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Journal ArticleDOI: 10.1039/D0AY02276D

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

04 Mar 2021-Analytical Methods (The Royal Society of Chemistry)-Vol. 13, Iss: 8, pp 1033-1042
Abstract: Efficient separation and preconcentration of inorganic Sb species in different water samples were performed in this work by a novel dispersive liquid-liquid microextraction (DLLME) method based on the application of a magnetic ionic liquid (MIL) and electrothermal atomic absorption spectroscopy (ETAAS) detection. The Sb(iii) species was selectively extracted by complexation with ammonium diethyldithiophosphate (DDTP) and 45 μL of the MIL trihexyl(tetradecyl)phosphonium tetrachloroferrate ([P6,6,6,14]FeCl4) as extractant. Subsequently, a magnetic rod was applied for phase separation, introducing it directly into the sample solution, and the MIL phase was then diluted in chloroform. Afterwards, 15 μL of this solution was injected into the graphite furnace of ETAAS for Sb determination. A multivariate study was performed to obtain the optimal extraction conditions. Selective reduction of Sb(v) to Sb(iii) with 1% (w/v) KI before preconcentration was applied for total inorganic Sb determination and Sb(v) concentration was calculated by subtraction. The analytical performance of the method included extraction efficiencies of 98.0% for Sb(iii) and 92.6% for Sb(v), LOD of 0.02 μg L-1 for Sb(iii) and relative standard deviations of 3.1% for Sb(iii) and 3.5% for Sb(v) (at 6 μg L-1 Sb(iii) and Sb(v), n = 10). The calibration linear range was 0.08-20 μg L-1. The results showed that the proposed methodology was highly sensitive and selective for Sb speciation analysis in tap, dam, mineral, wetland, underground, rain and river water samples.

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Topics: Magnetic ionic liquid (51%)

5 results found

Open accessJournal ArticleDOI: 10.1016/J.TRAC.2021.116398
Abstract: This work has been supported by Spanish Ministry of Economy and Competitiveness through the research project PGC2018- 101894-B-I00. BHS also thanks the Spanish Ministry of Education, Culture and Sports for the pre-doctoral grant FPU15/03924 and the University of Cadiz for the post-doctoral grant 2019-011/PU/ AY.PUENTE/CD.

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2 Citations

Journal ArticleDOI: 10.1039/D1AY00511A
Xiaoyu Jia1, Jun-Yi Zhao1, Jia-Ni Wang1, Hongyun Ren1  +2 moreInstitutions (1)
10 Jun 2021-Analytical Methods
Abstract: 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.

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Topics: Polyacrylonitrile (52%)

Open accessJournal ArticleDOI: 10.3390/IJERPH182212135
Abstract: 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.

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Open accessJournal ArticleDOI: 10.3390/SEPARATIONS8090153
13 Sep 2021-Separations
Abstract: 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.

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33 results found

Open accessBook
01 Apr 2005-
Abstract: 1 Introduction 11 Analytical problems 12 Errors in qunatitative analysis 13 Types of error 14 Random and systematic errors in titrimetric analysis 15 Handling systematic errors 16 Planning and design of experiments 17 Calculators and computers in statistical calculations 2 Statistics of Repeated Measurements 21 Mean and standard deviation 22 The distribution of repeated measurements 23 Log-normal distribution 24 Definition of a 'sample' 25 The sampling distribution of the mean 26 Confidence limits of the mean for large samples 27 Confidence limits of the mean for small samples 28 Presentation of results 29 Other uses of confidence limits 210 Confidence limits of the geometric mean for a log-normal distribution 211 Propagation of random errors 212 Propagation of systematic errors 3 Significance Tests 31 Introduction 32 Comparison of an experimental mean with a known value 33 Comparison of two experimental means 34 Paired t-test 35 One-sided and two-sided tests 36 F-test for the comparison of standard deviations 37 Outliers 38 Analysis of variance 39 Comparison of several means 310 The arithmetic of ANOVA calculations 311 The chi-squared test 312 Testing for normality of distribution 313 Conclusions from significance tests 314 Bayesian Statistics 4 The Quality of Analytical Measurements 41 Introduction 42 Sampling 43 Separation and estimation of variances using ANOVA 44 Sampling strategy 45 Quality control methods - Introduction 46 Stewhart charts for mean values 47 Stewhart charts for ranges 48 Establishing the process capability 49 Average run length: cusum charts 410 Zone control charts (J-charts) 411 Proficiency testing schemes 412 Method performance studies (collaborative trials) 413 Uncertainty 414 Acceptable sampling 415 Method validation 5 Calibration Methods in Instumental Analysis 51 Introduction: instrumentational analysis 52 Calibration graphs in instrumental analysis 53 The product-moment correlation coefficient 54 The line of regression of y on x 55 Errors in the slope and intercept of the regression line 56 Calculation of a concentration and its random error 57 Limits of detection 58 The method of standard additions 59 Use of regression lines for comparing analytical methods 510 Weighted regression lines 511 Intersection of two straight lines 512 ANOVA and regression calculations 513 Curvilinear regression methods - Introduction 514 Curve fitting 515 Outliers in regression 6 Non-parametric and Robust Methods 61 Introduction 62 The median: initial data analysis 63 The sign test 64 The Wald-Wolfowitz runs test 65 The Wilcoxon signed rank test 66 Simple tests for two independent samples 67 Non-parametric tests for more than two samples 68 Rank correlation 69 Non-parametric regression methods 610 Robust methods: introduction 611 Simple robust methods: trimming and winsorization 612 Further robust estimates of location and spread 613 Robust ANOVA 614 Robust regression methods 615 Re-sampling statistics 616 Conclusions 7 Experiimental Design and Optimization 71 Introduction 72 Randomization and blocking 73 Two-way ANOVA 74 Latin squares and other designs 75 Interactions 76 Identifying the important factors: factorial designs 77 Fractional factorial designs 78 Optimization: basic principles and univariate methods 79 Optimization using the alternating variable search method 710 The method of steepest ascent 711 Simplex optimization 712 Simulated annealing 8 Multivariate Analysis 81 Introduction 82 Initial analysis 83 Prinicipal component analysis 84 Cluster analysis 85 Discriminant analysis 86 K-nearest neighbour method 87 Disjoint class modelling 88 Regression methods 89 Multiple linear regression 810 Principal component regression 811 Partial least squares regression 812 Natural computation methods artificial neural networks 813 Conclusions Solutions to Exercises Appendix 1 Commonly used statistical significance tests Appendix 2 Statistical tables Index

