Equipment and methods

Ion Trap Specifications

• Mass Range: 50-2200, 200-4000
• ESI source with Agilent sheath flow CE-MS sprayer
• Sensitivity in the low femtogram range.
• Fast data acquisition with scan speeds up to 32,000 u/s at full isotopic resolution
• SmartFrag™ algorithm ensures optimal, reproducible fragmentation for MS/MS library searches
• On-the-fly polarity switching (delay <80 ms)
• Fragmentation up to the MS11 stage

 CE specifications

• UV-VIS and LIF detectors
• Temperature regulation controls samples independently from the electrophoresis buffers
• Sample introduction by all three injection modes; Electrokinetic, Pressure and Vacuum
• Automated Sample Introduction directly from 96 well plates, 2 mL autosampler vials, PCR vials and 0.5 mL tubes
• Modes of separation include: Voltage, Current, Power, Pressure and Vacuum

Current applications

• CE-MS of cationic metabolites (e.g. amines, amino acids)
• CE-MS of anionic metabolites (e.g. sugar phosphates & other "energy" metabolites)
• CE-MS/MS of peptides

Nano-LC Specifications

• Nano to micro flow range (50 nL/min to 50 µL/min)
• 0-800 bar pressure
• Integrated micro flow pump for flow rates up to 2500µL/min for pre-concentration onto trap columns
• UV-Vis detector
• Easy connection to ESI-MS via Bruker captivespray nano source

Specifications

• Mass range: 1.5 to 1090
• Scan speed: 10,000 u/sec
• Modes: scan, SIM, FASST
• Ionization: EI, CI and NCI
• Mass spectral libraries
• Automatic adjustment of retention times
• Library search using retention index

Current applications

• Identification of "unknowns" based on EI, CH4-CI and NH3-CI mass spectra
• Targeted analysis of amino acids/amines (t-BDMS derivatives), carbohydrates (TMS derivatives)
• Quantification of amino acid uptake and metabolism
• Untargeted metabolite profiling  (amino acids, organic acids, sugars, sugar alcohols, sugar phosphates, cyclic sugars etc.)
• Quantification of biomarker compounds (D/L amino acids, muramic acid, aminosugars, ergosterol)

Biotek Synergy 2 Specifications

• Detection: Fluorescence, Time Resolved Fluorescence, Fluorescence Polarization, Alpha Screen/ AlphaLisa, Luminescence, UV-Visible Absorbance
• Read methods: End point, kinetic, spectral scanning, well-area scanning
• Microplate types: 6- to 1536-well plates (luminescence 1-384)
• Absorbance wavelength selection: monochromator (200- 999 nm)
• Fluorescence wavelngth selection: Deep blocking bandpass filters/dichroic mirrors

• Tuneable diode laser (TDL) for measuring the stable isotopes of CO₂. The TDL is used for measuring the exchange of isotopes during photosynthesis and respiration by plants and soil. Measuring isotope exchange with the TDL is an extremely powerful technique for probing the limitations and determinants of photosynthesis and respiration (e.g. diffusion of CO₂ within leaves, determining the respiratory substrate of soil, partitioning C3 versus C4 photosynthesis). The TDL is integrated with gas exchange systems such as the LI 6400 described below.

• Li-Cor LI 6400 gas exchange and fluorescence system. This is used for measuring photosynthesis and transpiration of plants. More recently we have been using its capability of simultaneous gas exchange and fluorescence measurements to estimate the internal conductance to CO₂ transfer. It is field portable, but also spends a lot of time inside the lab and glasshouse.

• Li-Cor LI 8100 soil respiration system with a 20-cm roving chamber. Recent modifications mean that we can also measure respiration of soil covered by snow.

• Portable gas exchange system for short-term measurements on grass/shrub ecosystems. It is being used to measure gas exchange of grass and shrub ecosystems, in particular their response to pulses of rainfall. Initial tests show that the system can measure incredibly small fluxes of CO₂ and H₂O.