Identification of 4-methylspinaceamine--a Pictet-Spengler condensation reaction product of histamine with acetaldehyde--in human urine

This study reports the first identification of 4-methylspinaceamine (4-MSPA)-a Pictet Spengler condensation reaction product of histamine with acetaldehyde-in human urine. 4-MSPA was identified and quantified as follows: the target compound was partially purified by solvent extraction from a urine sample spiked with N-methylpiperazine (N-MP) as an internal standard, then derivatized to a naphthylthiourea derivative with 1-naphthylisothiocyanate (NITC) and finally analyzed by HPLC. For verification, 4-MSPA was also analyzed by ion spray-mass spectrometry (IS-MS), using 4-MSPA-d4 as an internal standard. The amount of 4-MSPA in human urine varied between individuals and from day-to-day, ranging from undetectable to 0.80 nmol/mL.