A New Dgt Technique Comprising a Hybrid Sensor for the Selective and Simultaneous High Resolution 2-D Imaging of Asiii, Criii and Sbiii and Dissolved Oxygen

A new diffusive gradients in thin films technique (HR-MPTS DGT) with mercapto-functionalized attapulgite in a binding gel was developed for simultaneous two-dimensional (2-D) chemical imaging of As III , Cr III and Sb III selectively at the submillimeter scale, combined with laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) analysis. The HR-MPTS DGT exhibited selective accumulation of As III , Sb III and Cr III (> 97%), yet negligible accumulation of As V , Sb V and Cr VI (< 2%). Accumulation of As III , Cr III and Sb III on the binding gel had a linear relationship (R 2 > 0.99) with the corresponding standardized laser ablation signals, proving the feasibility of LA-ICP-MS analysis. Analysis for As III , Cr III and Sb III was provided with favorable analytical precision (relative standard deviation < 10%). With the purpose of evaluating the dynamics of As III , Cr III , Sb III and O 2 in the rooting zone, a hybrid sensor, which comprises the HR-MPTS gel overlying an O 2 planar optode , was deployed in rhizosphere sediments. Results showed that the consumption of both As III and Sb III due to the oxidation extended ~4.48 mm into the sediments, which was consistent with the extension length of the oxidized sediment layers around the roots created by O 2 leakage