Ballpoint Ink Analyses Using LDI Imaging and SEM/EDS Techniques
Introduction
Recently, matrix assisted laser desorption/ionization (MALDI) imaging techniques have been developed for biological sciences to evaluate and understand the distribution of various chemicals on biological surfaces. In particular, this technique provides useful visual information about the locations of specific chemicals on surfaces.
In this work, we explored the use of laser desorption/ionization (LDI) imaging for forensically applicable samples such as a handwriting sample with a ballpoint ink. These measurements were done using a spiral-trajectory ion optics time-of-flight mass spectrometer (SpiralTOF-MS). This TOF system has a 17m flight path that provides high resolution capabilities even down into the lower m/z region. Additionally, we looked at the SEM/EDS imaging using the JEOL JSM-6510LV scanning electron microscope.
Experimental
Sample information and measurement conditions are listed below.
Samples
- A ballpoint pen (black)
- A permanent marker (black)
LDI Imaging measurement
- Measurement mode: SpiralTOF positive mode
- No matrix
- Spatial resolution: 50 or 100 μm
- 5000 laser shots at 1kHz laser repetition rate for each position
- Analytics Software Biomap 3.8
-Raw data was converted to imzML files