title: Comparison of gas chromatography and immunoassay methods for analysis of total DDT in calcareous soils.
abstract: Three different calcareous soil samples from Lebanon were analyzed for total DDT pesticide residue using GC and ELISA methods. Two experiments were conducted on three different calcareous soil samples. In each experiment, triplicates of 5 gm soil samples were each fortified with standard solutions of DDE to reach concentrations of 0, 5, 25, 50, 100 and 200 ng g(-1) and allowed to equilibrate at room temperature for 6 hours. Each sample was then extracted with 25 mL of 90% methanol by shaking in glass bottles on a mechanical shaker for 16 hours. The bottles were allowed to stand for 30 minutes and aliquots were taken from the clear supernatant for analyses without further cleanup. The total DDT in the extract was measured in triplicate by GC and ELISA. The results indicated that the two methods were highly correlated (R = 0.955-0.994). Differences in soil properties did not affect the accuracy of the detection limits of ELISA. Immunoassay technique can be used for rapid and accurate measurement of total DDT residues in mineral calcareous soils in Lebanon.
authors.affiliation: Faculty of Agricultural and Food Sciences, American University of Beirut, Beirut, Lebanon. ib02@aub.edu.lb
authors.forename: Isam I
authors.initials: II
authors.lastname: Bashour
authors.forename: Shawky M
authors.initials: SM
authors.lastname: Dagher
authors.forename: Gisele I
authors.initials: GI
authors.lastname: Chammas
authors.forename: Nasri S
authors.initials: NS
authors.lastname: Kawar
mesh_terms: D002119:Calcium Carbonate / Q000032:analysis; D002849:Chromatography, Gas / Q000379:methods*; D003634:DDT / Q000032:analysis*; D004305:Dose-Response Relationship, Drug; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D007861:Lebanon; D010573:Pesticide Residues / Q000032:analysis*; D012680:Sensitivity and Specificity; D012987:Soil / Q000032:analysis; D012989:Soil Pollutants / Q000032:analysis*
chemical_list: D010573:Pesticide Residues; D012987:Soil; D012989:Soil Pollutants; D003634:DDT; D002119:Calcium Carbonate