Follow the below rubric fully putting all of the terms and information asked for in the rubric inside the lab report. Please cross check all work for lab report with the rubric because this is how the assignments is graded using the below rubric. Answer all questions listed below inside the rubric.
Rubric to follow:
Phenolic Content – LAB REPORT
Purpose/Introduction – 25 points
- Clear, brief description of why the experiment was done, justifying entire laboratory.
- What are phenolic compounds and what factors affect the biosynthesis of phenolic compounds in the plants?
- What is Solid Liquid Extraction (SLE)? Discuss the mechanism of SLE
- Define antioxidant activity and Discuss the antioxidant mechanism of phenolic compounds.
- Why decrease in particle size increases the extraction yield and reduces the extraction time during SLE of phenolic compounds?andard used in the procedure for TPC quantification? Can we use other phenolic compound as a standard?
- What is the function of sodium carbonate in TPC quantification? Why DPPH was used to quantify antioxidant activity?
Material and Methods –
- Describe the material usedts)
- Clear explain the procedures.
* Results and Discussion –
- Clear summary of results using text before tables and figures are shown.
- Calibration curve included, Tables (titles above) and figures (titles below) clear, complete and not redundant.
- Calculations included and correct.
- Detailed discussion of what the results mean.
Conclusions – 20 points
- Information synthesized into cohesive conclusion.
- Conclude only what can be concluded from data collected.
Laboratory Report Format –
- Laboratory report was organized, cohesive, and easy to follow.
- Used additional references to help improve the quality report and overall understanding of material
See details under rubric and answer all questions related to the topic under this section.
- The objectives should briefly and specially state the purpose of the lab experiment for Phenolic Compounds and for using the Calibration Standard Curve for Total Phenolic Content (TPC).
- State what you are trying to do in the experiment with using Phenolic Compounds and using the Calibration Standard Curve for Total Phenolic Content (TPC): mention that you are carrying out this procedure and explain what procedure in order to get a result). “What is the Goal in Mind for this experiment”.
Principle of Method:
- Explain the science principles explode during this lab experiment on Phenolic Compounds.
- Outline the general process being studied in Phenolic Compounds.
- Use citations and references to back up information found on Phenolic Compounds.
Material for Phenolic Compound Lab experiment:
Please add and any material that I may have missed with your chemistry background on this subject and what I have highlighted below in this section, please make sure I listed it correctly according to the procedure sheet, if not please list it correctly according to the procedure sheets.
- Spectrophotometric 760 nm
- Sodium Carbonate Solution (20%)
- Deionized water
- Folin-Ciocalteu Reagent
- 80% Ethanol
- Plastic pipettes
- Graduated centrifuge tubes
- Erlenmeyer flask
- Vortex Machine
- Gallic Acid (2mg/ml stock solution)
- Volumetric flask
- Unsweetened pure Grape Juice
- Unsweetened pure Cranberry Juice
- Graduated Cylinder- 50ml
- Plastic blue racks for centrifuge tubes
- Distilled Water
- Micropipette tips
- Micropipette holder
- Beakers- 40ml, 100ml, 125ml, 200ml, 250ml
Procedure for preparation of Sodium carbonate solution (20%) reagents:
Dissolve 40 g of anhydrous sodium carbonate in 160 ml of deionized water. The solution was bought to a boil on a hot plate and after cooling, a few crystals of sodium carbonate were added to ensure that the solution is saturated.
Procedure for preparation of the gallic acid standards for the standard curve:
Prepare the stock solution of gallic acid standard (2mg/ml) by dissolving 25 mg of gallic acid standard powder in total volume of 10 ml 80% ethanol. Use 10 ml of volumetric flask to prepare the gallic acid standard stock solution or dissolve 12.5 mg of gallic acid standard powder in total volume of 5 ml 80% ethanol in a 5 ml volumetric flask
Pipette 0.5 ml of diluted sample ( from each sample) in a 15 ml centrifuge tube. Label the tubes properly.
There were five blank centrifuge tubes labeled: 2mg/ml, 1mg/ml, 0.5mg/ml, 0.25mg/ml, and 0.125mg/ml. And two blank centrifuge tubes labeled: Cranberry and Grape.
- Pipette 0.5 ml of 80% ethanol ( increases the transfer of mass) as a blank in a 15 ml centrifuge tube.
- Pipette 0.5 ml of gallic acid (stock solution) standards (different concentrations) in separate 15 ml centrifuge tubes.
- Add 0.5 ml Folin-Ciocalteu reagent (Dye) into standards, blank, and samples (tube was covered in foil).
- Mix thoroughly using vortex mixture.
- Keep the mixture in dark at room temperature for 5 mins.
- Add 1.5 ml of solution carbonate (20%) (helps to stop the reaction) to standard, blank, and the sample.
- Mix thoroughly.
- Bring the total volume of mixture to 10 ml with distilled water.
- Incubate standard, sample and blank at 75° C for 10 min.
- Take the tubes (sample, blank, and standards) out of the water bath. Let them come down to the room temperature (approximately).
