Ultra-sensitive Sb speciation analysis in water samples by magnetic ionic liquid dispersive liquid-liquid microextraction and multivariate optimization

Coupling ozone-based AOPs with DLLME for simultaneous determination of trace free antimony and total antimony in surface water

The traditional standard method for the determination of the heavy metal pollutant antimony (Sb) in water, 5-Br-PADAP spectrophotometry, involves the consumption of many kinds of chemical reagents and has low sensitivity. For highly toxic liquid and gas containing Sb(iii), this paper presents a green determination method based on UV/O3 synergistic oxidation-malachite green-dispersive liquid-liquid microextraction (DLLME)-spectrophotometry, which can achieve the enrichment of a trace amount of antimony in water and high-precision detection. Using the selective complexation and color development of protonated alkaline dye and the solubility difference of the complexes involved, an enrichment and determination method for trace Sb(v) in surface water was established for the first time. Based on the feature of the UV/O3 system of rapid and complete oxidation of Sb(iii), and the easy elimination of the disturbance of residual oxidant, the green determination method for trace total antimony (TSb) was constructed based on advanced oxidation processes (AOPs). To verify the validity of the proposed method, all the process parameters and environmental factors affecting the oxidation efficiency of Sb(iii) and the enrichment performance of DLLME were investigated and optimized. The results showed that the proposed method exhibited good linearity (R 2 = 0.9943), a low method detection limit (MDL = 0.3208 μg L-1), and high precision (1.63%) and accuracy (0.64%) in the range of 1-30 μg L-1, under the optimized process conditions. By the difference method, the trace free antimony (Sb(iii), Sb(v)) and total antimony (TSb) can be determined simultaneously.

On-site monitoring of dissolved Sb species in natural waters by an automatic system using flow injection coupled with hydride generation atomic fluorescence spectrometer

Antimony (Sb) is a toxic and potentially carcinogenic element in the environment. The toxicity of Sb(III) is ten times that of Sb(V). Therefore, on-site monitoring technique for dissolved Sb species is crucial for the study of Sb environmental processes. In this study, an automated, portable, and cost-effective system was developed for field simultaneous analysis of Sb(III) and Sb(III + V) in natural waters. The system comprised a portable atomic fluorescence spectrometer equipped with a built-in electrochemical H2 generator to reduce the consumption of acid/borohydride solution and make the atomizer more stable for on-site analysis. Flow injection technique was also used to achieve on-line pretreatment of water samples, including filtration, acidification, pre-reduction, and hydride generation procedures. Under the optimal conditions, the limits of detection (3σ, n = 11) of the developed method were 0.015 μg/L and the linear ranges were 0.05-5.0 μg/L for both Sb(III) and Sb(III + V). The relative standard deviations (n = 11) of the spiked samples of Sb(V) were 3.2% (0.05 μg/L), 3.3% (0.2 μg/L), and 1.7% (0.5 μg/L), respectively. The spiked recoveries of lake water, treated wastewater, and seawater ranged from 97.0% to 108.5%. The novel system of flow injection coupled with hydride generation atomic fluorescence spectrometer (FI-HG-AFS) was applied to carry out an 18-h fixed-point monitoring at a secondary settling tank of a wastewater treatment facility in Xiamen University, and a 6-h real-time underway analysis in the surface seawater of Dongshan Bay, China, proving that the system was capable of long-term monitoring in the field.

Magnetic Ionic Liquids: Current Achievements and Future Perspectives with a Focus on Computational Approaches

Magnetic ionic liquids (MILs) stand out as a remarkable subclass of ionic liquids (ILs), combining the desirable features of traditional ILs with the unique ability to respond to external magnetic fields. The incorporation of paramagnetic species into their structures endows them with additional attractive features, including thermochromic behavior and luminescence. These exceptional properties position MILs as highly promising materials for diverse applications, such as gas capture, DNA extractions, and sensing technologies. The present Review synthesizes key experimental findings, offering insights into the structural, thermal, magnetic, and optical properties across various MIL families. Special emphasis is placed on unraveling the influence of different paramagnetic species on MILs' behavior and functionality. Additionally, the Review highlights recent advancements in computational approaches applied to MIL research. By leveraging molecular dynamics (MD) simulations and density functional theory (DFT) calculations, these computational techniques have provided invaluable insights into the underlying mechanisms governing MILs' behavior, facilitating accurate property predictions. In conclusion, this Review provides a comprehensive overview of the current state of research on MILs, showcasing their special properties and potential applications while highlighting the indispensable role of computational methods in unraveling the complexities of these intriguing materials. The Review concludes with a forward-looking perspective on the future directions of research in the field of magnetic ionic liquids.

