Ultrasound leaching-dispersive liquid-liquid microextraction based on solidification of floating organic droplet for determination of polybrominated diphenyl ethers in sediment samples by gas chromatography-tandem mass spectrometry

Ultrasound-Assisted One-Pot Cloud Point Extraction for Iron Determination Using Natural Chelating Ligands from Dipterocarpus intricatus Dyer Fruit

An ultrasound-assisted, one-pot cloud point extraction was developed for the determination of iron in vegetable samples by UV-Visible spectrophotometry. This method was based on the complexation of iron with an environmentally-friendly natural chelating agent extracted from Dipterocarpus intricatus Dyer fruit at pH 5.5 in the presence of Triton X-114. Reagent extraction, complexation, and preconcentration were performed simultaneously using ultrasound-assisted extraction at 45 °C. The surfactant-rich phase was diluted with ethanol and loaded through a syringe barrel packed with cotton that acted as a filter to trap the reagent powder. Analyte-entrapped on cotton was eluted using 0.1 mol·L⁻¹ nitric acid solution. Filtrate and eluate solutions were measured absorbance of the dark-blue product at 575 nm. Influential parameters for the procedure were investigated. Under the optimum experimental conditions, the calibration curve was linear, ranging from 0.1 to 1.0 mg·L⁻¹ with r² = 0.997. Limits of detection and quantification were 0.03 and 0.09 mg·L⁻¹, respectively while precision values of intra-day and inter-day were less than 5%. Recovery at 0.5 mg·L⁻¹ ranged from 89.0 to 99.8%, while iron content in vegetable samples ranged from 2.45 to 13.36 mg/100 g. This method was cost-effective, reliable, eco-friendly, and convenient as a green analytical approach to determining iron content.

The use of ultrasound in the South Cone region. Advances in organic and inorganic synthesis and in analytical methods

In organic and inorganic synthesis and in analytical methods, an external conventional heat source is usually applied to carry out a chemical reaction at a high temperature, or an extraction procedure. In the last decades, the use of ultrasound as an alternative energy source has become an interesting field of research in these topics in the South Cone region (Argentina, Chile, Uruguay, Southern Brazil and Paraguay). For this reason, the present review, covering the period 2009 to mid-2021, is a compilation of ultrasound-assisted synthetic and analytical methodologies.

Determination of Polybrominated Diphenyl Ethers in Water Samples Using Effervescent-Assisted Dispersive Liquid-Liquid Icroextraction with Solidification of the Aqueous Phase

An effective and sensitive method is necessary for the determination of polybrominated diphenyl ethers (PBDEs) pollutants in water. In this study, effervescent-assisted dispersive liquid-liquid microextraction with solidification of the aqueous phase (EA-DLLME-SAP), followed by Gas Chromatography-Tandem Mass Spectrometry (GC-MS-MS) quantitative analysis, was established for the preconcentration and determination of PBDEs in real environmental water samples. 1,1,2,2-Tetrachloroethane was used as the extractant and directly dispersed into the water phase of the aqueous samples with the aid of a large number of carbon dioxide bubbles generated via the acid-base reaction of acetic acid and sodium bicarbonate, which did not require the use of a dispersant during the extraction process. The key factors affecting the extraction recovery were optimized, and an internal standard was used for quantitative analysis, which gave good linearity ranges of 1-100 ng·L^-1 (BDEs 28, 47, 99, and 100), 2-200 ng·L^-1 (BDEs 153, 154, and 183) and 5-500 ng·L^-1 (BDE 209) with limits of quantification in the range of 1.0-5.0 ng·L^-1. The accuracy was verified with relative standard deviations < 8.5% observed in tap, lake, river and reservoir water samples with relative recoveries ranging from 67.2 to 102.6%. The presented method contributes to the determination of PBDEs in environmental water samples.

Optimizing Mass Spectrometry Analyses: A Tailored Review on the Utility of Design of Experiments

Mass spectrometry (MS) has emerged as a tool that can analyze nearly all classes of molecules, with its scope rapidly expanding in the areas of post-translational modifications, MS instrumentation, and many others. Yet integration of novel analyte preparatory and purification methods with existing or novel mass spectrometers can introduce new challenges for MS sensitivity. The mechanisms that govern detection by MS are particularly complex and interdependent, including ionization efficiency, ion suppression, and transmission. Performance of both off-line and MS methods can be optimized separately or, when appropriate, simultaneously through statistical designs, broadly referred to as "design of experiments" (DOE). The following review provides a tutorial-like guide into the selection of DOE for MS experiments, the practices for modeling and optimization of response variables, and the available software tools that support DOE implementation in any laboratory. This review comes 3 years after the latest DOE review (Hibbert DB, 2012), which provided a comprehensive overview on the types of designs available and their statistical construction. Since that time, new classes of DOE, such as the definitive screening design, have emerged and new calls have been made for mass spectrometrists to adopt the practice. Rather than exhaustively cover all possible designs, we have highlighted the three most practical DOE classes available to mass spectrometrists. This review further differentiates itself by providing expert recommendations for experimental setup and defining DOE entirely in the context of three case-studies that highlight the utility of different designs to achieve different goals. A step-by-step tutorial is also provided.

