Sarin(GB)is a typical representative of nerve agents with high toxicity,and very low amount can cause death.GB can cause water and atmospheric environment poisoning,so the detection of GB in water and air is of great significance.In this work,a colorimetric sensor array(CSA)based on GB inhibition of cholinesterase activity was constructed to detect GB with high selectivity.A 4×4 colorimetric array was constructed using acetylcholinesterase(AChE),butyryl cholinesterase(BuChE)and the corresponding substrate acetylthiocholine iodide(S-ACh),butyryl thiocholine iodide(S-BCh),acetylcholine chloride(ACh),butyryl choline chloride(BCh)and 2,6-dichloroindophenol ethyl ester(DCIE).The linear curve of the sensor was Y=131.3×lgC+271.6(R2=0.997),where Y was the array response Euclidean distance,C was the concentration of GB(mg/L),the linear range was 0.03?0.32 mg/L,and the detection limit was 27.6 μg/L.The method could effectively distinguish chemical warfare agents(CWA)such as VX,Soman(GD),mustard gas(HD),Louie reagent(L),and had high anti-interference ability,sensitivity and good repeatability.It was successfully applied to the detection of GB in simulated water and simulated air samples,and the sample recovery rate was 97.2% ?100.9%.This method would be potentially applied to the field rapid detection of nerve agents.

Objective To investigate the main components and antioxidant activity of the extract of corn silk.Methods The extraction of proteins was determined by the Kjeldahl method,total sugar was determined by the phenol-sulfuric acid assay,reducing sugar by 3,5-dinitrosalicylic acid (DNS) assay,respectively.Sodium dodecyl sulfate-polyacrylamide gel electrophoresis assay (SDS-PAGE) profile was used to show the composition of the protein of the extract of corn silk.The antioxidant activity of the extract of corn silk was evaluated by the ABTS · + radical scavenging rate and oxygen free radical absorption capacity.Results The contents of total sugar,reducing sugar and protein were 51.70％,10.43％ and 21.80％,respectively.SDS-PAGE profile showed that the extract of corn silk contained soluble protein,and its molecular weight was between 9.5 kD and 20 kD.The experimental results showed that the free radical scavenging rate of ABTS · + had reached 70.29％ when the extract concentration was 0.40 mg · mL-1 In the reaction system,the half inhibition rate (IC50) of ABTS free radical scavenging activity was 0.23 mg · mL-1.The total antioxidant activities evaluated by ORAC assay were 3.40 mmol Trolox equivalents · g-1,equivalent to 1/3 of absorption capacity of Vitamin C free radical.Conclusion The extract of corn silk has prominent antioxidant activity.