The construction of a simple sensor for the simultaneous detection of nitrite and thiosulfate by heme catalysis

Several simple sensors were fabricated through a one-step method. By depositing electro-active compounds, such as β-cyclodextrins (β-CD), heme, dopamine (DA), or Fc-ECG, onto a screen-printed electrode (SPE), the successful simultaneous detection of nitrite (NO(2)(−)) and thiosulfate (S(2)O(3)(2−)) ions was observed. Under optimal operating conditions, the notable electrocatalytic abilities of a Heme/SPE sensor were detected for the oxidation of NO(2)(−) and S(2)O(3)(2−), with remarkable peak potential differences, after characterization via SEM, CV, and DPV. Linear relationships were obtained in the ranges of 5.0–200.0 μmol L(−1) and 1.0–100.0 μmol L(−1) for the current response versus concentration of NO(2)(−) and S(2)O(3)(2−), respectively. The limits of detection were determined to be 1.67 and 0.33 μmol L(−1) while the sensitivities of detection were noted to be 0.43 and 1.43 μA μM(−1) cm(−2), respectively. During the detection of NO(2)(−) and S(2)O(3)(2−), no interfering common ions were observed. Furthermore, average recoveries from 96.0 to 104.3% and a total R.S.D. of less than 3.1% were found for the detection of NO(2)(−) and S(2)O(3)(2−) in pickled juice and tap water using the simple sensor. These results showed that rapid and precise measurements for actual application in NO(2)(−) and S(2)O(3)(2−) detection could be conducted in food samples, indicating a potential use in food safety.