RESUMO
A polymethionine(p-Met)-modified laser-induced graphene(LIG)electrode was constructed and integrated with portable electrochemical workstations and handheld computer to achieve on-site,simultaneous detection of azo dyes sunset yellow(SY)and tartrazine(Tz)in environmental water.Firstly,the sensor interface with the best electrical conductivity was obtained by optimizing the laser processing parameters,and then the electrochemical responses of SY and Tz were improved by electropolymerization of methionine on the surface of LIG.Finally,a portable electrochemical sensor platform was built by connecting p-Met/LIG,a small electrochemical workstation and a handheld computer application program.Differential pulse voltammetry(DPV)was used to determine these two dyes.SY showed a good linear relationship in the concentration range of 0.2-20 μmol/L and 20-100 μmol/L,the detection limit was as low as 0.001 μmol/L.Tz showed a good linear relationship in concentration range of 0.3-40 μmol/L and 40-100 μmol/L,and the detection limits was as low as 0.005 μmol/L.p-Met/LIG also had excellent anti-interference performance and reproducibility.The portable electrochemical platform was applied to real-time detection of real water samples,and the results showed that the platform was expected to be applied in field detection of SY and Tz in real environmental water bodies.