Unleashing the power of receptor-based assay on high-throughput detection: Assessing the feasibility of enzyme-linked immunosorbent assay on large-scale antibiotic monitoring

Antibiotics are detected in aquatic environments with heterogeneity in their occurrence and associated risk levels. Thus, high spatiotemporal resolution monitoring in a large scale is essential to better cope with their risks. Mass spectrometry (MS) techniques are sensitive and precise, yet complex, expensive, and time-consuming for antibiotic detection. The enzyme-linked immunosorbent assay (ELISA) is among a mature receptor-based assays that offer a cost-effective alternative and are particularly notable for their high throughput analytical capabilities. However, its high throughput power on environmental monitoring is underutilized. ELISA is remarkably rapid (3800–37,000 tests per day), inexpensive ($1.8 per test, capital costs ranging from $35,000 to $270,000), and ready-to-use (97 commercial kits available) for detecting frequently reported antibiotics. Adopting solid phase extraction decreases their limits of detection to as low as 0.125 ng/L. Their quantification results are robust as they also generally agreed well with those of MS methods. A conservative way at present is to use ELISA for initial screening of large numbers of samples, with subsequent quantification of a small proportion of “positive” samples through MS methods. Yet, the applicability of ELISA can be further improved, such as developing a standardized quantification procedure for ELISA and microfluid chip-based ELISA kits and instruments.