Martínez Cisneros, Cynthia SusanaDa Rocha, ZairaSeabra, AntonioAlonso Chamarro, JuliánValdés, Francisco2023-12-132023-12-132018-07-01Lab on a chip (2018), 18(13), 1884-1890.1473-0197https://hdl.handle.net/10016/39083The successful integration of sample pretreatment stages, sensors, actuators and electronics in microfluidic devices enables the attainment of complete micro total analysis systems, also known as lab-on-a-chip devices. In this work, we present a novel monolithic autonomous microanalyzer that integrates microfluidics, electronics, a highly sensitive photometric detection system and a sample pretreatment stage consisting on an embedded microcolumn, all in the same device, for on-line determination of relevant environmental parameters. The microcolumn can be filled/emptied with any resin or powder substrate whenever required, paving the way for its application to several analytical processes: separation, pre-concentration or ionic-exchange. To promote its autonomous operation, avoiding issues caused by bubbles in photometric detection systems, an efficient monolithic bubble removal structure was also integrated. To demonstrate its feasibility, the microanalyzer was successfully used to determine nitrate and nitrite in continuous flow conditions, providing real time and continuous information.6engThis journal is © The Royal Society of Chemistry 2018.Lab-on-a-chipPhotometric detectionEnvironmental parametersresearch articleMaterialeshttps://doi.org/10.1039/c8lc00309bopen access1884131890LAB ON A CHIP18AR/0000021666