Post-acquisition Filters

POST-ACQUISITION FILTERS 3.2.1 Suppression of Strong Resonances... 

Figure 13 Post-acquisition suppression of residual parent resonances in the bi-selective HMQC spectra of Me2Si(NEt2)2 using binomial filters. The effect of (a) no filter, (b) 1 1 filter, (c) 1 2 1 filter and (d) 1 3 3 1 filter [60]. Reproduced from Magn. Reson. Chem. with permission...

Typically, colloidal suspensions are deposited on polycarbonate filters immediately following sampling to reduce post-collection precipitation or aggregation artifacts and mimic the operational procedures used to define dissolved and particulate sample components. Obviously, a well-dispersed dilute sample should be used to avoid artifactual particle overlap. Filter sections are then mounted on SEM stubs and carbon or metal coated (Au/Pd) for compositional analysis and micrographic imaging, respectively. The tedious nature of operator controlled analysis of particulate samples in the SEM and the TEM has often precluded the acquisition of statistically valid information regarding suspension composition. 

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