Inkjet-printed disposable metal complexing indicator-displacement assay for sulphide determination in water

[Display omitted] •Determination of sulphide by a colorimetric metal complexing indicator-displacement assay.•The change in colour measured from the image of membrane acquired by a digital camera is used as analytical parameter.•The assay uses immobilized Cu(II) complex of the PAN azo dye printed by inkjetting on a nylon support. A sulphide selective colorimetric metal complexing indicator-displacement assay has been developed using an immobilized copper(II) complex of the azo dye 1-(2-pyridylazo)-2-naphthol printed by inkjetting on a nylon support. The change in colour measured from the image of the disposable membrane acquired by a digital camera using the H coordinate of the HSV colour space as the analytical parameter is able to sense sulphide in aqueous solution at pH 7.4 with a dynamic range up to 145μM, a detection limit of 0.10μM and a precision between 2 and 11%.