Analytical chemistry gives you the ability to ask and answer the questions such as “What is something made of?” or “How much of each constituent is present in the sample?” The main purpose of analytical chemistry is to identify or quantify analytes in the sample. For example, give the analytical chemist a cup of coffee and he/she will tell you if there is caffeine in it, how much sugar you’ve added or what elements is your
Analytical chemistry revealed us that the average amount of caffeine in coffee is 40 mg per 100 g of the sample, that your lipstick can contain heavy metals and the concentration of vitamin C in commonly consumed fruits and vegetables.
Qualitative analytical chemistry identifies analytes in the sample. There are numerous qualitative tests, such as the iodine test for starch in food, or flame test for certain metal ions. On the other hand, the quantitative analysis determines the quantities of chemical constituents present in a sample. If purely chemical methods are used, then we talk about classical methods. However, if there are physical methods involved (e.g. the amount of absorbed or emitted light) then we are talking about instrumental methods.
Classical methods of analytical chemistry are gravimetry (the concentration of the analyte in the sample is determined based on the mass of product generated in a chemical reaction) and volumetry (the concentration of the analyte in the sample is determined based on the volume of reagent needed to complete reaction with the analyte).
Using classical analytical methods, which are precise and accurate, you can determine the concentration of the analyte in the sample, but the analyte must be present in at least 0.1% of the sample.
Nowadays, instrumental methods are commonly used because of much less sample used, lower analyte quantity that can be determined and results that can be produced more rapidly. On the other side, they are more expensive than classical methods, since sophisticated equipment is required.
Classical methods are the fundamentals of laboratory practice. They are still widely used in laboratories for the determination of water content in the
The purpose of this blog post is to introduce the audience to the basics of analytical chemistry, especially quantitative analysis