Laser Ablation Inductively Coupled Plasma Time-of-Flight Mass Spectrometer for Advanced Bioelement Imaging Applications

The proposed instrument is a TOFwerks Inductively Coupled Plasma Time-of-Flight Mass Spectrometer with ESI NWR Image Laser Ablation System. The instrument will be installed and operated by the Quantitative Bio-element Imaging Center (QBIC) in Silverman Hall Room B540. The instrument will be accessible to the entire Northwestern University research community on a recharge basis. The components consist of a Thermo iCap RQ ICP-MS, a TOFwerks time-of-flight upgrade, and NWR Image 266 nm laser ablation system. The two major barriers to the adoption of LA-ICP-MS for routine bioimaging are long acquisition times and limited lateral resolution (usually 20 μm or larger). The upgraded LA-ICP-TOF-MS system significantly decreases the acquisition time by using a time-of-flight mass analyzer which can record a complete mass spectrum every 30 μs, making it the optimum detection method for fast transient signals such as individual nanoparticles and laser ablation pixels. The TOF will provide up to 50-fold rate increases for detection. The proposed NWR image laser ablation system uses a 266 nm laser (as opposed to the 213 nm obsolete 11 year old system we currently run), which offers the best coupling with biological samples while minimizing ablation of the glass substrate. Additionally, the new ablation system enables true sub-micron ablation for genuine single-cell laser ablation. All of these attributes along with the new dual concentric injector (which allows for a 30-fold decrease in washout times and concomitant increase in transport efficiency) will provide the most state-of-the-art elemental imaging system on the market. These improvements will enable users to image multiple sections of tissue or multiple cells to generate real-time quantitative elemental maps that can help elucidate the mechanisms governing the spatiotemporal relationship between inorganic elements and the biological environment.