Rhodamine 110 Degradation Assay to Determine Optimal Storage Conditions

Science Center, Bent Corridor

Rhodamine 110 is a fluorophore , a substance that emits light when excited by light, that is used in Affinity Probe Capillary Electrophoresis (APCE) as an internal standard to account for the variability in injected sample volume. The APCE machine shines a laser at a sample and reads the amount of light the sample fluoresces. However, Rhodamine 110 has been found to be unstable, as it fluoresces less over time. The aim of the project was to determine the best condition in which the Rhodamine 110 solutions should be stored, and to determine the rate of degradation of the solutions, under different storage conditions. Fifteen solutions of Rhodamine 110 were prepared by using five different buffer solutions and making three solutions per buffer. One of each buffer solution was kept in a freezer at about -20°C, one of each in a refrigerator at about 4°C, and one of each at room temperature. The samples were kept in 2mL eppendorf tubes covered in aluminum foil to minimize light exposure. Every day, a dilution of each solution was prepared as a test sample. The test samples were put in a 96 well plate and inserted into a spectrofluorometer. The spectrofluorometer would illuminate each test sample and read how much light each sample emitted. Using this information, the overall trend of the degradation of each sample was observed, and it was determined that the Rhodamine 110 should be kept in a solution of MiliQ water at room temperature.