Additional file 1: Supplementary information Figure 1. Chromatographic separation of active ingredients, impurities, and internal standards. Supplementary information Table 1. Stability of compounds in 100% DMSO solvent. All compounds displayed stability over 18 h in 100% DMSO while response decreased over time when using mixture containing water. Supplementary information Table 2. Variability of Acetaldehyde and Acetal During Spike Recovery. The spike recovery assay of Product J and Product K resulted in variability of recovery for acetaldehyde and acetal. Product E displayed recovery of all compounds within the 80-120% specification. Supplementary information Table 3. Measured pH of Liquid Hand Sanitizer Products. Supplementary information Table 4. Acetal Kinetics Study (% Acetal remaining). The table reports the % acetal remaining over 6 h in the various buffers tested. Acetal displayed instability in pH 5 and pH 3. Supplementary information Table 5. Acetaldehyde Kinetics Study (% Acetaldehyde remaining). The table reports the % acetaldehyde remaining over 6 h in the various buffers tested. Acetaldehyde displayed stability in all buffers tested. Supplementary information Table 6. Ethanol Kinetics Study (% Ethanol remaining). The table reports the % ethanol remaining over 6 h in various buffers tested. Ethanol displayed stability in all buffers tested. Supplementary information Table 7. Spike Recovery after pH Neutralization of Acidic Liquid Hand Sanitizer Product. The recovery of acetaldehyde and acetal is improved after the pH of Product K is adjusted to pH 6 using ammonium hydroxide. Supplementary information Table 8. Intraday (n=3) and interday (n=9) accuracy of quality control standards. Supplementary information Table 9. Intraday (n=3) and interday (n=9) precision of quality control standards. Supplementary information Table 10. Signal-to-Noise at LLOQ. Supplementary information Table 11. Robustness Results. Supplementary information Table 12. Stock solution stability, 96 h. Supplementary information Table 13. Autosampler stability in DMSO, 72 h. Supplementary information Table 14. Autosampler Stability in Hand Sanitizer Products, QC LLOQ (25% of NMT Limit), 72 h. Supplementary information Table 15. Autosampler Stability in Hand Sanitizer Products, Spiking Solution (100% of NMT Limit), 72 h. Supplementary information Table 16. Autosampler Stability in Hand Sanitizer Products, QC High (300% of NMT Limit), 72 h. Supplementary information Table 17. Dilution Integrity. Supplementary information Table 18. Check QC standards to monitor instrument performance at QC LLOQ and QC High for accuracy and precision during product testing. Supplementary information Table 19. Spike Recovery Results During Method Application.