Laser ablation Inductively Coupled Plasma Time of Flight Mass Spectrometry (LA ICP-ToF-MS)

• Subject Area: Mineralogy, Petrology and Geochemistry
• Term: Funded in 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 550994788

The analytical instrument applied for in this proposal is based on mass spectrometry, which is one of the most important analytical tools for determining the chemical composition of materials and substances. The system consists of an inductively coupled plasma time-of-flight mass spectrometer (ICP-ToF-MS) and a 193nm excimer laser. The combination of a laser device and the mass spectrometer allows high spatial resolution analysis of trace elements in 2D and 3D in solid materials. During analysis a small amount of the sample material is ablated by firing a laser beam (diameter = 1-150um) on to the sample. The ablated material is then fed into the ICP-ToF-MS, where it is converted into charged particles in the inductively coupled plasma (ICP). Based on the mass to charge ratio (M/Z) of the ions, they move faster or slower through the ToF-MS and are thereby separated before they are counted in the detector. The measured count rates are subsequently converted to absolute chemical concentrations using calibrations. The advantage of the ToF-MS is the speed at which the ions are counted. Compared to other ICP-MS devices, the ToF-MS is theoretically able to measure all elements between atomic masses 6 to 260 quasi-simultaneously, which enables a rapid chemical characterization of materials. When the sample is moved under the laser beam, the distribution of trace elements in a specific area of the sample surface can be determined (2D element distribution images). If the laser beam scans several times over the same area or drills at a point into the sample, three-dimensional depth profiles can also be recorded. A particular strength of the device, compared to other spatially resolved methods, is its high sensitivity and the analysis of light elements such as lithium (Li). The ICP-ToF-MS can also be used to analyse the composition of dissolved substances. An autosampler is used to automatically feed the diluted solution from small sample vials into the mass spectrometer. Moreover, the very short acquisition time and almost simultaneous measurement of elements of the ICP-ToF-MS also makes it possible to analyse the complete composition of chemically complex, individual nanoparticles. These versatile analysis options allow the proposed analytical system to be applied by various research groups. Research applications relevant of the main applicant include the analysis in the field of technical mineralogy, the recovery of important elements from secondary raw materials (waste rock, tailings, slags), or the formation processes of ore deposits and geochemistry of primary mineral raw materials. Research groups at Clausthal University of Technology already have ongoing and future projects in which the proposed instrument can yield new data for e.g., the diffusion gradients at phase interfaces (battery research, semiconductors), the formation of surface alterations on materials, the distribution of lithium in various materials, and the analysis of nanoparticles.

• DFG Programme: Major Research Instrumentation
• Major Instrumentation: Laser ablation mit induktiv gekoppeltem Plasma Time-of-Flight Massenspektrometer (LA ICP-ToF-MS)
• Instrumentation Group: 1700 Massenspektrometer
• Applicant Institution: Technische Universität Clausthal
• Leader: Professor Dr. Thomas Ulrich