Pharmacies judicial and crime solving
Few processes are more important for society to solve crimes, protect the public both against criminals and protect the innocent from unjust punishment. Very often, the strength of a prosecution based on the ability of law enforcement to connect the accused with the victim, matching the physical evidence of the crime scene or victim with trace evidence found in or around the person accused of crime. to researchers to consult a wide range of experts to analyze evidence collected at crime scenes and forensic laboratory for analysis. to perform chemical expert legal analysis to identify the materials and learn the nature of the evidence. A highly qualified chemist court may determine the composition and nature of materials and predict the source and the sample match against the sample. Modern chemistry employs a wide range of analytical techniques and traditional methods analysis.
The physical evidence collected at the crime scene is sealed in special containers to prevent contamination and degradation is carefully cataloged. A chain of custody has been established and documented that the tests are sent to a forensic laboratory. In the laboratory, the evidence is reviewed by qualified personnel in a several areas: legal serologist examine body fluids, forensic experts examine human remains to classify firearms technicians and evidence of firearms and explosives and forensic chemists determine the composition and identity of materials.
The poisons were used by ancient Egyptians and the Greeks and Romans. Democritus was probably the first chemical study of poisons, and contacted some of its findings to Hippocrates. The poisons were used both murder and as a means of execution, the philosopher Socrates was condemned to death by drinking hemlock. The ancient Romans had laws against poisoning at 82 a. C. Before the development of systematic research, scientific criminal guilt has been determined largely by circumstantial evidence and hearsay. Arsenic poison is popular in Roman times. He was referred to the dust of succession to the French principles. Blandy, 1752 trial was the first instance of a poison chemical test real and the Marsh test, developed in 1836, was the first reliable analysis can prove scientifically that arsenic was present in the body of a victim.
Each school of pharmacy, in general, organic and analytical chemistry, forensic chemists but also specialize in specific areas of expertise. By example, an inorganic chemist can examine the remaining powder with microchemistry to identify the chemical composition of small particles. Another chemical thin could use reactions during the chromatography analysis of blood or urine traces of drugs and other chemicals could be used in test tubes identify the largest samples of compounds. Forensic chemistry include organic and inorganic analysis, toxicology, fire research and Criminal serology. Each method of analysis uses specialized techniques and instrumentation. The process can be as simple as establishing a density gradient column compare samples of soil or as complicated as using a mass spectrometer and neutron activation analysis to characterize an unknown substance.
A wide range of laboratory techniques and equipment used in forensic studies. This includes ultraviolet, infrared, visible spectrophotometry, activation analysis neutron gas chromatography and mass spectrometry, high pressure liquid chromatography and atomic absorption spectrophotometry. Techniques and the instruments chosen depending on the type of sample or the substance to be examined.
The fact that most of the samples tested are not pure substances, but often mixed with soil or waste is a major challenge for the forensic chemist. This can also be an advantage, as any substance contained in a crime scene is a unique blend of chemicals that can become identified. Arsonists, for example, often use accelerators such as gasoline or kerosene in the index combustion and flame propagation inside a building. A forensic chemist may sample material burned and unburned volatile hydrocarbons extracted and separated elements of analysis by gas chromatography.
The gas chromatograph (GC) separates the volatile components separated by passing the volatiles through a long absorption column. The technique is highly reproducible and reliable, since each sample may contain a defined number and type of impurities, it can provide a party near the accelerator on a known source known as a tank of gas or hardware. It may be necessary to vaporize a small sample of material to supply gas for volatile analysis. The components of the vapor is passed through the column and separated into a number of components, each of which can be captured and analyzed. In most cases, the gas is mixed with parts from paint or building materials burned, making identification impossible a simple test, but the ability of GC to separate small help in identification.
