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 ) and thiosulfate (SO ) ions was observed. Under optimal operating conditions, the notable electrocatalytic abilities of a Heme/SPE sensor were detected for the oxidation of NO and SO , with remarkable peak potential differences, after characterization SEM, CV, and DPV. Linear relationships were obtained in the ranges of 5.0-200.0 μmol L and 1.0-100.0 μmol L for the current response concentration of NO and SO , respectively. The limits of detection were determined to be 1.67 and 0.33 μmol L while the sensitivities of detection were noted to be 0.43 and 1.43 μA μM cm, respectively. During the detection of NO and SO , 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 and SO in pickled juice and tap water using the simple sensor. These results showed that rapid and precise measurements for actual application in NO and SO detection could be conducted in food samples, indicating a potential use in food safety.