Journal article

Development of a micro-distillation microfluidic paper-based analytical device as a screening tool for total ammonia monitoring in freshwaters

Jonathan J Peters, M Ines GS Almeida, Lenka O'Connor Sraj, Ian D McKelvie, Spas D Kolev

ANALYTICA CHIMICA ACTA | ELSEVIER | Published : 2019

Abstract

An easy-to-use, portable 3D microfluidic paper-based analytical device (μPAD) for the determination of total ammonia (i.e., ammonia + ammonium) in freshwaters is described. It consists of two layers of paper patterned with hydrophilic circular zones, one impregnated with sodium hydroxide (sample zone) and another (detection zone) with an acid-base indicator (nitrazine yellow (NY) or bromothymol blue (BTB)), separated by a μ-distillation chamber. Ammonium ions present in the water sample are converted into ammonia gas by reaction with sodium hydroxide in the sample zone. Ammonia then diffuses through a headspace and reacts with an acid-base indicator in the detection zone, the reflectance of ..

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