KM is often linked to a mass spectrometer. Mass spectrometry (MS) is broken and separated samples ionized fragments mass and charge. vast libraries of fragments compared with computer-assisted identification of materials as possible, even when the sample is very low. Most forensic laboratories have access to a gas chromatograph coupled with mass spectrometry (GC / MS). high pressure liquid chromatography (HPLC) separates many types of drugs and can also be combined with MS.
Analysts can use various types of spectroscopy. A typical spectrometer consists a light source that illuminates a known wavelength, the holder of the position of solid, liquid or gaseous samples, and a lens system and photocells that compared shine the light of the sample with the light passes through. A decrease in the intensity of light passing through the substance indicates the presence of absorbing materials light at this wavelength, absorbance is a measure of the amount and concentration of materials and the wavelength of maximum absorption is characteristic of type material. Infrared spectroscopy is particularly useful for identifying organic compounds such as links between certain atoms absorb radiation rapidly Infrared (IR).
Ultraviolet (UV) spectrophotometry distinguish between samples of proteins and nucleic acids such as deoxyribonucleic acid (DNA). Atomic absorption spectrophotometry provides the means to determine the absorption and emission spectra, useful tools in analyzing metals such as bullet fragments. nuclear magnetic resonance spectroscopy (NMR) uses the fact that the nuclei of certain molecules absorb radio frequency radiation by high magnetic fields. The nuclei of certain molecules absorb light in the frequencies of characters, which makes identification of the least impurity possible samples. X-ray analysis allows the forensic investigator to display foreign objects in the body.
In the activation analysis neutrons, a neutron beam from a nuclear reactor is a sample of test material. The material becomes temporarily radioactive, emitting gamma rays, γ rays that are characteristic of the composition, the analysis of γ-irradiation provides an accurate and reproducible determination of the contents of the samples. This technique has made possible the determination of arsenic in the hair of the corpses buried for hundreds of years. In one case, the body of an Arctic explorer who died in suspicious circumstances during the 1870s was found buried in a coffin surrounded by ice. Neutron activation analysis of hair from the body showed the hair was several inches long contained arsenic at low but short hair near the scalp (who grew up in the few days before his death) contained high concentrations of arsenic, indicating that death was probably caused by arsenic poisoning.
Often, the presence of impurities very low makes comparisons possible. For example, cars are painted with paints prepared according to certain specifications of color and composition, pigments and binders used vary from manufacturer to manufacturer and even between models of dealer. A small sample of the paint left at the scene of an accident can be color controls by spectrophotometry and composition analysis. The authors of numerous crimes hit and run has been convicted on the basis of the combined analysis GC / MS paint chips.
Residues left by the models of firearms burning powder composed of particles with physical and chemical properties. Burnt powder, for example, often contain traces of the chemical reactions that produce nitrites and trace metals such as barium, which are often present primers. Both reactions chemical and microscopic analysis (including electron microscopy) are employed in the identification of powder residues on clothing and skin. A rapid method for detection of gunshot residue on the hands of suspects involved covers his hand with melted paraffin wax, the wax cools, then peel off. gunshot residue transferred from the skin in paraffin turned blue or green in the presence of diphenylamine, but many common substances such as urine gave a result false positive. Greiss reagent is much more definitive, and additional tests can identify traces of lead in the bullet holes. Even microscopic particles are compositions are defined and can be identified clearly.
Toxicologists examine a broad range of materials such as stains of blood, urine and trace gases blood of toxic substances or drugs. Many companies now require drug testing of employees is the responsibility of the technician to distinguish between the presence of illicit drugs and their metabolites in foods such as poppy seeds. These tests can be as simple as paper or thin layer chromatography or as complicated as chromatography GC or electrophoresis and serological analysis of a blood sample. After the death of unknown cause, samples of the victim's lungs, blood, urine, vitreous and stomach contents were examined for traces of poisons or drugs. The insects found on or near carcasses were also collected and examined, can actually absorb traces of drugs or poisons in the body, indeed, traces of poisons are sometimes found in the neighborhood long after concentrations insect's body fell below detectable limits.
