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建立了白萝卜中4种四环素类抗生素(土霉素、四环素、金霉素、强力霉素)的高效液相色谱测定法.样品用0.02 mol·L-1的氯化镁-柠檬酸混合液提取2次,甲醇提取1次,甲醇提取液浓缩至干后用0.02 mol·L-1的氯化镁与0.02 mol·L-1柠檬酸混合溶液溶解残渣,合并3次提取液过Waters Oasis HLB固相小柱萃取,10 mL甲醇-乙酸乙酯(1∶9,V/V)洗脱.以反相C18柱为分离柱,甲醇、乙腈、0.01 mol·L-1草酸与0.01mol·L-1三氯乙酸为流动相进行梯度洗脱,11 min内分离4种抗生素.结果发现,在0.05~10.00μg·mL-1范围内,4种抗生素的峰面积与质量浓度的线性关系良好(R2≥0.999),土霉素、四环素、金霉素与强力霉素的定量限(LOQ)分别为2.9、4.3、8.9和5.2μg·kg-1;添加水平分别为10、100、1000μg·kg-1时,土霉素、四环素、金霉素与强力霉素的回收率分别在78.4%~88.8%、82.8%~92.4%、79.0%~83.0%和74.9%~84.5%之间,变异系数均小于8.9%.本方法成功用于实际样品的测定,结果表明,采集的样品中土霉素、四环素、金霉素和强力霉素的最大含量分别为53、41、79和91μg·kg-1.
A high performance liquid chromatographic method for the determination of four kinds of tetracycline antibiotics (oxytetracycline, tetracycline, chlortetracycline, doxycycline) in white radish was established.The samples were extracted with 0.02 mol·L-1 magnesium chloride-citric acid mixture Times, and the methanol was extracted once. After the methanol extract was concentrated to dryness, the residue was dissolved with a mixed solution of 0.02 mol·L-1 magnesium chloride and 0.02 mol·L-1 citric acid. The combined extracts were combined three times through a Waters Oasis HLB solid phase cartridge And eluted with 10 mL of methanol-ethyl acetate (1: 9, V / V) .The column was reversed-phase C18 with methanol, acetonitrile, 0.01 mol·L-1 oxalic acid and 0.01 mol·L- Acetic acid as the mobile phase.The four antibiotics were separated within 11 min.The results showed that the linear relationship between the peak areas and the mass concentrations of the four antibiotics was good (R2≥0.999) in the range of 0.05-10.00 μg · mL-1 , LOQ of oxytetracycline, tetracycline, chlortetracycline and doxycycline were 2.9, 4.3, 8.9 and 5.2 μg · kg-1, respectively. When the addition levels were 10, 100 and 1000 μg · kg-1, The recoveries of oxytetracycline, tetracycline, chlortetracycline and doxycycline were in the range of 78.4% -88.8%, 82.8% -92.4%, 79.0% -83.0% and 74.9% -84.5% respectively, and the coefficients of variation were all less than 8.9% .this Was successfully used for actual samples, the results show that the maximum content of the samples taken oxytetracycline, tetracycline, doxycycline, and chlortetracycline were 53,41,79 and 91μg · kg-1.