Dry-Wet MALDI Matrix Deposition for Latent Fingermark Analysis
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current MALDI-MSI methods face challenges in preparing samples for analysis, particularly for latent fingermarks on various surfaces, as they require surface-specific enhancement techniques and are not suitable for remote analysis, leading to limitations in sample recovery and preservation of fingermark characteristics.
Innovation Solution
A two-step 'dry-wet' method involving the application of finely ground MALDI matrix followed by solvent spraying, allowing for efficient analyte extraction and co-crystallization, which is independent of the substrate material and enables remote analysis of fingermarks with high sensitivity and image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional MALDI-MSI methods are used for fingermark analysis, then surface-specific enhancement techniques are required, but this increases device complexity and limits adaptability to different surfaces
Solution Approach 1:
The patent applies universality by developing a single matrix deposition method that works across multiple surface types (porous and non-porous). The matrix solution can be applied universally to different substrates without requiring surface-specific modification protocols, making the MALDI-MSI system adaptable to diverse forensic evidence surfaces while maintaining procedural simplicity
Solution Approach 2:
The patent employs parameter changes by optimizing matrix solution concentration, solvent composition, and deposition parameters to achieve universal applicability. By adjusting these parameters, the method accommodates different surface properties (porosity, texture) without changing the fundamental enhancement approach, thereby reducing device complexity while maintaining versatility
2Quantity of substance
If matrix is applied using conventional spray coating, then analyte extraction is limited, but optimizing spray parameters increases device complexity and reduces productivity
Solution Approach 1:
The patent applies preliminary action by performing matrix solution application followed by controlled drying before analysis. This pre-treatment step ensures optimal matrix crystallization and analyte co-crystallization occur before the actual MALDI-MSI measurement, maximizing analyte extraction efficiency without requiring complex real-time optimization during analysis
Solution Approach 2:
The method extracts analytes efficiently by using the matrix solution to co-crystallize with analytes on the fingermark surface. The optimized solvent system extracts analytes from the complex fingermark matrix while the matrix facilitates their desorption and ionization, achieving high analyte recovery without increasing procedural complexity
3Use of energy by moving object
If matrix concentration is increased to improve ion intensity, then crystal size increases reducing image resolution, but decreasing concentration reduces signal intensity
Solution Approach 1:
The patent resolves this contradiction by optimizing matrix concentration and solvent composition parameters. The specific matrix solution formulation enables sufficient ion intensity at moderate concentrations by improving ionization efficiency, while the controlled deposition and drying parameters prevent excessive crystal growth, thereby maintaining both signal intensity and spatial resolution
4Reliability
If fingermarks are analyzed at the crime scene, then sample characteristics are preserved, but remote analysis capabilities are limited by current methodology
Solution Approach 1:
The patent enables remote analysis by developing a universal matrix deposition method that works on diverse surfaces without requiring surface-specific preparation. This allows forensic analysts to perform MALDI-MSI analysis at the crime scene on various substrates (glass, metal, porous materials) using the same protocol, preserving fingermark characteristics while expanding remote analysis capabilities
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The dry-wet method provides superior image quality and ion intensity for latent fingermarks on diverse surfaces, including porous and non-porous materials, and allows for the analysis of low-abundance substances, enhancing the forensic analysis capabilities by integrating MALDI-MSI with standard operational procedures.
Implementation Method 1
matrix assisted laser desorption ionisation mass spectrometry imaging (MALDI-MSI)
Implementation Method 2
The matrix can also be applied through a matrix aerosol created by vibrational vaporization
Implementation Method 3
spraying the sample with a solvent to facilitate extraction of the analyte from the sample and co-crystallisation with the matrix
Implementation Method 4
facilitate extraction of the analyte from the sample and co-crystallisation with the matrix
Data Source
Figure 1A~1B
Figure 1C~1E
Figure 2A~2B
AI summary
A method of preparing a sample for matrix assisted laser desorption ionisation mass spectrometry imaging analysis by a two-step process. Firstly, a MALDI matrix is dusted on to the sample followed by a spray of a suitable solvent onto the dusted sample. The present method has been successfully applied to the detection and mapping of several analyte classes in latent fingermarks. Using the present two-step method, fingermark enhancement, recovery and analysis from different substrate surfaces is now possible enabling visual and chemical information to be obtained simultaneously via remote testing.