Miniaturized matrix solid-phase dispersion based on deep eutectic solvent and carbon nitride associated with high-performance liquid chromatography: A new feasibility for extraction and determination of trace nitrotoluene pollutants in soil samples

Determination of nitrobenzene potential genotoxic impurities in nifedipine with GC-MS

There is an increasing scientific interest in the detection of genotoxic impurities (GTIs), with nitrobenzene compounds being considered potential genotoxic impurities due to their structural alerts, which demonstrates a threat to drug safety for patient. While current reports on the detection of nifedipine impurity primarily focus on general impurities in nifedipine. In this study, an effective and simple gas chromatography-mass spectrometry (GC-MS) method was established and verified for the separation and quantification of 2-nitrotoluene, 2-nitrobenzyl alcohol, 2-nitrobenzaldehyde, 3-nitrobenzaldehyde, 4-nitrobenzaldehyde, and 2-nitrobenzyl bromide in nifedipine, which have not been previously reported. The validation of this GC-MS method was conducted following the International Conference of Harmonization (ICH) guidelines, exhibiting good linearity within the range of 2-40 μg/g and accuracy between 84.6 % and 107.8 %, the RSD% of intra-day and inter-day precision was in the range of 1.77-4.55 %, stability and robustness also met acceptance criteria. This method filled the gap in detection method for nitrobenzene compounds in nifedipine, offering a novel method and technical support for nifedipine quality control.

Miniaturized matrix solid-phase dispersion assisted by deep eutectic solvent for acrylamide determination in bread samples

Acrylamide determination is important to state its quantity in baked food preventing any potential carcinogenic effects. Matrix solid-phase dispersion (MSPD) extraction is an extraction procedure based on a homogenization phase between a solid sample and a solid dispersing material to break sample increasing analyte extraction yield, often used for acrylamide determination. The addition of a green deep eutectic solvent (DES) during the MSPD homogenization phase improves the analyte extraction, giving the possibility to reduce the amount of organic solvent used. In this work, a miniaturized MSPD extraction assisted by a DES was developed to determine acrylamide in bread, using high-performance liquid chromatography coupled with mass spectrometry detection. The optimized procedure provides 1:1 (w/w) matrix-to-dispersing material ratio, 2 mL of methanol as extraction solvent, and 50 μL of choline chloride-glycerol DES added during the homogenization phase. Method validation ensured good results with minimum recoveries of 90%, high precision with a maximum intra-day error of 4%, and inter-day error of 6%. Limit of detection and limit of quantification resulted to be 16 μg/kg and 35 μg/kg, respectively. This miniaturized extraction procedure represents a good alternative to those reported in the literature, guaranteeing great performance and respecting green chemistry principles.

Application of deep eutectic solvents on extraction of flavonoids

Deep eutectic solvents (DESs), as a new type of eco-friendly solvent, have attracted increasing attention on the extraction and separation of flavonoid compounds from various samples, owing to their excellent properties such as biodegradability and ease of handling with very low toxicity. This article provides a status review of the applications of DESs in the extraction of flavonoids, including the introduction of flavonoid compounds, the properties and superiority of DESs, and extraction methods (ultrasonic-assisted extraction, heating reflux extraction, matrix solid-phase dispersion, and solid-phase extraction). Finally, prospects and challenges in the application of DESs on extraction and separation are extensively elucidated and critically reviewed.

Critical overview on the use of hydrophobic (deep) eutectic solvents for the extraction of organic pollutants in complex matrices

During the last decades, many efforts have been devoted to the adaptation of sample preparation techniques and methods to the principles of Green Analytical Chemistry. Among them, this article review focusses on those aimed to green the solvents involved in sample treatment. Research in this field started in the late 1990s with the synthesis of room temperature ionic liquids, which were later replaced by the deep eutectic solvents (DESs). During the last years, a subclass of DESs, the so-called hydrophobic deep eutectic solvents (HDESs) have attracted attention. HDESs have contributed to circumventing some of the limitations of early-synthesised hydrophilic DESs regarding the cost of raw materials, the simplicity of synthesis, and the biocompatibility and, apparently, the biodegradability of the mixtures. In addition, these mixtures allowed the treatment of aqueous samples and the extraction of non-polar analytes. This article discusses fundamental aspects regarding the nomenclature used concerning HDESs, summarises the main physicochemical properties of these mixtures, and through discussion of key application studies, describes current progress in the use of these green solvents for the extraction of trace organic contaminants from a variety of matrices. Remaining gaps and possible lines of future development in this emerging, active and attractive research area are also identified and critically discussed.

