Spectrophotometric Determination of Dye Content in Beverages
Rebecca Nagurney and Jillian Grudzinski
Advisor: Dr. Pham
Abstract
In this work we determined the amount of dyes in some commercial
food products using spectrophotometric methods. We tested red and
yellow Powerade drinks which according to the manufacturer contain
red #40 and yellow #6 respectively. By applying Beer’s law, we found
that the red Powerade contained 0.051 grams of dye and the yellow
Powerade contained 0.059 grams of dye per bottle. These amounts
may not seem like much; however, because most food products
contain dyes the amount of dyes we consume in our diet per year
could be rather large. An individual consuming one bottle of
Powerade a day is consuming more than 18 g/yr.
Introduction
Food dye is included in almost everything we eat.
Even food and drinks that claim they are “100
percent natural” contain dye. Artificial food dyes
such as Red #40 and Yellow #5 are approved by the
FDA; however, some studies prove that these dyes
have carcinogenic effects and can cause
hyperactivity in children. Dyes are also included in
medicine and are used as a way to identify and
classify ourselves with familiar items. Other
countries besides the United States use all natural
resources as food dyes. The coloring that naturally
occur in many different fruits, vegetables, and
flowers are extracted and used instead of artificial
dyes. In this experiment, we obtained the amount
of dye in Powerade by using spectrophotometric
methods. Different dilutions of red and yellow dye
solutions were made and absorbance levels were
obtained from 375nm to 700nm wavelengths with
25nm increments.
Materials and Methods
Results
To test the amount of red and yellow dye in each drink, stock solutions of the red #40 and yellow
#5 dyes were made. The stock solution of Red #40 had a concentration of 5.4 x 10-5 , and the
Yellow #5 stock solution had a concentration of 5.8 x 10-5. To determine the wavelength that had
the highest absorbance level for each dye, a spectrophotometer was used and the dyes were
tested across the visible wavelength spectra of 375nm to 700nm. The absorbance values
obtained for the stock solutions were plotted on a graph to easily show the lambda max values.
Three additional solutions were made for each dye and were tested at the lambda max values
obtained from the stock solutions. The absorbance level readings for the four red #40 and yellow
#5 dye solutions were plotted on graphs to form the standard curves. The slope of the line of
the standard curve was used to find the concentration of the dye in each drink. The powerade
drink was the diluted and its absorbance level was measured. The concentrations were then
used to find the amount of dye in grams in each bottle of powerade. This was done by using to
formula:
(dye concentration (mol/L)) X (L of solution) X (Molecular Mass of dye (g/mol)) X
(L of powerade/L of powerade in the solution) = Grams of Dye
The results obtained show that there is a
substantial amount of dye in each .946 L bottle
of powerade. The amount of dye calculated for
the red powerade was 0.051 grams and the
amount of dye calculated for the yellow
powerade was 0.059 grams.
Discussion
Most foods we eat contain artificial dyes, but do we
really know how much dye we are consuming per
year? If a person consumes one bottle of powerade
per day for a whole year, that person will be
consuming over 18 grams of dye per year just from
the powerade. Because most foods that a person
eats on a daily basis contains dye , the amount of
dye that a person would consume per year is be
quite large. Red #40 has a MSDS heath rating of 1
and Yellow #5 has a health rating of 2. If the MSDS
health hazard level is that high for handling, how
could it be safe to consume even in small amounts?
Tests have been conducted on rats that have
consumed dye in their water, and each test showed
the dye had a negative effect on the rat’s health.
Other tests showed that the dyes may have been a
cause of cancer and infertility in the rats tested.
Soon, food and drink items that contain Red #40 dye
will have to place a warning on the label because of
the adverse effects the dye can do to a person’s
health.
References
“Material Safety Data Sheet FD&C Red 40 MSDS.” Science Lab. Web.
11 April 2012.
“Material Safety Data Sheet FD&C Yellow 5 MSDS.” Science Lab.
Web. 11 April 2012.
Vorhees, Charles V., et al. “Developmental Toxicity and Psychotoxicity
of FD and C Red Dye # 40 (Allura Red
AC)
in Rats.” Toxicology 28.3 (2003): 207217. Web. 11 April 2012.
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