Liquid DPIP was removed from kits in 2018 due to issues of chemical stability over time. It was replaced with powdered DPIP to ensure best results when performing experiments. 

Prepare the powdered DPIP for your experiment:

1. Add 50 mL of distilled water to the bottle. 
2. Replace the cap 
3. Shake vigorously to dissolve the powder. 
4. Follow all additional instructions as written in your experiment protocol.