A novel mixed matrix membrane of phenolphthalein hydrazide and polysulfone for the detection of copper ions in environmental water samples.

The novel membrane test strip of phenolphthalein hydrazide (PH)-polysulfone has been designed and demonstrated for Cu2+ ions detection. Before finding performance of membrane the studies with PH alone has been performed. Aqueous solutions of PH are colorless, but upon interaction with Cu2+ ions become pink (when 8.2 ≤ pH ≥ 12). The colorimetric change is initiated by the coordination of Cu2+ with PH as a polydentate ligand, opening the spirolactam ring that subsequently hydrolyses releasing phenolphthalein (P). Further membrane was preloaded with PH that could be used as a simple, low cost, and portable sensor for Cu2+ ions in environmental water samples. Given the detection limits of this sensor, a maximum response would warn the tester that Cu2+ concentrations were above safe drinking regulation values. Approximate concentrations can be determined via a color comparison chart. Different metal ions were tested in order to determine the chemodosimeters specificity, of the 12 tested ions only Hg2+ induced a similar molecular transformation (i.e., PH to P). The chemodosimeter allows the quantification of Cu2+ ions in the linear dynamic range of 0–22 μM. The Sandell sensitivity, limit of detection, limit of quantification, and relative standard deviation were found to be 0.276 μg/mL/cm2, 0.279 μM, 1.674 μM, and 0.682% respectively