Forensic Biochemists out blood typing and testing of enzymes in body fluids in cases of assault, and also in paternity cases. Even small samples of blood, saliva or semen can be separated by electrophoresis and subjected to enzymatic analysis. In the case of rape, traces of semen on the clothes or the person becomes an important test, the composition of semen varies from person to person. Some of people excrete acid phosphatase enzymes and other proteins that are rarely found outside of seminal fluid, and chemicals are typical sperm. The presence of semen can be demonstrated by the microscopic analysis of the presence of sperm or a positive test for prostate specific antigen.
In sexual assault cases, small samples of DNA in the blood, semen, skin or hair is found on the victim can be purified and the largest amount of DNA in a reaction Polymerase chain to produce sufficient quantities for analysis. Since DNA is the most accurate of an individual as fingerprints, DNA corresponding to an author a sample found on the victim is regarded as proof of contact. In the United States' efforts are creating a national Combined DNA Index System (CODIS) to collect data from many states and agencies for law enforcement and ensure that the rate of particular DNA profile, a test on the scene many may be compared and matched. Many perpetrators were convicted and many innocent people released after years in prison after a DNA test.
Accidents caused by drunken drivers kill about 15,000 people per year in the United States alone (about half of the fatalities are vehicle related alcohol), so a blood alcohol kit is standard equipment on most cars brigade or police patrol vehicles in the state. breath analyzers are used to estimate the blood alcohol content of drivers suspected of being drunk, the driver may appear sober, but with all the blood alcohol level above the limit legal. Although it is impossible to take blood samples on the way, research has shown that the concentration of ethanol in the breath has a definite relation concentration in the blood. Many communities have established a legal limit of 0.08 percent (which means that 100 ml [3.38] ounces of blood contain 0.08 grams [0.0028] ounces of ethanol). In fact, officials now believe that the ability to drive a person is likely to affect the blood ethanol levels of 0.05 percent.
There various types of analytical devices are available to administer breath tests. A test using a portable infrared spectrophotometer, another uses a fuel cell, and the most common test used several tubes of glass or plastic and some common chemicals reagents. The test subject blows through a tube blowing bubbles through a chemical solution containing acid, sulfuric acid, potassium dichromate, water and silver nitrate. Oxidation results of alcohol in the reduction of dichromate ions of chromium ions, with a corresponding change in color from orange to green. An electrical device that uses a photocell compare the color of the test solution with a standard solution, giving a quantitative determination of alcohol content. The test provides a rapid determination reproducible and the amount of alcohol in the breath of a person and is a numerical measure of the amount of alcohol in the blood. The use of a chemical test avoids the subjective opinions sobriety and provides reliable evidence of the judicial process. The test can be easily and quickly administered by trained law enforcement, but the team legal and calibrate chemical analysis and testify to its accuracy.
The fingerprints on smooth surfaces can often be visible through the application of dust is light or dark, but the fingerprints on checks or other documents are often occult (hidden). Hidden tracks are sometimes visible by the use of ninhydrin, which removed by reaction with amino acids in perspiration. Fingerprints or other marks are sometimes visible by exposure to high power laser light. Some fingerprints can be treated with chemicals, resulting in a model that fluoresces when exposed to laser light. cyanoacrylate vapors ester is used fluorescent dyes for visible fingerprints.
judicial chemicals are commonly used by laboratories in agencies law enforcement or private testing laboratories and are often called to testify in court as expert witnesses. In these cases, the pharmacist can compare the evidence in the event that it is a large number of similar cases, he or she has reviewed and is frequently invited to give an expert opinion about the quality tests. Since chemical forensic generally have a degree in chemistry and graduated from forensic science degree, their academic degrees and years of experience and the ability to compare the case concerned with many other cases, the evidence makes them valuable and credible.
About the Author
Dr. Badruddin Khan teaches chemistry in the University of kashmir, Srinagar, India.
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