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direct MS analysis from DBS and solid-phase microextraction devices by use of direct MS interfaces such as DESI and DART.
“ One exciting area of development is ”
and allow for minimum required sample to be acquired remotely. This reduces the need for onsite collection laboratories, and can allow patients to sample themselves with proper training.
Advantages of solid-phase microextraction include isolation of unstable metabolites,
differentiation of free fraction versus protein bound analytes and in situ sample clean up. One exciting area of development is direct MS analysis from DBS and solid-phase
microextraction devices by use of direct MS interfaces such as DESI and DART. In some cases, these techniques entirely eliminate the LC portion of the assay, allowing for rapid direct analysis and real-time monitoring.
Q Are current microsampling techniques easily amenable to automation?
One area to address for this topic is post acquisition of sample, or how easily microsampling devices can be transferred into an automated workflow. In all cases, the sampling devices need to allow for sample identity to be retained during transfer into the sample preparation workflow. In some cases, the sample preparation can be executed using robotic liquid handling systems or other automated workflows. In the case of DBS media, this necessitates the selection of a spot either using a punching system or online desorption. In each case, optical systems that can recognize the optimum location to punch or desorb are necessary.
There are devices that are designed to work with liquid robotic systems. Solid-phase
microextraction along with a few absorptive media devices have been developed on 96-well tip platforms. This allows for automated post collection processes, such as sample preparation and desorption.
Q Q What do you think remains the greatest challenge to microsampling?
Because there is such a long and well known history of data collected using plasma derived assays, introduction of any new sampling technique will necessitate thorough validation and statistical comparison to this historical technique. This may require replication of sample collection during the validation and early-stage studies.
Do you believe microsampling techniques will ever be universally accepted in the bioanalytical community or do you see them becoming reserved for more niche applications?
Microsampling, as with other sampling techniques, certainly has its utility for specific applications. To say that one sampling technique is acceptable for all assays would be quite limiting. There will
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