Detection of engineered silver nanoparticle contamination in pears.

Engineered nanomaterials such as silver nanoparticles (Ag NPs) have been increasingly used in agriculture owning to their antimicrobial and insecticidal properties. However, the contamination of Ag NPs in foods and water may pose a great risk to public health and the environment. In this study, the contamination of Ag NPs in pears was detected, characterized, and quantified by a combination of techniques, including transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), and inductively coupled plasma optical emission spectrometry (ICP-OES). Pear samples were treated with two different sizes (20 and 70 nm in diameter) of Ag NPs and stored for different times. Quantification results of Ag NPs in pear samples by ICP-OES demonstrate that there is a good linear relationship (R(2) = 0.983) between the spiked values and recovered values. Residual Ag NPs of both 20 and 70 nm were still detected in samples after 4-day treatment followed by rinsing with water. The penetration study reveals that 20 nm Ag NPs might penetrate the pear skin and pulp after 4-day treatment, while this phenomenon was not observed for 70 nm Ag NPs. These results demonstrate that a combination of techniques could provide accurate results for detection, characterization, and quantification of engineered nanoparticles in agricultural products.