外文翻譯--hplc法分析圓珠筆油墨在不同光照條件下的保存（英文）

1、21REFERENCE: Andrasko J. HPLC analysis of ballpoint pen inks stored at different light conditions. J Forensic Sci 2001; 46(1):21–30.ABSTRACT: A method for comparison of ink entries on docu- ments stored in different ligh

2、t conditions is presented. Various blue inks were exposed to light, both daylight and artificial light from fluorescent tubes. Inks were then extracted from the document and analyzed by HPLC (high performance liquid chro

3、matography). Sig- nificant changes in composition were noted on exposure to light. These changes were followed by using ternary diagrams con- structed for dyes generally present in blue-colored inks—Crystal Violet, Methy

4、l Violet, and Tetramethyl Para Rosaniline. Also, the amount of the various compounds formed by decomposition of these dyes on exposure to light was measured and employed for comparison of inks. An example of the use of t

5、he proposed method in casework is given.KEYWORDS: forensic science, inks, HPLC, ternary diagrams, effect of light, document examinationIt is a common task for forensic document examiners to investi- gate if two or more i

6、nk entries on one or more documents have been written with the same type of ink. Several techniques are available for such an examination, including optical techniques, thin layer chromatography (TLC), microspectrophotom

7、etry, proton induced X-ray emission (1), X-ray microanalysis (2), Fourier transform in- frared spectrophotometry (FTIR), high performance liquid chro- matography (HPLC) (3–6), capillary electrophoresis and related techni

8、ques (1,7,8). A historical review of several methods for writ- ing-ink differentiation has been written by Harris (9). Roux et al. recently investigated the evidential value of ballpoint pen inks ex- amination (10). The

9、most common type of ink in these investigations is ballpoint pen ink. It has been stated (11) that at least 80% of all evidence re- quiring ink analysis contains ballpoint pen ink. If the ink entries occur on the same do

10、cument, the investigation is straightforward. A more complicated situation appears when the ink entries occur on different documents or on different sides of the same document (e.g., on the front and back). Generally, st

11、orage of these documents can be different in terms of humidity, temperature, and exposure to light. Particularly, storage with different amounts of light exposure might cause significant differences in the optical proper

12、ties (color shade, IR luminescence etc.) of the inks, as well as differences in chemical composition. The knowledge of the effect of light on the composition and on the optical properties of inks is essential forcorrect

13、conclusions in forensic casework. To our knowledge, only one study has been devoted to monitor changes in dye composition of ballpoint pen inks after light exposure (12). In this study, HPLC analysis with diode array det

14、ection was em- ployed to monitor changes in the chemical composition of ballpoint pen inks after exposure to light and under normal aging conditions. Blue ballpoint pen inks on ordinary writing paper were studied. Change

15、s in dye composition have been evaluated quantitatively and a way to compare ink entries stored in different light conditions has been proposed.Materials and MethodsExamined InksBlue colored ballpoint pen inks, manufactu

16、red by Ballograf Bic AB (Göteborg, Sweden) were examined. The manufacturer sup- plied the information about the code system used (year and month of production). Many different production lots from this manufac- ture

17、r were analyzed in our laboratory, thus inks with various com- positions suitable for this investigation could be chosen. Ink entries in the form of asterisks on ordinary writing paper (KONTORAB Copy, A4 80 g paper for p

18、hotocopy machines) were examined. Each asterisk corresponded to about 1 cm ink in length. A series of inks was exposed to daylight inside a laboratory, close to the windows, but not exposed to sunshine. Another series of

19、 inks was exposed to light from a fluorescent tube from a short distance (about 10 cm). Normally aged ink was taken from an or- dinary notebook, where all the text was intentionally written by the same pen. The text was

20、up to three years old and the notebook stored unopened and, to our knowledge, not unnecessarily exposed to light.Extraction of InksSingle asterisks (or a single letter from the notebook) were cut out from the writing pap

21、er and placed inside 2 mL glass vials. Ap- proximately 0.2 mL methanol (HPLC grade) was added and the ink material extracted for 30 min at room temperature followed by heating the vial content up to boiling point for 1 t

22、o 2 min. The methanol extract was then transferred to a 200 ?L conical glass in- set and evaporated to dryness by a stream of nitrogen. The dry residue was dissolved in 20 ?L methanol. During the whole ex- traction proce

23、dure, the ink and the extract were kept in darkness or protected from the exposure to intense light. Aliquots of 20 ?L were taken for analysis. It means that the whole sample was taken for one analysis. Methanol has been

24、 used as extracting solvent as the analytical method used, HPLC, employs the mobile phase, which is much weaker in comparison with those used for TLC.Jan Andrasko,1 Ph.D.HPLC Analysis of Ballpoint Pen Inks Stored at Diff

25、erent Light Conditions1 Associate professor, SKL, National Laboratory of Forensic Science, S- 58194 Linköping, Sweden. Received 14 Sept. 1999; and in revised form 3 Dec. 1999; accepted 24 March 2000.Copyright ©

26、 2001 by ASTM InternationalThis standard is for EDUCATIONAL USE ONLY.ANDRASKO ? INKS STORED IN LIGHT 23FIG. 2—Changes in the composition of Crystal Violet (CV) when exposed to light. Methyl Violet (MV) is the first peak

27、on the left side from CV. Next peak, on the left side from MV, is Tetramethyl Para Rosaniline (TPR). Note the decrease in the peak height of CV exposed to daylight. HPLC chromatograms were obtained at the detection wavel