Electrochemical Investigation and Determination of Sulfite Using Modified Carbon Paste Electrode with Nano

Sulfite is widely used as a broad-spectrum preservative to prevent microbial spoiling and browning reactions across a wide range of consumable products. Sulfites are commonly used in the food and pharmaceutical industries as preseatives and antioxidants and brewing industry as an antibacterial agent [1-3]. In large quantities, sulfite and its oxidation products are pollutants. In particular, sulfiting agents have received extensive attention, as a result of their allergenic effect on those individuals who are hypersensitive. Previous methods for determining sulfite have included titration, chromatography, spectrophotometricand chemiluminescence methods [ 4,5]. In turn, electrochemical techniques provide reasonable results under laboratory conditions. On electroanalysis, modified electrodes have the capable potential to satisfy the requirements of a sensor to be fast and exact. Alternatively, it has been demonstrated that sulfite can undergo catalytic or mediated oxidation using some chemically modified electrodes (CMEs). The important group of are the transition metals compounds [6]. The presence of transition metals in zeolite framework of zeolite modified electrode (ZME) benefits its catalytic and electro-catalytic characteristics. The goal of this research is electrochemical investigation and determination of sulfite using modified carbon paste electrode with nanozeolite. Iron (II) ions doped to nano ZSM-5 zeolite framework through ions exchange mechanism and electrochemical behavior of this electrode ،CPE (unmodified carbone paste electrode) and ZSM-5/CPE (nano zeolite modified carbon paste electrode) were studied by using cyclic voltammetry technique. Iron (II) doped nano zeolite (FeZSM-5/CPE) was the optimum electrod for electrochemical determination of sulfite. The optimized pH was 7.0 and the optimized percent of modifier was 30:70 of nano zeolite – graphite. In optimum condition ،linear dynamic range (LDR) of sulfit by voltammetry was 2×10-5–1.8×10-4 M and limit of detection was9.1×10-6 M.