Low transition temperature mixture-based extraction of 14 pesticides from tomato samples and their high-performance liquid chromatography-tandem mass spectrometry analysis

The extensive use of pesticides to control pest infestations has led to the development of analytical methods to determine pesticide residues in food matrices to prevent food exposure. However, most developed analytical methods do not consider impact on the environment in terms of the toxicity of the chemicals used and the amount of waste produced. An environmentally-friendly method, based on a miniaturized matrix solid-phase dispersion followed by high-performance liquid chromatography-tandem mass spectrometry, for the analysis of fourteen pesticides in tomatoes, was exploited. For the recovery of pesticides from tomato samples, a low transition temperature mixture (LTTM), containing choline chloride and sesamol 1:3 molar ratio, was employed. Extraction parameters like sample-to-dispersant ratio, extraction solvent volume and LTTM volume were optimized through a Box-Behnken design. The 1:4 sample-to-dispersant ratio, 900 µL of ethanol as extraction solvent and 50 µL of LTTM ensured the best result considering the pesticides' peak areas. The optimized analytical method was validated obtaining the following results: linearity range was between LOQ and 5 mg kg-1 with a minimum R2 of 0.9944 for tebufenozide, values in the range of 0.001-0.023 and 0.004-0.076 mg kg-1 were obtained for LOD and LOQ respectively, while peak areas intra-day and inter-day repeatability were maximum of 10.19 and 9.15 %, respectively. The analytical method was then applied to real samples studying whole, pulp and peel tomato pool. The analysis of whole and tomato pulp revealed the presence of seven and eight of the fourteen investigated pesticides, respectively. However, their concentration was lower than the limit of quantification. In tomato peel, five pesticides, namely dimethomorph, methoxyfenozide, pyraclostrobin, pyriproxyfen, and spiromesifen were quantified and their concentrations were below maximum residue levels.

Determination of tetrabromobisphenol A and its brominated derivatives in water, sediment and soil by high performance liquid chromatography-tandem mass spectrometry

Tetrabromobisphenol A (TBBPA) was typical brominated flame retardant and potential environmental endocrine disruptor, and it had persistence, bioaccumulation and chronic toxicity. Simultaneous determination of ultra-trace TBBPA, tribromobiphenol A (tri-BBPA), dibromobiphenol A (di-BBPA), monobromobisphenol A (mono-BBPA) and bisphenol A (BPA) was developed by high performance liquid chromatography-tandem mass spectrometry(HPLC-MS/MS), the parent ion charge ratios (m/z) had been optimized. The linear range was wider and the limit of detection was (LOD) 0.09 ~ 0.21 ng mL-1, which could detect trace pollutants. The extraction efficiency was improved by optimizing the parameters, HLB cartridge was used in the water sample by solid phase extraction (SPE), the recovery rates in water samples were over 80.28% with three concentration levels, the relative standard deviations (RSD) were less than 7.12%, and the minimum detection limit of the method was 0.90 ~ 2.10 × 10-3 ng mL-1. Soil and sediment samples were extracted by accelerated solvent extraction (ASE), the recovery rates in soil and sediment were over 79.40% and 75.65%, the minimum detection limit was 0.0225 ~ 0.0525 ng g-1, RSD was less than 7.19%. The proffered method was successfully utilized to detect actual samples, the residue of di-BBPA and mono-BBPA are detected in Naihe River and Shuxi River in Tai'an City, residue of di-BBPA and mono-BBPA was detected in the soil, and there was low residual amount of di-BBPA, mono-BBPA and BPA in the sediment of Shuxi River.

Chemical reduction as a facile colorimetric approach for selective TNT detection by spectrophotometry and photothermal lens spectroscopy

In this study, the simple determination of TNT is achieved through the vivid stable red color products generated after chemically reduction by NaBH₄ as a common and accessible reducing/colorimetric reagent. Some other nitroaromatics were impressed under reduction reaction and led to the colorful products. The color of these reduced nitroaromatics were unstable and approximately vanished after some few minutes which ameliorated the selectivity in TNT determination. Utilizing the time-dependent selectivity, the method was applied specifically for discriminating of TNT from other nitroaromatic compounds (NACs). UV-vis spectrophotometry and photothermal lens spectrometry were employed as detection techniques. The former was simpler and more available in various laboratories while the latter provides higher sensitivity. It was revealed that the photothermal lens responses were linear from 2.0 to 55.0 nM with a limit of detection (LOD) of about 0.8 nM. The LOD of the photothermal lens measurement were found to be 241 times lower than that of the UV-vis spectrophotometry in TNT quantification. The evolved method was successfully carried out for TNT vapor determination after trapping into the colorimetric reagent. The recoveries and relative standard deviations (RSD, n = 3) calculated for 3 gas samples were ≥91% and ≤7%, respectively.

