Research Article

Sample Preparation and Extraction in Small Sample Volumes Suitable for Pediatric Clinical Studies: Challenges, Advances, and Experiences of a Bioanalytical HPLC-MS/MS Method Validation Using Enalapril and Enalaprilat

Figure 4

Comparison of different extraction methods on the internal standard normalized matrix effect. The SPE extraction by Oasis MCX is compared to the two-step extraction by Oasis WAX + MCX. Each boxplot describes median, 25th, 75th percentile + 10th, and 90th percentile as whisker. measurements per boxplot. Statistical analysis was performed by a Mann-Whitney- test (two-tailed value).