The spectra for the trial using 0.75% sodium alginate was processed next. Again the data was pulled into Excel and MATLAB. The calibration curve was used to interpolate the concentration of methylene blue in solution when the sample was drawn. Using this concentration with the volume of water(50mL), the mass of dye in the solution can be found. Because each trial used 9mL of sodium alginate solution at 5.9 mg/L, the initial mass of methylene blue in the beaker can be determined. Subtracting the mass of methylene blue in the solution from the initial mass in the hydrogels, the mass remaining in the hydrogels can be found. Because the volumes of each are known, the concentrations can also be found.