Small-scale method for the determination of organophosphorus insecticides in tea using sulphuric acid as clean-up reagent

Sulfuric acid pretreatment for the simultaneous GC screening of organochlorine and organophosphorus pesticides in herbal essential oils

“…There was a discrepancy in the results of the recovery reported. Bernal et al [11] reported that malathion after sulfuric acid treatment was unstable but Wan [12] found it to be stable.This suggests that reaction time and ratio of sulfuric acid is extremely critical especially when you work with a vulnerable compound like OP. Our results of the recovery was consistent with those of Bernal et al [11] and Wan [12] except for malathion and tetradifon.…”

“…Wan [12], which determined OP pesticide in tea extracts, found that a sulfuric acid treatment was necessary before the Florisil column clean-up which mean two-step method. We describe a one-step sulfuric acid treatment with reliability, requires much less time than the twostep method [15] which should be performed with sulfuric acid treatment followed by solid matrix column.…”

“…This method was combined with either gel permeation chromatography (GPC) or one of the adsorption column methods, silica gel [11][12][13], which have been applied to food [3-7, 12, 13], biological samples [1,2], and drinking water [8] as a clean-up procedure against interference from pesticide residue analyses. Previously, most of the pesticides being applied to sulfuric acid treatment were mainly acid stable organochlorine pesticides [1][2][3][4][5][6][7][8], not OP or carbamate pesticide because they were partially or entirely destroyed during concentrated sulfuric acid treatment.…”

A gradual advancement of the extraction and cleanup techniques for residue analysis of pesticides in food matrices and liquid products: a review

“…For the analysis plant material, Florisil has been recommended often in the framework of multi-residue procedures for fruits and vegetables. Florisil columns have been used for the clean-up of plant extracts by many authors [19][20][21][22][23][24][25][26][27][28] . In many cases, Florisil can be replaced by alumina, particularly for the analysis of fatty foods.…”

“…Its importance in the analysis of plant material resides in the fractionation of certain residues according to their polarity without appreciable losses. Many authors 32,[22][23][24][25][26][27]33 have used silica gel columns or mini-columns for the clean-up of sample extract. Lores et al, 34 used an improved silica gel clean-up method for organophosphorus pesticides.…”