Determination of malathion residues in some medicinal plants by liquid chromatography with gas chromatographic/mass spectrometric confirmation.
A method for determining malathion residues by reversed-phase liquid chromatography (LC) using methanol only as mobile phase is described. Malathion [diethyl(dimethoxyphosphinothiol)succinate] was applied on marjoram, mint, and chamomile. Residues were detected in fresh and dry crops by LC and confirmed by gas-LC/mass spectrometry. Average recovery of malathion was 85%. Residues detected in fresh marjoram, mint, and chamomile were 0.18, 0.23, and 0.083 mg/kg, respectively. Residues detected in dry marjoram and mint were 0.024 and 0.050 mg/kg, respectively. No malathion residues were detected in dry chamomile. The minimum detectable concentration with this method is 0.013 mg/kg. The study suggests it is safe to use malathion up to 2 sprays per season provided the crop is harvested not less than 3 weeks from the last spray.
Suez Canal University, Faculty of Agriculture, Plant Protection Department, Ismailia, Egypt.
M T
MT
Ahmed
S M
SM
Ismail
Y Y
YY
Mosleh
D020843:Chamomile; D002853:Chromatography, Liquid; D005419:Flavonoids / Q000737:chemistry; D008401:Gas Chromatography-Mass Spectrometry; D019686:Lamiaceae / Q000737:chemistry; D008294:Malathion / Q000032:analysis*; D009822:Oils, Volatile / Q000737:chemistry; D010573:Pesticide Residues / Q000032:analysis*; D010946:Plants, Medicinal; D017365:Spices / Q000032:analysis
D005419:Flavonoids; D009822:Oils, Volatile; D010573:Pesticide Residues; D008294:Malathion