Microfluidic derivatisation technique for determination of gaseous molecular iodine with GC–MS

AbstractGaseous molecular iodine (I2) is an important source of reactive iodine in the marine atmosphere, but the sources of I2 are not well understood due to the lack of an easily accessible, sensitive and robust technique for analysis. In this study a microfluidic derivatisation technique combined with GC–MS has been developed to measure gaseous I2. Good linearity in the range of 0.2–416ppb and low detection limits varying from 6 to 25ppt for different derivatisation reagents have been achieved, which is a substantial improvement in sensitivity compared with the spectrophotometric method (detection limit of 1.20ppb) in our previous study [L.J. Carpenter, S.M. MacDonald, M.D. Shaw, R. Kumar, R.W. Saunders, R. Parthipan, J. Wilson, J.M.C. Plane, Nature Geoscience, 6 (2013) 108–111]. The microfluidic technique was employed to quantify I2 produced from the heterogeneous reactions of potassium iodide solution and ozone. Good agreement was observed between the results of the microfluidic technique and the simulation of a coupled surface water–air kinetic model in the amount of I2 produced on the ozonolysis of iodide solutions