Digital image determination of copper in food and water after preconcentration and magnetic tip separation for in-cavity desorption/color development.

A new analytical method for measuring copper in food and water was developed and validated, employing a solid-phase extraction (SPE) technique combined with digital-image-based (DIB) detection. A novel magnetic adsorbent of zinc ferrite/Citrullus colocynthis biochar (ZF@C.BC) was used to preconcentrate copper.

Analysis of total phenolic compounds in tea and fruits using diazotized aminobenzenes colorimetric spots.

The present work describes a novel and rapid approach for evaluating total phenolic compounds (TPCs) in tea and fruits using colorimetric spots and the digital image-based (DIB) method. Colorimetric spots were formed by reacting diazotized aminobenzenes namely sulfanilic acid, sulfanilamide, or aniline with TPCs in the extract to form an azo dye. The limit of detection (LOD) was 6.

On-line Determination of Zinc in Water and Biological Samples after Its Preconcentration onto Zincon Anchored Polyurethane Foam.

A fast and sensitive on-line procedure for the determination of zinc in water and biological samples was developed. Zinc was preconcentrated in a mini-column packed with polyurethane foam (PUF) chemically modified with zincon via -N=N- bonding. The optimal conditions for preconcentration were pH 8.