Perspective: What constitutes a quality paper in atomic spectrometry

Quality papers are essential for scientific dissemination as well as to instigate new researches in the field. This corollary also applies to atomic spectrometry, which has experienced amazing developments in concepts, instruments, and applications. This article highlights the main characteristics expected in a quality paper overall and particularly in atomic spectrometry. The aim is to bring guidelines for research students, newcomers in the field, and practicing chemists

An overview of the Brazilian contributions to Green Analytical Chemistry

Abstract: Green Analytical Chemistry (GAC) is a research field that seeks for more sustainable analytical approaches to minimize the toxicity and amounts of wastes without hindering the analytical performance. This is a trend in Analytical Chemistry worldwide and because of the diversity of innovations on this subject, Brazil stands out as the third in the list of the main contributors to GAC, with ca. 11.2% of the published articles. Significant innovations and interesting applications in several fields have been presented and Brazil is continuously moving from Chemistry to Green Chemistry also in the Analytical Chemistry field. Selected contributions for sample preparation, spectro- and electroanalysis, separation techniques, chemometrics, and also procedures for point-of-care measurements are critically reviewed

Salt-assisted liquid-liquid extraction and on-column concentration for chromatographic determination of phenolic compounds in beer

Salt-assisted liquid-liquid extraction (SALLE) and on-column concentration were evaluated to simplify the chromatographic determination of phenolic compounds in beer. Resveratrol, flavonoids (quercetin and kaempferol), and phenolic acids (caffeic, p-coumaric, and trans-ferulic acids) were used as model compounds based on their concentrations reported in craft beers. SALLE with acetonitrile was effective for sample cleanup, with recoveries ranging from 84 % to 112 %. The on-column concentration was carried out in high performance liquid chromatography by starting the gradient elution with acidified water (sample carrier stream) in a reversed-phase mode. Consequently, the analytes were retained in a narrow band, and highly polar/ionic potentially interfering species were flushed from the column. The effectiveness of the approach was demonstrated by linear correlations between the peak areas and the injected volumes from 10 to 200 µL (r ≥ 0.999), without significant variations in peak width ( 0.999), with limits of detection within the range of 9–82 µg L−1. The approach was also effective for on-column concentrations of resveratrol, quercetin, and kaempferol in sequential injection chromatography (SIC), with injected volumes up to 750 µL and linear responses within 100–1000 µg L−1 (r > 0.997). The proposal reduced consumption of organic solvents (with only 770 µL required per determination in SIC) and avoided solid-phase extraction cartridges for analyte preconcentration

Influence of Na, K, Ca and Mg on lead atomization by tungsten coil atomic absorption spectrometry

A atomização de chumbo em atomizador eletrotérmico de filamento de tungstênio, na presença e ausência de altas concentrações de Na+, K+, Ca2+ e Mg2+, foi investigada com o objetivo de entender os processos de interferências. A atomização do chumbo foi menos comprometida por Ca2+ e Mg2+ do que por Na+ e K+. Na ausência dos concomitantes, a eficiência da atomização de chumbo foi melhorada com a presença de H2 (10% v/v) na composição do gás de purga, durante as etapas de pirólise e atomização. As interferências causadas por Na+ e Ca2+ foram desprezíveis quando a etapa de pirólise foi realizada sem o H2 na composição do gás de purga. Os resultados mostraram que Na+, K+, Ca2+ e Mg2+ podem estar diretamente envolvidos nas reações de competição pelo H2 nos processos em fase condensada.The atomization of lead in an electrothermal tungsten coil atomizer in the presence and absence of Na+, K+, Ca2+ and Mg2+ was investigated with the objective of understanding the interference processes. The lead atomization was less affected by Ca2+ and Mg2+ than by Na+ and K+. In the absence of concomitants, lead atomization efficiency was improved by the presence of H2 (10% v/v) in the purge gas composition, during pyrolysis and atomization steps. The interference caused by Na+ and Ca2+ was negligible when the pyrolysis step was accomplished without H2 in the purge gas composition. The results showed that Na+, K+, Ca2+ and Mg2+ are directly involved in competition reactions for H2 in condensed phase

Solid-phase extractions in flow analysis

ABSTRACT Coupling solid-phase extraction (SPE) to flow systems has promoted a synergistic development. Whereas SPE mechanization leads to improved precision and higher sample throughput, as well as diminishes systematic errors and contamination risks, analyte concentration and separation from the sample matrix provides a remarkable impact on detectability and selectivity in flow analysis. Historical aspects, main cornerstones, tips for system design, and recent applications are critically reviewed, in the context of analyte(s) separation/concentration, sample clean-up, and release of sorbed chemical species involving both packed (e.g. mini-columns, cartridges, and disks) or fluidized (e.g. beads and magnetic materials) particles. Novel (bio)sorbents, selective synthetic materials, and stationary phases for low-pressure chromatography are also discussed. Moreover, the feasibility of SPE for sample treatment before chromatographic separation, as well as the exploitation of direct measurements on the solid phase (optosensing) are emphasized

Solid-phase extractions in flow analysis

<div><p>ABSTRACT Coupling solid-phase extraction (SPE) to flow systems has promoted a synergistic development. Whereas SPE mechanization leads to improved precision and higher sample throughput, as well as diminishes systematic errors and contamination risks, analyte concentration and separation from the sample matrix provides a remarkable impact on detectability and selectivity in flow analysis. Historical aspects, main cornerstones, tips for system design, and recent applications are critically reviewed, in the context of analyte(s) separation/concentration, sample clean-up, and release of sorbed chemical species involving both packed (e.g. mini-columns, cartridges, and disks) or fluidized (e.g. beads and magnetic materials) particles. Novel (bio)sorbents, selective synthetic materials, and stationary phases for low-pressure chromatography are also discussed. Moreover, the feasibility of SPE for sample treatment before chromatographic separation, as well as the exploitation of direct measurements on the solid phase (optosensing) are emphasized.</p></div