A highly sensitive and direct competitive enzyme-linked immunosorbent assay for the detection of di-(2-ethylhexyl) phthalate (DEHP) in infant supplies

Abstract

A sensitive and specific direct competitive enzyme-linked immunosorbent assay (dc-ELISA) was studied in this paper for the detection of di-(2-ethylhexyl) phthalate (DEHP) based on an antigen-coating format. The DEHP-specific polyclonal antibody was raised in rabbits and used to construct the dc-ELISA for the measurement of DEHP. The conjugates of the antibody with horseradish peroxidase (HRP) were used as the detection probe. Under optimal conditions, the assay had a detection limit (LOD) of about 0.0042 ng mL⁻¹, with an apparent linear range of 10⁻³−10³ ng mL⁻¹ (R² = 0.998). The cross-reactivity with six other structurally related phthalate esters was below 1%. The recoveries of DEHP ranged from 80.8% to 119.2% indicating that the method was successfully applied for the determination of DEHP in infant supplies.