Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) allows for qualitative and quantitative analysis of solid materials. It was first demonstrated in 1985 and has since been improved. LA-ICP-MS has various forensic applications for analyzing glass, soil, paper, ink, and tapes. It has advantages over other methods like reduced analysis time and ability to analyze inert elements. However, it also has limitations like lack of reference materials and issues with quantitative analysis. LA-ICP-MS is still considered a powerful forensic analysis method.

1. LA ICP MS
Submitted BY
Harish TS

2. INTRODUCTION
• Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-
MS) is considered as one of the most versatile methods for the
compositional analysis of solid materials due to its sensitivity and
conceptual simplicity
• LA–ICP–MS provides qualitative and quantitative measurements of the
elemental and isotopic composition of materials that are of interest to
forensic scientists

3. HISTORY
• 1985 – Alan Gray First demonstrated LA-ICP-MS
• 1997 – Jeffries and Gunther showed the improvement of Fractionation
• 2002 – Russo described the use of ultra fast pulse width lasers
• 2005 – Eggins introduced of two-volume sample chamber designs

5. FORENSIC APPLICATIONS OF LA-ICP-MS
• Glass
• Soil
• Paper and Ink
• Tape

6. GLASS
The two types of glass evidence most commonly received in forensic laboratories are
(1) architectural float glass (manufactured by flotation on molten tin) and used for
fabricating windows
(2) glass from automobiles, which can be of different types:
• laminated (combination of two glass sheets with one or more interlayers of plastic or
resin) for windshields
• tempered (float and hardened glass) for left/right/ back car windows
• blown manufactured glass for bulbs and headlights

7. SOILS
• A Quantitative Approach for a Heterogeneous Material Chemical analysis of soils is useful in
cases where exposure to heavy metals may pose a risk to the environment or to human health.
• Soil analysis may also become a valuable piece of evidence in criminal investigations such as
murders, kidnappings, rapes, robberies, and trafficking. In forensic investigations,
comparative analyses are often performed to determine if a soil sample found on objects
(shoes, tires, fingernails, carpets) originated from the crime scene or another location.
• The utility of soil as evidence relies on its transfer characteristics, the wide diversity of soils
by geographical location and the variety of analytical methods that can be used to identify its
chemical and physical characteristics.

8. PAPER AND INK
• Ink and paper are relevant materials in document examinations involving
counterfeit currency, identity theft, and security documents. The paper itself may
contain valuable information about sources of origin .
• In forensic examinations of paper, preservation of a document is of fundamental
importance.
• ink analysis is qualitative analysis. Instead of conducting semiquantitative
analysis, the ink’s chemical analysis is observed as a full mass spectrum

9. TAPES
• Duct and electrical tape are regularly found in kidnappings, drug trafficking,
murders and other violent crimes, including the use of improvised explosive.
• Tapes are multi-layered materials, with at least one layer of backing and one
layer of adhesive.
• The superior performance of LA–ICP–MS not only allows scientists to
discriminate between tape from different sources but it also provides correct
associations of tape pieces originating from the same roll and the correct classifi
cation by manufacturing source.

10. ADVANTAGES OF LA-ICP-MS
• A significant reduction of analysis time, since minimal or no sample and
standards preparation is needed
• Chemically inert elements (e.g., zirconium, hafnium, tantalum, niobium,
titanium, thorium and uranium) can be analyzed
• Contamination problems, which are very important for the determination of trace-
level elements, are avoided
• A minute quantity of solid sample, compared to that required for solution
nebulization, is needed, and a micro-amount of material is ablated each laser
pulse
• Lower personal risks, because solvents and hazardous reagents needed for acid
digestion are eliminated

11. LIMITATIONS IN LA – ICP - MS
• There are serious limitations in quantitative analysis:
• The lack of many types of matrix-matching reference materials and well-
established external calibration standards
• The impossibility of diluting the sample to optimize the amount of elements to be
analyzed; and, the impracticability to use simple calibration approaches typical of
the analysis of aqueous solutions (single standard addition and isotope dilution).
• Long-term sensitivity drift due to the ICP-MS instrument, sample position in the
cell and laser focusing
• Reduced precision and accuracy, due to the nonstoichiometric representation of the
elemental composition of the sample in the mass spectrum (fractionation process)

12. CONCLUSION
• Different qualitative or quantitative approaches have been
demonstrated to be fit for several analytical purposes.
• Laser ablation ICP–MS is a powerful method that provides valuable
information in comparative analysis, classification, and characterization
of materials and identification of their potential sources of origin.

13. REFERENCE
• Koch, J., & Günther, D. (2017). Laser Ablation Inductively Coupled Plasma Mass Spectrometry.
Encyclopedia of Spectroscopy and Spectrometry, 526–532. doi:10.1016/b978-0-12-803224-4.00024-8
• Orellana, F. A., Gálvez, C. G., Orellana, F. A., Gálvez, C. G., Roldán, M. T., García-Ruiz, C., … García-
Ruiz, C. (2013). Applications of laser-ablation-inductively-coupled plasma-mass spectrometry in chemical
analysis of forensic evidence. TrAC Trends in Analytical Chemistry, 42, 1–
34. doi:10.1016/j.trac.2012.09.015
• Almirall, J. R., & Trejos, T. (2016). Applications of LA–ICP–MS to Forensic Science. Elements, 12(5), 335–
340. doi:10.2113/gselements.12.5.335
• Sylvester, P. J., & Jackson, S. E. (2016). A Brief History of Laser Ablation Inductively Coupled Plasma
Mass Spectrometry (LA–ICP–MS). Elements, 12(5), 307–310. doi:10.2113/gselements.12.5.307

14. THANK YOU