On Wednesday 3rd and Thursday 4th June, our enthusiastic A-level Chemistry students participated in the ‘Schools’ Analyst Competition’ led by the Royal Society of Chemistry.
During the briefing, the students were told that they were to act as analytical chemists assisting the police, who are investigating the cause of a mysterious illness. Through a combination of forensic, cosmetic and analytical science, it was the student’s responsibility to work out if foul play may be involved. Students were provided with items for analysis and had to attempt to identify some unknown substances using their skills in the lab. Through gravimetric analysis, titrations and thin-layer chromatography, students provided valuable insight and conclusions.
The project was split up into three key experiments.
Experiment 1 – Analysis of caffeine in coffee
Students performed a back titration to determine the amount of caffeine in a coffee sachet using iodine solution. When combined with iodine, potassium iodide and sulfuric acid, caffeine forms an insoluble precipitate. The students filtered off this precipitate, determined how much iodine remains by titration and then worked out how much caffeine was in the original sample.
Experiment 2 – Identification of lipstick
Students were asked to separate out the different pigments which the lipstick was made of. Students were provided with some standard extracts of the lipsticks along with the cutout piece of the shirt with the lipstick mark. It was then their responsibility to use thin-layer chromatography to see if there was a match.
Experiment 3 – Identification of an unknown cream
Students were tasked with a simple gravimetric analysis which would help identify what the contents of the tube may include. The pupils separated the oils and fats from the other ingredients then compared their results to a range of standards.
Overall, the students thoroughly enjoyed participating in the competition, with many favouring the titration experiment. The tasks enabled students to demonstrate and expand their existing chemistry knowledge and skills through practical experiments based on relevant problems. Well done to everyone for showing integrity and perseverance throughout the day. Take a look below at the gallery of images.
