Rhodamine concentration curve
Lingyun and I used the stir cell and spectrometer to measure the diffusion of rhodamine across the membrane. This was the first time I was able to construct an experiment in the stir cell while keeping both membranes intact. In the past one membrane would rupture or the cell would leak too much. For this trial I used membranes from wafer 218 positions: 1,2 on the right and -2,-2 on the left. The membranes were intact at the beginning of the experiment. 320 uL of liquid was loaded into each cell, and each time a measurement was taken, 5 uL of liquid was taken out of each well, and added to 70 uL of water in the quartz cuvette. The quartz cuvettes require a minimum of 75 uL in order to gain an accurate absorption reading. The spectrometer was set at 530 nm for rhodamine.
Below is the concetration curve for rhodamine as a retentate and filtrate.
I think the concentration of rhodamine was too high, so I’m going to dilute it 10:1 with de-ionized water and re-do the experiment on Monday.