This service quantifies intermediates of the pentose phosphate pathway (PPP), which is crucial for generating NADPH (for reductive biosynthesis and antioxidant defense) and ribose-5-phosphate (for nucleotide synthesis). Intermediates are quantified by LC/QQQ using external calibration curves. This analysis provides insights into cellular defense against oxidative stress, nucleotide biosynthesis, and the interconnections between PPP and other metabolic pathways like glycolysis.