▎ 摘　　要

Two stochastic microsensors based on graphene powders and protoporphyrin IX were proposed for the simultaneous assay of nitrite and nitrate in water samples. The proposed microsensors can provide a fast screening of water samples with a qualitative and quantitative analysis for NO2- and NO3- at very low concentration levels. The linear concentration ranges were wide, covering clean as well as polluted waters. The results provided by the stochastic microsensors were in agreement with those obtained by utilization of standard methods, recoveries higher than 99.00% and RSD lower than 1.00%, proving that the method can be reliable used for simultaneous assay of NO2- and NO3- in water samples.