Optimization of antibiotic analysis in leafy vegetables by simple solid-phase extraction and liquid chromatography triple quadrupole mass spectrometry

Abstract

The reuse reclaimed water for irrigation and the application of reclaimed biosolids in agriculture have sparked global concerns regarding the potential contamination of farmland and crops with pharmaceuticals and personal products (PPCPs). This concern is especially relevant to vegetables that are consumed raw by humans. To address this issue, we have developed a straightforward and robust method for concurrently screening of eight antibiotic compounds, including quinolones, tetracyclines, and sulfonamides, in vegetables. The detection and quantification of antibiotics were accomplished using high-performance liquid chromatography-electrospray tandem mass spectrum (HPLC-ESI-MS/MS) in positive mode. We optimized the sample preparation and instrumental operations to enhance the signal peak area of the target analytes. The recoveries of antibiotics in the five tested vegetables ranged from 84 % to 127.5 %, with a relative standard deviation(RSD) below 12.11 %. Additionally, the method exhibits limits of detection (LODs) ranging from 1.834 to 4.97 ng/g dry weight (dw). Following validation, we successfully applied the method to analyze antibiotic accumulation in hydroponic lettuce in a greenhouse. All antibiotics were detected in three different concentration treatment groups (0.1ppm, 1ppm and 3ppm), and the bioconcentration increased with higher antibiotic concentrations spiked to the nutrient solution. Given the various physicochemical properties of the antibiotics used in this study, our work suggests that the developed method offers a simple, reliable and effective means to identify and quantify antibiotic residues in leafy vegetables and other crops that may be impacted by contaminated treated wastewater or biosolids.