Graphene-based hydrogel modified o-DGT device for in situ sampling of atenolol

This work aimed to develop an o-DGT device with a graphene-based hydrogel-modified binding layer (3D-rGO) to sample atenolol in water. The boundary conditions of the device were determined by the diffusion coefficients and by the evaluation of the influence of pH and ionic strength. Afterward, the device was practically applied to a tap water sample. The results obtained for the device showed that atenolol can be efficiently quantified, presenting a diffusion coefficient at 25 °C of 3.75 x 10 -6 cm 2 s −1 . The pH had no effect on the device; however, elution optimization studies indicated interference from ionic strength during the sampling step. This interference can be overcome by using the apparent diffusion coefficient or adjusting the binding layer’s ionic strength before sampler assembly. The experimental diffusion coefficient was compared with theoretical diffusion coefficients found by the Hayduk-Laudie equation and Archie’s law, verifying the greater reliability of the experimental results. When applied to a sample of tap water, with a concentration of 0.1 mg L −1 , the device performed well, with 92% recovery of atenolol in tap water. These results were obtained from an LOQ of 0.2 mg L −1 . The results were promising, and the use of 3D-rGO proved favorable, primarily due to its environmentally friendly synthesis route, thereby consolidating its potential for environmental applications.