Over the last couple hundred years
Over the last couple hundred years, people have been attempting to find synthetic alternatives to sugar. One of the earliest discoveries was by a chemistry researcher, Constantine Fahlberg, in 1879. At the time, he had been attempting to create new preservatives and accidentally spilled some of a compound he had synthesized onto his hands. Later that night, when he was home and was eating dinner, he noticed an intense sweetness on his hand. The next day, he went back to the lab and by retracing his steps, he was able to recreate the compound. He would later go on to name it saccharin after the Latin word for sugar. 1
Following its creation, this compound began to be marketed as a new sweetener. This sweetener really began to take off during World War I and II when natural sugar was being rationed. Even following the war, this sugar continued to be popular. However, around the 1960’s, researchers began to question how safe this compound was. At the time, they were experimenting on rats and ended up finding that it had the potential to lead to an increase in the chance that the rat would develop cancer over time. 2 This study among many others, would eventually lead to many countries like Canada outright banning the compound and the USA considering it but never actually followed through.
With this ban in Canada and its controversial nature in the USA, researchers were attempting to find replacements for it. Since then, we now have four other artificial sweeteners that have been approved by the Food and Drug Administration (FDA). Those four are acesulfame potassium by Sunett, Aspartame by either NutraSweet and Equal, Sucralose by Splenda, and D-Tagatose by Sugaree. 3 With all these new artificial sweeteners, there are many advantages and disadvantages to each.
For this experiment, we will be looking specifically at Aspartame. This is an artificial sweetener which is sold under both NutraSweet and Equal, it is said that this artificial sugar is approximately 200 times sweeter than that of natural sugar. 4 Over the years, researchers have been attempting to see if this artificial sweetener has any chance of causing disease in humans. As of recently, the only thing that has been found is that when this compound is given to monkeys in doses of over 1 gram per day, it has the potential to provoke seizures. 5 In humans though, no effects have been shown when exposed to high levels of aspartame. In theory, researchers believe that it is acceptable for humans to have a daily intake of 40 milligrams per kilogram per day. For the average consumer though, this number will be hard to reach since most manufacturers use a cocktail of sweeteners, making it hard for anyone artificial sweetener to ever reach a number higher than the recommended daily amount. 6
In this experiment, we want to see how much aspartame is present in packets of Equal. To do this, we will be making using a method that was first presented by Christopher Fenk and Nathan Kaufman in 2007. When creating this method, these researchers wanted a method that was safe and reliable which could be used by undergraduate students in class. In the end, they came up with a method that follows three simple steps. The first step is for the students to add analyte to a volumetric flask. In practice, this analyte is a solution of stock aspartame solution with a concentration of 5 mg/ml which is prepared in advance by the instructor. From there, students add their biuret reagent to each sample. The biuret reagent used is CuSO4, which is a relatively safe compound and is easier to work with than that of chemicals described in earlier methods. Then the final step for preparation is just to have the student dilute the sample with water. If followed, students then can use spectroscopic analysis to analyze their samples. 7
The benefit of this method is that it can be slightly modified in several different ways to get different results. By following different protocols, we can look at different methods such as external calibration or standard addition. Along with that, it is possible to modify the experiment to use other methods of quantification of artificial sweeteners than just that of spectrophotometry. Researchers in 2015, released a paper talking about how simple smartphones can be used to analyze assay results. In their paper, they placed a multi-well plate on top of a tablet inside a dark box. Then with the sample in the box, they used a simple smartphone to take a picture of the sample. This picture was then analyzed, and it allowed them to determine the concentrations of the samples they were analyzing. 8
By looking at each of these methods, we will be seeing how the results change regarding using either external calibration or standard addition. Along with that, we will be comparing how our results change using spectrophotometry and the method described above using our phones. By doing this, it should allow us to see the differences associated with each method and see how they change in terms of accuracy and precision.