User:Jacob Esenther/Notebook/581/2014/09/03

Biomaterials Design Lab

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Objective Continue synthesis of the polymer and polymer-clay films for experimentation. The creation of a calibration curve via the UV-Vis for malachite green absorbance will be used to determine the equilibrium of their malachite green/dye samples. Description Synthesis of new films was started. The procedure may be viewed here. Finish the synthesis of clay films started on 08/29. The procedure may be viewed here. Calibration Curves Take UV Vis spectra for Malachite green concentrations: 0ppm, 0.20ppm, 0.50ppm, 1.1ppm, 1.4ppm, 1.7ppm, and 2.0ppm Malachite Green. The stock solution concentrations may be found here. Find the two absorbance maxima in the spectra. Plot the absorbance value vs concentration at each ppm for each maximum you find. For each absorbance max, determine the slope of your A vs concentration plots. This will give you the extinction coefficient for the wavelengths you are analyzing Malachite Green Equilibrium We will use UV-Vis spectroscopy to determine the amount of Malachite green absorbed into a film Upon determining the amount of Malachite green in the film, we can determine the equilibrium of free Malachite green vs bound malachite green by creating an I.C.E. table. We can also determine the mass of malachite green absorbed per mass of film To properly determine MG concentration, we will need to dilute our samples so that their absorbance is similar to the absorbance of our calibration curve samples. You can see from the intense color of your MG/film solutions that they are much darker (and will absorb more light) than those you used for your calibration curves. Dilutions were determined before arrival at lab. Dilution information can be viewed below. Use a 10mL volumetric flask. Transfer your dilutions to a glass test tube and label. Only 3mL is necessary for an absorbance measurement. 6 calibration samples and 8 diluted samples were run. Data The only sample solutions that required dilution were the 80ppm PVA film and the 200ppm PVA-Clay film. PVA 80ppm → 200μL into 10 mL (50x dilution) PVA-Clay 200ppm → 100μL into 10mL (100x dilution) New Film Synthesis 1.0256g PVA 107272g PVA + 0.1176g Clay Absorbance of Malachite Green Solutions This is a calibration curve of the Malachite Green at various concentrations. This graphic was made by collecting data from the UV-vis. A quartz cuvette was utilized. Absorbance of Malachite Green in Sample Films This is a curve of Malachite Green absorbance after the solution was treated with either a PVA or a PVA-clay film. Interpretation of Curves Calibration Curve of 423nm and 617nm peaks Note Initially the graphs created from the Uv-vis were only saved up to the 700nm wavelength. The files were resaved and no data was lost, but in the future make sure the parameter extends to 800nm.