“…As a result, the timely and effective diagnosis of NB is very significant. Urinary homovanillic acid (HVA) and vanillylmandelic acid (VMA), which are terminal metabolites of catecholamines, serve as biomarkers to support clinical diagnosis of NB (Brodeur et al, ; Pritchard et al, ). Traditionally, the measurement of HVA and VMA was performed on high‐performance liquid chromatography coupled with electrochemical detection (HPLC‐ECD) or fluorescence detection (FLD) (Davidson, ; Manickum, ; Mercolini, Gerra, Consorti, Somanini, & Raggi, ; Barco et al, ), and gas chromatography–mass spectrometry (GC–MS) (Cole et al, ; Fauler et al, ; Park, Hong, Shin, & Hong, ; Tran et al, ).…”