pass the volatile oil on the bed of florosil, elute with hexane , followed by acetone, methanol. Esimate the pesticide residues by concentrating the elutants from the column and injecting to GC with Ec detector for chlorinated pesticides, GC with FID detector for phosphorous conaining pesticides. Qualitative detection can be done by spotting on  a TLC plate with standard pesticides and spraying with chromogenic reagent.

 Thanks sowbhagya but can you send me an article, review paper or validation data I need to check for scope recovery percentage and working procedure

Than you very much Dr/ Noel W Davies