Adenine nucleotides (AN): adenosine 5’-triphosphate (ATP), adenosine 5’-diphosphate (ADP), and adenosine 5’-monophosphate (AMP) are essential for energy transfer and supply of countless processes within the cellular metabolism. Their concentrations can be expressed as adenylate energy charge (AEC), a measure of cellular metabolic energy that directly correlates with the homeostasis of the organism. AEC index can be used as a clinical health indicator with broad diagnostic potential, as a decrease in ATP levels is associated with various conditions, such as inflammatory diseases, metabolic disorders, and cancer. We introduce a novel methodology for rapid isolation, purification, and quantification of AN from just a drop of capillary blood obtained from a healthy volunteer. Of all the stationary phases tested, activated carbon proved to be the most efficient for the purification of adenine nucleotides, using an automated micro-solid phase extraction (µ-SPE) platform. By removing interfering substances, we achieved high chromatographic selectivity and resolution, facilitating the quantification of AN. The analyzed AN concentrations from capillary blood correspond to the values found in the literature, which corroborates reliability of the developed extraction method. Overall, this study presents a streamlined and precise approach for analyzing AN from microliters of blood that offers promising applications in clinical diagnostics.