NCJ Number
57782
Journal
Journal of Forensic Sciences Volume: 22 Issue: 4 Dated: (OCTOBER 1977) Pages: 807-814
Date Published
1978
Length
8 pages
Annotation
RESULTS OBTAINED FROM AN ANALYSIS OF OVER 150 TYPEWRITER RIBBON INKS BY THIN-LAYER CHROMATOGRAPHY (TL) ARE ANALYZED.
Abstract
THE RIBBONS WERE CUT INTO 1 CM PIECES AND PLACED INTO GLASS VIALS. REAGENT-GRADE PYRIDINE WAS ADDED TO EACH SAMPLE TO EXTRACT INK FROM THE RIBBONS. IT WAS ALLOWED TO REMAIN FOR 30 MINUTES TO INSURE SUFFICIENT EXTRACTION. THE DISSOLVED INK WAS THEN SPOTTED ON A PRECOATED SILICA GEL GLASS PLATE AND THE SPOT ALLOWED TO DRY. EACH CHROMATOGRAPHIC PLATE WAS THEN DEVELOPED IN EITHER OF 2 SOLVENT SOLUTIONS. AFTER DRYING, THE PLATES WERE VISUALLY COMPARED WITH ORDINARY WHITE LIGHT AND ULTRAVIOLET LIGHT. RESULTS OF THE STUDY REVEALED THAT TLC IS A RAPID, HIGHLY DISCRIMINATORY TECHNIQUE FOR DISTINGUISHING TYPEWRITING INKS, ALTHOUGH A MEANINGFUL COMPARISON COULD BE CONDUCTED WITH ONLY ONE TYPEWRITTEN CHARACTER. EXCELLENT SEPARATION AND RESOLUTION OF DYE COMPONENTS WAS ACHIEVED. TYPEWRITER INKS FROM DIFFERENT COMPANIES COULD BE READILY DISTINGUISHED AS COULD INKS OF DIFFERENT DYE MIXTURES FROM THE SAME MANUFACTURER. HOWEVER, IT WAS NOT POSSIBLE TO IDENTIFY THE MANUFACTURER OF A SPECIFIC RIBBON INK. THE RESULTS SHOWED THAT TLC ANALYSIS IS AN EXCELLENT INVESTIGATION TOOL TO THE EXAMINER OF QUESTIONED DOCUMENTS. TABULAR DATA AND A LIST OF REFERENCES ARE GIVEN. (AUTHOR ABSTRACT MODIFIED -- MJW)