Scientists Develop Needle Sensor to Detect Active Heavy Metals in Seawater

Needle Sensor
Fabrication of the needle sensor and detection mechanism for Cu by ASV. (Image by YIC)

Trace heavy metals in seawater are harmful pollutants to human health and ecological environment. The toxicity of heavy metals is closely related to their existing forms in seawater environment, not their total concentration.

Anodic stripping voltammetry (ASV) is the most simple and effective technique for the speciation analysis of metal elements. Due to the limitation of sensors’ sensitivity, novel sensors with high sensitivity for speciation analysis of trace active heavy metals in seawater are needed.

Researchers from the Yantai Institute of Coastal Zone Research (YIC), Chinese Academy of Sciences (CAS), prepared a new needle-shaped sensor based on the acupuncture stainless steel needle, through the processes of insulation, sealing and functionalization.

The active heavy metals (copper as template) in seawater were successfully determined by the needle sensor. Thanks to the special morphology, size of needle electrode and the electrochemical catalysis and enrichment performance of functional nanomaterials, the needle sensor exhibited excellent performance and ultra-high sensitivity (detection limit 15.4 pM) for the detection of Cu by ASV.

Through different sample pretreatment processes, the determination of three different forms of Cu (dissolved active, dissolved acid extractable and total acid extractable) in seawater was realized by using the needle sensor with ASV.

As an improved construction method of needle sensor, self-assembly method was used to modify the surface of acupuncture needle with functional nanomaterials, making the sensor more stable. The novel needle sensor based on stainless steel acupuncture needle showed advantages of high hardness, puncture ability and easy integration of sensors.

The relevant researches, published in Electrohimica Acta and Anlytic Methods, respectively, were supported by the Youth Innovation Promotion Association of CAS, the Key Research and Development Plan of Shandong Province and Yantai City.

Speciation analysis of Cu in seawater. (Image by YIC)