Fig. 2.

Representative chromatograms of vitamin B6 and standard curves. A: Overlay chromatograms PLP and PA from five levels of calibrators. B: A typical standard curve of PLP. C: A typical standard curve of PA. D: Chromatogram of a patient sample with normal level of PLP (130.5 ​nmol/L) and normal concentration of PA (154.5 ​nmol/L). E. Chromatograms of a patient sample with vitamin B6 deficiency (PLP 11.3 ​nmol/L, PA 10.0 ​nmol/L). The yellow diamond indicates the highest calibrator. (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)