Application of a tandem air-agitated liquid–liquid microextraction technique based on solidification of floating organic droplets as an efficient extraction method for determination of cholesterol-lowering drugs in complicated matrices

To enhance sample clean-up in dispersive liquid–liquid microextraction in complicated matrices, a low-toxicity and sensitive extraction method, tandem air-agitated liquid–liquid microextraction, based on solidification of floating organic droplets is introduced.

State of the art of environmentally friendly sample preparation approaches for determination of PBDEs and metabolites in environmental and biological samples: A critical review

Green chemistry principles for developing methodologies have gained attention in analytical chemistry in recent decades. A growing number of analytical techniques have been proposed for determination of organic persistent pollutants in environmental and biological samples. In this light, the current review aims to present state-of-the-art sample preparation approaches based on green analytical principles proposed for the determination of polybrominated diphenyl ethers (PBDEs) and metabolites (OH-PBDEs and MeO-PBDEs) in environmental and biological samples. Approaches to lower the solvent consumption and accelerate the extraction, such as pressurized liquid extraction, microwave-assisted extraction, and ultrasound-assisted extraction, are discussed in this review. Special attention is paid to miniaturized sample preparation methodologies and strategies proposed to reduce organic solvent consumption. Additionally, extraction techniques based on alternative solvents (surfactants, supercritical fluids, or ionic liquids) are also commented in this work, even though these are scarcely used for determination of PBDEs. In addition to liquid-based extraction techniques, solid-based analytical techniques are also addressed. The development of greener, faster and simpler sample preparation approaches has increased in recent years (2003-2013). Among green extraction techniques, those based on the liquid phase predominate over those based on the solid phase (71% vs. 29%, respectively). For solid samples, solvent assisted extraction techniques are preferred for leaching of PBDEs, and liquid phase microextraction techniques are mostly used for liquid samples. Likewise, green characteristics of the instrumental analysis used after the extraction and clean-up steps are briefly discussed.

Ultra-preconcentration and determination of organophosphorus pesticides in soil samples by a combination of ultrasound assisted leaching-solid phase extraction and low-density solvent based dispersive liquid–liquid microextraction

USAL-SPE-LDS-DLLME has been applied for the determination of OPPs in soil samples.

Use of microextraction by packed sorbents following selective pressurised liquid extraction for the determination of brominated diphenyl ethers in sewage sludge by gas chromatography-mass spectrometry

In this work, a method based on selective pressurised liquid extraction followed by microextraction by packed sorbents (MEPS) for the determination of brominated diphenyl ethers (BDEs) in sewage sludge is presented. The factors affecting the MEPS procedure were optimised. Acetone:water (25:75) sPLE extracts were drawn-ejected 10 times through C18 cartridges at 5 μL s(-1). The cartridge was dried five times with 250 μL of air and the BDEs were eluted at 25 μL s(-1) with 100 μL of n-hexane that were directly injected at 13 μL s(-1) in the GC-MSMS system. Under these conditions, there were no carry-over effects. The method was characterised in terms of limits of detection, repeatability, intermediate precision and accuracy. The use of MEPS for the determination of BDEs in sewage sludge means an improvement of the limits of detection due to the preconcentration and clean-up performed before the injection of the whole elute in the PTV injector. The GC-MSMS LODs (25 pg mL(-1)) were improved with MEPS to less than 3 pg mL(-1). RSD less than 7% and recovery values from 92% to 102% were shown. Finally, the method was applied to the sPLE extract analyses of sewage sludge from several wastewater treatment plants in La Rioja. To our knowledge, this is the first time that the MEPS technique has been applied to the analysis of BDEs, and the first time that it has been used for the analysis of extracts from a solid sample.

Applications of liquid-phase microextraction in the sample preparation of environmental solid samples

Solvent extraction remains one of the fundamental sample preparation techniques in the analysis of environmental solid samples, but organic solvents are toxic and environmentally harmful, therefore one of the possible greening directions is its miniaturization. The present review covers the relevant research from the field of application of microextraction to the sample preparation of environmental solid samples (soil, sediments, sewage sludge, dust etc.) published in the last decade. Several innovative liquid-phase microextraction (LPME) techniques that have emerged recently have also been applied as an aid in sample preparation of these samples: single-drop microextraction (SDME), hollow fiber-liquid phase microextraction (HF-LPME), dispersive liquid-liquid microextraction (DLLME). Besides the common organic solvents, surfactants and ionic liquids are also used. However, these techniques have to be combined with another technique to release the analytes from the solid sample into an aqueous solution. In the present review, the published methods were categorized into three groups: LPME in combination with a conventional solvent extraction; LPME in combination with an environmentally friendly extraction; LPME without previous extraction. The applicability of these approaches to the sample preparation for the determination of pollutants in solid environmental samples is discussed, with emphasis on their strengths, weak points and environmental impact.