Figure 5. Incorporation of internal standards in direct analysis of blood samples.

(A) Coating internal standard inside a capillary sampler (0.4 mm inner diameter, ~8 mm long). The internal standard solution is sucked into the capillary via capillary action and allowed to dry. (B) Collecting finger prick blood sample using a capillary sampler with a pipette tip holder. (C) Photograph of eight dried blood spots prepared on chromatography paper for paper spray ionization measurement. Paper triangles are cut out along the dashed lines manually using scissors. (D) Quantitative analysis of imatinib in blood using capillary sampler for dried blood spot preparation and paper spray ionization for detection.

con.: Concentration.

Adapted with permission from [45].