A multiresidue method of extraction based on matrix solid-phase dispersion (MSPD) technique was optimized and validated for chromatographic analyses of twenty seven pesticides residues [hexachlorocyclohexane (HCH) isomers (a, b, g, d), dieldrin, endrin, heptachlor and its epoxide (HE), a and b-endosulfan, o,p'-DDD, p,p'-DDD, o,p'-DDE, p,p'-DDE, o,p'-DDT p,p'-DDT, dicofol, methoxychlor, mirex, hexachlorobenzene (HCB), chlorotalonil, parathion methyl, fenitrothion, malathion, folpet, diazinon, permethrin (cis and trans) in oranges. The sample was blended with C18 and then the homogenized sample was introduced onto a glass column containing silica. Ten mL of ethyl acetate was added to the column as elution solvent. The eluent was concentrated, diluted in isooctane and 1mL was injected into the gas chromatograph. The analyses of pesticides were performed using a GC/ECD. Confirmation was done by mass spectrometry. The recovery ranged from 70 to 120% in the concentration range of 0.02 to 2.0mg/kg. The limits of quantification ranged from 0.01 to 0.5mg/kg.
pesticides; oranges; gas chromatography; matrix solid phase dispersion