The Case

 Detection and Quantification of Caffeine in Decaf Coffee 

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By: Theresa Tiang & Goh Chew Lin (2M02)

In today's world, with the heavy workload and limited time we have in a day, we have to burn midnight oil to finish work, complete a drama or to play games. Lack of sufficient sleep results in dozing off in school and work. However, we are not allowed to do so. We are required to be attentive in classes and be alert at all times during work. 

So, how can we keep ourselves awake? Caffeine, or more commonly known to people, coffee. Many of us depend on coffee to keep ourselves vigilant - both students and working adults alike. Some people cannot make it through the day without having at least 1 to 2 cups of coffee. Many are dependent on coffee to keep them awake for their daily activities.

 

Ultimately, what is Caffeine?

• Xanthine alkaloid compound, acting as a stimulant in humans. 

• Called guaranine when found in guarana.

• Called mateine when found in mate.

• Called andtheine when found in tea.

•  Found in leaves and beans of the coffee plant, in tea, yerba mate, and guarana berries, and in small quantities in cocoa, the kola nut and the Yaupon Holly. 

• Can act as a natural pesticide that paralyzes and kills certain insects feeding upon them.

• Central nervous system (CNS) stimulant, temporarily warding off drowsiness and restoring alertness.

There are also articles that tells people of how good caffeine is to our body. For example, it has been found to protect us against Parkinson's disease and depression.
However, caffeine is not entirely good for other body. Many of the detrimental effects of it are:

• Studies have shown that having 4 cups or more of coffee per day (under the age of 55) is linked to early death

• Reduced fertility in women 

• May raise blood pressure in people with hypertension

• Caffeine can cause headaches and migraines

 This is an alarming warning that caffeine is harmful for our body. 

 Now, with the creation of decaffeinated coffee, it is good news for coffee lovers. Many people switch to decaffeinated coffee as commercial companies convince them that coffee is caffeine-free whilst retaining the original aroma of coffee. 

So, how does decaffeinated coffee come about?

Water extraction

Coffee beans are soaked in water. The water containing various components, including caffeine and contributors to the taste of coffee, is then passed through activated charcoal to remove caffeine. Water is placed back with the beans and evaporated, resulting in decaffeinated coffee with its original flavor. Coffee manufacturers get back the caffeine and resell it for use in soft drinks and over-the-counter caffeine tablets.

Supercritical carbon dioxide extraction

Supercritical carbon dioxide is a great nonpolar solvent for caffeine. Also, it is less hazardous than organic solvents which are alternatively used. The extraction process is conducted by forcing CO₂ through the coffee beans at temperatures above 31.1 °C and pressures above 73 atm. In these conditions, CO₂ is in a "supercritical" state. It has gas-like properties, allowing it to penetrate deep into the beans. In addition, it also has liquid-like properties that dissolve 97–99% of the caffeine. The caffeine-laden CO₂ is then sprayed with high pressure water to remove the caffeine. The caffeine is isolated by charcoal adsorption or by distillation, recrystallization, or reverse osmosis.

Many others who are allergic to caffeine are tempted to try decaf coffee to provide themselves with a wider range of drink variety.

   However, are these decaffeinated coffee really caffeine-free as how commercial companies claim them to be? Hence, we have decided to detect and quantify the amount of caffeine found in decaf coffee.