稻田土壤及水中多抗霉素残留量的分析与检测方法研究

采用高效液相色谱法建立了稻田土壤及水中多抗霉素残留量的分析方法。水样品经氨水调节pH值至8.0,以乙酸乙酯萃取去除有机杂质,水相经浓缩后定容;土壤样品用碱性甲醇和水的混合溶液(70∶30)提取,提取液经浓缩后定容。上述萃取液采用C18亲水性不锈钢色谱柱(AQ-C18,4.6 mm×250 mm,5μm)进行液相色谱分离,紫外检测器检测,外标法定量,流动相为水(用冰乙酸调节pH值为4.0)-甲醇(87∶13),流速:0～8 min为1.0 mL/min,8～16 min为0.3 mL/min,柱温30℃,检测波长272 nm。结果表明,多抗霉素的浓度在0.05～2.00 mg/L范围内与其对应的峰面积呈良好的线性关系,相关系数(r2)为0.998 8;多抗霉素的最小检出量为1.00×10-9g,在稻田水中的最低检出浓度为0.05 mg/L,在稻田土壤中的最低检出浓度为0.05 mg/kg;在0.06、0.60、1.00 mg/kg加标水平下,多抗霉素在稻田水中的平均加标回收率为97%～99%,相对标准偏差为0.71%～2.4%;在稻田土壤中的平均加标回收率为95%～97%,相对标准偏差为1.7%～4.5%。该方法操作简便,分离效果好,准确度和精密度良好,符合农药残留的检测要求。

A Method on Residue Analysis of Polyoxin in Paddy Soil and Water

A high performance liquid chromatography(HPLC) method was developed for the determination of polyoxin residue in paddy soil and water.The paddy water was adjusted to pH 8.0 with ammonia water,and extracted with acetic ether to remove organic impurities.The water phase was concentrated to constant.The paddy soil was extracted using alkaline mixed with solution of carbinol-water(70 ∶ 30),and concentrated to constant.The above extracts were separated on a C18 hydrophilic stainless steel chromatographic column(AQ-C18,4.6 mm×250 mm,5 μm) and detected with ultraviolet detector(UVD).The quantification analysis of polyoxin was performed by the external standard.The other optimal conditions were as follows:mobile phase:carbinol-water(13 ∶ 87);flow rate:1.0 mL/min for first 0-8 min,and 0.3 mL/min for the next 8-16 min,column temperature:30 ℃,detection wavelength:272 nm.Under the optimal conditions,the calibration curve was linear between peak area and polyoxin concentration in the range of 0.05-2.00 mg/L with correlation coefficient of 0.998 8.The limit for detection for polyoxin was 1.0×10-9 g,and the detection limits of polyoxin in paddy soil and water were 0.05 mg/kg and 0.05 mg/L,respectively.The spiked recoveries of polyoxin in paddy water and soil at spiked concentrations of 0.06,0.60,1.00 mg/kg were in the range of 97%-99% and 95%-97%,with RSDs of 0.71%-2.4% and 1.7%-4.5%,respectively.This method showed the advantages of easy operation,good separation effect and high accuracy,and could meet the requirements for pesticide residue detection.