Data Table Stock Solution Conc. % v/v Volume of Stick Solution (mL) Concentration of Dilute solution % v/v Final Volume of Dilute Solution mL 4% 50.00 27% 8% 50.00 27% 10% 50.00 27% 12% 50.00 27% 16% 50.00 27% 20% 50.00 27% 7.41 Standards Volume of Juice Final Volume of Solution 4 % V/V 8 % V/V 10 % V/V 12% V/V 16% V/V 20% V/V Standards % v/v Absorbance Values 4 8 10 12 16 20 1 Line of Best Fit Equation: Concentration of Unknown: = % V/V 2 Experimental Procedure Calibration Curve of Dilutions of 100% Cranberry Juice The calibration curve of Standard cranberry juice (27%) will be used to help determine the concentration of cranberry products. The data collected from the dilutions of cranberry standard will be used to generate the calibration curve. The calibration standard will be prepared by preparing 50.00 ml of each of the following dilute solutions: 4%, 8%, 10%, 12%, 16%, and 20%. Example of Dilution using 27% Cranberry Standard Solution. Use the Dilution equation from the concentration lab exercise. Conc1 (Stock) X Vol1 (of Stock) = Conc2 (Dilute) X Vol2 (of dilute solution) Solution 1: Information Provided: Concentration of Stock: Volume of Stock: Concentration of Dilute Solution: Volume of Dilute Solution: 27% Unknown 4% 50.00 mL or 0.05000 L Enter the information into the equation from above: High Conc Low Conc 27% V/V * Needed = 4% * 0.0500 Liters Solve 4% V/V 𝑆𝑡𝑜𝑐𝑘 𝑉𝑜𝑙𝑢𝑚𝑒 = ∗ 0.0500 𝐿𝑖𝑡𝑒𝑟𝑠 27% V/V 0.00741 Liters or 7.41 mL (V/V denotes the ratio of Volume cranberry juice to Volume Apple Juice) 1 Complete the following Dilution Table Base the volume transferred on the precision of a buret. Stock Solution Conc. Volume of Stock Concentration of Dilute % v/v Solution (mL) solution % v/v 27% 7.41 Final Volume of Dilute Solution mL 4% 50.00 27% 8% 50.00 27% 10% 50.00 27% 12% 50.00 27% 16% 50.00 27% 20% 50.00 1. Measuring the Absorbance of the Diluted Concentrations of 100% Cranberry Juice. Measure each cuvette at the λmax, 520 nm. Concentration Absorbance of Dilute Cranberry solution % v/v 4 0.07 8 0.15 10 0.27 12 0.59 16 0.71 20 0.84 Unknown 0.163 % Conc Abs 4 8 10 12 16 20 0.07 0.15 0.27 0.59 0.71 0.84 Data entered in Excel should have no units As displayed above. 2 2. Graph the Data. Plot an absorbance vs. concentration graph is submitted on line. Use the data collected for the 4%, 8%, 10%, 12%, 16%, and 20% Solutions The graph should include the following: ▪ ▪ ▪ Data table Chart title Label both axis Equation of the line R2 value Note: The line for the best-fit equation may not go through zero, which is acceptable; this may occur because of random error effects, which are noticeable due to the small sample size. The graph you generate will be the calibration curve. Sample Graph & Data Calibration Curve for Cranberry Juice 2.50 2.00 Absorbance ▪ ▪ 1.50 y = 0.018x + 0.6 R² = 0.9893 1.00 0.50 0.00 0 10 20 30 40 50 60 70 80 90 Cranberry Juice Concen. (%v/v) 3 3. Unknown Concentration: Measure the absorbance and calculate the concentration using the line of best-fit equation. Example: The numbers in the following problem are made up. Do not use them in your calculations. Use your data! Using the line of best-fit equation from the above graph, we can determine the concentration of any cranberry solution that has an absorbance within the range of our calibration curve absorbance values. (Sample Problem) Y (Abs) = 0.018 * X(Cranberry Conc.) +0.6 (Sample Problem) The y-axis represent the absorbance by the machine in response to the color of the solution. Darker color, Greater absorbance. If the unknown returned an Absorbance of 1.04 (my y value), I would calculate the concentration (my unknown x value) as follows: Y (Abs) = 0.018 ∗ X(Cranberry Conc. ) + 0.6 1.014 (Abs) = 0.018 ∗ X(Cranberry Conc. ) + 0.6 1.014 (Abs) − 0.6 = X(Cranberry Conc. ) 0.018 The concentration of the unknown is 23 % V/V 4 Name: Last Name, First Name Week 14: Cranberry Lab Calculations Standards 4 % V/V 8 % V/V 10 % V/V 12% V/V 16% V/V 20% V/V Volume of Juice Final Vol of Solution Graph Concentration % V/V Absorbance ~4% ~8% ~10% ~12% ~16% ~20% Line of best fit R2 value y= R2 = Do NOT enter units into the cells 14: Cranberry Lab Concentration of standard: Unknown Absorbance: Unknown Concentration: Place Graph Here What is in the food you eat and Drink On Line Wk 14 Cranberry FDA • The first attempt to regulate drug safety in the U.S. came in the wake of Dr. Edward Jenner's discovery of the smallpox vaccine in 1796. As smallpox was still a common, dreaded, and often fatal sickness at the time. It was not long before hucksters and charlatans began exploiting demand for the treatment by selling fraudulent, ineffective, and sometimes dangerous versions of the vaccine. • It took another 86 years before Congress passed an effective law addressing