Detection of tampered morphine using Infrared, refractometry, and Raman spectrometry. Or you may call it a Validation study using Raman spectrophotometry for the detection of tamperedorphine.

Chapter 1

Introduction

In recent years, the seizure of money obtained from drug trafficking has been associated with the arrests of drug dealers.  The presence of drugs on seized banknotes has been used as evidence in drug trafficking cases.  Until now, the method of drug analysis on paper currency has involved considerable sample handling and is destructive to the evidence, hence preventing future reanalysis.  Infrared spectroscopy is used extensively for compound identification and routine analysis in the forensic science laboratory. (Strommen, D. P.; Nakamoto, Pp. 474-478)

Raman spectroscopy involves the interaction of light with matter. It is a non-destructive technique based on inelastic light scattering, i.e., the energy, or the frequency, of the incident laser light is changed, or shifted. The difference between the incident and scattered frequencies corresponds to an excitation of the molecular system, most often an excitation of a vibrational mode. By measuring the intensity of the scattered light as a function of the frequency difference, we obtain a Raman spectrum, which reveals information about a sample's chemical structure and physical state. Raman spectrum is similar to an infrared spectrum (IR/NIR), though different vibrational modes are observed in these two complementary techniques.

What is a Raman Instrument?

A Raman instrument is made up of three basic components the spectrograph which channels the light and separates the component frequencies delivered to 3) the detector that measures the energy, or intensity, of each component frequency. Many complete Raman systems also include an operating software for instrument control, data acquisition, data processing and analysis.

What are the Advantages of the Raman Technique?

Raman spectroscopy now provides quick, easy, and most importantly, non-contact and non-destructive analysis, both qualitative and quantitative, with no sample preparation required. Samples may be tested directly with fiber probes or through glass, quartz, sapphire cells, and fibers. Other advantages include:

1. Raman is ideal for the studies of biological samples and chemical compounds in aqueous solutions, as water is only a weak Raman scatterer and adds little interference.

2. Raman can cover a broad range, 50 - 4000 cm-1, in a single recording, which allows for characterization of both organic and inorganic compounds. In contrast, gratings, beam splitters, filters, and detectors must be changed to cover the same range by IR.

3. Raman spectra are cleaner and sharper, and thus are more amenable to quantitative studies such as quantification of isolated Raman bands as well as qualitative studies such as database searching.

4. As the diameter of the laser beam at its focal point is normally 0.2 - 2 mm, Raman spectra can be obtained with only a small quantity of sample. This is a great advantage over conventional IR. Furthermore, Raman microscope objectives can focus the laser beam down to 20 µm or even smaller, thus distinct small sample areas can be analyzed.

5. Resonance Raman effects can be used to selectively enhance vibrations of ...