Determination of the β-glycosylate fraction of contaminants of emerging concern in lettuce (Lactuca sativa L.) grown under controlled conditions

Abstract

The uptake of a large variety of contaminants of emerging concern (CECs) by crops has already been reported, and the occurrence of phase II metabolites or conjugates has only been detected in plant cell cultures. However, the extent of their formation under cropping conditions is largely unknown. In this study, an analytical strategy to assess the conjugation of 11 CECs in lettuce (Lactuca sativa L.) irrigated with different concentrations (0, 0.05, 0.5, 5, and 50 μg L−1) of CECs was developed. The methodology involved enzymatic digestion with β-glucosidase to obtain the total fraction (free form + conjugates) of CECs. The conjugation fraction was then obtained based on the difference. The highest extent of conjugation (i.e., 27 to 83%) was found with the most hydrophobic compounds, such as bisphenol A, carbamazepine, methyl paraben, and triclosan. So, the CEC conjugate fraction cannot be neglected in the estimate of human daily intake.