Cuvette Concentration Lab Report

In experiment 1 there were five cuvettes of decreasing concentrations from the initial 0.01 mg/ml concentration of Fast Green solution (cuvette 1). The diluted concentration of cuvettes #2 through #5 were calculated using the dilution formula, C1V1 = C2V2 ; the calculations for the dilute concentrations are in Results section. The concentration for each tube were as follows: 0.015 mg/ml for tube 1, 0.0075 mg/ml for tube 2, 0.00375 mg/ml for tube 3, 0.001875 mg/ml for tube 4, and 0.000935 mg/ml for tube 5. The absorption spectrum was performed for cuvette 1 to determine the maximum absorbance wavelength Figure 1. Cuvette #6, with 5ml of distilled water, acted as a blank to recalibrate the spectrophotometer to 0.000 absorbance between changing wavelengths. …show more content…
As indicated in Table 1, the maximum wavelength was at 625 nm at 1.063 absorbance. The absorbance values from cuvettes #1 through #7 were recorded at 625 nm to create the concentration curve Figure 2. The concentration curve is conducted at the maximum wavelength to produce the optimal results for the diluted concentrations of Fast Green.The purpose of the graph is to locate the unknown; Beer-Lamberts law, the concentration is proportional to the absorbance. The slope of the trend line was y = 71.333x + 0.0014 and the length travelled through the sample was 1 cm, the absorbance at the unknown substance was 0.112. After calculating using Beer-Lamberts law, the unknown concentration was 0.001550474 mg/ml. Calculations are described in the Results section. As shown on the graph, a straight line is drawn from the absorbance value, 0.112, until it intersects with the trend line of the graph. The perpendicular line that corresponds with the abscissa is the concentration 0.001550474