DIAMOND AND SAPPHIRE CELL INFRARED SPECTROSCOPY - A POWERFUL NEW TOOL IN THE FORENSIC LABORATORY

• NCJ Number: 64139
• Journal: Journal of Police Science and Administration Volume: 7 Issue: 4 Dated: (DECEMBER 1979) Pages: 426-438
• Author(s): C R MIDKIFF; W D WASHINGTON; R J KOPEC
• Date Published: 1979
• Length: 13 pages
• Corporate Author: International Assoc of Chiefs of Police
• Publication Format: Article
• Language: English
• Country: United States of America

Annotation

USE OF DIAMOND AND SAPPHIRE WINDOW SAMPLE HOLDERS FOR INFRARED (IR) ANALYSIS IS DESCRIBED AND SHOWN TO BE APPLICABLE TO A WIDE RANGE OF MATERIALS USUALLY ENCOUNTERED IN THE FORENSIC LABORATORY.

Abstract

CONVENTIONAL IR TECHNIQUES HAD LIMITED APPLICABILITY TO THE EXAMINATION OF EVIDENTIARY MATERIALS BECAUSE OF THEIR FREQUENTLY MINUTE SAMPLE SIZE, AS IN A FEW GRAINS OF A DRUG, SEVERAL FIBER FRAGMENTS OR TINY FLECKS OF PAINT. TECHNIQUES EMPLOYED TO SUBMIT THESE TO IR ANALYSIS WOULD DESTROY THE EVIDENCE ITSELF, LIMIT SENSITIVITY, OR PRESENT DIFFICULTIES IN SAMPLE PREPARATION. HOWEVER, A NEW APPROACH TO IR ANALYSIS HAS BEEN DEVISED, SUITABLE FOR RAPID, NONDESTRUCTIVE ANALYSIS OF MICRO SAMPLES, THAT UTILIZES A PAIR OF DIAMONDS OR SAPPHIRES MOUNTED IN A CLAMP AS BOTH SAMPLE HOLDER AND WINDOW. WITH THIS APPROACH, EXCELLENT SPECTRA CAN BE OBTAINED WITH ONLY A SINGLE CRYSTAL OF A DRUG OR EXPLOSIVE OR WITH MICROGRAM SAMPLES OF OTHER MATERIALS. AUTOMOBILE IDENTIFICATION FROM MINUTE SPECS OF PAINT IS NOW POSSIBLE AND IS TO BE REFINED FURTHER THROUGH A SYSTEM DEVISED FOR ENCODING IR DATA FROM KNOWN SAMPLES ON PUNCH CARDS, ACCUMULATING A DATABASE CONTAINING PAINT SPECTRAL DATA ON ALL AUTOMOBILES. IN ADDITION, DIAMOND CELL IR IS ALSO WELL SUITED FOR THE EXAMINATION OF SMALL AMOUNTS OF PLASTIC MATERIALS, SUCH AS BITS OF INSULATION MATERIAL RETRIEVED THROUGH POST-BLAST BOMBING INVESTIGATIONS, OR OF THE PARTIALLY BURNED SMOKELESS POWDER SOMETIMES DEPOSITED ON THE FIRING HANDS OF INDIVIDUALS DISCHARGING FIREARMS. SIMILARLY, IR SPECTROSCOPY PROVIDES INFORMATION ON THE CHEMICAL COMPOSITION OF FIBERS, ENABLING ACCURATE IDENTIFICATION OF FIBER TYPE; THE SAME IS TRUE FOR ANALYSIS OF DRUGS AND NARCOTICS. AS SAMPLE HOLDERS BECOME MORE READILY AVAILABLE, APPLICATION OF DIAMOND CELL IR TO PHYSICAL EVIDENCE ANALYSIS WILL EXPAND EVEN FURTHER. FOOTNOTES ARE INCLUDED. GRAPHS ARE ILLUSTRATIONS ARE PROVIDED. (MRK)