A new magnetic ionic liquid based salting-out assisted dispersive liquid-liquid microextraction for the determination of parabens in environmental water samples

In this study, a new magnetic ionic liquid (MIL) was designed and prepared, containing a magnetic cation from the ligand N,N-dimethyl biguanide (DMBG) complexing with magnetic center Co²⁺ and a bis-trifluoromethanesulfonimide (NTf₂^-) anion. Using the MIL as the extraction solvent, a salting-out assisted dispersive liquid-liquid microextraction (SA-DLLME) combined with high performance liquid chromatography-ultraviolet detection (HPLC-UV) was established for the enrichment and detection of four parabens in environmental water samples. The one-factor-at-a-time experiment was employed to optimize the conditions affecting the extraction efficiency. Under the optimized extraction conditions, the limits of quantification (LOQs) of the four target analytes ranged from 2.0 ng mL^-1 to 2.8 ng mL^-1, and the coefficients of determination (R²) were above 0.9996 in the linear range of 2.8-400 ng mL^-1. On the other hand, the method displayed good repeatability and accuracy with intra-day and inter-day relative standard deviations (RSDs) of 2.1-13.0% and recoveries of 82.0-114.6%. The established method was applied to real samples with recoveries within 81.6-125.4%, and the results demonstrated that the method was practical.

Elemental Speciation Analysis in Environmental Studies: Latest Trends and Ecological Impact

Speciation analysis is a key aspect of modern analytical chemistry, as the toxicity, environmental mobility, and bioavailability of elemental analytes are known to depend strongly on an element’s chemical species. Henceforth, great efforts have been made in recent years to develop methods that allow not only the determination of elements as a whole, but also each of its separate species. Environmental analytical chemistry has not ignored this trend, and this review aims to summarize the latest methods and techniques developed with this purpose. From the perspective of each relevant element and highlighting the importance of their speciation analysis, different sample treatment methods are introduced and described, with the spotlight on the use of modern nanomaterials and novel solvents in solid phase and liquid-liquid microextractions. In addition, an in-depth discussion of instrumental techniques aimed both at the separation and quantification of metal and metalloid species is presented, ranging from chromatographic separations to electro-chemical speciation analysis. Special emphasis is made throughout this work on the greenness of these developments, considering their alignment with the precepts of the Green Chemistry concept and critically reviewing their environmental impact.

Magnetic Ionic Liquids in Sample Preparation: Recent Advances and Future Trends

In the last decades, a myriad of materials has been synthesized and utilized for the development of sample preparation procedures. The use of their magnetic analogues has gained significant attention and many procedures have been developed using magnetic materials. In this context, the benefits of a new class of magnetic ionic liquids (MILs), as non-conventional solvents, have been reaped in sample preparation procedures. MILs combine the advantageous properties of ionic liquids along with the magnetic properties, creating an unsurpassed combination. Owing to their unique nature and inherent benefits, the number of published reports on sample preparation with MILs is increasing. This fact, along with the many different types of extraction procedures that are developed, suggests that this is a promising field of research. Advances in the field are achieved both by developing new MILs with better properties (showing either stronger response to external magnetic fields or tunable extractive properties) and by developing and/or combining methods, resulting in advanced ones. In this advancing field of research, a good understanding of the existing literature is needed. This review aims to provide a literature update on the current trends of MILs in different modes of sample preparation, along with the current limitations and the prospects of the field. The use of MILs in dispersive liquid–liquid microextraction, single drop microextraction, matrix solid-phase dispersion, etc., is discussed herein among others.

Amine functionalized polyacrylonitrile fibers for the selective preconcentration of trace metals prior to their on-line determination by ICP-MS

Amine functionalized polyacrylonitrile fibers (PANFs) were prepared and applied for the simultaneous separation and preconcentration of V(v), As(iii), Sn(iv), Sb(iii) and Bi(ii) from environmental water samples in this paper. The functional PANFs were first prepared by nucleophilic substitution reaction between hydroxylamine hydrochloride and polyacrylonitrile fibers, and then the reactant obtained in the first step was subjected to a ring opening reaction with epichlorohydrin, followed by modification with triethylenetetramine (TETA). The structure of the final polymer fibers was analyzed by Fourier transform infrared spectroscopy (FT-IR), and the morphology was characterized by scanning electron microscopy (SEM). A home-made solid phase extraction (SPE) pretreatment column was filled with PANFs, and then online connected with inductively coupled plasma mass spectrometry (ICP-MS) for quantitative determination of metal ions. Under the optimized experimental conditions, the target metal ions were eluted rapidly and quantitatively using 0.3 mol L-1 HNO3 solution. Only with 30 mL sample solution, high enrichment factors of 120 were obtained for V(v), As(iii), Sn(iv) and Sb(iii), and 115 for Bi(ii), respectively. The detection limits achieved were low: 1.2, 0.9, 1.7, 1.5 and 2.3 ng L-1 for V(v), As(iii), Sn(iv), Sb(iii) and Bi(ii), respectively, and the relative standard deviations (RSDs) were below 3.0%. The advanced fiber materials prepared in this work have the advantages of low cost, environmental friendliness and high adsorption efficiency, and the on-line preconcentration method has greatly improved the analysis efficiency. Finally, the feasibility and accuracy of the method were validated by successfully analyzing Certified Reference Materials (CRMs) as well as lake, river and sea water samples.