水土中抗生素赋存形态提取方法的优化与应用

Optimization and application of extraction methods for antibiotic-endowed forms in soil and water

为优化水土中抗生素赋存形态的提取方法,选取典型抗生素诺氟沙星(NOR)、土霉素(OTC)和磺胺甲噁唑(SMX)为研究对象,通过改进固相萃取参数和色谱条件,确立高效提取方法。研究结果表明:结合絮凝法絮凝12 h可高效分离水中抗生素的不同形态;当固液比为1∶10时,连续超声萃取法可高效分离土中抗生素的不同形态;研究区NOR水溶态含量分布不均,OTC各形态含量差异较大,SMX以可交换态、吸附态为主;水土中抗生素各赋存形态提取后回收率均大于80%,且回收能力大小依次为SMX>NOR>OTC。该研究结果可为其他抗生素赋存形态提取和抗生素生态风险评估提供一定理论依据。

[Objective]The soil-water ecosystem is a complex network of biogeochemical processes where pollutants such as antibiotics can enrich,degrade,and transform.In recent years,antibiotics have been widely employed in animal husbandry,medicine,and other industries.However,current research on environmental behavior and antibiotic accumulation features in soil-water settings is only focused on the total concentration of antibiotics.The toxicity,chemical activities,and migratory and transformation capacities of antibiotics vary depending on their accumulation type.Therefore,it is crucial to establish an analytical method for the effective extraction of antibiotics in different forms in each medium of the interaction zone to accurately assess the ecological and human health risks posed by antibiotics.[Methods]To determine and optimize the extraction method of antibiotics in soil and water environments,this study focused on common antibiotics found in the water-sediment of the Soap River’s lateral interaction zone,such as oxytetracycline(OTC),sulfamethoxazole(SMX),and norfloxacin(NOR).The study also utilized the solid-phase extraction and high-performance liquid chromatography(SPE-HPLC)technique to optimize the solid-phase extraction of the samples.By refining the sample solid-phase extraction parameters and chromatographic circumstances,an extraction method geared to the antibiotic-endowed morphology in the interaction bands was established and improved.[Results]The experimental results revealed the following:1)When equilibrium dialysis and combined flocculation were compared,it was determined that 12 hours of combined flocculation could separate the various types of antibiotics in the aquatic environment more efficiently.2)Upon comparing the two leaching methods of oscillation and ultrasonic extraction,it was discovered that continuous ultrasonic extraction could separate the unused forms of antibiotics in sediments more efficiently.The optimal extraction conditions were identified as a solid–liquid ratio of 1:10 and ultrasonic leaching for 20 minutes.3)All three antibiotics showed good linearity under the above optimized assay conditions with correlation coefficients higher than 0.99 or above.4)The free dissolved state predominated for all three antibiotics in the surface water and groundwater in the Soap River’s lateral interaction zone.Among them,OTC was bound to organic materials in water more effectively than SMX and NOR.This variation is contingent upon the ionic form and strength of interaction between the three antibiotics under weakly alkaline circumstances.The morphologies of the three antibiotics in sediments differed significantly,influenced by the kind of sediment texture,physicochemical characteristics including acidity,alkalinity,and organic matter concentration,as well as the interaction between groundwater and rivers.5)After extraction,the recovery of antibiotics in water sediment was above 80%for different forms of antibiotics.The recovery ability of the antibiotics was in the following order:SMX>NOR>OTC.Meanwhile,the recovery rate of antibiotics in surface water was higher than that in groundwater.This phenomenon is mainly influenced by the combination of pH,temperature,and DOM in the environment.[Conclusions]The results of the study demonstrated the feasibility and efficiency of combining flocculation and ultrasonic extraction methods in the extraction of antibiotic-endowed forms from soil and water environments.This study provides a theoretical and scientific basis for the extraction of fugitive forms of other types of antibiotics and the comprehensive assessment of the ecological risk of antibiotics in the interaction zone.