Brown, Charlotte

Kirk, Paul L.

English

Northwestern University Illinois, School of Law: Scholarly Commons

Journal of Criminal Law and CriminologyVolume 45 | Issue 3 Article 121954Horizontal Paper Chromatography in theIdentification of Ball Point Pen InksCharlotte BrownPaul L. KirkFollow this and additional works at: https://scholarlycommons.law.northwestern.edu/jclcPart of the Criminal Law Commons, Criminology Commons, and the Criminology and CriminalJustice CommonsThis Criminology is brought to you for free and open access by Northwestern University School of Law Scholarly Commons. It has been accepted forinclusion in Journal of Criminal Law and Criminology by an authorized editor of Northwestern University School of Law Scholarly Commons.Recommended CitationCharlotte Brown, Paul L. Kirk, Horizontal Paper Chromatography in the Identification of Ball Point Pen Inks, 45 J. Crim. L.Criminology & Police Sci. 334 (1954-1955)HORIZONTAL PAPER CHROMATOGRAPHY IN THE IDENTIFICATIONOF BALL POINT PEN INKS*CHARLOTTE BROWN A N PAUL L. KIRKCharlotte Brown is a graduate of the School of Criminology, University of California,and research assistant to Professor Kirk, with whom she has coauthored other articlesappearing in this Journal.Paul L. Kirk, Professor of Criminalistics, School of Criminology, University ofCalifornia, has published in this Journal numerous research papers on various phasesof scientific criminal investigation. He is the author of Crime Investigation and hasbeen an Associated Editor of this Journal since 1945.-EDITOR.Paper chromatography is well known to virtually all chemists, biochemists, andbiologists because of the tremendous achievements in those fields that it has madepossible (1). Its bibliography is now so extensive (2, 3, 4, 5) that few people can hopeto read even the more important papers in the field. Only within the last two orthree years have publications appeared (6, 7, 8, 9) describing its application to thefield of ink identification. The early work of Souder and Somerford (6, 7) utilizing anascending strip method with water as the developing solvent for fluid ink was shownto be effective despite its somewhat crude technique. Later work (8) while morerefined was still more difficult to apply to original ink lines from which minute quanti-ties of ink must be removed than the technique described here.No publication describing the application of paper chromatography to ball pointpen inks has been noted, though this development is a very obvious one (8). Theproblem of identifying these inks is in several respects different from that of liquidwriting inks, because of the completely different type of dye dispersing agents em-ployed (10). In fact, treatment of ball point pen inks from the standpoint of thedocument examiner has been quite incomplete in all respects, though isolated papershave appeared (11, 12). Formulas of these inks have altered rapidly as the manu-facturing information has increased. Early studies are virtually obsolete since nowthe oily vehicles so commonly used in the first ball point pens have been quite gener-ally superseded, and a wider variety of dyes are now employed than at first. Anotherfactor that has made the study difficult is the very large number of brands of pensthat has appeared on the market and the almost bewildering rate of increase in them.It is nearly hopeless to attempt to obtain all of the pens of this type that are nowsold. Positive identification of all of them does not now seem possible because variouspens appear to contain'the same or very similar inks possibly because a single manu-facturer of ink may supply several manufacturers of pens. However, the techniquedescribed in this paper has been quite effective in identifying the group in which anysuch ink falls and in distinguishing between most of the inks that are used.EXPERIRENTALChromalographic Technique. The method adopted was similar to that of Giri andcoworkers (13, 14). The chromatograms were made with whole circular Whatman 9 1* Aided by a grant from the Research Committee of the University of California.IDENTIFICATION OF BALL POINT PEN INKSFigure 1Small Horizontal Chromatography Outfit (/ rds actual size)filter papers held between a pair of circular flat glass dishes with ground surfaces ofcontact as shown in Figure 1. Six inch diameter Pyrex pie dishes were found verysatisfactory after the top surface of the flange was ground flat in the manner of adesiccator lid.' The papers were drilled in the center with a cork borer or punch ofapproximately 3L inch diameter, and around the hole, but with the same center,were arranged the ink spots to be chromatographed equidistant from the center. Aglass tube of very slightly less diameter than the center hole (a small vial is satis-factory) was wrapped with a strip of filter paper and placed at the center of thebottom vessel. This served as a wick up which the solvent in the bottom of the vesselwas delivered to the circumference of the center hole. The solvent front, traveling asan expanding circle, encountered and acted upon all the spots approximately simul-taneously moving each of them out in a narrow fan-shaped pattern. Ordinarily sixor eight samples were placed on the same paper though more or less could be runsimultaneously. An additional feature of this method was the fact that as the spotmoved toward the periphery, it broadened in the circumferential dimension andnarrowed in the radial