Drug IdentificationDrug Identification

Screening tests vs. ConfirmationScreening tests vs. Confirmation

• Screening- a test that is nonspecific Screening- a test that is nonspecific and preliminary in nature.and preliminary in nature.

• Confirmation- a single test that Confirmation- a single test that specifically identifies a substancespecifically identifies a substance

Drug IdentificationDrug Identification

• Color TestsColor Tests

• Microcrystalline TestsMicrocrystalline Tests

• ChromatographyChromatography

• SpectrophotometrySpectrophotometry

• Mass SpectrophotometryMass Spectrophotometry

Color Tests: Color Tests: Five (5) primary test Five (5) primary test reagentsreagents• MarquisMarquis (2% formaldehyde (2% formaldehyde

in sulfuric acid) Turns in sulfuric acid) Turns purplepurple in presence of opium in presence of opium derivatives derivatives Turns Turns orange-brownorange-brown when when mixed with amphetamines mixed with amphetamines and methamphetaminesand methamphetamines

• Dillie-KoppanyiDillie-Koppanyi (1% cobalt (1% cobalt acetate in methanol is 1acetate in methanol is 1stst added to the suspect added to the suspect material, followed by 5% material, followed by 5% isopropylamine in methanol)isopropylamine in methanol)Turns Turns violet-blueviolet-blue in in presence of barbiturates.presence of barbiturates.

• Duquenois-LevineDuquenois-Levine (Solution A a mixture of 2% (Solution A a mixture of 2% vanillin and 1% vanillin and 1% acetaldehyde in ethyl acetaldehyde in ethyl alcohol; sol. B concentrated alcohol; sol. B concentrated hydrochloric acid; sol C is hydrochloric acid; sol C is chloroform)chloroform)Turns Turns purplepurple in the in the presence of marijuana.presence of marijuana.

• Van Urk Van Urk (1% solution of p-(1% solution of p-dimethylaminobenzaldehyde dimethylaminobenzaldehyde in 10% concentrated in 10% concentrated hydrochloric acid and ethyl hydrochloric acid and ethyl alcohol)alcohol)Turns Turns blue-purpleblue-purple in presence in presence of LSD.of LSD.

• Scott Test Scott Test ( solution A is 2% ( solution A is 2% cobalt thiocyanate dissolved cobalt thiocyanate dissolved in water and glycerine 1:1; in water and glycerine 1:1; solution B is concentrated solution B is concentrated hydrochloric acid; solution C is hydrochloric acid; solution C is chloroform)chloroform)This is a test for cocaine. Will This is a test for cocaine. Will turn blue in the presence of turn blue in the presence of solution A, pink in the solution A, pink in the presence of solution B, and presence of solution B, and back to blue in the presence back to blue in the presence of solution C.of solution C.

Page 255

Microcrystalline TestsMicrocrystalline Tests

• Test to identify specific substances Test to identify specific substances by the color and morphology of the by the color and morphology of the crystals formed when the substance crystals formed when the substance is mixed with specific reagents.is mixed with specific reagents.

What is a crystalline What is a crystalline precipitate?precipitate?

Microcrystalline TestsMicrocrystalline Tests

• These tests are rapid and often do These tests are rapid and often do not require the isolation of the drug not require the isolation of the drug from its diluents.from its diluents.

• Most color and crystal tests are Most color and crystal tests are largely largely empiricalempirical, that is we do not , that is we do not fully understand why they produce fully understand why they produce the results that they do.the results that they do.

ChromatographyChromatography

• We know it is used to separate mixtures.We know it is used to separate mixtures.

• QualitativeQualitative versus versus QuantitativeQuantitative

QualitativeQualitative tells us a substance is a tells us a substance is a mixturemixture of heroin and quinine of heroin and quinine

QuantitativeQuantitative tells us that tells us that mixturemixture is is 10% heroin and 90% quinine10% heroin and 90% quinine

Chromatography Chromatography

• The theory of chromatography works due The theory of chromatography works due to to Henry’s LawHenry’s Law. (page 125). (page 125)

• The law states “ When a volatile chemical The law states “ When a volatile chemical compound is dissolved in a liquid and is compound is dissolved in a liquid and is brought to equilibrium with the air, there is brought to equilibrium with the air, there is a fixed ratio between the concentration of a fixed ratio between the concentration of the volatile compound in air and its the volatile compound in air and its concentration in the liquid, and this ratio concentration in the liquid, and this ratio remains constant for a given temperature.remains constant for a given temperature.

ChromatographyChromatography : Henry’s Law : Henry’s Law

• An equivalent way of stating the law is that the An equivalent way of stating the law is that the solubilitysolubility of a gas of a gas in a liquid at a particular temperature is proportional to the in a liquid at a particular temperature is proportional to the pressure pressure of that gasof that gas above the liquid. Henry's law has since been above the liquid. Henry's law has since been shown to apply for a wide range of dilute solutions, not merely shown to apply for a wide range of dilute solutions, not merely those of gases.those of gases.