the issue of food and drug safety. That law, signed by President Theodore Roosevelt in 1906, led to the establishment of the Food and Drug Administration, a federal agency tasked with protecting the public from dangerous medications. This week we are gong to analyze the concentration of % cranberry juice provided in local stores. No band names will be listed There have been numerous research studies performed analyzing the effects of cranberry in the human body. The results have shown that aside from cranberries treating urinary tract infections and kidney diseases, they also contain moderate levels of Vitamin C, dietary fiber, dietary minerals, manganese and micronutrients that benefit the cardiovascular and immune systems. • Cranberries also contain phytochemicals, such as anthocyanin which have alternating single and double bonds that give cranberries their deep red color, and which result in the high absorbance of ultraviolet radiation. Color vs Concentration Measuring Anthocyanin not Just a red dye You will remember the lines in the light lab. You observed that each elements had a specific visible spectrum, a sort of electronic finger print The anthocyanin will not emit light but will absorb visible light in the visible spectrum You can see that anthocyanin absorbs in all regions of the visible spectrum. It has the greatest Abs in the 520 nm region, green light. Absorbance, Transmittance, Reflection • Absorbance is a measure of the amount of light absorbed by a sample as a beam of light passes through it • Transmittance is the amount of light transmitted by a sample Transparency As Concertation The following will Result Absorbance & % Transmittance How do we measure Light Energy in solutions When Cu+2 ions are added to the sovnt. As the concertation of Cu+2 increases there are more molecules or atoms with electrons that can absorb the energy. Greater absorbance, less energy to the detector. Light in Light Out 0.5 Abs 0.8 Abs Light in Light Out 1.0 Abs When all the light passes through a sample no energy is absorbed: 0 Abs As the concertation increases so does the absorbance Absorption Spectrum Calibration Curve Sample Equation Y(Abs) = 123* X(conc) + 0.06 Unknown Abs = 0.86 Solve for X (conc) We can use the concentrations and Abs Values to construct a reference graph or Standard Curve We can use the line of best Fit to solve for the concentration of any Sample You will need to calculate the volume of stock to prepare the dilute calibration solution Conc1 (Stock) X Vol1 (of Stock) = Conc2 (Dilute) X Vol2 (of dilute solution) Stock Solution Conc. % v/v Volume of Stock Solution (mL) Concentration of Dilute solution % v/v Final Volume of Dilute Solution mL 27% 7.41 4% 50.00 27% ? 8% 50.00 27% ? 10% 50.00 27% ? 12% 50.00 27% ? 16% 50.00 27% ? 20% 50.00 Solution 1: Information Provided: Concentration of Stock: 27% V/V Volume of Stock: Unknown Concentration of Dilute Solution: 4% V/V Volume of Dilute Solution: 50.00 mL or 0.05000 L Enter the information into the equation from above: High Conc Low Conc 27% V/V * Needed = 4% * 0.0500 Liters Solve : 𝑆𝑡𝑜𝑐𝑘 𝑉𝑜𝑙𝑢𝑚𝑒 = Complete the volume calculations of the Stock Solution needed to prepare the dilute solutions. 8% - 20% 4 % V/V ∗ 27 % V/V 0.0500 𝐿𝑖𝑡𝑒𝑟𝑠 Units of concentration cancel Stock Volume = 0.00741 Liters or 7.41 mL Use the data below to construct the Graph Do not graph the unknown value Concentration of Dilute Cranberry solution % v/v 4 Absorbance 0.07 8 0.15 10 0.27 12 0.59 16 0.71 20 0.84 Unknown 0.163 • Plot an absorbance vs. concentration graph . Graph is to be a scatter plot. • This will be submitted online • Use the Abs data collected for the 4%, 8%, 10%, 12%, 16%, and 20% Solutions • (Shown to the Left) • Do not graph the unknown value Calibration Curve for Cranberry Juice 2.50 • The graph should include the following: • Chart title • Label both axis • Equation of the line • R2 value 2.00 y = 0.018x + 0.6 R² = 0.9893 Absorbance 1.50 1.00 0.50 0.00 0 10 20 30 40 50 Cranberry Juice Concen. (%v/v) 60 70 80 90 Unknown Analysis: Line of Best-fit • Use the line of best Fit Equation: Y (Abs) = 0.018 * X(Cranberry Conc.) + 0.6 • The y-axis represent the absorbance by the machine in response to the color of the solution. Darker color, Greater absorbance. • If the unknown returned an Absorbance of 1.04 (my y value), I would calculate the concentration (my unknown x value) as follows: • Y(Abs) = 0.018 ∗ X(Cranberry Conc.) + 0.6 • 1.014(Abs) = 0.018 ∗ X(Cranberry Conc.) + 0.6 • 1.014 (Abs) − 0.6 0.018 = X(Cranberry Conc.) • The concentration of the unknown is 23 % V/V Due Next Week • Complete the Data tables • Down Load the excel file • Enter your data and the Graph • Upload the Excel File and the Word data file. 
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