so as to produce the chromatogram ultimately as a series ofcurved bands. In this study it was found advantageous to reduce the time so thatband formation rarely occurred, but the dyes were completely separated and visibleas individual colors. The rate of movement was such, that a run consumed about 8minutes under the conditions used here. This short time minimized diffusion effectswhich would tend to enlarge the colored areas and make them diffuse. The effect isvery important with small samples such as may be readily obtained from single inklines. With original ink, placed on the paper, the time factor is not very importantbecause of the large amount of dye initially present.Sample Treatment. Ink samples were treated in two ways. Original ink was placedwith the pens as a single spot of ink on the paper. All spots were placed in a circlearound the center wick. Ink removed from pen lines was taken up by means ofacetone-water mixtures. A fine capillary pipet was used to deposit a droplet of sol-vent, either an equal mixture of acetone-water, or for more rapid solution, 2:1acetone-water. Immediately, before the droplet could soak extensively into the paperand spread, it was taken up with a fine capillary with a small enough diameter toallow capillary action to draw up the solvent rapidly. The paper on which the inkCHARLOTTE BROWN AND PAUL L. KIRKFigure 2Horizontal Chromatograms of Typical Ball Point InksLeft: Standard inks; right: Removed from ink lines. Dyes separated but run stopped beforezones move apart.was to be deposited was placed between two aluminum rings' to hold it over thevertical delivery tube of a hot air blower such as is used for hand hair dryers. Ontouching the capillary to the paper, the liquid was drawn out by capillary action, andrapidly dried so that a very small spot could be formed. This was critical to obtainingsharp separation and minimizing diffusion of the dyes during their movement onthe paper.As soon as the samples were placed on the paper and dried, the paper was forcedover the wick in the center of the bottom vessel, solvent was added to the vessel, andthe top chamber placed so as to hold the edge of the paper between the ground sur-faces. After the solvent had run a satisfactory distance to produce good separation ofdyes, the top chamber was removed, the paper taken off the wick and dried forinspection. Movement was limited here to a total of about 12 to 34 inch since completeseparation was achieved in this distance without serious spreading and loss of colorintensity. Chromatograms similar to those shown in Figure 2 were obtained.Solvent. Various solvents were tested for this system. Since the solubilities of ballpoint inks were completely different from those of liquid writing inks, such simplesolvents as water were not satisfactory, even for preliminary results. Organic solventsof various types showed such large differences in the observed Rf values that it wasdifficult to locate a solvent that did not carry some dyes with the solvent front whileleaving others very close to the origin. The most generally satisfactory solventtested was a mixture of 15 ml. of Shellacoll with 8 ml. water. This mixture waschosen because the separations were slightly cleaner than with other solvents, and theI Horizontal paper chromatography equipment is supplied by Microchemical Specialties Co.,1834 University Avenue, Berkeley, Calif.2 A mixed solvent manufactured by Commercial Solvents Corporation and obtainable in paintand hardware stores.[Vol. 45IDENTIFICATION OF BALL POINT PEN INKScost and difficulty of making the solvent were negligible. Other solvents that producedessentially the same degree of differentiation were:a. t-butanol: water: acetone: Hydrochloric acid (conc). (10: 20:10:1)b. n-butanol: acetone: water (4:2:1)c. n-butanol: acetone: water (2:1:2)d. n-butanol: acetone: Shellacol: water (50:25:7:15)Solvent mixture a. was essentially as good as the mixture recommended but in-volved more difficulty in obtaining and mixing the constituents. The others hadsimilar drawbacks and produced slightly less clean-cut results including: n-butanol:acetone (1:1); acetone: Shellacol (1:1); several acetic acid-containing solvents andothers. Even acetone water mixtures produced separations that were definite butwith very high Rf values that showed small differences only.Supplementary Tests. A number of inks that could not be distinguished on thebasis of chromatographic separation alone could be further differentiated by sprayingwith dilute HCI (1: 5) solution. M1ost of the chromatograms were essentially unalteredby this treatment except for dulling or bleaching of the colors. Other reagents weretried but none aided in the differentiation except the hydrochloric acid. Ultravioletlight also did not greatly aid in further differentiation because the only constituentwith marked fluorescence was a red dye found in several inks and which was alreadyvery apparent on the chromatogram.RESULTSA total of 58 ball point pens or refills were tested. Of these 41 were essentially blueinks, 3 were black, 8 red, and 6 green. The blue inks, of special interest, were readilyand distinctly divided into seven main groups as follows.I. Turquoise and red dyes. Rol-rite (green cap); Rol-rite (maroon cap); Flo-ball; Skripto;King retractable; Waterman; Arnold; Lord Baltimore; Flo-ball (new Coronation ink);Cascade; One for All refill; Lindy Pen blue.II. Blue green dye only. E. Faber (old pen).IL. Single blue dye. Spraying with HCl separated Windsor from remainder. Windsor Jet-0-matic; Rite King; Eversharp "CA"; Wahl refill.IV. Deep blue dye only. Howard (old pen); No designation (Made in U.S.A.).V. Purple dye only. King (old pen); Presdon (old pen); Dura (old pen).VI. Lavendar dye only. All Rite; Sheaffer; Long Writer; Top Riter; Venus Pen-cil; PresdonVu-Riter; Val-U-Riter; Wearever; Perma Matic.VII. Turquoise dye and blue dye. Spraying with HCI divided this group into three subgroupsas follows:A. Two bands of blue green. Bankers Approved.B. Blue-green and green bands. Esterbrook desk set; Venus American approved; Wear-ever; Best Rite.C. Blue-green and blue bands. Eversharp Star Reporter; Papermate regular; Papermatedeluxe; Eversharp "Kec-5"; Folgers.The broad classes into which the inks studied fell leave much to be desired as re-gards individual identification. Some of this may be accomplished with a considerabledegree of certainty by direct comparison of chromatograms with each other in theCHARLOTTE BROWN AND PAUL L. KIRKsame class. The amounts of dye present vary considerably in some instances, and thismay be determined directly from duplicate chromatograms of the inks compared,especially when two or more dyes are present. When only one dye may be dis-tinguished, differences in quantity of dye are more likely to arise from a differentamount of ink than from a different proportion in the ink though small color differ-ences become much more apparent on the chromatogran than in the ink line. An-other useful comparison may be made by carefully comparing the original ink lines.In several cases differences were noted that allowed distinctions to be made betweeninks with almost identical chromatograms. This may be due to differences in composi-tion of vehicle which could impart a different appearance to the ink line. Such com-parisons also must be made with great care to avoid effects from different types ofpaper, soiling of the paper, and other similar effects not related to the ink composi-tion.Inks of other colors than blue were compared similarly and found to be distinguish-able in most cases. They divided into the following groups.Black InkA. Papermate blackB. Eversharp black "Kec-54"C. Lindy Pen blackRed InkA. All rite; Wearever Tri-color; Velvet Pen-cil; Three Way reload.B. One for All refill; Eversharp- red "Kec-54"; Papermate red; Lindy Pen red.Green InkA. Wearever Tri-color greenB. Three-Way reloadC. Eversharp "Kec-54"D. Papermate Green; One for All refill; Ready (Lindy Pen) green.Despite the fact that dyes of some of the above inks were apparently identical,there were in most instances marked differences, presumably in the composition of thevehicle, to allow differentiation of the inks on the basis of the way they appeared inthe ink line. It is unfortunate that the technique of paper chromatography has notyet been sufficiently refined to study in detail the vehicle of ball point inks, for it ishere that some of the most marked differences in such inks apparently occur. It isalso this factor that is most significant in the behavior of the pen, and the reliabilityof its operation as well as the physical character of the line.SUMM!ARYAn improved technique for the chromatography of ink is described, and its ap-plication to the identification of ball point pen ink discussed. Blue inks (includingpurple) could be divided rapidly into 7 groups, and distinctions made between manyof the members of the multi-component groups. Identification of every ink individu-ally was not found possible from the dye components separated by chromatography.Identification of nearly all of the inks was possible from the chromatogram combinedwith study of the ink line to reveal major differences in vehicle.[Vol. 451954] IDENTIFICATION OF BALL POINT PEN INKS 339REFERENCES1. K=RK, P. L., AND DUGGAN, E. L., Anal. Chem., 26, 163 (1954).2. BALSTON, J. N., AN TALBOT, B. E., "Guide to Filter Paper and Cellulose Powder Chromatogra-phy," London and Maidstone, H. Reeve Angel Co., and W. & R. Balston, Ltd., 1952.3. BLOCK, R. J., LESTRANGE, R., AND ZWEIG, G., "Paper Chromatography. A Laboratory Man-ual," New York, Academic Press, 1952.4. Smnn, 0. C., "Inorganic Ions, Chromatography," New York, Van Nostrand, 1953.5. STRAN, H. H., SATO, T. R., AI.' ENGELKE, J., Anal. Chem., 26, 90 (1954).6. SOUDER, W., AND So 0PFoRD, A. W., (Conference of International Association for Identifica-tion at Philadelphia).7. SomERoRD, A. W., J. Crim. Law, Criminol. and Police Science, 43, 124 (1952).8. BRAcKETr, J. W., JR., AND BRADF ORD, L. W., J. Crim. Law, Criminal. and Police Science, 43,530 (1952).9. VIroI.O, A. E., Mineroa Medicolegale e arch. antropl. criminale, 71, 102 (1951); VrFOLo, A. E.,AND FoRNAm, A., ibid, 72, 59 (1952).10. GouLD, D. E., AND McComACK, T. A., Am. Ink Maker, 29, 32, 61, 63 (1951).11. STEm, E. W., AND HILTmrO,, 0., Amer. Bar Assoc. J., 34, 373 (1948).12. LnDsLy, C. H., AND CASEY, R. S., Amer. Bar Assoc. J., 34, 376 (1948).13. GInR, K. V., KiSHNAM =RTHY, K., AND VENKATASUBRAmAN1AN, T. A., Current Sci. (India), 21,11, 44 (1952).14. Gr, K. V., AND RAO, N. A. N., J. Indian Inst. Sci., 34, 95 (1952).

Horizontal Paper Chromatography in the Identification of Ball Point Pen Inks

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Horizontal Paper Chromatography in the Identification of Ball Point Pen Inks

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