I have gained excellent laboratory skills throughout the four years I spent studying at Letterkenny Institute of Technology in Ireland.
To quickly summarise some of the work I have done, I have listed several experiments. They include:
1. Identification of a mixture of unknown organic compounds
2. Extraction of natural oils by stem distillation
3. The separation of serum proteins by electrophoresis
4. Identification of an unknown bullet sample
5. Qualitative and quantitative analysis using spectrometric and chromatographic instruments
1. Identification of a mixture of unknown organic compounds
This experiment involved liquid-liquid extraction, melting point measurements, filtration, recrystallization and instrumental analysis in order to separate and identify the compounds.
In this particular experiment IR was chosen to identify the components. The results were then compared to the library resources and the identification was successful.
Figure 1 Liquid-liquid extraction
Figure 2 KBr disk containing the sample for IR analysis
Figure 3 IR graph of the sample compared to the IR graph (extracted from the library) of a compound that closely matched physical and chemical properties of the unknown sample
2. Extraction of natural oils by stem distillation
This method involved chopped lemon skins to be placed in a large chamber. Within this chamber, the lemons were subjected to steam that fills the entire chamber. Once filled, the steam travelled through the interior of the lemons and picked up the oils that were hidden inside. The steam continued upward until it travelled to a condenser, where the steam was cooled and was consequently turned back into water. Also the oil that was captured by the steam was equally returned to its former state.
Figure 4 Stem distillation used to extract essential oils
Figure 5 Labelled illustration of the distillation apparatus
3. The separation of serum proteins by electrophoresis
Electrophoresis is a separations technique that is based on the mobility of ions in an electric field. Positively charged ions migrate towards a negative electrode and negatively-charged ions migrate toward a positive electrode. Electrophoresis can separate sample that has a charge, like DNA or proteins.
A strip of cellulose acetate was first soaked into a buffer and then placed on to a rack. A sample of serum was placed onto the strip together with protein stain. The sample was then placed into electrophoresis apparatus that was filled with buffer. The current was adjusted to 0.4mA per centimeter width of strip. The apparatus was left to run for an hour, before the sample goes over the strip. The result was successful as all the proteins were separated.
Figure 6 Electrophoresis apparatus that was used to separate serum proteins by electrical currents
4. Identification of an unknown bullet sample
In order to analyse bullet powder for various metals, the metal compounds had to be extracted first before applying AAS (Atomic Absorption Spectrometry) to avoid clogging the instrument. For that reason Microwave digestion was performed.
It was important to acid-wash all the glassware and to use ultra-pure water instead of distilled water to avoid false measurements.
Figure 7 Microwave digestion used to extract metal compounds from a bullet sample
5. Qualitative and quantitative analysis using spectrometric and chromatographic instrument
Many analytical instruments were used throughout the years that include HPLC, Ion chromatograph, electrophoresis, IR spectrometer, UV spectrometer and Atomic absorption spectrometer.
There are wide variety of applications for each instrument and also they each have their limitations; therefore it is crucial to choose the right instrument for each analysis.
I have come across alcohol analysis, vitamin and mineral analysis, water analysis, plastic, paint, fiber, drug and DNA analysis. For each method development, the right equipment was chosen.
Figure 8 HPLC (High-Performance Liquid Chromatograph)
Figure 9 GLC (Gas-Liquid Chromatograph)
