A digital microfluidic method for dried blood spot analysis

Blood samples stored as dried blood spots (DBSs) are emerging as a useful sampling and storage vehicle for a wide range of applications. Unfortunately, the surging popularity of DBS samples has not yet been accompanied by an improvement in automated techniques for extraction and analysis. As a first step towards overcoming this challenge, we have developed a prototype microfluidic system for quantification of amino acids in dried blood spots, in which analytes are extracted, mixed with internal standards, derivatized, and reconstituted for analysis by (off-line and in-line) tandem mass spectrometry. The new method is fast, robust, precise, and most importantly, compatible with automation. We propose that the new method can potentially contribute to a new generation of analytical techniques for quantifying analytes in DBS samples for a wide range of applications.