Journal of Analytical Methods in Chemistry / 2021 / Article / Tab 3 / Research Article
Combination of a Green and a Traditional Method for Estimating Relative and Absolute Ink Age: A Case Study of Ballpoint Pen Ink Dating in Vietnam Table 3 Peak wavelength number (cm−1 ) and reference data for reference dyes and samples M1, A3.2, and A3.1.
M1 (50 months) A3.2 (39 months) A3.1 (date) Reference data [6 ] Type of vibrations 525 525 525 524 (CV) δ (CNC)+ + + 558 (CV) γ (CCC)/δ (CNC)/δ (CC center C) 726 724 726 724 (CV) ν (CN)912 916 912 915 (CV) ν (CC) ring 997 993 997 995 (MY) 1137 1141 1141 1147 (MY) 1184 1180 1180 1178 (CV) ν s (CC center C)/δ (CCC) breathing /δ r (CH 3 ) 1188 1188 1188 1188 (MY) 1300 1295 1306 1300 (CV) ν as (CC center C)/δ (CCC) ring /δ (CH) 1361 1365 1365 1369 (CV) ν (CC center C) 1430 1436 1428 1447 (CV) δ as (CH 3 ) 1539 1540 1534 1536 (CV) ν (C ring N)/δ s (CH 3 ) 1586 1582 1586 1591 (CV) ν (C-C) ring + 1622 1622 1622 (CV) ν (C-C) ring
, stretching vibrations;
δ , planar deformation vibrations;
s , symmetric; “+,” small peak observed; as, asymmetric. Values in bold indicate the matching peaks of crystal violet (CV). Values in italics indicate the matching peaks of metanil yellow (MY).