Ohio BCI Crime Laboratory LM-Trace Evidence Methods Issuing Authority: Laboratory Director Effective Date: 10/01/2020 Revision 14 Page 1 of 95 Trace Evidence Methods Manual Contents 1 Purpose .............................................................................................................................................................................. 5 2 Examination Guidelines ..................................................................................................................................................... 6 2.1.1 General Examination Approach ........................................................................................................................................ 6 2.2 Documentation .................................................................................................................................................................. 9 2.3 Verifications ....................................................................................................................................................................... 9 2.4 Safety Considerations ...................................................................................................................................................... 10 2.5 Instrumentation/Equipment ........................................................................................................................................... 10 2.6 References ....................................................................................................................................................................... 10 3 Microscopy ...................................................................................................................................................................... 10 3.2 Instrumentation / Equipment ......................................................................................................................................... 10 3.3 Procedure ........................................................................................................................................................................ 10 3.3.1 Maintenance.................................................................................................................................................................... 10 3.3.2 Illumination ..................................................................................................................................................................... 10 3.3.3 Use of Compensators ...................................................................................................................................................... 10 3.4 References ....................................................................................................................................................................... 11 4 Fourier Transform Infrared Spectroscopy (FTIR)............................................................................................................. 12 4.2 Safety Considerations ...................................................................................................................................................... 12 4.3 Minimum Standard and Control ...................................................................................................................................... 12 4.3.1 Month of use: .................................................................................................................................................................. 12 4.3.2 Day of use: ....................................................................................................................................................................... 12 4.4 Equipment/Instrumentation ........................................................................................................................................... 12 4.5 Analytical method ........................................................................................................................................................... 13 4.5.1 Bench ............................................................................................................................................................................... 13 4.5.2 ATR ................................................................................................................................................................................... 13 4.5.3 Microscope ...................................................................................................................................................................... 13 4.5.4 Diamond Anvil Cell (DAC) ................................................................................................................................................ 13 4.6 Sample preparation for transmission/ATR/microscope: ................................................................................................ 13 4.7 Spectral Evaluation and Comparison .............................................................................................................................. 14 4.8 Interpretation Criteria ..................................................................................................................................................... 14 4.9 References ....................................................................................................................................................................... 14 5 Visible Microspectrophotometry (MSP) .......................................................................................................................... 16 5.2 Equipment/Instrumentation ........................................................................................................................................... 16 5.3 Minimum Standard and Control ...................................................................................................................................... 16 5.4 Sample Preparation Procedure ....................................................................................................................................... 17 5.5 Analysis Method .............................................................................................................................................................. 17 5.6 Spectral Evaluation and Comparison .............................................................................................................................. 17 5.7 Interpretation Criteria ..................................................................................................................................................... 17 5.8 References ....................................................................................................................................................................... 18 6 Scanning Electron Microscopy/Energy Dispersive X-ray Spectroscopy (SEM/EDS) ........................................................ 19 6.2 Safety Considerations ...................................................................................................................................................... 19 6.3 Equipment/Instrumentation ........................................................................................................................................... 19 6.4 Minimum Standards and Controls .................................................................................................................................. 20 This document is uncontrolled if viewed outside the BCI document management system. Ohio BCI Crime Laboratory LM-Trace Evidence Methods Issuing Authority: Laboratory Director Effective Date: 10/01/2020 Revision 14 Page 2 of 95 6.5 Sample Preparation Procedure ....................................................................................................................................... 20 6.6 Analysis Method .............................................................................................................................................................. 22 6.6.1 Imaging analysis............................................................................................................................................................... 23 6.6.2 Bulk analysis .................................................................................................................................................................... 23 6.6.3 Individual component analysis ........................................................................................................................................ 23 6.6.4 Analysis of a primarily organic matrix ............................................................................................................................. 23 6.6.5 Qualitative analysis .......................................................................................................................................................... 24 6.6.6 Quantitative analysis ....................................................................................................................................................... 25 6.7 Spectral Evaluation and Comparison .............................................................................................................................. 25 6.8 Interpretation Criteria ....................................................................................................................................................