Rhodol-conjugated polymersome sensor for visual and highly-sensitive detection of hydrazine in aqueous media

Hydrazine is a hazardous environmental pollutant, which contaminates land, air and water posturing a severe risk to human health. For the first-hand estimation, a qualitative approach (colorimetric) for recognition of hydrazine could suffice. However, for accurate measurement, under the threshold limit value (TLV), a quantitative technique is desired. We report the polymersome-based sensor for visual detection and quantification of hydrazine in water. The rhodol-functionalized amphiphilic hyperbranched multiarm copolymer (HSP-RDL) was self-assembled into vesicles. The HSP-RDL vesicle probe exhibited high sensitivity and selectivity for hydrazine recognition in presence of various competitive species such as cations, anions, and neutral species. The fast responsive pink color change from colorless could be visualized with naked eye due to spirolactone ring opening by hydrazinolysis triggered strong fluorescence emission. The vesicle probe could detect hydrazine in water with a limit of detection (LOD) value of 2 nM (0.0652 ppb), which is lower than TLV (10 ppb) given by USEPA (United States Environmental Protection Agency). Furthermore, the vesicle probe could quantify hydrazine (recovery ≥ 99 %) in a wastewater sample collected from Huangpu river. The membrane-permeable characteristics of HSP-RDL led hydrazine detection in live cells through confocal fluorescence microscopy.