Measuring the Caffeine Content in Energy Drinks

Background Knowledge

Caffeine is a stimulant of a nervous system of the methylxanthine class and it’s an addictive drug which is produced by extracting steeping (the material of the plant in the water) through infusion. Infusion is an action taking place for extracting flavours and chemicals compounds from the plant substances such as oil, alcohol and water by steeping. Caffeine (C8H10N4O2), is a source of stamina in energy drinks but it does not provide with energy in the body. Energy drinks must have a minimum of 80 mg of caffeine (Wikipedia, 2019).

Introduction

Caffeine it’s an alkaloid which is established in the leaves, fruits and seeds. Caffeine is normally involved in the coffee, energy drinks, tea and soft drinks. The concentration of caffeine in energy drinks is a solution of dichloromethane (CH2Cl2) and chloroform (CHCl3), a technique produced commercially as a result of decaffeinated tea and coffee (Quincy, A.E/ Ibrahim, L/ Leah, D.G/ Sergei, M.K 2015). After being extracted, the caffeine can be analysed straight by calculating the absorbance of the solvent solution at 292nm. To find the amount of caffeine in the energy drinks, UV Spectrophotometer experimental technique can be used. Using dichloromethane to extract caffeine from energy drinks is useful as caffeine is not much soluble in water as it’s in the dichloromethane (Amrita, 2011). The average caffeine content should be from 27-164 mg in energy drinks and 24-46 mg in cola drinks, from these values, I can predict that the amount of caffeine should be less or equalled to the average content of caffeine (Mayo Clinic Staff, 2017). The UV Spectrophotometer is a very common and very useful technique to measure the caffeine content in any drink such as coffee, soft drinks, energy drinks and other source of drinks that provide temporary energy.

Aims and Objectives

The aim of this experiment is to determine the concentration of caffeine in three different energy drinks, along with comparing the caffeine solution through calibration graph of a known concentration used to prepare standard solutions to the amount of caffeine in the energy drinks. The objective of this study is to perform a UV Spectrophotometer of the commercial samples of different energy drinks using dichloromethane, and distilled water. To determine the amount of caffeine solutions to the calibration standard samples in contrast to pure caffeine five solution made and measured its absorbance (y)-axis vs concentration (x)-axis in the calibration graph. then according to the results obtained through the calibration graph compare the caffeine standard solution to the crushed caffeine solutions. To accurately evaluate the amount of caffeine in each of the energy drinks can be done by analysing the collected data.

Hypothesis

The hypothesis of this investigation is that the level of caffeine in all the samples would be very similar to each other, at a minimum of a 5ml as I’m not using much concentrated energy drinks with high caffeine content, which is typical to the energy drinks that are produced for consumption as caffeinated drinks. I predict that as the level of concentration increases, the absorption rate will increase too, which will result in calibration graph to be a positive correlation.

Investigation Plan

A plan was discussed among the group and approved by the tutor. The plan was to finish practical investigation within 15 hours of practical work, including the material and chemical reagents listed above. Then writing up the report involving data analysis, graph representations and calculations carried forward.

Date Action

• Friday, 8th November 2019 Choose an experiment and apply background theory, note down the aims and objectives
• Saturday, 9th November 2019 + Sunday, 10th November 2019 Write down all the required materials, discuss the plan and process of how experiment will be carried out (method)
• Monday, 11th November 2019 Summarise the risks involved, health and safety hazards of the investigation (experiment)
• Wednesday, 13th November 2019 With tutor discuss the hypothesis and procedures
• Thursday, 14th November 2019 Carry the practical investigation (trial to see if the experiment is working or not)
• Thursday, 15th November 2019 to Thursday, 28th November 2019 Practical investigation (make caffeine solutions) + record calibrate results + energy drink solutions (comparing)
• Friday, 29th November 2019 Calculations/graph representations
• Wednesday, 4th December 2019 Write up the data analysis and conclusions
• Thursday, 5th December 2019 Evaluate the experiment (methodology) and write down the limitations and improvements for the future experiments
• Friday, 6th December 2019 Structure the essay including research + report + references.

Risk Assessment

In overall the procedure of this practical investigation is medium risk of potential harm to investigators, because the use of dichloromethane can cause skin irritation if liquid remained on skin and inhalation can lead to milk affects such as vomiting or headaches. Safety precautions were taken including gloves, lab coats and goggles, through avoiding inhalation as during the vent of separating funnel containing dichloromethane had a lot of gas which was released, and reporting any faulty or broken material to the lab technician such glass which might result in cut.

Investigation/ Data Collected

Beginning with a preliminary investigation which was carried out to find out the suitable volume of each energy drink solutions needed thought which we found that 10ml would be a suitable volume to use in the investigation and the suitable wavelength used to find the absorbance rate in caffeine solutions and the energy drinks to make at the level of standard solutions as using different wavelength for both caffeine and energy drinks solutions is not allowed which could result in inaccurate values obtained through the experiment.

Results of Caffeine Solutions

Samples of caffeine solutions prepared by diluting in the water. Caffeine concentration in grams (g) Absorbance at 352nm (wavelength) Total volume of water diluted in the caffeine in (ml) 0.2 (0.0625)

• 0.4 (0.125) 25
• 0.6 (0.1875) 25
• 0.8 (0.25) 25
• 1.0 (0.3125) 25

Calculations

Through the leaflet of pro plus tablets, I found that each tablet contains 160g of ingredients where caffeine content is 50g in each tablet. To find the correct caffeine content in each concentration of 0.2, 0.4, 0.6, 0.8 and 1.0 g in which I am going to use in each of the caffeine solution, the calculations were required as to make sure I’m using the correct amount of caffeine in each of the solutions. How much caffeine does each tablet of caffeine pro plus contains?

