METHOD DEVELOPMENT FOR DETERMINATION OF TRACE HEAVY METALS BY SEQUENTIAL INJECTION-ANODIC STRIPPING VOLTAMMETRY USINGANTIMONY-GRAPHENE OXIDE MODIFIED ELECTRODE

Abstract

A sequential injection, an automated flow-based system, coupled with voltammetric method has been developed for the simultaneous determination of heavy metals using antimony-graphene oxide modified electrode (SbF-GO-SPCE). Graphene oxide was synthesized via Hummer’s method and was characterized by ATR-FTIR and UV-vis spectrometry. Antimony film was obtained by on-line in situ electrodepositing at constant potential. The determination was done with square wave anodic stripping voltammetry (SWASV) because of high sensitivity and low-cost technique. Optimal conditions to determine four heavy metals; which are Cd(II), Pb(II), Cu(II), and Hg(II) ions by sequential injection-SWASV, has been investigated. Using sequential injection-SWASV, the relationship between peak height and concentration of all heavy metal ions was linear in the range of 0.1-1.5 µM. Calculated limits of detection (LOD = 3.3σ/s) were 0.054, 0.026, 0.060, and 0.066 µM for Cd(II), Pb(II), Cu(II) and Hg(II), respectively. The individual determination of all metal ions could be performed under the optimal conditions with a great sensitivity and reproducibility. The interfering species in real water sample were studied. In addition, practical water samples were analyzed using standard addition method and calibration method. This technique could be used for determination of heavy metal ions in real samples with a 94.3 – 113% recovery.