**Contents**


Colorimetric Determination of Nitrate after Reduction to Nitrite in a Paper-Based Dip Strip Reprinted from: *Chem. Proc.* **2021**, *5*, 9, doi:10.3390/CSAC2021-10459 ................ **51**




Evaluation of Olive Oil Quality Grade Using a Portable Battery-Operated Sensor System Reprinted from: *Chem. Proc.* **2021**, *5*, 40, doi:10.3390/CSAC2021-10614 ............... **227**


Reprinted from: *Chem. Proc.* **2021**, *5*, 49, doi:10.3390/chemproc2021005049 ............. **279**





Detection of Indoor Air Pollutants Using Reactive Sputtering/GLAD of Tin Oxide Thin Films Reprinted from: *Chem. Proc.* **2021**, *5*, 89, doi:10.3390/CSAC2021-10548 ............... **549**


Reprinted from: *Chem. Proc.* **2021**, *5*, 91, doi:10.3390/CSAC2021-10421 ............... **559**
