Electrical asymmetrical flow field-flow fractionation: Fundamentals, evolution, applications, and prospects.

Among the plethora of techniques that conforms the Field-Flow Fractionation (FFF) family, electrical field-flow fractionation (ElFFF) was designed to separate different analytes based on their size and electrophoretic mobility (µ). However, major technical and operational issues made this technique to fall into oblivion. Many of those drawbacks can be circumvented if another field is employed as the main driving force for the elution in the same channel, such as the most successful and useful FFF-related technique, asymmetrical flow field-flow fractionation (AF4).

Critical evaluation of key parameters in single particle ICP-MS data processing for the correct determination of platinum nanoparticles in complex environmental and biological matrices.

There is an urgent need for the harmonization of critical parameters in single particle inductively coupled plasma mass spectrometry (SP-ICP-MS) and they have been deeply studied and optimized in the present work using platinum nanoparticles (PtNPs) as a representative case of study. Special attention has been paid to data processing in order to achieve an adequate discrimination between signals. Thus, a comparison between four different algorithms has been performed and the method for transport efficiency calculation has also been thorougly evaluated (finding the use of a well-characterized solution of the same targeted analyte (30 nm PtNPs) as adequate).

Assessment by a multi-technique approach of PtNPs' transformations in waters under relevant environmental concentrations and conditions.

Once released to the environment, platinum nanoparticles (PtNPs) can undergo different transformations and are affected by several environmental conditions. An only analytical technique cannot provide all the information required to understand those complex processes, so new analytical developments are demanded. In the present work, the potential of asymmetric flow field flow fractionation hyphenated to inductively coupled plasma mass spectrometry (AF4-ICP-MS) for these studies, has been investigated, and classical dynamic and electrophoretic light scattering (DLS & ELS) have been used as complementary techniques.

A method based on asymmetric flow field flow fractionation hyphenated to inductively coupled plasma mass spectrometry for the monitoring of platinum nanoparticles in water samples.

An analytical methodology based on asymmetric flow field flow fractionation hyphenated to inductively coupled plasma mass spectrometry (AF4-ICP-MS) has been developed for monitoring citrate coated platinum nanoparticles (PtNPs) of different sizes (5, 30, and 50 nm) in water samples. Several factors have been optimized, such as carrier composition, AF4 separation program, focusing step or cross flow values. Under the optimum conditions, PtNPs can be fractionated in about 30 min in a single run with quantitative recoveries of the membrane (100 ± 7%, n = 5).

Analytical strategy based on asymmetric flow field flow fractionation hyphenated to ICP-MS and complementary techniques to study gold nanoparticles transformations in cell culture medium.

An analytical methodology based on asymmetric flow field flow fractionation (AF4) hyphenated to inductively coupled plasma mass spectrometry (ICP-MS) has been developed to study gold nanoparticles (AuNPs) in cell culture medium (Dulbecco's Modified Eagle Medium, DMEM, containing 10% fetal bovine serum, FBS, and antibiotics) used for in vitro toxicological studies. AF4-ICP-MS separation of AuNPs was performed using a regenerated cellulose membrane (molecular weight cut-off, MWCO, of 10 kDa). The carrier composition and the AF4 separation program were optimized.

Methodology for monitoring gold nanoparticles and dissolved gold species in culture medium and cells used for nanotoxicity tests by liquid chromatography hyphenated to inductively coupled plasma-mass spectrometry.

An analytical methodology based on coupling reversed-phase liquid chromatography (HPLC) to an inductively coupled plasma mass spectrometry (ICP-MS) has been developed for the characterization and identification of gold nanoparticles (AuNPs) and gold dissolved species (Au) in culture medium (Dulbecco's Modified Eagle Medium, DMEM) and HeLa cells (a human cervical adenocarcinoma cell line) used in nanotoxicity tests. The influence of the culture medium was also studied and the method applied for nanotoxicity tests. It was also observed that AuNPs can undergo an oxidation process in the supernatants and only a small amount of AuNPs and dissolved Au was associated with cells.

Mercury and selenium binding biomolecules in terrestrial mammals (Cervus elaphus and Sus scrofa) from a mercury exposed area.

Mercury (Hg) is likely bound to large biomolecules (e.g. proteins) in living organisms, and in order to assess Hg metabolic pathways and possible toxicological effects, it is essential to study these Hg containing biomolecules.

Comparison of gas chromatographic hyphenated techniques for mercury speciation analysis.

In this study, we evaluate advantages and disadvantages of three hyphenated techniques for mercury speciation analysis in different sample matrices using gas chromatography (GC) with mass spectrometry (GC-MS), inductively coupled plasma mass spectrometry (GC-ICP-MS) and pyrolysis atomic fluorescence (GC-pyro-AFS) detection. Aqueous ethylation with NaBEt(4) was required in all cases. All systems were validated with respect to precision, with repeatability and reproducibility <5% RSD, confirmed by the Snedecor F-test.

Multiresidue determination of organochlorines in fish oil by GC-MS: a new strategy in the sample preparation.

A rapid, economic and environmentally friendly analytical methodology has been implemented for the determination of alpha-, beta-, gamma- and delta-HCH, p,p'-DDT, p,p'-DDD and p,p'-DDE, PCBs congeners #28, #52, #101, #153, #138 and #180 and Hexachlorobenzene in fish oil. 1,2,3,4-Tetrachloronaphtalene was used as internal standard. The sample preparation, consisting of a single step of clean-up and fractionation, took place in a column filled with different layers of neutral and sulphuric acid modified silica.