Liquid-Liquid Extraction/Low-Temperature Purification (LLE/LTP) Followed by Dispersive Solid-Phase Extraction (d-SPE) Cleanup for Multiresidue Analysis in Palm Oil by LC-QTOF-MS

Table 1

The mean retention times (𝑡_𝑅) with RSD (%) and LC-QTOF-MS accurate mass measurements of the protonated molecules and the main fragment ions of the pesticides studied in the matrix-matched standard (fragmentor voltage 190 V, spiking level: 50 ng g⁻¹).

Analyte	𝑡𝑅^a (min)	RSD(%)	Elemental composition	Theoritical m/z	Experimental m/z	Error
						mDa	ppm
Dimethoate	13.91	1.13	C5H13NO3PS2	230.0069	230.0071	0.2	0.87
			C4H8O3PS2	198.9885	198.9879	−0.6	−3.01
			C3H7O2PS2	170.9698	170.9693	−0.5	−2.92
			C2H6O2PS	124.9821	124.9825	0.4	3.20
			C5H12NO3PS2Na	251.9888	251.9894	0.6	2.38
Simazine	17.07	1.02	C7H13N5^35Cl	202.0854	202.0859	0.5	2.47
			C7H13N5^37Cl	204.0824	204.0827	0.3	1.47
			C5H9N5^35Cl	174.0541	174.0542	0.1	0.57
			C4H7N3^35Cl	132.0323	132.0324	0.1	0.75
Carbaryl	19.38	0.84	C12H12NO2	202.0863	202.0863	0.0	−0.1
			C10H9O	145.0648	145.0654	0.6	4.13
Atrazine	19.41	0.61	C8H15N5^35Cl	216.1010	216.1016	0.5	2.32
			C8H15N5^37Cl	218.0980	218.0982	0.2	0.92
			C5H9N5^35Cl	174.0541	174.0540	−0.1	−0.57
Diuron	19.98	1.85	C9H11N2O^35Cl2	233.0243	233.0243	−0.1	−0.43
			C9H11N2O^35Cl^37Cl	235.0213	235.0214	0.1	0.42
			C9H11N2O^37Cl2	237.0183	237.0189	0.6	2.53
			C9H10N2OCl2Na	255.0062	255.0059	−0.3	−1.17
			C3H6NO	72.0444	72.0447	0.3	4.16
Terbuthylazine	22.19	0.92	C9H17N5^35Cl	230.1167	230.1169	0.2	0.87
			C9H17N5^37Cl	232.1137	232.1138	0.1	0.43
			C5H9N5^35Cl	174.0541	174.0543	0.2	1.15
Malathion	22.23	1.90	C10H20O6PS2	331.0433	331.0429	−0.4	−1.21
			C10H19O6PS2Na	353.0253	353.0259	0.6	1.70
			C8H14O5PS2	285.0015	285.0014	−0.1	−0.35
			C2H8O2PS	128.0055	128.0051	−0.3	−2.34

^a𝑛=20.