The Light Energy Absorbed By Colored Compounds

This experiment was used to measure the buildup of the colored product, benzoquinone, to observe the change in the absorbance of the mixture in a spectrophotometer at a wavelength of 486 nm. It was hypothesized that over a longer period catechol oxidase activity and reaction in the mixture will continue, creating more benzoquinone resulting in an increase in the absorbance. The hypothesis was supported by the data as seen in figure 2 which shows the positive relationship between time and absorbance. As can be seen, with more time the catechol oxidase can catalyze the reaction and turn catechol (substrate) into benzoquinone (product). This in turn increased absorbance of the blue light at 486 nm by the solution containing benzoquinone which has a dark brown

Colorimetric assay is a process of determining a concentration of a solution based on absorbance of light. The purpose of this lab is to determine if the Bradford assay is an accurate way to determine an unknown concentration of two samples of protein. The Bradford assay is done by measuring wavelength of light passing through a cuvette filled with Bradford dye and concentrations of PBS and proteins. After the cuvettes are mixed they are placed into a spectrophotometer to measure wavelength. The wavelength given will be used to plot a standard curve based on concentration (x-axis) and wavelength (y-axis). The standard curve is then used to measure an educated guess on the concentrations of unknown protein concentrations. We hypothesized that if we use the Bradford assay and colorimetric spectrophotometry we can determine an accurate concentration of two unknown concentrations of proteins. The results of this lab failed to reject our hypothesis based on accurate measurements of protein concentrations. The standard curves are drawn with a linear increasing slope. The Bradford assay is an accurate way to demine the concentration of an unknown concentration.

This is how we separate the different compounds in the mixture because they go at different rates. This process is slightly similar to gel electrophoresis in biology. In the fact that both separate at different speeds. For gel electrophoresis the smaller fragments move faster than the large ones. In adsorption column chromatography, the compound that is more attracted to the liquid phase, the mobile phase, will move faster than the one attracted to the stationary phase.

The dark, navy blue colored graph represented the absorbance curve for the S1 sample. The red colored graph represented the absorbance curve for the S2 sample. The green colored graph represented the absorbance curve for the P1 sample. The purple colored graph represented the absorbance curve for the P2 sample. The gaps between the P2 curve was due to the oversaturation that led to the inconclusive spectrophotometer readings. The blue colored graph represented the absorbance curve for the P1 low salt sample. The orange colored graph represented the absorbance curve for the P2 low salt sample. The light blue colored graph represented the absorbance curve for the P1 medium salt sample. The light pink colored graph represented the absorbance curve for the P2 medium salt sample. The light green colored graph represented the absorbance curve for the P1 high salt sample. The light purple colored graph represented the absorbance curve for the P2 high salt

Chromatography is a fairly simple process. First, you put a dot of ink(or in our case, the M&M food dye) near the bottom of some chromotography paper (also known as filter paper), and then hang the paper vertically with its lower edge (the one closest to the spot of dye) dipped in a solvent (In our case, the sodium chloride solution). Capillary action forces the solvent to travel up the paper, where it meets and dissolves the ink. The dissolved ink (which is the mobile phase) slowly travels up the paper (the stationary phase) and separates out into its different elements. Another way of describing it is to think of the liquid as an adhesive-like liquids, some of which stick more to the solid and can travel more slowly than others. This is

On a thin chromatography plate, five spots were placed ( as shown in table 2) and the plate was developed using chloroform/methanol. This was later visualized with dragendorff’s reagent under the UV light. All separated components were observed, identified and recorded.

The purpose of this experiment was to determine the pKa of the bromothymol blue (indicator) through absorption spectroscopy. Bromothymol blue being a monoprotic acid base indicator, displays different colors at different pH because of the differences in the ratio of the conjugated acid and base form. The fraction of conjugate acid and base was interpolated for the solutions through the acquired absorbance spectrum of the bromothymol blue at various pH. The rearranged form of Henderson Hasselbalch equation was graphed as a function of pH to determine the pKa of the indicator.

The methodology for this experiment required a lot of careful measurement and calculations. The procedure consisted of many detailed steps to ensure accuracy when recording measurements. This experiment was carried out in an enclosed, darkened room because the the nature of the experiment requires a controlled temperature. Carrying out eight trials for each color of construction paper was a more accurate way of collecting a large quantity of data. In this experiment there were five groups of material (color) and eight experimental units in each group. There was a total of forty sheets of construction paper used; eight sheets of each of the five colors. The reason for testing five different colors was to determine a trend across the color spectrum in regards to the amount of radiant energy each color is able to absorb.

First, we can talk about error in the standard curve made which could be related to measurements of the absorbance leading to the equation of the straight line that could affect all of the calculations. Another source of error, as mentioned before, could be in the choice of the alkaline phosphatase concentration in B. Choosing a concentration that is not very accurate would have affected part C in the experiment. As of what concerns future improvements of this experiment, more standard dilutions could be used to generate the standard curve so that there is a wider range of values of concentrations of PNP for a more accurate conversion from absorbance values to PNP concentration values along the experiment. Furthermore, in part B and C more alkaline phosphatase dilutions and more PNPP dilutions could be prepared for the same reason: providing a wider range of values and therefore more accuracy in calculations. An addition area of improvement could also be related to the preparation of alkaline phosphatase in the first, trying to make a preparation that is as pure as possible for a higher value for the specific activity.

The tube was shaken up until it become uniformly green and the spectrophotometer was set at zero using this tube. Tube #1 acted as a control for reduction of DCIP in absence of CMS. 0.5 ml of DCIP and 1.5 ml of water was added to the tube and it was shaken up until it was well mixed. The absorbance was taken at that time. After that, with the light off, the tube was placed on the slanted portion of the foam pad in the light box. The light was turned on again and the tube was exposed to light for 1 minute.

Chromatography is a separation technique in which the mixture to be separated is dissolved in a solvent and the resulting solution, often called the mobile phase, is then passed through or over another material, the stationary phase. The separation of the original mixture depends on how strongly each component is attracted to the stationary phase. Substances that are attracted strongly to the stationary phase will be retarded and not move alone with the mobile phase. Weakly attracted substances will move more rapidly with the mobile phase.

According the results displayed in Figure 1. The absorbance rate increased as the pH increased. This was the same through the three types of experiments. These results do not support our original hypothesis. We predicted that that the two extrema pH s would slow down the rate of absorption, which turned out to not be true. What was true was that the rate of absorption at pH3 was the lowest out of the 3 pH tested. While the highest absorption rates occurred in a pH of 11, which was one of the extrema we tested. These results also do not support our prediction that pH 7 would be the level at which the rate of absorption would be the

In this lab, paper chromatography will be used to separate the components of known and unknown mixtures and then used to identify those components. Paper chromatography is a technique where a drop of solution containing a mixture is placed on a piece of filter paper. One end of the filter paper is then placed into a liquid solvent. The mixture will separate into its different components as the solvent moves up the filter paper. The filter paper is known as the stationary phase. The solvent is known as the mobile phase because it uses capillary action to move up the paper. The mixture will be separated into its different components because each component will have a unique chemical affinity for the paper and for the solvent. Theses affinities

The five solutions are then transferred into cuvettes and placed into a spectrophotometer, which is used to measure the absorbance of the five solutions in the UV range (535nm). The data obtained was then used to plot a graph in

Chromatography can be defined as a series of steps used to identify, analyze and separate compound. It is a method used to obtain components from a non-volatile mixture (Preethi, Harita & Rajesh, 2017). There are various types of chromatography separations methods. These include: column, gas, supercritical fluid chromatography and Thin layer chromatography. All these separation techniques operate under the same procedure;