Multiresidue Method for Quantification of Sulfonamides and Trimethoprim in Tilapia Fillet by Liquid Chromatography Coupled to Quadrupole Time-of-Flight Mass Spectrometry Using QuEChERS for Sample Preparation

Table 1

Elemental composition, retention time, the m/z experimental (precursors and fragment) ions, and mass error determined in standard solution for the studied analytes.

Compound	Molecular formula	Retention time (min)	Monoisotopic mass (Da)	m/z experimental [M + H]^+ (Da)	Mass error (ppm)	m/z experimental fragment ion (Da)
Trimethoprim	C14H18N4O3	0.83	290.1379	291.1460	1.0	123.0592
Sulfapyridine	C11H11N3O2S	1.08	249.0572	250.0650	0.0	156.0128
Sulfamerazine	C11H12N4O2S	1.18	264.0681	265.0760	0.4	108.0483
Sulfathiazole	C9H9N3O2S2	0.99	255.0136	256.0210	1.6	156.0127
Sulfamethazine	C12H14N4O2S	1.25	278.0837	279.0920	1.4	108.0475
Sulfadimethoxine	C12H14N4O4S	2.19	310.0736	311.0810	1.3	156.0771
Sulfamethoxazole	C10H11N3O3S	1.81	253.0521	254.0600	0.4	156.0124
Sulfamethoxypyridazine	C11H12N4O3S	1.44	280.0630	281.0710	0.7	156.0125