Towards In-Situ Environmental Monitoring: On-Chip Sample Preparation and Detection of Lead in Sediment Samples Using Graphene Oxide Sensor

This manuscript reports, a novel, integrated on-chip sample-to-answer platform capable of detecting lead ions (Pb+2) directly in sediment samples. As sediment is one of the main sources of hazardous heavy metals in aquatic ecosystems, rapid and real-time detection of heavy metals in sediment is crucial in the field of environmental monitoring. Electrochemical sensors can provide rapid detection capability, but in-situ measurement of heavy metals with such sensors has been limited by complicated pretreatment steps. To overcome this drawback, an integrated system was developed consisting of a porous matrix for purification and extraction of Pb+2 onto a graphene oxide thin film that serves as an active sensing material. The integrated sensor with a 3D porous matrix was used as an in-situ platform to detect lead directly in complex sediment samples. The proposed electrochemical sensor has a detection limit of 4 ppb and a linear working range. The ability to directly detect lead in sediment samples with minimal pretreatment agents and time makes this system a promising solution for on-site monitoring of heavy metals in environmental samples. Although the current study focused on lead for platform validation, the proposed sensing platform can be further developed for the detection of a wide panel of toxic metals.