Colorimetry

Colorimetry is used to determine the Concentration of a Glucose Solution.

• To do this, we need to use Benedict's Reagent and a Colorimeter to get an Estimate of how much Reducing Sugar there is in a solution.
• A Colorimeter measures the strength of a coloured solution by detecting how much Light Passes Through it, the More Concentrated the colour, the Higher the Abundance of Reducing Sugars

PAST PAPER QUESTION!

Describe how the concentration of a reducing sugar can be measured using a colorimeter?

Using Known Concentrations of reducing sugar (1)

Heat with Benedict's Solution at least 80°C (1)

The Colour Changes to  green, yellow, orange, brown or (brick) red (1)

Then press zero on the colorimeter by using  a Blank Cuvette With Benedict's solution. (1)

Then take a Reading of Transmission (how much light passes through the cuvette) of the Solution. (1)

Plot a Calibration Curve for Transmission against Reducing Sugar Concentration then use the reading of the Unknown Sugar Solution and read off graph to find the Concentration of the Unknown sugar solution (1)