施粪肥土壤中抗生素的提取条件优化及残留特征

为确立高效的土壤抗生素提取条件，揭示施用粪肥土壤中抗生素的残留水平，分别采集江苏省常州市某养猪场新鲜猪粪样品6份、施用粪肥及无机肥水稻土壤样品各13份，对土壤抗生素提取液配比与超声提取时间进行筛选，利用高效液相色谱-串联质谱（HPLC-MS/MS）对生猪粪便和土壤中的四大类（四环素类、磺胺类、喹诺酮类和大环内脂类）15种抗生素含量进行检测分析。结果表明，最优提取条件选择为：提取液配比为甲醇：EDTA=1：1，超声提取时间为10 min，四环素类抗生素的加标回收率为73.2%~93.4%，磺胺类为81.2%~101.1%，喹诺酮类为106.3%~110.8%。该养猪场猪粪与施粪肥土壤中均未检测到大环内脂类抗生素，其余各类抗生素平均残留量从高到低排序分别为：猪粪中四环素类 > 磺胺类 > 喹诺酮类；施粪肥土壤中四环素类 > 喹诺酮类 > 磺胺类，四环素类是最主要的抗生素污染物，残留量分别为猪粪中1.9~12.5 mg·kg-1、施粪肥土壤中23.9~212.4 μg·kg-1；施无机肥土壤中未检测出抗生素，施粪肥土壤中的抗生素来源于生猪粪便。

Optimization of extraction conditions and residual characteristics of antibiotics in manure-amended soils

In order to establish effective extraction conditions for soil antibiotics and determine the residual levels of antibiotics in manure-amended soils, six samples of fresh pig manure and thirteen samples of paddy soil fertilized with manure and inorganic fertilizers were collected. The extraction conditions of soil antibiotics including the ratio of the extraction liquid and ultrasonic extraction time were selected. The concentrations of fifteen types of antibiotics that belong to four categories (tetracyclines, sulfonamides, quinolones, and macrolides) in manure-amended soils and pig manure were detected and analyzed by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The optimal extraction conditions were determined as follows:methanol-to-EDTA ratio of 1 and ultrasonic extraction time of 10 min. The recovery rates of tetracyclines, sulfonamides, and quinolones ranged from 73.2% to 93.4%, from 81.2% to 101.1%, and from 106.3% to 110.8%, respectively. The macrolides were detected in neither pig manure nor in manure-amended soil samples. The average concentrations of the other three categories of antibiotics decreased in the order of:tetracyclines > sulfonamides > quinolones in pig manure and tetracyclines > quinolones > sulfonamides in manure-amended soils. The main contaminants were tetracyclines with concentrations ranging from 1.9 mg·kg-1 to 12.5 mg·kg-1 in pig manure and from 23.9 μg·kg-1 to 212.4 μg·kg-1 in manure-amended soils. Antibiotics were not detected in soil samples fertilized with inorganic fertilizer. The source of antibiotics in manure-amended soils was determined as pig manure.