Table 3. Exact Mass of TRIAC vs the Accurate Masses by LC–QToF–MS in the Site2_Sep Sample^a.

exact mass (M-COOH)	accurate mass (M-COOH)	Δ value (exact – accurate)	mass error (ppm)
576.7658	576.7658 (±0.00017)	0.0002 (±0.000047)	0.3 (±0.082)

^aExact mass means a theoretical value calculated from a molecular formula. Accurate mass is acquired by measurement using QToF–MS. Δ value is the difference between the exact mass and the accurate mass. Mass error is parts per million (ppm) of the Δ value. All values except for the exact mass are represented as the mean of three replicates (n = 3). M is a molecule; it is TRIAC (C₁₄H₉I₃O₄ = 621.7635). “M-COOH” means desorption of “COOH” from a molecule. Each mass spectrum including the accurate mass has been shown in Figure S2.