In the experiment, Iron-Rich Foods: How to Get the Most Out of Them, there is a colorimetric scale used to indicate iron and copper levels. I was wondering whether this scale utilizes Lambert's law and Beer's law of colorimetry (log I0/I = kcd) and if yes, how so?
Here is the link to the experiment I am talking about:
https://www.sciencebuddies.org/science- ... background
Colorimetric Scale in Iron-Rich Foods: How to Get the Most Out of Them
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Re: Colorimetric Scale in Iron-Rich Foods: How to Get the Most Out of Them
Hi - This project uses a color chart during the procedure. (You can see it in Figure 3.)
The Lambert-Beer Law is used in colorimetry to determine the concentration of a compound in a solution. The Law states that there is a linear relationship between the absorbance of light and concentration. The iron measurement in the project is based on a colorimetric reaction, so Lambert-Beers Law does apply to that reaction. Usually, spectrophotometers are used to measure the absorbance, which is not the case in this project. (This project has a difficulty rating in the middle school range.)
In the project, our eyes basically replace the spectrophotometer, and the absorbance of the solution (which is reflected in the color) is assessed visually. The color chart is based on the fact that the color of the solution (absorbance) linearly correlates with the concentration of the iron. So the color scale does utilize Lambert-Beer’s Law as each color on the chart represents a different light absorbance of the solution. You could maybe think of the color chart as a calibration curve where each color (or absorbance value) corresponds to a specific concentration of iron in solution.
I hope this helps.
Amy
Science Buddies
The Lambert-Beer Law is used in colorimetry to determine the concentration of a compound in a solution. The Law states that there is a linear relationship between the absorbance of light and concentration. The iron measurement in the project is based on a colorimetric reaction, so Lambert-Beers Law does apply to that reaction. Usually, spectrophotometers are used to measure the absorbance, which is not the case in this project. (This project has a difficulty rating in the middle school range.)
In the project, our eyes basically replace the spectrophotometer, and the absorbance of the solution (which is reflected in the color) is assessed visually. The color chart is based on the fact that the color of the solution (absorbance) linearly correlates with the concentration of the iron. So the color scale does utilize Lambert-Beer’s Law as each color on the chart represents a different light absorbance of the solution. You could maybe think of the color chart as a calibration curve where each color (or absorbance value) corresponds to a specific concentration of iron in solution.
I hope this helps.
Amy
Science Buddies