| Sample | Raw sample | Preparation | Sample obtained for EC treatment |
| A: Zimapan | Turbid water with [As] = 249.3 μg∙L−1 | 0.45 μm filtration | [As] = 61.9 μg∙L−1 |
| B: Tap water | Water with [As] = 10 μg∙L−1 | Addition of Na2HAsO4∙7H2O | [As] = 500 μg∙L−1 |