
LC/MS/MS is often regarded as the technique of choice in identifying components from complex mixtures; however, it is not without its limitations. An alternative approach is to consider LC/MALDI.
LC/MALDI has a number of advantages in that the LC is decoupled from the MALDI mass spectrometer. MALDI can support:
The AccuSpot was designed for online collection of fractions eluting from Capillary/Nano LC.
The AccuSpot automates LC micro-fractionation, spotting and preparation for MS analysis. With the AccuSpot system, LC eluent can be accurately and continuously spotted onto target plates, in trace amounts (eg.50nL). This allows for automatic preparation of target plates for MALDI-TOF-MS measurements. When used in conjunction with Shimadzu's Two-Dimensional Micro LC System and Shimadzu Biotech's
AXIMA MALDI-TOF instruments, proteome analysis can be performed with a higher
degree of precision and with greater sequence coverage.
The "Half-Contact" spotting method (see above) uses plate sensors (patent pending) to ensure accurate spotting and virtually eliminates carryover from spot to spot.
Click here to see the AccuSpot in action.
9 Shimadzu or 18 ABI target plates can be loaded at one time.
The matrix solution can be added at flow rates from 0.1μL/min to 50 μL/min. To accommodate different needs the spotting direction can be either straight row and column or zigzag row and column.
To ensure that the droplet formation and collection is consistent, a CCD camera is used to monitor micro-fractionation.
Spotting is carried out in one of two ways: Continuous Mode to collect the entire chromatographic run or Programmable Time Window Mode to collect only the areas of interest in the chromatographic run. Both modes allow spotting intervals from 5 to 60 sec/spot.