Optimization of an automated IS addition system for use in high-throughput quantitative DBS analysis

Background: Automated DBS direct elution systems are available that incorporate IS spray modules which, unlike conventional IS addition via the extraction solvent, apply IS prior to DBS samples prior to extraction, allowing analyte and IS to be coextracted. Results: IS spray system parameters were optimized to identify the conditions that produced the best analytical performance in quantitative bioanalytical assays, without interfering with the integrity of the DBS sample prior to extraction. Conclusion: LC–MS/MS method validations across four representative small molecule assays using the optimized IS spray conditions were demonstrated to produce analytical performance comparable to conventional methods of IS addition, demonstrating that the spray technique is a viable alternative.