Plumbagin as colorimetric and ratiometric sensor for arginine

- A simple and selective naphthoquinone based plumbagin for arginine sensing.
- Ratiometric and colorimetric sensor in aqueous solution.
- The 1:1 Pn/arg complex was characterized by Job's plot and ESI-mass spectrometry.
- Upon arginine binding intermolecular proton transfer from Pn to arginine occurs.
- The observed detection limit (DL) is 1.0 × 10−6 mol L−1.