Forensic Science Example

Forensic Science Example Forensic Science â€" Assignment Example > 1.0TitleChromatography is the processes used to separate dyes after exposing pen marks to a solvent that will dissolve the ink. 2.0. AbstractThe processes used here is for separating ink pigments with the use of paper chromatography. As the water moves through the paper strip it dissolves the pen ink. The water/alcohol moves past the ink and begins to carry the particles that make the ink up. It is clear that, the lightest colour particles move very fast and covers the longest distance. The process separates all the pigments that make up the ink being tested. It was clearly indicated that, even though a pen may be using a specific ink, that ink is made up of different colours and this processes can be very effective in uncovering criminal activities. 3.0 Introduction Most of the substances that people come into contact with on a daily basis are impure. This means that they are mixtures. Therefore a major focus of research in chemistry is coming up with methods and ways of separati ng and indentifying components of mixtures (Cai et al, 2007). Many separation methods solely rely on physical differences between the component mixture like where there is the use of filtration, centrifugation and distillation. Chromatography uses the differences in solubility and adsorption. Chromatography is a method that is used to analyze mixtures by separating them into the chemicals they were made from (Warren, 2005) It is derived from Greek words ‘Chromat’ which means colour and ‘graphon’ which means to write. While it is an ink chromatography, one separates the colour pigments that make up the colour of the pen. This entails that, even if a pen write in one color, the ink is made up from a variety of different color pigments (Horrocks, Coulson, Walsh, 1999). This process can be used to separate ink, blood and gasoline just to mention but a few. Forensic scientists use ink chromatography to solve crimes by matching the documents or stains found at a crime scene to the marker or pen that belongs to a suspect (Gunn, 2009). They then analyze the unknown ink and compare it to writing utensils collected from a possible suspect. When performing this experiment, one puts a dot of ink to be separated at one end of a strip of paper (Wistuba Schurig, 2001). The end is then placed on a solvent which moves up the paper slip dissolving the mixture of chemicals and pulls them up the paper. The results of this process are referred to as chromatogram. It is worth noting, chromatography involves separation of molecules through the stationary phase and the mobile phase. The stationary phase is the paper while the mobile phase is the solvent used. This being the case, the molecules move through the stationary phase at different rates; meaning that, those strongly attached to the paper move slowly and also those that are large while the small ones move very quickly. Substances can be separated on the basis of pH, polarity or even size (Warren, 2005). This pro cess is actually a process that is used to explore capillary action on how a solvent moves up the paper and chromatography which is how different elements of ink are carried along at different rates. To separate several dyes, one must expose the pen marks to a solvent that will dissolve the ink (Trapp Schurig, 2001). In this experiment, two solvents are used: water and alcohol. This is due to the fact that some ink is soluble in water and therefore it is used as solvent. Those inks that are not soluble in water are often soluble in alcohol and therefore alcholol is used to separate the dyes.