▎ 摘　　要

High sodium ion (Na+) consumption leads to high blood pressure which causes many health issues. Real-time determination of Na(+)content in food is still important to limit Na(+)intake and control the taste of food. In this work, we have developed an electrochemical sensor based on agglomeration of silver nanoparticles (AgNPs) and graphene oxide (GO) modified on a screen-printed silver electrode (SPE) for Na(+)detection at room temperature by using cyclic voltammetry (CV). The AgNPs were synthesized through a simple green route usingPistia stratiotesextract as a reducing agent under blue light illumination and mixed with the GO to be a Na(+)selective sensing nanocomposite. The AgNPs/GO/SPE sensor showed high sensitivity (0.269 mA/mM/cm(2)), high selectivity, linear relationship (0-100 mM), good stability, and excellent reproducibility to Na(+)detection as well as low limit of detection (9.344 mM) for food application. The interfering species such as K+, Zn2+, Na+, Mg2+, glucose, and ascorbic acid did not have any influence on the Na(+)determination. The AgNPs/GO/SPE sensor was successfully applied to determine Na(+)in real samples such as fish sauce and seasoning powder of instant noodle.