• 1 tablet = 160g Caffeine content in each pro plus tablet = 50g
• 160g – 50g = 110g not caffeine

Caffeine concentration used*caffeine content each tablet/total content of tablet

• 0.2*50/160 = 0.0625g in 25ml
• 0.4*50/160 = 0.125g in 25ml
• 0.6*50/160 = 0.1875g in 25ml
• 0.8*50/160 = 0.25g in 25ml
• 1.0*50/160 = 0.3125g in 25ml

Results of Energy Drinks

Samples of energy drinks. Samples Energy drink concentration in (mg) Absorbance at 352nm (wavelength) Total volume of water diluted in the drinks (ml) Volume of dichloromethane used in (ml)

• Mountain Dew 10 0.186 15 5
• Monster 10 0.810 15 5
• Coca Cola 10 3.000 15 5

Data Analysis

The purpose of this experiment was to determine the amount of caffeine in each energy drink, through the results obtained, I found out that Coca Cola has the higher caffeine content than the Mountain Dew and the Monster drink. From data collected, the absorbance at 352 no (wavelength) of each of the drinks is as following:

• Mountain Dew (0.186)
• Monster (0.810)
• Coca Cola (3.000)

Published caffeine content in the drinks used in the experiment were as following:

• Mountain Dew = 1.522 mg of caffeine content in 10ml solution
• Monster = 3.381 mg of caffeine content in 10ml solution
• Coca Cola = 3.14 mg of caffeine content in 10ml solution

I expected that the monster drink should have a higher content of caffeine as amongst the drinks that I’ve chosen. Through the results obtained I found that caffeine content in Coca Cola was higher than expected, this could be because cola might have additional ingredients or colouring agents which absorb in a same wavelength as caffeine. The drinks were extracted into the dichloromethane solution, so that the absorption light at the wavelength could be accurately measured in each drink. However, I could extract the additional compounds from the Coca Cola to accurately measure the absorption at the particular wavelength by investigating the compounds included in the drink that could excluded from the extracted solution made for each drink. Through the investigation carried out, I found that monster drink which I expected to obtain a higher absorbance at 352nm than other drinks such cola drink which is commonly known as soft drink should have a lower absorbance at 352nm. However, Mountain Dew and monster drink had a very low caffeine content which is quite good in comparison to coca cola, the most common bought drink commercially.

Conclusion

The procedure of this investigation was to see wether my hypothesis was accurate or not, to analyse this I was testing the concentration of caffeine content in each energy drink and compare it to the caffeine solutions by using the method known as UV spectrophotometer which I think worked very well. This states that UV spectrophotometer it’s extremely good technique or method to find the caffeine content in each selected drink. I have selected my drinks very carefully as my point was to find the caffeine concentration in only drinks that are mostly sold commercially, overall the drinks were less caffeine concentrated but as I investigated the caffeine content in the drinks, I realised that Coca Cola was the most concentrated amongst the drinks I’ve chosen for the experiment.

Evaluation (Methodology)

The course of action conducted in this investigation was planned to lower down the possibility of error that might occur. The solutions were measured accurately as possible using laboratory apparatus cautiously, the readings were seen twice each time to avoid error while noting down the results. The regents were properly handled, used and transferred using measuring apparatus and funnel carefully avoiding skin contact and inhalation. Each of the equipment was washed properly using distilled water to avoid any further contamination in the experiment. The samples of each of the energy drinks were prepared at the amount of 10 ml, 3x using dichloromethane and distilled water at the same level of volume to get accurate and reliable results. However, precautions, data collected, conclusions and planning were carried very carefully based on experiment results achieved and time management which lead to a successful investigation. Alternatively, the accuracy of the experiment was based on patience and the work of different subject areas could possibly create distraction which could result in an error in the obtained results as frame work of this experiment was 15 hours, where everyone had to balance the time for carrying experiment only as a part of group.

Improvements/Limitations

One of the clear and plain limitation was the time, where laboratory room was varied from time to time as other classes would have lessons during various day times. As I’ve used only 5x caffeine solutions and plotted in the calibration graph represented, 3x the solutions of energy drinks and caffeine tablets which were not pure according to the leaflet of Pro plus caffeine tablets. If I get another chance to carry this experimental investigation again in the future, I will carry each solution of energy drink 3x to calculate the average of caffeine content in the drinks by repeating the procedure. Also I will make 10x the solutions of caffeine for calibration graph and for comparing the both solutions of caffeine and energy drinks, and use pure caffeine tablets or powder to avoid any time taken for calculations of caffeine content in each of the solutions made varying from 0.2 to 1.0 g.

From this I can obtain more reliable and reasonable results. However, it’s not easy to get a pure caffeine powder from any pharmacy as it’s a very high stimulant which is not sold commonly to anyone. Another limitations was the samples of energy drinks which I’ve used were three, Coca Cola, Mountain Dew and monster drink by dissolving in dichloromethane and distilled water to determine the amount of caffeine in each of the drink. In the future I will use more samples of drinks and also tea, coffee and other soft drinks including energy drinks with higher caffeine levels to find the similarity in between those and average them to get good reliable results. An additional limitation was the measurement while reading the results from the measuring cylinder and pipette. These are the minor errors which could happen to anyone during the procedure of an experiment but these can be lowered by checking accurately the number showed on the measuring equipment.