Pressure-driven mesofluidic platform integrating automated on-chip renewable micro-solid-phase extraction for ultrasensitive determination of waterborne inorganic mercury

A flow-batch lab-in-syringe foam microextraction platform for the simultaneous preconcentration and in situ membraneless gas-liquid separation of mercury prior to cold vapor atomic absorption spectrometry

Herein, the proof-of-concept of a novel lab-in-syringe (LIS) foam microextraction platform is presented as a front-end to cold vapor atomic absorption spectrometry (CVAAS) for the simultaneous preconcentration and membraneless gas-liquid separation (GLS) of inorganic mercury in biological samples. The proposed method is based on the on-line formation of the ammonium pyrrolidine dithiocarbamate complex with mercury that was retained in the pores of polyurethane foam immobilized on the piston of the LIS system. Metal complex elution and in situ mercury vapor generation are accomplished inside the microsyringe in a flow-batch format, while the separation of vapor species is achieved via the membraneless GLS found at the top of the syringe's barrel. Under optimized operation conditions, for 90 s preconcentration time, the limit of detection was 0.02 μg L-1 and the repeatability (RSD) was 3.8% (at the 0.5 μg L-1 concentration level), within a working range extending up to 4.0 μg L-1. The practicality of the novel manifold was demonstrated using the Blue Applicability Grade Index, while the accuracy of the method was evaluated using certified reference materials and spiked samples.

Recent Developments in the Speciation and Determination of Mercury Using Various Analytical Techniques

This paper reviews the speciation and determination of mercury by various analytical techniques such as atomic absorption spectrometry, voltammetry, inductively coupled plasma techniques, spectrophotometry, spectrofluorometry, high performance liquid chromatography, and gas chromatography. Approximately 126 research papers on the speciation and determination of mercury by various analytical techniques published in international journals since 2013 are reviewed.

Flow analysis in Brazil: contributions over the last four decades

Timeline with the main contributions of Brazilian researchers to flow analysis.

On-line sample processing involving microextraction techniques as a front-end to atomic spectrometric detection for trace metal assays: a review

Within the last decade, liquid-phase microextraction (LPME) and micro-solid phase extraction (μSPE) approaches have emerged as substitutes for conventional sample processing procedures for trace metal assays within the framework of green chemistry. This review surveys the progress of the state of the art in simplification and automation of microextraction approaches by harnessing to the various generations of flow injection (FI) as a front end to atomic absorption spectrometry (AAS), atomic fluorescence spectrometry (AFS) or inductively coupled plasma atomic emission spectrometry or mass spectrometry (ICP-AES/MS). It highlights the evolution of flow injection analysis and related techniques as vehicles for appropriate sample presentation to the detector and expedient on-line matrix separation and pre-concentration of trace levels of metals in troublesome matrices. Rather than being comprehensive this review is aimed at outlining the pros and cons via representative examples of recent attempts in automating green sample preparation procedures in an FI or sequential injection (SI) mode capitalizing on single-drop microextraction, dispersive liquid-phase microextraction and advanced sorptive materials including carbon and metal oxide nanoparticles, ion imprinted polymers, superparamagnetic nanomaterials and biological/biomass sorbents. Current challenges in the field are identified and the synergetic combination of flow analysis, nanotechnology and metal-tagged biomolecule detection is envisaged.