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Forensic Examination of Drugs by Thin Layer Chromatography.

Extracts from this document...

Introduction

But Forensic Science

Skills for the Laboratory

Experiment Title:        Forensic Examination of Drugs by Thin Layer Chromatography

Aims:                        To determine the constituents of four unknown drugs.

To establish good safe & organised working practice.

To encourage consistent & meticulous keeping of data & records.

To develop consistent & accurate laboratory procedures.

To establish team work & investigative approaches.

Background Info:        The majority of evidence submitted to crime labs comes from drug-related crimes. Often, this evidence includes unidentified powders that may be illegal drugs. In order to prosecute individuals for possession of illegal substances, it is necessary for forensic scientists to positively identify any suspected drugs submitted to the laboratory. In addition, forensic toxicologists must determine the identity of drugs found in the bodies of drug-overdose victims. Although illegal substances can cause overdose, people also overdose on common over-the-counter (OTC) drugs, like aspirin, when attempting to take their own lives. Thin-layer chromatography (TLC) is one technique used to identify unknown drugs.

Thin-Layer Chromatography (TLC) is a simple & inexpensive technique that is often used to judge the purity of a synthesized compound or to indicate the extent of progress of a chemical reaction. In this technique, a small quantity

...read more.

Middle

Student 3

Spot 1

Spot 2

Spot 3

Spot 1

Spot 2

Spot 3

Spot 1

Spot 2

Spot 3

ASP

0.52

PAR

0.71

CAF

0.5

A

0.48

A

0.42

0.65

A

0.4

0.86

B

0.35

0.6

B

0.51

0.63

B

0.72

0.9

ASP

0.63

PAR

0.68

CAF

0.5

C

0.38

0.66

C

0.54

0.87

C

0.5

0.91

D

0.34

0.5

0.65

D

0.46

0.63

0.77

D

0.52

0.72

0.89

Table 2 Rf value of each compound in solvent 2

Solvent 2

Student 1

Student 2

Student 3

Spot 1

Spot 2

Spot 3

Spot 1

Spot 2

Spot 3

Spot 1

Spot 2

Spot 3

ASP

0.24

PAR

0.76

...read more.

Conclusion

figure one:

The instrumental methods include those mentioned earlier, for example:

Figure 2: HPLC Equipment

image06.jpg

Figure 3: GC-MS equipment

image07.jpg

Such equipment would be used to confirm the identity of the drugs after initial screening has been completed (providing there is sufficient sample).

References:        Table 1        Rf value of each compound in solvent 1

Table 2        Rf value of each compound in solvent 2

Graph 1        Solvent 1, Student 1 (Aspirin)

Graph 2        Solvent 1, Student 2 (Paracetamol)

Graph 3        Solvent 1, Student 3 (Caffeine)

Graph 4        Solvent 2, Student 1(Aspirin)

Graph 5        Solvent 2, Student 2 (Paracetamol)

Graph 6        Solvent 2, Student 3 (Caffeine)

Figure 1        Routes taken by toxicologist

Figure 2         HPLC Equipment

Figure 3         GC-MS equipment

...read more.

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