TY - JOUR
T1 - Depth-Dependent Chemical Analysis of Handwriting by Nanospray Desorption Electrospray Ionization Mass Spectrometry
AU - Lee, Gwangbin
AU - Cha, Sangwon
N1 - Publisher Copyright:
©
PY - 2021/1/6
Y1 - 2021/1/6
N2 - Nanospray desorption electrospray ionization (nano-DESI) has been utilized in direct sampling mass spectrometry (MS) that requires highly spatially resolved sampling with minimal sample destruction. In this study, we explored the applicability of nano-DESI MS for the forensic chemical analysis of ink directly from handwriting on paper. Nano-DESI readily ionizes dyes, including the polyanionic ones, with minimal fragmentation and produces chemical fingerprints of ballpoint pens directly from a paper surface. Further, we specifically focused on how the potential of nano-DESI that changes the mass spectral profiles over time could reflect the differential distribution of analytes in a vertical direction because mildly extracted analytes are immediately transferred and analyzed in real time. To test this, we wrote the character "X"with various combinations of two different pens and analyzed the crosspoints by nano-DESI MS. As a result, the time-course changes in the chemical fingerprints of the ink, which were consistent with the order of the pen strokes, were successfully obtained by nano-DESI MS in most cases. After confirming the capability of the depth-dependent analysis of nano-DESI MS, we analyzed a simulated forgery in which the original and forged writings were made before and after affixing a seal and clearly distinguished the two portions based on the time-dependent changes in the profile of the ink compound.
AB - Nanospray desorption electrospray ionization (nano-DESI) has been utilized in direct sampling mass spectrometry (MS) that requires highly spatially resolved sampling with minimal sample destruction. In this study, we explored the applicability of nano-DESI MS for the forensic chemical analysis of ink directly from handwriting on paper. Nano-DESI readily ionizes dyes, including the polyanionic ones, with minimal fragmentation and produces chemical fingerprints of ballpoint pens directly from a paper surface. Further, we specifically focused on how the potential of nano-DESI that changes the mass spectral profiles over time could reflect the differential distribution of analytes in a vertical direction because mildly extracted analytes are immediately transferred and analyzed in real time. To test this, we wrote the character "X"with various combinations of two different pens and analyzed the crosspoints by nano-DESI MS. As a result, the time-course changes in the chemical fingerprints of the ink, which were consistent with the order of the pen strokes, were successfully obtained by nano-DESI MS in most cases. After confirming the capability of the depth-dependent analysis of nano-DESI MS, we analyzed a simulated forgery in which the original and forged writings were made before and after affixing a seal and clearly distinguished the two portions based on the time-dependent changes in the profile of the ink compound.
KW - ambient desorption ionization
KW - direct sampling mass spectrometry
KW - forensic analysis
KW - handwriting
KW - ink
KW - nanospray desorption electrospray ionization
UR - http://www.scopus.com/inward/record.url?scp=85099429178&partnerID=8YFLogxK
U2 - 10.1021/jasms.0c00333
DO - 10.1021/jasms.0c00333
M3 - Article
C2 - 33176422
AN - SCOPUS:85099429178
SN - 1044-0305
VL - 32
SP - 315
EP - 321
JO - Journal of the American Society for Mass Spectrometry
JF - Journal of the American Society for Mass Spectrometry
IS - 1
ER -