an external magnetic field (thus enormously simplifying the entire process) and their easy combination with other materials, which implies the inclusion of a countless number of different functionalities, highly specific in some cases. Therefore, MNMs can be used as sorbents or as magnetic support for other materials which do not have magnetic properties, the latter permiting their combination with novel materials. The greenness of these magnetic sorbents in miniaturized extractions techniques is generally demonstrated in terms of their ease of separation and amount of sorbent required, while the nature of the material itself is left unnoticed. However, the synthesis of MNMs is not always as green as their applications, and the resulting MNMs are not always as safe as desired. Is the analytical sample preparation field ready for using green magnetic nanomaterials? This review offers an overview, from a green analytical chemistry perspective, of the current state of the use of MNMs as sorbents in microextraction strategies, their preparation, and the analytical performance offered, together with a critical discussion on where efforts should go.

A magnetic fluorinated multi-walled carbon nanotubes-based QuEChERS method for organophosphorus pesticide residues analysis in Lycium ruthenicum Murr

In order to meet the requirements of pesticide residues' detection in complex matrix samples, the magnetic fluorinated multi-wall carbon nanotubes (M-F-MWCNTs) were prepared and applied as new QuEChERS clean-up materials. Combined with GC-MS, an improved QuEChERS method was successfully developed for the detection of organophosphorus pesticide residues. The results showed that the M-F-MWCNTs could effectively remove the interfering substances in Lycium ruthenicum Murr. (L. ruthenicum) samples. The recoveries of 10 tested targets were 74.9% to 113.5% with the relative standard deviations (RSDs) of 3.9-14.7%. The experiment results pointed out that the M-F-MWCNTs were qualified as QuEChERS clean-up materials and expected to be applied to other complex matrix samples and pesticide targets.

Lemon juice, but not tea, reduces the glycemic response to bread in healthy volunteers: a randomized crossover trial

PURPOSE

The inhibition of enzymes that hydrolyze starch during digestion could constitute an opportunity to slow down the release, and ultimately the uptake, of starch-derived glucose. Simple dietary approaches consisting in pairing starch-rich foods with beverages that have the capacity to inhibit such enzymes could be an effective and easily implementable strategy. The objective of this work was to test the impact of black tea and lemon juice on the glycemic response to bread and subsequent energy intake in healthy adults.

METHODS

A randomized crossover study was conducted with equal portions of bread (100 g) and 250 ml of water, black tea or lemon juice. Capillary blood glucose concentrations were monitored during 180 min using the finger-prick method. Ad libitum energy intake was assessed 3 h later.

RESULTS

Tea had no effect on the glycemic response. Lemon juice significantly lowered the mean blood glucose concentration peak by 30% (p < 0.01) and delayed it more than 35 min (78 vs. 41 min with water, p < 0.0001). None of the tested beverages had an effect on ad libitum energy intake.

CONCLUSION

These results are in agreement with previous in vitro studies showing that lowering the pH of a meal can slow down starch digestion through premature inhibition of salivary α-amylase. Furthermore, the effect of lemon juice was similar to what has been repeatedly observed with vinegar and other acidic foods. Including acidic beverages or foods in starchy meals thus appears to be a simple and effective strategy to reduce their glycemic impact.

Improved QuEChERS for Analysis of Polybrominated Diphenyl Ethers and Novel Brominated Flame Retardants in Capsicum Cultivars Using Gas Chromatography

One of the main challenges for analytical laboratories and food safety authorities is the control of food contaminants hazardous to human health. For the first time, a simple, fast, and cost-effective sample preparation method is proposed as an extraction technique to determine 12 brominated flame retardants (BFRs) (seven polybrominated diphenyl ether (PBDE) congeners and five novel BFRs) in Capsicum cultivars. Different QuEChERS and dispersive solid-phase extract (d-SPE) sorbent compositions were evaluated in terms of recovery and matrix effects. The best results were obtained with citrate-buffered version QuEChERS and a cleanup step, with 150 mg of MgSO₄, 50 mg of primary secondary amine (PSA), 50 mg of C18, and 5 mg of carbon. The limit of detection (LOD) was between 1.4 and 9.3 μg/kg and R² > 0.99. Recoveries and matrix effects were between 66 and 104% and 0.58 and 2.18, respectively. The relative standard deviations from repeatability and reproducibility studies and estimation of measurement uncertainty were lower than 20%. Gas chromatography coupled with a mass spectrometer was used to confirm the presence of BFRs in the samples. Novel BFRs were detected lower than the LOD.