Capillary Electrophoresis with Interchangeable Cartridges for Versatile and Automated Analyses of Dried Blood Spot Samples

A novel concept forhighly versatile automated analyses of driedblood spot (DBS) samples by commercial capillary electrophoresis (CE)is presented. Two interchangeable CE cartridges with different fused-silicacapillaries were used for the DBS elutions and the DBS eluate analyses,respectively. The application of one CE cartridge with a wide-borecapillary reduced DBS processing times to a minimum (1-2 minper sample) while fitting the other CE cartridge with a narrow-borecapillary served for highly efficient CE analyses. A comprehensiveinvestigation of major variables affecting liquid handling in CE (capillarylength, internal diameter, and temperature) was carried out with theaim of optimizing both procedures and enabling their maximum flexibility.The application of two CE cartridges also enabled the employment ofCE detectors with different instrumental set-ups and/or principlesas was demonstrated by the optical detection of nonsteroidal anti-inflammatorydrugs (NSAIDs) and the conductivity detection of amino acids (AAs).The presented methods were optimized for the automated CE analysesof 36 DBS samples formed by a volumetric collection of 5 & mu;Lof capillary blood onto Whatman 903 discs and processed by directin-vial elution using the CE instrument. The precision of liquid transfersfor the automated DBS elutions was better than 0.9% and the precisionof CE analyses did not exceed 5.1 and 12.3% for the determinationof NSAIDs and AAs, respectively. Both methods were linear (R (2) & GE; 0.996) over the therapeutic (NSAIDs)and the endogenous (AAs) concentration ranges, had limits of quantificationbelow the typical analyte concentrations in human blood, and achievedsample throughputs of more than 6 DBSs per hour.

Automated summary

A novel concept for highly versatile automated analyses of dried blood spot (DBS) samples by commercial capillary electrophoresis (CE) is presented in this study. Two interchangeable CE cartridges with different fused-silica capillaries were used for the DBS elutions and the DBS eluate analyses, respectively. The application of two CE cartridges also enabled the employment of CE detectors with different instrumental set-ups and/or principles, such as the optical detection of nonsteroidal anti-inflammatory drugs (NSAIDs) and the conductivity detection of amino acids (AAs).