Dolliver Holly, Kumar Kuldip, Gupta Satish, Singh Ashok
Dep. of Plant and Earth Science, Univ. of Wisconsin-River Falls, 410 S. 3rd St., River Falls, WI 54022, USA.
J Environ Qual. 2008 May 2;37(3):1220-6. doi: 10.2134/jeq2007.0394. Print 2008 May-Jun.
There is growing concern that antibiotic use in livestock production is contributing to contamination of soil and aquatic environments. Monensin, a polyether ionophore antibiotic, accounts for approximately 13% of total subtherapeutic livestock antibiotic usage in the USA and has been widely detected in aquatic environments. Due to insufficient ultraviolet absorbance, liquid chromatography analysis of monensin in environmental samples is limited to equipment with mass spectrometry (e.g., liquid chomatography-mass spectrometry [LC-MS]). However, LC-MS equipment is costly, and extensive sample preparation and clean-up is often required. Rapid, low-cost analytical techniques are needed to monitor for monensin residues in the environment. In this study, a commercially available enzyme-linked immunosorbent assay (ELISA) for detecting monensin in animal feed extracts was evaluated for determination of monensin in water, soil, and manure. The monensin ELISA was highly sensitive, with limits of detection and quantification at 1.5 and 3.0 microg L(-1), respectively. Recovery of monensin in spiked water samples was approximately 100%. Cross-reactivity was not observed with similar polyether ionophores, tetracyclines, macrolides, or sulfonamides. Concentrations of monensin using ELISA were greater than concentrations measured with LC-MS. This is attributed to cross-reactivity of the monensin ELISA toward structurally similar monensin compounds, such as factors (slight naturally produced structural variants) and metabolites. Results from this study showed that ELISA can be a reliable, rapid, and low-cost alternative to LC-MS analysis of environmental samples.
人们越来越担心畜牧业生产中抗生素的使用会导致土壤和水生环境受到污染。莫能菌素是一种聚醚离子载体抗生素，在美国畜禽亚治疗性抗生素总使用量中约占13%，并且已在水生环境中被广泛检测到。由于紫外线吸光度不足，环境样品中莫能菌素的液相色谱分析仅限于配备质谱仪的设备（例如液相色谱 - 质谱联用仪[LC - MS]）。然而，LC - MS设备成本高昂，而且通常需要进行大量的样品制备和净化处理。因此需要快速、低成本的分析技术来监测环境中的莫能菌素残留。在本研究中，对一种用于检测动物饲料提取物中莫能菌素的市售酶联免疫吸附测定法（ELISA）进行了评估，以测定水、土壤和粪便中的莫能菌素。莫能菌素ELISA灵敏度很高，检测限和定量限分别为1.5和3.0 μg L⁻¹。加标水样中莫能菌素的回收率约为100%。未观察到与类似的聚醚离子载体、四环素、大环内酯类或磺胺类药物有交叉反应。使用ELISA测得的莫能菌素浓度高于用LC - MS测得的浓度。这归因于莫能菌素ELISA对结构相似的莫能菌素化合物（如因子（轻微天然产生的结构变体）和代谢物）的交叉反应。本研究结果表明，ELISA可以成为环境样品LC - MS分析的一种可靠、快速且低成本的替代方法。
