Food Dye Proposal 1 v4.1.docx (2)

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Chemical ThinkingFood Dye Proposal 1 v4.1 | 1 Food Dye Proposal 1 Your name: Angelica Rivera Your email: angelicacrivera@arizona.edu Your lab partner’s name(s): Ciara Boyle Your lab partner’s email(s): ciaraboyle@arizona.edu Your lab instructor’s name: Daniel Chavez Your lab section: 5A All work must be very neat and organized . If you need to collect your thoughts, please use a separate sheet of paper. Proposals are a group effort . Please submit the completed document as a PDF to the Food Dye Proposal 1 D2L DropBox before the scheduled end of lab. 1. In a complete, well-written sentence, summarize in your own words the overall goal(s) for the Food Dye Project . The overall goal of the Food Dye Project is to identify the FD&C food dyes in an assigned drink by taking wavelengths of maximal absorbance of known and unknown solutions using spectrometry and logger pro. The second goal is to quantify the mass of each FD&C dye present per 500mL serving by applying Beer's Law to create a calibration curve. Then, using this information to build a parallel dilution set for each dye to create the set of dye solutions with different known dye concentrations. 2. In your own words, the goals for this first session of the Food Dye Project are … The goal for this first session is to learn how to use a micropipette, become familiar with absorbance readings of solutions using logger pro and a spectrophotometer as well building a parallel dilution set for one FD&C stock solution. Also, to develop a proposal to determine the molar concentration of each FD&C food dye present in our assigned drink. 3. Assigned Drink Absorption Spectrum. Carefully reproduce (draw) or paste-in the Logger Pro generated absorption spectrum of your assigned drink , clearly noting the wavelength(s) of maximal absorbance(s) ( λ max ). Remember to title and label your spectrum correctly if drawn by hand . Absorption Spectrometry of Dye J76 Wavelength (nm) CHEM 151 FDPP1 v4.1 8-10-22

Chemical ThinkingFood Dye Proposal 1 v4.1 | 2 Peak #1: 506 nm Maximal absorption at wavelength of 506 nm. Peak #2: 630 nm Maximal absorption at wavelength 630 nm 4. Stock (Reference) FD&C Food Dye λ max Values . Record in Table 1 below the wavelength of maximal absorbance ( λ max ) and apparent color of all the stock/reference FD&C food dye solutions your group decided to test. Include corrects units . Table 1. Stock (Reference) FD&C Food Dye Wavelength of Maximal Absorbance ( λ max ) FD&C Dye ( color + number ) λ max Observed Color of Stock (Reference) Solution Red #3 527 nm Light pink red Red #40 502 nm bright red Green #3 624 nm bright turquoise Blue #1 630 nm bright blue Yellow #6 470 nm light orange Yellow #5 422 nm bright yellow Blue #2 610 nm dark blue 5. FD&C Food Dyes Present in the Assigned Drink . In complete sentences state the identity of the FD&C food dyes (by FD&C color + number ) present in your assigned drink and how you identified the dyes . Dyes blue #1 and red #40 were present in our unknown drink (J76). Blue #1 and red #40 had lambda maxes that were the closest to the peaks in our drink which we had noted, 502 nm and 630 nm, on the absorption spectrum. Red #40 was the identity of the first peak since the lambda max is 502 nm and blue #1 being the identity of the second peak since its lambda max is 630 nm. 6. FD&C Dye Practice Parallel Dilution Set . Complete Table 2 below for your group’s practice parallel dilution set of one FD&C dye, specifying by FD&C color + number which stock dye solution was used. Note that one parallel dilution set member is the undiluted stock solution , hence V diluent and V D must be 0.00 mL for this member. In the space below the table, present in a very organized manner, the concentration calculation for one dilution set member that is not the stock, clearly stating symbolically the equation(s) used and then substituting in actual values. Include correct units throughout . Table 2. Practice Parallel Dilution Set Using FD&C Food Dye ___J76_________ Volume of Stock ( V S ) Volume of Diluent ( V diluent ) Volume of Dilution ( V D ) Concentration 5 mL 0 mL 5 mL 496.42 3.88 mL 1.12 mL 5 mL 385.2219 2.78 mL 2.22 mL 5 mL 276.0095 1.66 mL 3.34 mL 5 mL 164.8114 0.55 mL 4.45 mL 5 mL 54.6062 Notes and work: CHEM 151 FDPP1 v4.1 8-10-22

Chemical ThinkingFood Dye Proposal 1 v4.1 | 3 7. Proposal 1 . Based on your exploration and skill development, propose a plan (procedure) to determine the molar concentration of each FD&C food dye present in your assigned drink. Please NUMBER your procedural steps. Procedural Steps CHEM 151 FDPP1 v4.1 8-10-22

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Chemical ThinkingFood Dye Proposal 1 v4.1 | 4 1) Start by collecting 20ml of red #40 with a transfer pipette into a plastic vial. Label with a marker on the white cap “Red #40”. Repeat this step with Blue #1, also labeling with a marker “Blue #1” on the white cap. 2) In separate vials, collect two 20ml of Nanopure water with a pipette and label the white caps “Nanopure” with a marker. 3) Grab 10 different plastic vials, 10 cuvettes, 10 transfer pipettes, a 100-1000 μ l micropipette, and 1000 μ l pipette tips. 4) Fill the cuvette with nanopure using a new transfer pipette until the nanopure water reaches the arrow line. Plug in your laptop to the absorbance spectrometer and turn on Logger Pro. Then select “Experiment” on the top bar and click on “Calibrate”, allowing the absorbance spectrometer to warm up. 5) Place the nanopure cuvette into the spectrometer and press “Finish Warmup” then press “Ok”, a line on the bottom of the graph should appear. 6) Once the line appears, press the pause button and record the previous data by clicking “Save previous data”. 7) Begin with the red #40, and with using the micropipette, create a full parallel dilution set using the dye and nanopure water using the same stock volume and diluent volume created with the original dilution set. 5 plastic vials, 5 cuvettes and 5 transfer pipettes will be used. Discard the micropipette tip once all of the solutions have been made. 8) Create an identical dilution set with the blue #40. 5 plastic vials, 5 cuvettes and 5 transfer pipettes will be used as well as a new micropipette tip. 9) After running each dilution set (from least solvent to most solvent) through the Logger pro app, record the absorbance and wavelengths of each trial into two tables by finding the lambda maxes. Then, find the concentration of dye in each solution: Concentration of dye= (concentration of stock)(volume of stock)/ volume of dilution 10) Create an A vs. C (calibration curve) in excel including all measurements found. Then using the formula for Beer’s Law (Absorbance = (molar absorptivity coefficient)(1nm)(Concentration)), find molar absorptivity for each trial and record it in a table. Use Beer’s Law to find the concentration of dye in 500ml of the drink. This can be done by putting absorbance in the equation of the graph to find x. 11) Lastly convert the units from moles/liters to grams/liters. CHEM 151 FDPP1 v4.1 8-10-22