Establishment of an appropriate method for determining multiple heterocyclic amines in soy products processed with various methods

A method using UPLC-MS/MS and a core–shell C18 column was developed to simultaneously determine 21 heterocyclic amines (HAs) in 15 min. Appropriate QuEChERS conditions were also established to conveniently extract HAs from soy products cooked with various methods. These conditions presented good analytical performance; limit of detection, limit of quantification, recovery (%), repeatability (coefficient of variation (CV) %) and intermediate precision (CV%) were 0.008 ∼ 0.150 ng/g, 0.025 ∼ 0.500 ng/g, 62 ∼ 91%, ≤ 28% and ≤ 23% for tofu sample, and 0.003 ∼ 0.100 ng/g, 0.010 ∼ 0.350 ng/g, 64 ∼ 93%, ≤ 19% and ≤ 20% for soy milk sample, respectively. HAs contents in the samples increased with cooking temperature and time. The tofu samples cooked by frying had much higher HAs content than those cooked by boiling and roasting. Norharman and Harman mainly contributed HAs content in all samples. For the general population in Taiwan, the highest estimated level of HAs consumed from the samples is 373.67 ng/day.