Autoflex maldi tof mass spectrometer

FTIR spectra were recorded at room temperature at a resolution of 4 cm⁻¹ within the range from 4000 to 400 cm⁻¹ from 32 scans, using a Nicolet 320 FTIR spectrometer and the typical KBr pellet method. NMR spectra were recorded using an INOVA 500 instrument with CDCl₃ or DMSO-d₆ as the solvent. The molecular weights of the DDSQ-based PS block copolymers were evaluated from their ¹H NMR spectra; their polydispersity indices (PDIs) were determined using GPC (Waters 510 apparatus) where the molecular weight calibration was used by PS standard and MALDI-TOF mass spectrometry (Bruker Daltonics Autoflex MALDI-TOF mass spectrometer). The thermal properties of the DDSQ-based block copolymers were determined through DSC using a TA Q-20 instrument; the sample was placed in an aluminum pan and heated at a rate of 20 °C min⁻¹ from room temperature to 250 °C under a N₂ atmosphere (50 mL/min) after the sample was cooled quickly to −90 °C from the first scan. TEM images were recorded using a JEOL 2100 microscope (Japan) operated at 200 kV; ultrathin films were prepared using a Leica Ultracut microtome featuring a diamond knife and placed on a Cu grid coated with a carbon film. The P4VP-b-PS-DDSQ-PS-b-P4VP thin film was imaged after staining with I₂ to display its P4VP segments; the PVPh-b-PS-DDSQ-PS-b-PVPh thin film was stained with RuO₄ to display its PVPh segments.

Isolates were sub-cultured twice on MHA at 30 °C for 24 h. Then approximately 100 μg of the bacterial colony were directly transferred to the MALDI target spot. Followed by drying at room temperature and overloading with 1uL of matrix solution (10 mg/ml a-cyano-4-hydroxycinnamic acid in 50% acetonitrile and 2.5% trifluoroacetic acid), each measurement was performed in two replications. MS analysis was carried out on an Autoflex MALDI-TOF mass spectrometer using Flex Control 3.4 software (Bruker Daltonics, Germany). Soil isolates with a valid MALDI-TOF MS score of 2 were undoubtedly assigned to the genus/species level.