On-chip electromembrane extraction followed by sensitive digital image-based colorimetry for determination of trace amounts of Cr(vi)

Abstract

In this work, an on-chip electromembrane extraction coupled with the micro solid phase extraction step was developed for extraction, preconcentration, and determination of trace amounts of chromium(vi) in water samples.

Electromembrane extraction in microfluidic formats

“…In a related article, microchip EME was combined with smartphone detection for the determination of chromium(VI) in water samples [26]. Chromium(VI) was complexed with 1,5-diphenylcarbazide in the sample, and was then extracted and preconcentrated into acceptor by EME.…”

Combination of a methylene blue-iodide system with a smartphone-based portable colorimeter for the on-site determination of nitrite

“…The RGB's vast color space can provide a rich database for the quantitative analysis. 14 In this study, the potential of a novel colorimetric method was evaluated for the determination of nitrite ions in different aqueous samples. The proposed method is based on the liberation of triiodide in an acidic medium, which was equivalent to the amount of nitrite ions present.…”

Surface nanodroplet-based nanoextraction from sub-milliliter volumes of dense suspensions

“…Enriching traces of target compounds by extraction is an effective way of improving detection sensitivity. 25,26 Various forms of extraction have been demonstrated including use of porous membranes in extraction driven by an electric field, [27][28][29][30] formation of tiny extractant droplets generated by ultrasonication for liquid phase extraction, 31,32 or use of nanoparticles as sorbents in solid phase extraction. 33,34 In particular, liquid-liquid extraction by using extractant microdroplets can reach high extraction efficiency, due to efficient mass transfer enabled by the high surface area-to-volume ratio of small droplets.…”