ALDH7A1 and pyridoxine-dependent epilepsy: Additionally,we measure the IR spectra of two closely eluting diastereomeric biomarkersfor the inborn error of metabolism pyridoxine-dependent epilepsy (PDE-ALDH7A1),which shows that the heartcutting LC-IRIS setup has good sensitivity(requiring ∼μL injections of ∼μM samples)and that the separation between closely eluting isomers is maintained.We envision applications in a range of research fields, where theidentification of molecular structures detected by LC–MS isrequired.