Axima resonance maldi quadrupole ion trap tof instrument

Dried lipid A samples were dissolved with 10 μl of 50% (v/v) methanol/chloroform. Then, 1 μl of the lipid A sample was mixed with 1 μl of 50 mg 2,5-dihydroxybenzoic acid (DHB) solution in 1 mL 70% (v/v) acetonitrile/water. Subsequently, 2 μl of the mixture was loaded on a MSP 96 target polished steel MALDI plate and dried at room temperature. The lipid A samples were analyzed via a Bruker Daltonics Microflex LRF MALDI-TOF MS instrument and controlled by FlexControl 3.0 software (Bruker, Bremen, Germany). The operating conditions were as follows: negative-ion and reflectron mode, detector gain = 6.9, laser frequency = 60.0 Hz and laser power = 70%. Data acquisition and processing were performed by Flexanalysis 3.3 software (Bruker, Bremen, Germany). MS/MS analysis was performed using an Axima Resonance MALDI-quadrupole ion trap-TOF instrument (Shimadzu, Manchester, UK). The instrument was operated in negative ion and reflectron mode. Fragment ions were analyzed by collision-induced dissociation (CID) of the precursor ions and argon gas was used as a collision gas. Operating conditions were as follows: intro endcap = −5.5 kV, extr endcap = 10.0 kV, flight tube = 10.0 kV, reflectron center = −0.2 kV, reflectron back = −0.2 kV, and Detector = 2.2 kV. The data acquisition and processing were performed using the Launchpad 2.9.3 software (Kratos Analytical, Manchester, UK).

N-glycans were prepared and purified from the mutant and wild-type rice leaves according to Karg et al. [55 (link)]. The N-glycan analysis was performed in positive-ion reflectron mode using a matrix-assisted laser desorption ionization-time of flight mass spectrometer (MALDI-TOF MS) with an Autoflex system from Bruker Daltonics (Bruker, Billerica, MA, USA). The tandem mass spectrometric analysis was carried out using an Axima Resonance MALDI-quadrupole ion trap-TOF instrument (Shimadzu, London, UK). 5-Dihydroxybenzoic acid (10 mg/mL in 50% methanol) was used as the matrix. The data analysis was performed with Flex Analysis 3.3 software (Bruker) and Launchpad 2.9.3 software (Kratos Analytical Ltd., Cambridge, UK). The calculated mass of the major N-glycans was compared with earlier reports to assign the corresponding structures [12 (link),13 (link),56 (link)].