Determination of Sodium Nitrite in Pickle by Electrochemical Sensor Based on Nano-Ag/Poly L-Glutamic Acid Modified Glass Carbon Electrode
Nano-Ag/poly L-glutamic acid modified glass carbon electrode(Poly-L-Glu/Nano-Ag/GCE)was prepared by the means that nano-Ag and L-glutamic acid were modified on glass carbon electrode by electrochemical deposition and polymerization.Using 0.2 mol·L-1 phosphate buffer solution(pH 7.0)as the supporting electrolyte,the cyclic voltammetry was used for determination under the best detection conditions with Poly-L-Glu/Nano-Ag/GCE as the working electrode,saturated calomel electrode as the reference electrode and platinum electrode as the auxiliary electrode.It was shown that Poly-L-Glu/Nano-Ag/GCE had good selectivity for sodium nitrite,and linear relationship between concentration and the absolute value of corresponding oxidation peak current of sodium nitrite was kept in the range of 4.14×10-6-1.35×10-3 mol·L-1,with detection limit(3s/k)of 4.14×10-7 mol·L-1.The preparation method of the electrode had good repeatability.Poly-L-Glu/Nano-Ag/GCE was used for determination of sodium nitrite in pickle sample,giving results of detection amount of 1.33×10-5 mol·L-1,and the spiked recoveries in the range of 98.9%-103%.
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