11-2-22
Paper Chromatography
Purpose: To study the separation of different inks
Procedure: I used a pencil to draw a line 1 cm from the edge of the chromatography paper. I placed the first mark 1 cm from the edge and made marks 2 cm apart along the line. I then placed three drops of copper nitrate and three drops of bromophenol blue into well H1 of the supplied 96-well reaction plate and mixed the solutions with a mini pipet. With the pipet I put one drop from the mixture on the first drawn mark allowing it to dry before repeating the drop process four or five times on the same mark. While the first mark was drying I used a black felt-tip pen to put a dot on the second mark.
Distance Solvent moved (in mm): 90mm
Table 1: Average Distance Each Component Traveled
| Chemical | Color Band | Distance Traveled | Rf Value (distance traveled by color / distance solvent front traveled) |
| Copper nitrate and Bromophenol blue | Yellow Blue | 85mm2mm | 0.9mm0.02mm |
| Black felt pen (supplied with kit) | Brownish green | 40mm | 0.4mm |
| Blue | 50mm | 0.5mm | |
| Black | 60mm | 0.6 | |
| Dark red | 40mm | 0.4mm | |
| Blue food coloring | Blue | 70mm | 0.7mm |
| Red food coloring | Red | 35mm | 0.3mm |
| Yellow food coloring | Yellow | 90mm | 1mm |
| Green | 3mm | 0.03mm |
Results:
The bromophenol blue had the smallest Rf value and the yellow food coloring had the largest. The yellow food coloring moved drastically further than the red food coloring and it surprised me. I was expecting red to move quickest.
Discussion:
The bromophenol blue moved the least, staying where it was placed not moving with the solvent. The larger the atomic mass the slower and more resistant the solution is to moving with the solvent. I was confused at first as to why a blue sphere of the bromophenol blue stayed while the yellow of the copper went so far but after reading about it, I now understand how their atomic masses affect their ability to move.
The copper has a much smaller atomic mass then the bromophenol blue and was thus able to move much quicker. The copper moved 85mm while the bromophenol blue moved 2mm in the same time.
The blue and red food colorings stayed the same colors but the yellow turned green around the place the dye was placed. The black felt pen turned the most colors. It had a bit of brownish green, red, and blue. Each color stopped at a different distance.