Nanographite-assisted matrix solid phase dispersion microextraction of active and toxic compounds from complex food matrices using cyclodextrin aqueous solution as elution solvent

In this study, a cyclodextrin aqueous solution was used as an environmentally friendly eluent to simultaneously extract active and toxic compounds from food matrices with the aid of nanographite-assisted matrix solid phase dispersion microextraction (NG-MSPDM). The NG-MSPDM procedure was optimized by single-factor experiments and response surface methodology to obtain optimum conditions. The proposed method achieved excellent linearity at 0.10-20 μg/mL for all target analytes with a coefficient of correction (R²) ≥ 0.9909, limits of detection < 52.01 ng/mL, satisfactory reproducibility below 3.21 %, and acceptable recoveries of 82.0-112 %. To accurately determine the target components in the complex matrix, collision cross-section values of the analytes were obtained using ion mobility quadrupole time-of-flight mass spectrometry (IM-Q-TOF/MS). Results indicated that the NG-MSPDM method successfully achieved the simultaneous extraction of flavonoids and phenoxyacetic herbicides from Alpinia officinarum.

Miniaturized ternary deep eutectic solvent-based matrix solid-phase dispersion: A green sample preparation method for the determination of chlorophenols in river sediment

New ternary deep eutectic solvents were prepared and applied as efficient green dispersing solvents in miniaturized matrix solid-phase dispersion to extract chlorophenols from river sediments for the first time. High-performance liquid chromatography coupled with a photodiode array detector was used to analyze the target analytes. The significant factors affecting the extraction were optimized as follows: dispersant (100 mg), sample (100 mg), ternary eutectic solvents (150 μl), grinding for 1 min, 450 μl of acetonitrile as the elution solvent, and vortex mixing for 20 s. Under the optimal conditions, the method exhibited excellent linearity (correlation coefficient > 0.9980), low limits of detection between 1.039-2.478 μg/g, and extraction recoveries between 93.9% and 99.2%. Furthermore, the method demonstrated excellent precision in the intra- and inter-day analysis with a relative standard deviation below 6%. When compared to conventional extraction techniques, the miniaturized matrix solid-phase dispersion considerably reduced samples and solvent usag, offering important environmental benefits. The green profile of the method was assessed using the complementary green analytical procedure index tool confirming its eco-friendship. The technique was finally employed to evaluate sediment samples from three distinct locations along the Zuibaiji River, indicating its applicability for monitoring environmental samples.

Silica gel impregnated with deep eutectic solvent-based matrix solid-phase dispersion followed by high-performance liquid chromatography for extraction and detection of triazine herbicides in brown sugar

A novel method was developed to determine six triazine herbicides from brown sugar samples using matrix solid-phase dispersion (MSPD) based on silica gel impregnated with deep eutectic solvent (DES) followed by high-performance liquid chromatography with photodiode array detector (HPLC/PDA). Several factors involved in the MSPD procedure such as DES type, DES content in impregnated silica gel, adsorbent-to-sample mass ratio, type and volume of washing solvent, type and volume of eluent, and grinding time were screened using single-factor experiments and then optimized using Box-Behnken design to accomplish the highest recoveries. The above method demonstrated a good linear range (20-1000 μg kg^-1) with a determination coefficient exceeding 0.9962, low limits of determination (1.59-3.77 μg kg^-1), acceptable limits of quantifications, and acceptable spiking recoveries (95.0-101.7%) for six triazines under optimized conditions. The proposed MSPD-HPLC/PDA method is a convenient, effective, and sensitive method for rapidly isolating and quantifying six triazines from brown sugar.

