Chemically modified cellulose strips with pyridoxal conjugated red fluorescent gold nanoclusters for nanomolar detection of mercuric ions.

One-pot approach was adopted for the synthesis of highly luminescent near-infrared (NIR)-emitting gold nanoclusters (AuNCs) using bovine serum albumin (BSA) as a protecting agent. The vitamin B cofactor pyridoxal was conjugated with the luminescent BSA-AuNCs through the free amines of BSA and then employed for the nanomolar detection of Hg in aqueous medium via selective fluorescence quenching of AuNCs. This nano-assembly was successfully applied for the real sample analysis of Hg in fish, tap water and river water. The study also presents chemically-modified cellulosic paper strips with the pyridoxal conjugated BSA-AuNCs for detecting Hg ion up to 1nM.