- Take spectrophotometric reading at 760 nm of sample against the blank for all samples listed: 2mg/ml, 1mg/ml, 0.5mg/ml, 0.25mg/ml, and 0.125mg/ml and for the reading labeled Cranberry and Grape
- Plot the absorbance reading for the gallic acid standards in the excel and determine the regression equation. I will upload a picture with an example of the gallic acid standard curve and this is how it should look in the lab report with the numbers obtained from the readings of the spectrophotometer for tubes labeled: 2mg/ml, 1mg/ml, 0.5mg/ml, 0.25mg/ml, and 0.125mg/ml and for the reading labeled Cranberry and Grape. Will also take a picture and upload of the section labeled: How to calculate Concentration for the Regression equation( this has to be included in the lab for these samples(2mg/ml, 1mg/ml, 0.5mg/ml, 0.25mg/ml, and 0.125mg/ml and for the reading labeled Cranberry and Grape). All samples should be shown on the same standard curve of TPC using Gallic Acid in an aqueous solution of EtOH 80%.
*Put in the report that the tubes labeled: 2mg/ml, 1mg/ml, 0.5mg/ml, 0.25mg/ml, and 0.125mg/ml used the same dilution factor of 4. However, Cranberry and Grape have a higher concentration, so you have to multiply by the dilution factor of 40.
Things that have to be included in the lab:
- The professor provided us with some background information on Phenolic Compounds that I will upload for you to read and decide if it should be included in the lab report as a resource and reference. (will uploaded photos of this information).
- Explain in the discussion why this lab concerning Phenolic Compounds is important and why we are performing this experiment.
- Explain the purpose of performing this lab concerning Phenolic Compounds and using the Calibration Standard Curve for Total Phenolic Content (TPC) to plot your results for centrifuge tubes 2mg/ml, 1mg/ml, 0.5mg/ml, 0.25mg/ml, and 0.125mg/ml and for Grape and Cranberry Juice (In the Introduction section).
- In this report under results, there should be listed a Table 1 with the Preparation of Gallic Acid Standards of the concentrations: 2mg/ml, 1mg/ml, 0.5mg/ml, 0.25mg/ml, and 0.125mg/ml as shown in the above table labeled Gallic Acid Standards. Also once you obtain the averages from the three trails using the spectrophotometer for each sample 2mg/ml, 1mg/ml, 0.5mg/ml, 0.25mg/ml, and 0.125mg/ml and for Grape and Cranberry fill the averages in on the above table labeled Gallic Acid Standards of Concentration. Provide a title for Table 1 and mention it’s a guide used to prepare Gallic Acid Standards of the above concentrations. Table 2: Should be of the below readings for the three trails in the spectrophotometer for: 2mg/ml, 1mg/ml, 0.5mg/ml, 0.25mg/ml, and 0.125mg/ml, and readings for the three trails in the spectrophotometer for Grape and Cranberry juice and provide a proper name for the table 2.
- Show calculations and work related for all tables and figures in the report. This is very important.
- Under results section provide a bar graph of the numbers for tubes (2mg/ml, 1mg/ml, 0.5mg/ml, 0.25mg/ml, and 0.125mg/ml) and for Grape and Cranberry Juice. Use the numbers below from the table to make the bar graph. Show all calculations and work related.
- Discuss the variation difference in the numbers below obtained from the spectrophotometer and plot them on the Calibration Standard Curve for Total Phenolic Content (TPC)(In the Discussion section). Do this for Table 2 numbers: the tubes (2mg/ml, 1mg/ml, 0.5mg/ml, 0.25mg/ml, and 0.125mg/ml) and Grape and Cranberry Juice.
- Also under results section, from the numbers obtained from the three trails in the spectrophotometer for tubes(2mg/ml, 1mg/ml, 0.5mg/ml, 0.25mg/ml, and 0.125mg/ml) and for Grape and Cranberry Juice use Excel to make the Calibration Standard Curve for Total Phenolic Compounds labeled Figure 1 showing tubes (2mg/ml, 1mg/ml, 0.5mg/ml, 0.25mg/ml, and 0.125mg/ml) and for tubes with readings for Grape and Cranberry Juice. So that means, only one Calibration Curve with results for the tubes (2mg/ml, 1mg/ml, 0.5mg/ml, 0.25mg/ml, and 0.125mg/ml) and for Grape and Cranberry Juice. Label Calibration Curve properly ( Figure 1) and this goes under the Calibration curve and also a brief paragraph explaining what the different samples on the curve represent and are showing. Show all calculations and work related for figure 1.
- In the report note: There were three readings for each tube (2mg/ml, 1mg/ml, 0.5mg/ml, 0.25mg/ml, and 0.125mg/ml) when ran inside the spectrophotometer and there were also three reading for the Grape and Cranberry Juice when ran inside the spectrophotometer.
- Calculate Concentration using the Regression Equation for all of the sample tubes (2mg/ml, 1mg/ml, 0.5mg/ml, 0.25mg/ml, and 0.125mg/ml) and for the Grape and Cranberry Juice. Will upload photo on how to calculate this section. Show calculations and work on the report.
- Also in the discussion talk about the Cranberry and Grape Juice samples and their concentration ( which one had a higher concentration) and how their concentration could play a role in the numbers obtained from the spectrophotometer and why they both had a dilution factor of 40, compared to the other samples (2mg/ml, 1mg/ml, 0.5mg/ml, 0.25mg/ml, and 0.125mg/ml) having a dilution factor of 4.
How to calculate Concentration using the Regression Equation?