Chemistry: Glucose and Sports Drinks

2098 Words Jul 12th, 2012 9 Pages
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

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
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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

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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