Earth Science: the Work of Chemists – Searching for Clues
Analytical chemists often use detective skills as well as an ability to apply multiple methods of analysis to reach their goal: a better understanding of what lies inside molecules.
Analytical chemists can tackle problems as varied as confirming the age of a piece of art or detecting hazardous substances in air or food, or examining the quality of crystals to be used in microchips.
Progress through analytics
The 19th-century German chemist Carl Remigius Fresenius observed, “It can be easily proved that all great advances in chemistry are more or less directly related to new or improved analytical methods.”
Since chemical reactions must be identified before they can be improved, his statement remains valid. Only when we understand the exact structure and composition of a chemical can improvements be made in medicine, solar cells, aircraft engines, or other products.
Solving crimes in the lab
Today people can be identified and in the case of a criminal be convicted with only a tiny amount of sperm or skin. The evidence is in the cells. The genetic material—such as DNA—in even a tiny sample can be duplicated with enzymes, using the technique called polymerase chain reaction (PCR).
Next, the DNA is analyzed and fragments are separated onto a gel based on their sizes. Ultimately, the fragments are displayed in the form of a bar code, very similar to the codes on today’s retail products. Except for identical twins (who have the same genetic makeup), each person’s gene code is unique and can be used to identify them.
Doping analysis
Traces of drugs remain in urine longer than in blood. However, it is not always possible to find an athlete guilty of doping using only evidence found in urine. The analysts must also
determine the quantity of the substance.
For example, the consumption of a massive amount of caffeine can be determined and prohibited, but an athlete with caffeine levels expected from normal consumption of drinks like coffee, tea, or cola is not considered to be doped. Human bodies produce many sub-stances at known and established levels.
Medical tests are used to establish whether an abnormally high amount of a particular substance is present.
TOOLS OF ANALYSIS
For analysis, a substance is usually separated from other materials. Often, high-performance liquid chromatography (HPLC) is used for this purpose. A mass spectrometer may then be used to identify the separated molecules.
This equipment can detect a billionth of a gram of a substance in a kilogram of material, roughly the equivalent to detecting one lump of sugar in a swimming pool. To test very high concentrations of a sub-stance, chemists may turn to a nuclear magnetic resonance (NMR) spectrometer.
Because any one particular analytical method can provide only part of a total answer, analysts often use a combination of testing methods before answering a question.