SEC(GPC)-MALDI TOF MS
Trace Analysis of By-Products and Additives in Synthetic Polymers
MALDI-MS is widely used as an analytical tool for the characterization of synthetic polymer samples. However, in complex mixtures, the minor components may not be detected due to ion suppression by more abundant species also present in the sample. Gel Permeation Chromatography (GPC)-MALDI is an effective method for detailed analysis of such samples. In GPC-MALDI, complex samples are fractionated by GPC prior to MALDI-MS analysis. When preparing polymer samples for MALDI-MS analysis, the sample (e.g., an aliquot of a GPC fraction) must be mixed with MALDI matrix and a salt (to promote cationization of the analyte) prior to loading on to the MALDI target. To automate this process, we have developed an organic solvent-resistant fraction collector / MALDI spotting robot (AccuSpot), which mixes the GPC eluent with MALDI matrix solution on-line and then automatically deposits the resulting solution onto the MALDI sample target. The new AccuSpot provides a fully automated solution for the GPC-MALDI analysis of synthetic polymer samples.
Detection and Structural Analysis of Trace Amount of Samples
- In addition to the measurement of molecular weight distribution of SEC (GPC) system with refractive index detector, MALDI-TOFMS provides detailed structural information such as structure of monomers in polymers.
- Mass spectrometry after separation by SEC decreases the ionization suppression by main component, and makes easier to detect and perform structural analysis of trace amount of samples.
- High-resolution gel permeation chromatography (GPC) system
- AccuSpot: fully automated fraction collection and spotting of GPC eluent on a MALDI sample target
- AXIMA series MALDI-TOF MS: high performance MALDI-TOF mass spectrometer for the analysis of GPC-fractionated synthetic polymer samples
- Modified AccuSpot, compatible with standard GPC organic solvents (THF, chloroform etc.)*
- with optional kit (including exhaust function)
- Microflow HPLC for improved chromatographic resolution
- Intelligent 'Polymer Analysis' software: calculates monomer unit molecular weight, end termini masses, polydispersity and average molecular weight
Analysis Example of Co-polymer
The following figure is an example showing the analysis and detection of minor homo polymers in a complex synthetic polymer sample. A two component copolymer [poly(methilmethacrylate-b-n-butylmethacrilate) (poly(MMA-b-n-BMA)] was used as a model complex polymer sample. Fifty fractions were prepared on a MALDI sample target by spotting GPC eluted solution every 6 seconds (T = 8 min 20 sec to 13 min 20 sec). Automated MALDI-MS analysis of the fraction collected at T = 11 min 18 sec resulted in the detection of two polymer series which could not be easily detected in the unseparated sample (see figure below). The newly developed GPC-AccuSpot-MALDI system facilitates the detection of PnBMA and PMMA homo polymer components, present as minor components, in complex copolymer samples, allowing Polymer Analysis calculations to be performed.