A fun chromatography lab with filter paper as the solid phase and isopropyl alcohol/water as the mobile phase. We tested 2 brands of water-soluble markers and 2 brands of permanent markers. The students got an appreciation that "green" isn't just "green".
"To increase students' awareness of possible invisible pollutants in drinking water sources, students perform an exciting lab requiring them to think about how solutions and mixtures exist even in unsuspecting places such as ink. They use alcohol and chromatography paper to separate the components of black and colored marker ink. Students witness first-hand how components of a solution can be separated, even when those individual components are not visible in solution."