Topic 2 Flashcards
- this refers to a relationship to a court of justice and legal proceeding.
Forensic
– this refers to branch of science that deals with the identification of the substances of which matter is composed.
Chemistry
– this refers to the branch of chemistry that deals with the application of chemical principles in the solution of problems that arise in connection with the administration of justice.
Forensic Chemistry
– Police is usually inclined to be niggardly (not generous) in taking samples. This mistake should be avoided.
Sufficiency of the specimen
– If the evidence in question is found in the presence of foreign substance, a sample of the foreign substance must be submitted for analysis.
Standard for comparison
– Each evidence must be collected and preserved as a separate sample. There must be no mixing or intermingling of unknown to known.
Maintenance of Individuality
– Evidence will have no value in court in spite of the good report of the expert if the specimen cannot be identified and possibility of tampering excluded.
Labeling and Sealing
– the first step in the examination of an article is to scrutinize it carefully and write down the laboratory notebook a complete description of its external appearance including the manner in which it is secured and particulars of the sealing.
ACTUAL EXAMINATION OF SPECIMEN
– the results of the examination conducted will be communicated to the requesting party in the form of a written report which must include an enumeration of the articles received for examination with detailed description of the packing, sealing and labeling date of receipt and from whom receive the purpose of the examination, the findings and conclusion. T
COMMUNICATION OF RESULTS
– the written report of the chemist is usually supplemented at a later date by oral evidence if the case is brought to court or fiscal’s office. In court appearance the witness must be composed and as much as possible avoid being irritated by upbraiding of the opposite counsel.
COURT APPEARANCES
– Good work cannot be buried, therefore take all the time necessary to make the case complete, no matter how urgent it may appear or how pressing others may be of the results; it is generally possible to adjourn a case if the work cannot be finished in time.
Go Slowly
– Make a careful and minute examination of everything and do not be satisfied with a qualitative analysis if a quantitative one be possible; it always pays to do too much rather than to little and it is difficult to foresee what will or will not be requires in court.
Be thorough
- Keep a full, neat and clear record of everything seen and done.
Take notes
– Many cases will lead the expert into paths with which he is not familiar, and when this happens he should consult others who are most likely to know.
Consult others
– it enables and deduction to be made from slender and incomplete premise is very useful.
Use imagination
– the simplest explanation is usually the right one.
Avoid complicated theories
– Requires much time and effort
Wet Method
– this refers to the utilization of UV and IR Spectrophometry.
High Precision Method
– this refers to the technical field of using microscope to view samples and object that cannot be seen with the unaided eye (objects that are not within the resolution range of the normal eye).
Microscopy
– (Preservation of evidence) this refers to the study concerning the duplication of images through the action of light, upon sensitized materials (photographic paper or film) with the aid of mechanical device (camera) and its accessories and the chemical processes (film developing and printing) involved therein.
Photography
– this refers to the use of invisible spectrum of light such as UV, IR, X-ray and etc. for the identification and evaluation of pieces of evidence.
Invisible Rays
– this refers to biophysical techniques that enables the separation, identification and purification of the component of a mixture for qualitative and quantitative analysis.
Chromatography
– this refers to laboratory technique used to separate DNA, RNA or protein molecules based on their size and electrical charge. An electric current is use to move molecules to be separated through a gel. Pores in the gel work like a sieve, allowing smaller molecules to move faster than larger molecules.
Electrophoresis
– this refers to the technique of using spectrograph, an optical device for breaking the light down into a spectrum and recording the results photographically.
Spectrography
– this refers to a nuclear process used for determining the concentrations of elements in a vast amount of materials. NAA relies on excitation by neutrons so that the treated sample emits gamma – rays. It allows the precise identification and quantification of the elements above all of the trace element in the sample.
Neutron Activation Analysis
