Spacer layer engineering for ultrasensitive Hg(II) detection on surface plasmon-coupled emission platform

Abstract

In this work, we demonstrate for the first time the ultrasensitive detection of Hg²⁺ ions with femtomolar sensitivity in water samples with the use of the surface plasmon-coupled emission (SPCE) platform. The use of portable network diagnostic tools for water security and integrated water shed management is a topic of recent research interest. In this context, the current study explores Hg²⁺ monitoring using a rhodamine-6G (Rh6G) derivative bearing a monothiospirolactone mounted onto a SPCE substrate. Thus far, the limit of detection for mercury ions by the conventional fluorescence technique has been 0.15 nm. However, we have achieved 1 fm Hg²⁺ detection using silver nanoparticle-based spacer layer engineering on an SPCE sensor chip. Using this technology, a field device can be fabricated for rapid, ultrasensitive, multi-analyte detection (of contaminants) in water samples.