Forensics Journal - Stevenson University 2011 | Page 20

STEVENSON UNIVERSITY

latter representing good results. The examiners were asked to look at
the bands that were close together on the chromatograph; an example
of these dyes is shown in Figure 1, ink two. Examples of separation
ratings of three and one are shown below in Figures 1 and 2. It is
important to note that over-concentrated spots were not examined
because separation could be due to the concentration of the ink. The
examiners were then asked to choose the solvent system that gave the
best separation and clarity to set as the standard solvent system. The
grades given by the three examiners can be found in Table 5. Two
examiners agreed on the grade of every solvent system. The difference in grades did not differ by more than one point. This showed
consistent grades between the examiners. The bolded values represent
the best solvent system combination chosen by that examiner. Two
examiners chose solvent system AFG as giving the best separation and
clarity of the ink components.

Preparing the Chamber:
Two 11 inch by 11.5 inch General Glassblowing Company Laboratory Apparatus glass tanks were used to perform the thin-layer chromatography. The graduated cylinder containing 75 mL of SSI mixture
of choice was poured into the glass tank. The tank was then rotated
to allow the mixture to make contact with every area inside the tank.
The mixture was poured out and then the graduated cylinder containing 60 mL of the same SSI mixture was poured into the tank. A
piece of 46 inch by 57 inch Whatman Filter Paper (Catalog number
1002-917) was cut to the size of the chamber [