Nd yag smartbeam laser

MSI or mass spectrometry profiling was performed on tissue sections using a 9.4 T Apex-ultraTM hybrid Qh-FTICR MS equipped with a 355 nm and 200 Hz Nd:YAG Smartbeam laser (Bruker Daltonics, Billerica, MA, USA). MSI data were acquired on two adjacent tissue sections at the spatial resolution of 150 μm in the negative ion modes. A full scan mass spectrum was acquired at 80 laser shots each over a mass range of 100–1000 Da in negative ion mode with the resolutions of 66,000 at m/z 400. External calibration was performed using a mixture of FA(16:0) (m/z 255.23295), FA(18:1) (m/z 281.24860), FA(20:4) (m/z 297.27990), LPE(18:0) (m/z 480.30956), PA(18:0/18:0) (m/z 703.52833), PE(18:0/18:0) (m/z 746.57053), PI(18:0/20:4) (m/z 885.54985) (Avanti Polar Lipids Inc., Alabaster, AL, USA).
The profiling data were acquired at the same experimental parameters as those of the MSI data acquisition. To confirm data reliability and to assess the heterogeneity of tissues, ten mass spectra at different positions of the cancerous area and the adjacent area were acquired randomly.

Imaging mass spectrometry was performed on a Autoflex III mass spectrometer equipped with a Nd:YAG SmartBeam® laser (355 nm, Bruker Daltonic, Bremen, Germany). The samples on the slide were mounted via a MTP Slide Adapter II (Bruker Daltonic, Bremen, Germany). The experiments were performed in reflectron mode by the use of instrumental parameters as follows: Ion Source 1: 19.11 kV, ion source 2: 16.65 kV, lens: 8.74 kV, reflector: 21.09 kV, reflector 2, 9.7 5 kV, detector gain: 1.0–5.0, sample rate 2.0, shots: 10, repetition rate: 200 Hz, laser attenuator: offset: 75%, range: 20%, set: 1_minimum, fine adjustment: 60%. The mass spectra were acquired in the m/z range up to 1000 without deflection. The instrument was controlled by the FlexControl 3.0 and FlexImaging 2.1 software (Bruker Daltonic, Bremen, Germany). Data were further processed in FlexImaging 2.1.