A cartridge-based device for automated analyses of solid matrices by online sample prep-capillary LC-MS/MS

Sample preparation is an essential step focused on eliminating interfering compounds while pre-concentrating the analytes. However, its multiple steps are laborious, time-consuming, and a source of errors. Currently, automated approaches represent a promising alternative to overcome these drawbacks. Similarly, miniaturisation has been considered an ideal strategy for creating greener analytical workflows. The combination of these concepts is currently highly desired by analytical chemists. However, most automated and miniaturised sample preparation techniques are primarily concerned with liquid samples, while solids are frequently overlooked. We present an approach based on a cartridge packed with solids (soil samples) coupled with a capillary LC-MS, combining sample preparation and analytical steps into a unique platform. As a proof-of-concept, nine pesticides used in sugarcane crops were extracted and analysed by our proposed method. For optimisation, a fractional factorial design (2^5-1) was performed with the following variables: aqueous dilution of the sample (V₁), extraction strength (V₂), matrix washing time (V₃), extraction flow (V₄), and analytical flow (V₅). After, the most influential ones (V₁, V₂, and V₃) were taken into a central composite design (2³) to select their best values. Under optimised conditions, the method reported linear ranges between 10 and 125 ng g^-1 with R² > 0.985. Accuracy and precision were in accordance with the values established by the International Council for Harmonisation (Q2(R1)). Therefore, the proposed approach was effective in extracting and analysing selected pesticides in soil samples. Also, we carried out initial qualitative tests for pesticides in honeybees to see if there is the possibility to apply our method in other solids.

Application of Extraction and Determination Based on Deep Eutectic Solvents in Different Types of Environmental Samples

Water sources are an indispensable resource for human survival. Monitoring the pollution status of the surrounding environment is necessary to protect water sources. Research on the environmental matrix of deep eutectic solvents (DESs) has expanded rapidly because of their high extraction efficiency for various target analytes, controllable synthesis, and versatile structure. Following the synthesis of hydrophobic deep eutectic solvents (HDESs), their application in aqueous matrices broadened greatly. The present review conducted a survey on the pollutant extraction methods based DESs in environmental matrices from two aspects, application methods and matrix types; discussed the potential risk of DESs to the environment and future development trends; and provided some references for researchers to choose DES-based extraction methods for environmental research.

Establishment of Deep-Eutectic-Solvent-Assisted Matrix Solid-Phase Dispersion Extraction for the Determination of Four Flavonoids in Scutellariae Radix Based on the Concept of Quality by Design

BACKGROUND

Sample preparation is the most crucial step in analytical schemes. Micro-matrix solid-phase dispersion, as a method for microextraction of analytes, has prevailed recently for its low sample and extraction solvent consumption. However, small amounts of adsorbent or sample, or a short extraction time, always bring uncertainty to the result when using this method.

OBJECTIVE

The aim was to develop a simple and reliable method of deep-eutectic-solvent-assisted ultrasonic-synchronized matrix solid-phase dispersion microextraction for the analysis of four flavonoids in Scutellariae Radix based on the concept of quality by design.

METHOD

The ZSM-5 molecular sieve was used as a new adsorbent in the micro-matrix solid-phase dispersion process. Single-factor and Box-Behnken designs were used to construct the design space.

RESULTS

Verification of the experiment demonstrated that the design space is robust. Under optimal conditions, all analytes showed good linearity (R2 > 0.999), high reproducibility (RSD < 2.24%) and stability (RSD < 2.87%), and satisfactory recoveries (95.90-102.31%), which indicated that the established method is reliable and reproducible. Moreover, it has been successfully applied to determine the flavonoids in nine batches of Scutellariae Radix.

CONCLUSIONS

The results indicate a great potential for analyzing complicated samples especially with small amount and helping to promote the quality control of the sample preparation process for traditional Chinese medicines.

HIGHLIGHTS

A systematic approach using a facile deep-eutectic-solvent-assisted ultrasonic-synchronized matrix solid-phase dispersion extraction coupled with HPLC for the analysis of flavonoids in Scutellariae Radix has been developed based on the concept of quality by design.

An overview of surface-enhanced Raman scattering substrates by pulsed laser deposition technique: fundamentals and applications

Metallic nanoparticles (NPs), as an efficient substrate for surface-enhanced Raman scattering (SERS), attract much interests because of their various shapes and sizes. The appropriate size and morphology of metallic NPs are critical to serve as the substrate for achieving an efficient SERS. Pulsed laser deposition (PLD) is one of the feasible physical methods employed to synthesize metallic NPs with controllable sizes and surface characteristics. It has been recognized to be a successful tool for the deposition of SERS substrates due to its good controllability and high reproducibility in the manufacture of metallic NPs. This review provides an overview about the recent advances for the preparation of SERS substrates by PLD technique. The influences of parameters on the sizes and morphologies of metallic NPs during the deposition processes in PLD technique including laser output parameters, gas medium, liquid medium, substrate temperature, and properties of 3D substrate are presented. The applications of SERS substrates produced by PLD in the environmental monitoring and biomedical analysis are summarized. This knowledge could serve as a guideline for the researchers in exploring further applications of PLD technique in the production of SERS substrate.