Compare+the+amount+of+sugar+found+in+different+soft+drinks

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 * Research Question/Statement: ** Compare the amount of sugar in three different soft drinks. **(DCP)**

Benedicts Quantitative reagent can be used to measure the % glucose present in different solutions. You are given 3 different types of clear, colourless soft drink to test. Measure their sugar content and compare your reading to find out if they are significantly different or not.
 * Introduction: **


 * Step 1: Building a calibration curve **

Apparatus
 * 250ml Benedict’s quantitative solution (BQS)
 * 100ml 10% Glucose solution
 * Distilled water
 * 2 x burettes and stands
 * 12 x 100ml beaker
 * 2 x 5ml syringe
 * 11 test tubes and sufficient racks to hold them
 * 11 cuvettes
 * Access to a colorimeter
 * Access to a waterbath set to 100oC

Method 1.Place a 10% solution of glucose in a burette. 2.Place water in another burette and prepare a series of glucose solutions (0%, 1%, 2% … 10%) 3.Label a series of test tubes to match the glucose concentrations. 4.Using a 5ml syringe add 5 ml of the appropriate concentration to each of the labelled test tubes. Rinse in distilled water between uses. 5.Using a 5ml syringe Add 5 ml of BQS to each tube and place in a boiling water bath for a few minutes. 6.Allow the solutions to cool and any precipitates to settle (alternatively after cooling centrifuge the sample and use a pipette to extract the supernatant) then add each of the solutions to a different cuvette. 7.Setup the colorimeter to use a red or orange filter (590-750nm). Use a cuvette of distilled water to zero the colorimeter. 8. Record the absorbance of all the different glucose concentrations including the blank. 9.Use the readings to construct concentration calibration curve of % glucose and absorbance.


 * Step 2: Measuring the sugar content of the soft drinks **

Apparatus
 * 3 different sweet colourless soft drinks (multiple bottles/cans of each)
 * 500ml Benedict’s quantitative solution (BQS)
 * 2 x 5ml syringe
 * 30 test tubes and sufficient racks to hold them
 * 30 cuvettes
 * Access to a colorimeter
 * Access to a waterbath set to 100oC

Method 1.In to a test tube, add 5 ml (using the 5ml syringe) of the soft drink to 5 ml (using the other 5ml syringe) of BQS. 2.Label the test tube appropriately and place in a boiling water bath for a few minutes. 3.Read the absorbance using the colorimeter as setup in the calibration process 4.Repeat for each type of drink a minimum of 10 times to gain sufficient data

// -- Manage the order of tasks to maximise your effective use of laboratory time -- //


 * Lab Report **

Write up DCP only for this lab and answer the following points:
 * You were given a number of different cans/bottles of drinks. Did the sugar content of the each drink vary from bottle to bottle? What is your assessment of the quality control of the manufacturers?
 * Suggest further steps: consider the problems, and if you can, potential solutions of using this method to measure the amount of sugar present in sweetened tea drinks and solid foods such a varieties of apple