• An everyday example of Henry's law is given by An everyday example of Henry's law is given by carbonatedcarbonated soft drinkssoft drinks. Before the bottle or can is opened, the gas above the . Before the bottle or can is opened, the gas above the drink is almost pure drink is almost pure carbon dioxidecarbon dioxide at a pressure slightly higher at a pressure slightly higher than than atmospheric pressureatmospheric pressure. The drink itself contains dissolved . The drink itself contains dissolved carbon dioxide. When the bottle or can is opened, some of this gas carbon dioxide. When the bottle or can is opened, some of this gas escapes, giving the characteristic hiss (or "pop" in the case of a escapes, giving the characteristic hiss (or "pop" in the case of a champagnechampagne bottle). Because the pressure above the liquid is now bottle). Because the pressure above the liquid is now lower, some of the dissolved carbon dioxide comes out of solution lower, some of the dissolved carbon dioxide comes out of solution as bubbles. If a glass of the drink is left in the open, the as bubbles. If a glass of the drink is left in the open, the concentration of carbon dioxide in solution will come into concentration of carbon dioxide in solution will come into equilibrium with the carbon dioxide in the air, and the drink will go equilibrium with the carbon dioxide in the air, and the drink will go "flat"."flat".

ChromatographyChromatography

What is it and how does it worWhat is it and how does it work?k?

Types of ChromatographyTypes of Chromatography

• Gas Chromatography (GC)Gas Chromatography (GC)

• High Performance Liquid High Performance Liquid Chromatography (HPLC)Chromatography (HPLC)

• Thin-Layer Chromatography (TLC)Thin-Layer Chromatography (TLC)

Types of Chromatography:Types of Chromatography:Gas ChromatographyGas Chromatography• A A gas chromatographgas chromatograph is a chemical analysis instrument is a chemical analysis instrument

for separating chemicals in a complex sample. A gas for separating chemicals in a complex sample. A gas chromatograph uses a flow-through narrow tube known chromatograph uses a flow-through narrow tube known as the as the columncolumn, through which different chemical , through which different chemical constituents of a sample pass in a gas stream (carrier constituents of a sample pass in a gas stream (carrier gas, gas, mobile phasemobile phase) at different rates depending on their ) at different rates depending on their various chemical and physical properties and their various chemical and physical properties and their interaction with a specific column filling, called the interaction with a specific column filling, called the stationary phasestationary phase. As the chemicals exit the end of the . As the chemicals exit the end of the column, they are detected and identified electronically. column, they are detected and identified electronically. The function of the stationary phase in the column is to The function of the stationary phase in the column is to separate different components, causing each one to exit separate different components, causing each one to exit the column at a different time (the column at a different time (retention timeretention time). Other ). Other parameters that can be used to alter the order or time parameters that can be used to alter the order or time of retention are the carrier gas flow rate, and the of retention are the carrier gas flow rate, and the temperature.temperature.

Gas ChromatographyGas Chromatography

Gas ChromatographyGas Chromatography

• Look at page 129Look at page 129Figure 5-6 shows a Figure 5-6 shows a chromatogramchromatogram

• GC is highly sensitive GC is highly sensitive and can yield and can yield quantitative results. quantitative results. This is seen if This is seen if compared with a compared with a known amount of known amount of substance compared substance compared with the peaks of the with the peaks of the unknown in the unknown in the chromatogram.chromatogram.

Gas ChromatographyGas Chromatography

• An added extension to GC for forensic scientist is An added extension to GC for forensic scientist is PYROLYSIS gas chromatography.PYROLYSIS gas chromatography.

This is where solid physical evidence material such This is where solid physical evidence material such as paint chips, fibers, and plastics which normally as paint chips, fibers, and plastics which normally can not be dissolved in a gas can be subjected to can not be dissolved in a gas can be subjected to very high temperatures (500-1000’C) so they will very high temperatures (500-1000’C) so they will decompose into numerous gaseous products. decompose into numerous gaseous products. These can now be ran through a GC to produce a These can now be ran through a GC to produce a pyrogram. The complexity of the pyrogram serves pyrogram. The complexity of the pyrogram serves as a “fingerprint”. See figure 5-7 page 131.as a “fingerprint”. See figure 5-7 page 131.

High-Performance Liquid High-Performance Liquid Chromatography (HPLC)Chromatography (HPLC)

• Liquid is used as the ‘moving’ phase Liquid is used as the ‘moving’ phase through the column instead of gas.through the column instead of gas.

