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    液-液萃取结合免疫亲和柱层析净化-高效液相色谱测定烘焙咖啡中赭曲霉毒素A

    HPLC Determination of Ochratoxin A in Roasted Coffee with Purification by Liquid-Liquid Extraction in Combination with Immunoaffinity Column Chromatography

    • 摘要: 烘焙咖啡样品中赭曲霉毒素A用氯仿提取分离,所得提取液经碳酸氢钠溶液液-液萃取和免疫亲和柱层析净化.用甲醇将赭曲霉毒素A从层析柱上洗下,进行高效液相色谱测定,用KR100-10 C18色谱柱(4.6 mm×250 mm,5 μm)作固定相.用水、乙腈、乙酸(以体积比51比48比1)混合溶液作流动相,从色谱柱上将被测物洗下,流速为1.0 mL·min-1.采用荧光检测,分析波长为333 nm(λex)和460 nm(λem).赭曲霉毒素A的质量浓度在1.0~50.0 μg·L-1范围内峰面积与浓度呈线性关系,在1.0,10.0,50.0 ng·g-1添加水平的回收率在74.1%~78.0%范围内,相对标准偏差(n=8)在5.2%~9.6%范围内.方法测定限(S/N=10)为1.0 ng·g-1.

       

      Abstract: Ochratoxin A in roasted coffee was extracted with chloroform,and purified by back-extraction with sodium bicarbonate solution and passing the aqueous extract after dilution with PBS of pH 7.0 through Ochra TestTM immunoaffinity column.Ochratoxin A was eluted from the column with methanol,and determined by HPLC.The KR100-10 C18 chromatographic column (4.6 mm×250 mm,5 μm) was used as the stationary phase,and a mixture of H2O,acetonitrile and acetic acid (mixed in the ratio of 51∶48∶1) was used as the mobile phase with a flow-rate of 1.0 mL·min-1,to elute the ochratoxin A from the column.Fluorescence detection at the wavelengths of (λex) 333 nm and (λem) 460 nm was used in the determination.Linear relationship between values of peak area (A) and concentration of ochratoxin A was obtained in the range of 1.0-50.0 μg·L-1.Determination limit (S/N=10) of the method was found to be 1.0 ng·g-1.Recovery and precision were tested by adding standard solutions of ochratoxin A at 3 different concentration levels of 1.0,10.0 and 50.0 ng·g-1,values of recovery found were in the range of 74.1%-78.0%,and values of RSD′s (n=8) obtained were in the range of 5.2%-9.6%.

       

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