| Sodium nitrite is a kind of industrial salt composed by sodium and nitrite. Due tothe property of saline taste, sodium nitrite is usually used as false salt by criminals. Itis well known that nitrite is generally found within the environment and live processand is commonly used as an additive or corrosion inhibitor in some foods. In addition,nitrite can be used as poisoning antidote in pharmaceutical industry. As an importantintermediate of nitrogen cycle, nitrite widely exists in water, soil and food. However, itthreatens human’s health and can interact with amines to form carcinogenicnitrosamines. Therefore, it is necessary and critical to carry out the determination ofnitrite in practical analysis.Metallophthalocyanine(MPc) is a compound with special physical and chemicalproperties，which is usually used as an catalysis for the oxidation of various types ofpollutants. In recent years, MPc is usually used as an electrode material forelectrochemistry oxidation and detection nitrite. But it’s not proper to prepare electrodedirectly using MPc because of its low conductivity.Carbon nanotube is one-dimensional nano material with the hollow structure. Thehexagonal carbocycle units compose the primary carbon nanotube. Carbon nanotube isgrandly used as supporting material for catalyst. Since the pore structure, carbonnanotube has the property of high absorption and it is resistant to acid and base. Inaddition, carbon nanotube has advantages of large specific surface area, goodconduction and excellent property of hydrogen storage. Grapheme nanosheets is two-dimensional nano material with excellent property of absorption. They are all grandlyused as supporting material. In this paper, we adopted CoTAPc as catalyst and CNTs,GNSs as supporting material for preparing the CoTAPc/CNTs electrode. The detectionproperty of modified electrode is characterized.The main contents as follows: In this paper, CoTAPc/CNTs/G/GC electrode was prepared using the method ofabsorption. CoTAPc was attached onto the CNTs and grapheme (G) hybrid forpreparing the modified electrode. The prepared electrode was used to detection nitrite.The results show: CoTAPc/CNTs/G/GC electrode was sensitive to nitrite, the oxidationcurrents displayed a good linear behavior in the range from0.2μM to1.0μM and thelimitation of detection was8.4×10-8M.To improve the property of modified electrode for detecting nitrite, electrochemicaldeposition was adapted. CoTAPc/CNTs/GC electrode was prepared under the constantpotential deposition and the prepared electrode was used as work electrode to detectnitrite. The results show: Compared with the bare GC electrode, the oxidation peekpotential of CoTAPc/CNTs/GC electrode is shifted0.2V to negative direction, the peekcurrent increased125μA, which reflects the excellent detection property for nitrite. Atthe potential of0.7V, the oxidation currents displayed a good linear behavior in therange from6μM to200μM with a coefficient of0.994and the limitation of detectionwas9×10-8M.To further improve the property of modified electrode for detecting nitrite, CNTswas replaced by array CNTs (ACNTs). The CoTAPc/ACNTs/GC electrode wasprepared using the method of CV deposition and the modified electrode was used todetect the concentration of nitrite. The results showed: under the constant potential of0.7V, the current responded to the dropped nitrite instantly. The response currentdisplayed a good linear behavior in the range from2.0×10-5to0.48M. The dependentlinear equation is Ip=2.9725+56.4c (mM) with the detection limitation of5.85×10-8M. |
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