Special Projects 1 Enlightening Chemistry Dyes Lab and Thin Layer Chromatography Crime Lab Abstract The goal of the first lab was to identify a pen used to write a note The pen was identified through the use of both Thin Layer Chromatography TCL and UV Vis analysis as pen 3 In the TCL part solutions of four unknown inks and the ink used to write the pen were dabbed onto an alumina plate and solvent was run up them By comparing the distance the highest dye in an ink traveled pen 3 was matched as the ink used to write the note In order to perform UV Vis analysis methanol ink solutions were made and a UV Vis spectrophotometer was used to compare wavelengths of the maximum absorbencies The second part of the lab dealt with fluorescence phosphorescence and chemiluminescence The goal of this part was to be able to identify the differences in the three processes Several of each were preformed and qualitative observations were recorded Introduction The goal of the crime lab is to make use of ink analysis in order to match the ink from an unknown pen to that of a known pen The goal of the luminescence lab is to utilize different techniques to make objects light up in a specified way This shows how chemical light can be produced in various ways This lab highlights three separate methods of creating chemical light Those are phosphorescence fluorescence and chemiluminescence Each of the chemical light systems has a source of energy as well as an organic molecule that receives light and then emits that energy as light When a photon hits an electron in a nonbonding orbital it excites it so that it bounces up to the anti bonding level When the electron comes back down it releases energy in the form of light This transmitted light is what the human eye sees if it is on the visible spectrum The energy gap of the bonding and nonbonding molecules in a certain molecule directly relates to a wavelength of light that can be absorbed The crime lab was centered on solving an investigation The prompt for this lab was that an anonymous note and several possible suspects pens were provided and it needed to be determined which pen wrote the note Through the use of multiple techniques the ink that wrote the note Ink extraction is a method used in this lab Methanol is painted onto the notes in a test tube and the test tubes are placed in hot water Boiling extracts the ink because it causes ink to leach off paper and into the methanol solution Another technique that is used isanalysis through the use of a UV Vis spectrophotometer The UV Vis spec emits light through a sample and records the amount of each wavelength that is transmitted It then calculates the absorbance values from the transmittance values and graphically displays this information The graph that it displays is an absorbance vs wavelength graph The highest point on the graph is considered the maximum wavelength or lambda max for that given samples In a research case in China a test was run in which 33 blue inks were examined through UV Vis data analysis Using the absorbance values of the inks after being dissolved in DMF as variables in principle component analysis reliability of the three components was able to be determined greater that 86 The results were then verified through the use of thin layer chromatography This is one instance that clearly displays that UV Vis and thin layer chromatography are comparable methods in this type of analysis 1 Another way to separate compounds is through the use of thin layer chromatography TLC Using silica or alumina a plastic or glass plate is coated in a thin layer Because both silica or alumina are polar other polar materials will adhere to the plate In TLC a drop of ink dotted onto bottom of the plate The plate is then placed in a chamber containing a solvent The solvent then runs up the plate carrying the carrying the compound mixture with it Every component in the mixture has a different polarity as a result each component has a different adherence to the plate The different solvents containing ink then run toward the top of the plate which results in the separation of the components of the solvent because of the different polarities of the components Every ink has an Rf factor The Rf factor is a ratio of the distance a compound traveled to the distance the rest of solvent traveled It is in effect a way to determine different compounds are located on the plate relative to each other Methods and Materials Dyes Half Phosphorescence Onto two pieces of filter paper polyaromatic acids was squirted over a sink Filter paper was placed onto a hot plate on low for 5 15 minutes until bone dry Filter paper was placed under UV lamp Long and Short UV radiation Colors were observed under a UV lamp The lamp was turned off The color intensity and duration of glow all were observed Fluorescence A Beaker of tonic water under UV lamp was observed from the top What happened when the lamp was turned off was observed The large beaker of water was placed under lamp To the beaker 1 to 3 drops of the concentrated fluorescein solution was added UV lamp was shone on the solution The solution was observed with UV lamp on and off A drop of fluorescein was added to the beaker of tonic water and observed A chromatography plate containing fluorescent indicating dye was placed under UV lamp Chemiluminescence To an Erlenmeyer flask 2 mL of TKDE Tetrakis dimethylaminoethylene was added The flask was observed under a UV lamp About 5mL of Luminol was mixed in DMSO with 5 mL of dye in a scintillation vial The steps with TKDE were repeated DMSO and luminal with Fluorescein Rhodamine B Rubrene Perylene and once with no dye To these 1 mL of 1 0M NaOH was added The solutions were covered and shook The solutions were observed In an Erlenmeyer flask 4 grams of Al2O3 and 4 mL 2 H2O2 were mixed To the flask 25 mL of one of the dyes was added Perylene Tetracene 2 3 benzanthracene 9 10Dipehenylanthracene or Rubrene With a pipette 2 mL of oxalyl chloride was added in the CH2Cl2 solution The solutions were swirled and observed Crime Half Ink Extraction A water bath was put together at a bench and heated to 65oC Notes were cut into small strips and placed into a marked test tube To each test tube added 2 mL of methanol Test tubes were heated using hot water bath 65oC until the methanol boiled for 5 minutes Test tubes were allowed to cool to room temperature Observations were made about the solutions The identity of the culprit was guesses based on