A new assembly for biosensing ultra-trace levels of mercury in a continuous flow system

Abstract

A new assembly was designed for the determination of mercury ions in a continuous flow system with a Chlorella sp.-based amperometric biosensor. The biosensor system was used to measure bioavailable mercury ions in an aqueous medium. The calibration curve for Hg(II) measurement was reproducible in the concentration range of 10⁻¹¹ M to 10⁻⁶ M. The biosensor shows an excellent selectivity for mercury ions in the presence of silver and other potential interfering ions and shows sensitivity and reproducibility in an aqueous stream with a flow rate varying in the range of 0.5 mL min⁻¹ to 1.5 mL min⁻¹. Real sample analysis in continuous flow stream was carried out and validated with chronoamperometric measurements, taken in batch mode and with atomic absorption spectrometry. Results were compared with existing measurement methods and found to be better in terms of selectivity and detection limit.