• Major advantage is the entire process Major advantage is the entire process takes place at takes place at room temperatureroom temperature..

This helps with organic explosives This helps with organic explosives and and drugs that are generally heat drugs that are generally heat sensitive. sensitive. LSD is an example of LSD is an example of such a drug.such a drug.

Thin-Layer Chromatography Thin-Layer Chromatography (TLC)(TLC)

• Is a SHEET chromatographyIs a SHEET chromatography

• Has solid stationary phase Has solid stationary phase and liquid moving phase.and liquid moving phase.

• If the sample to be If the sample to be analyzed is solid, it must analyzed is solid, it must first be dissolved in a first be dissolved in a suitable solvent.suitable solvent.

• Once the liquid has moved Once the liquid has moved a sufficient distance a sufficient distance (usually 10cm) the (usually 10cm) the development is complete.development is complete.

• Then it must be Then it must be visualized.visualized.Separation of black ink via TLC

Thin-Layer Chromatography Thin-Layer Chromatography (TLC)(TLC)

To visualize:To visualize:

1.1. Plates can be placed under Plates can be placed under ultraviolet ultraviolet lightlight revealing those materials that revealing those materials that fluorescefluoresce as bright spots on dark as bright spots on dark background.background.

2.2. The plate can be sprayed with a chemical The plate can be sprayed with a chemical reagent that reacts with the separated reagent that reacts with the separated substances and causes them to form substances and causes them to form colored spots.colored spots.

Thin-Layer Chromatography Thin-Layer Chromatography (TLC)(TLC) Turn to page 133. See figure 5-9 and 5-10Turn to page 133. See figure 5-9 and 5-10

What is a RWhat is a Rff value? Value defined as the value? Value defined as the distance traveled by the component divided distance traveled by the component divided by the distance traveled by moving liquid by the distance traveled by moving liquid phase.phase.

In fig 5-10 the moving liquid was allowed to In fig 5-10 the moving liquid was allowed to move 10 cm and the heroin moved 8 cm. move 10 cm and the heroin moved 8 cm. The RThe Rff value is 8/10 which = .8. value is 8/10 which = .8.

The quinine moved 4 cm. What is the RThe quinine moved 4 cm. What is the Rff value? value?

Thin-Layer Chromatography Thin-Layer Chromatography (TLC)(TLC)

Powerful tool to forensic scientist due Powerful tool to forensic scientist due to:to:

• Both rapid and sensitiveBoth rapid and sensitive

• Takes less than 100 micrograms for Takes less than 100 micrograms for analysisanalysis

• Minimal costs and space to useMinimal costs and space to use

• Numerous samples can be analyzed Numerous samples can be analyzed simultaneouslysimultaneously

SpectrophotometrySpectrophotometry• In physics, spectrophotometry is In physics, spectrophotometry is

the the quantifiablequantifiable study of study of electromagnetic spectra. It is electromagnetic spectra. It is more specific than the general more specific than the general term electromagnetic term electromagnetic spectroscopy in that spectroscopy in that spectrophotometry deals with spectrophotometry deals with visible light, near-ultraviolet, and visible light, near-ultraviolet, and near-infrared. Also, the term does near-infrared. Also, the term does not cover time-resolved not cover time-resolved spectroscopic techniques.spectroscopic techniques.

• Spectrophotometry involves the Spectrophotometry involves the use of a spectrophotometer. A use of a spectrophotometer. A spectrophotometer is a spectrophotometer is a photometer (a device for photometer (a device for measuring light intensity) that can measuring light intensity) that can measure intensity as a function of measure intensity as a function of the color (or more specifically the the color (or more specifically the wavelength) of light. Important wavelength) of light. Important features of spectrophotometers features of spectrophotometers are spectral bandwidth and linear are spectral bandwidth and linear range of absorption measurement.range of absorption measurement.

Spectrophotometer

SpectrophotometrySpectrophotometry

• Three measurement typesThree measurement types

1.1. Ultraviolet (UV)Ultraviolet (UV)

2.2. VisibleVisible

3.3. Infrared (IR)Infrared (IR)

Compare figures 5-16 and 5-17 on page Compare figures 5-16 and 5-17 on page 141141

IR provides a much more complex pattern.IR provides a much more complex pattern.

Mass SpectrometryMass Spectrometry

• Combination of gas chromatography Combination of gas chromatography and mass spectrometry (GC/MS).and mass spectrometry (GC/MS).

GC separates the mixture and GC separates the mixture and immediately sends to spectrometer immediately sends to spectrometer in combination of a computer. in combination of a computer.

Figure 5-18 page 144Figure 5-18 page 144

Collection / Preservation of Collection / Preservation of drug evidence.drug evidence.

• Refer to Appendix I starting on page Refer to Appendix I starting on page 543.543.