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Topics: Robust regression (64%), Segmented regression (63%), Unit-weighted regression (63%) ... show more

3,666 Citations

Journal ArticleDOI: 10.1039/B711189D
Abstract: A series of ionic liquids containing different paramagnetic anions have been prepared and all show paramagnetic behavior with potential applications for magnetic and electrochromic switching as well as novel magnetic transport; also, the tetraalkylphosphonium-based ionic liquids reveal anomalous magnetic behavior.

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Topics: Magnetic ionic liquid (64%), Ionic liquid (61%), Paramagnetism (55%) ... show more

273 Citations

BookDOI: 10.1002/0470868384
20 Jun 2003-
Abstract: Different techniques and methods have been developed for (15) Cornelis, R., Crews, H., Caruso, J. and Heumann, K., Handbook of elemental speciation: Techniques and methodology, Chapter 5.9. Speciation Analysis by Electrochemical. 1.1.2 Magnetic Sector Field Devices for Elemental and Isotopic Analysis in Handbook of Elemental Speciation: Techniques and Methodology, eds. Indiana University Course C612SPECTROCHEMICAL METHODS OF (22) “Handbook of Spectroscopy (Book Review)”, Andrade, F.J., Ray, S.R., and Hieftje, Seminar: “New Techniques and Instrumentation for Elemental Speciation.”.

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164 Citations

Journal ArticleDOI: 10.1021/AC504260T
Kevin D. Clark1, Omprakash Nacham1, Honglian Yu1, Tianhao Li1  +3 moreInstitutions (1)
Abstract: DNA extraction represents a significant bottleneck in nucleic acid analysis. In this study, hydrophobic magnetic ionic liquids (MILs) were synthesized and employed as solvents for the rapid and efficient extraction of DNA from aqueous solution. The DNA-enriched microdroplets were manipulated by application of a magnetic field. The three MILs examined in this study exhibited unique DNA extraction capabilities when applied toward a variety of DNA samples and matrices. High extraction efficiencies were obtained for smaller single-stranded and double-stranded DNA using the benzyltrioctylammonium bromotrichloroferrate(III) ([(C8)3BnN+][FeCl3Br–]) MIL, while the dicationic 1,12-di(3-hexadecylbenzimidazolium)dodecane bis[(trifluoromethyl)sulfonyl]imide bromotrichloroferrate(III) ([(C16BnIM)2C122+][NTf2–, FeCl3Br–]) MIL produced higher extraction efficiencies for larger DNA molecules. The MIL-based method was also employed for the extraction of DNA from a complex matrix containing albumin, revealing a competitive...

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Topics: Extraction (chemistry) (54%), Magnetic ionic liquid (52%), Ionic liquid (51%) ... show more

147 Citations

Journal ArticleDOI: 10.1016/J.ACA.2016.06.011
Abstract: Magnetic ionic liquids (MILs) have recently generated a cascade of innovative applications in numerous areas of analytical chemistry. By incorporating a paramagnetic component within the cation or anion, MILs exhibit a strong response toward external magnetic fields. Careful design of the MIL structure has yielded magnetoactive compounds with unique physicochemical properties including high magnetic moments, enhanced hydrophobicity, and the ability to solvate a broad range of molecules. The structural tunability and paramagnetic properties of MILs have enabled magnet-based technologies that can easily be added to the analytical method workflow, complement needed extraction requirements, or target specific analytes. This review highlights the application of MILs in analytical chemistry and examines the important structural features of MILs that largely influence their physicochemical and magnetic properties.

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Topics: Paramagnetism (51%)

138 Citations