A reagentless renewable N,N′-diphenyl-p-phenylenediamine loaded sensor for hydrogen sulfide

The electrochemically induced reaction of sodium sulfide with N,N′-diphenyl-p-phenylenediamine (DPPD) has been studied in aqueous solutions (pH 1–7) at glassy carbon (GC) electrodes. The DPPD indicator has been shown to form a thin film on the electrode surface capable of sensing sulfide at the triple phase boundary (DPPD/electrolyte/electrode) in the range 20–200 μM with a limit of detection of 18 μM. The low solubility of DPPD has been exploited further by incorporating the species in the design of a modified renewable carbon-epoxy electrode whereby the detection process can occur in an inexpensively constructed device suitable for single shot determinations.