Staggered-parallel limitations

Ayrton et al. have experimented with TFC with microbore (1 mm) and capillary (0.18 mm) formats for TFC. These columns reduce the excessive amount of mobile phase required for this technology and can provide greater sensitivity for sample-limited situations. At a flow rate of 130 /zL/min, these authors demonstrated the ability to achieve sub-ng/mL quantitation for an assay based on only 2.5 /zL of plasma [76]. More recently, this group performed TFC in a parallel four-column format. MS analysis was accomplished with a multiple sprayer-ESl interface and allowed for simultaneous LC-MS/MS detection [77]. In another example. King et al. used a commercial system based on four staggered TFC systems in conjunction with a modified autosampler to demonstrate increased throughput. These authors demonstrated the ability to pass a GLP-level validation with this system [78]. 

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