Development of a sensitive monoclonal antibody-based enzyme-linked immunosorbent assay for the analysis of cadmium ions in water, soil and rape samples

Abstract

Cadmium is classified as a probable human carcinogen. A monoclonal antibody (mAb) against Cd 2+-ethylene-diamine-N,N,N′,N′-tetraacetic acid (EDTA) complex was generated by immunising mice with the conjugate of Cd 2+-EDTA-aminobenzyl-ovalbumin. An indirect competitive enzyme-linked immunosorbent assay (icELISA) was developed and applied for the analysis of Cd 2+ in water, soil and rape samples. The half-maximum inhibition concentration and detection range were 2.59 ng/ml and 0.20-40 ng/ml, respectively. The assay cross-reactivities with non-target metal-EDTA complexes were all below 1%, except Mn 2+ (2.9%) and Hg 2+ (1.6%). The average recoveries of Cd 2+ in tap water, Jingmi Canal, Xiaoqing River (at concentrations of 2-20 ng/ml), soil (0.25-10 ug/g) and rape (0.1-1.2 ug/g) samples were 103.0%, 101.0%, 103.0%, 82.4% and 93.7%, respectively. Concentrations of Cd 2+ measured by this immunoassay agreed well with those determined by graphite furnace atomic absorption spectroscopy (GFAAS) (k=1.1225, r 2=0.9873).The established icELISA was a quick, reliable and sensitive method to detect Cd 2+ in environmental and vegetable samples. © 2012 Copyright Taylor and Francis Group, LLC.