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Chemistry: Glucose and Sports Drinks

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Determination of Sugars in Sports Drinks: A Spectrophotometric Analysis

By: Crystle Culling Student Number: 2686923 Class: Tuesday 12pm (odd weeks)

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1015MSC Lab Report

Crystle Culling 2686923

Abstract
The concentration of sugars in two well-known sports drinks, Powerade and Gatorade, were determined by monitoring an enzyme-catalysed reaction sequence involving the appearance of NADPH. Sucrose and glucose concentrations were calculated from the concentration of NADPH formed by the reaction of glucose-6-phosphate and NADP+. Spectrophotometric absorbance readings were taken at 340nm, this is because NADPH absorbs strongly at this wavelength, whilst NADP+ does not (1015MSC, 2010). The concentration of glucose and sucrose in …show more content…

Absorbance of NADPH at 340nm
1.2 1.0 0.8 0.6 0.4 0.2 0.0 0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 Concentration (mM) y = 0.1897x R2 = 0.99

Calculations
To calculate the concentration of the sucrose and glucose after the first reaction, and the final concentration of glucose of the samples of Powerade and Gatorade, the Beer-Lambert equation was used.

Absorbance Difference

Beer – Lambert Equation: A = εcl
A = Absorbance difference  = Molar extinction coefficient C = Concentration L = Path length

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1015MSC Lab Report

Crystle Culling 2686923

The molar extinction coefficient () was determined from the gradient of the line of best fit. Path length was neglected from the calculations as it was equal to 1cm. As the samples were prepared with a 1:100 dilution factor, this was included in the calculations (DF=100).

Sucrose plus Glucose Calculations (from Table 1 and Figure 1) Powerade Dilute = 0.36 / 0.1505 =2.39 mM/L C = Dilute x DF = 2.39 x 100 = 239 mM/L = 0.239 M/L Gatorade Dilute = 0.39 /

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