title: Preparation of colloidal gold immunochromatography strip for detection of methamidophos residue.
abstract: Methamidophos (Met) is a broad spectrum organophosphorus insecticide and acaricide. Even a trace of its residue is harmful to humans and many animals. In this study, the synthesis and identification of colloidal gold particles and antibody-colloidal gold conjugates were performed, and the preparation of colloidal gold immunochromatography strip was conducted for detection of Met residue. The size of colloidal gold particles was checked using a transmission electron microscope (TEM). The formation of antibody-colloidal gold conjugates was monitored by UV/Vis spectroscopy. The preparation of colloidal gold immunochromatography strips, analysis of Met standard solutions, and other four pesticides and vegetable samples were operated with common methods and principals. The TEM images showed the average diameter of colloidal gold particles was almost the same size: approximately 40.0 nm in diameter. For the conjugation of colloidal gold and monoclonal antibody (MAb), 0.03 mg/ml of MAb was confirmed to be the minimum amount for stabilization of colloidal gold. With the prepared colloidal gold immunochromatography test strip to determine the standard Met solution, the results demonstrated a detection limit of approximately 1.0 mg/ml. Cross-reaction indicated that the strip had a high specificity to Met. The results of 10 green vegetable sample tests confirmed that one sample was positive by HPLC analysis. There was evidence to suggest that colloidal gold particles and antibody-colloidal gold conjugates were synthesized successfully. The prepared colloidal gold immunochromatography strip was applicable for preliminary screening of Met residue.
authors.affiliation: The Third Affiliated Hospital of Sun Yat-sen University of Medical Sciences, Guangzhou 510630, China. ericshi412@sina.com
authors.forename: Chenggang
authors.initials: C
authors.lastname: Shi
authors.forename: Suqing
authors.initials: S
authors.lastname: Zhao
authors.forename: Kun
authors.initials: K
authors.lastname: Zhang
authors.forename: Guobao
authors.initials: G
authors.lastname: Hong
authors.forename: Zhenyu
authors.initials: Z
authors.lastname: Zhu
mesh_terms: D000911:Antibodies, Monoclonal / Q000276:immunology*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D003116:Color; D003429:Cross Reactions; D017979:Gold Colloid / Q000737:chemistry*; D046529:Microscopy, Electron, Transmission; D009946:Organothiophosphorus Compounds / Q000032:analysis*; D010573:Pesticide Residues / Q000032:analysis*; D011934:Reagent Strips; D012015:Reference Standards; D012996:Solutions; D013056:Spectrophotometry, Ultraviolet; D014675:Vegetables / Q000737:chemistry
chemical_list: D000911:Antibodies, Monoclonal; D017979:Gold Colloid; D009946:Organothiophosphorus Compounds; D010573:Pesticide Residues; D011934:Reagent Strips; D012996:Solutions; C014655:methamidophos