Analysis method for determination of nisin A and nisin Z in cow milk by using liquid chromatography-tandem mass spectrometry.

Kyung Yuk Ko, So Ra Park, Chae A Lee, Meehye Kim

Journal of dairy science 2015 Mar

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Nisin, a polypeptide with antimicrobial properties, is known as a natural preservative. It is used in various foods, including dairy products. This study validated a novel procedure using liquid chromatography-tandem mass spectrometry (LC-MS/MS) for the determination of nisin A and nisin Z in cow milk. An extraction solution of 0.1 M acetate buffer containing 1 M NaCl (pH 2.0) and MeOH (1:1) was used to extract nisin A and nisin Z from milk samples. After the addition of extraction buffers, the samples were homogenized and centrifuged. The supernatant was filtered and injected for LC-MS/MS analysis. The linearity of the analytical method had a high correlation coefficient (r≥0.9987). The limits of quantitation of nisin A and nisin Z were approximately 12.9 and 10.9 µg/kg, respectively. The accuracy of the analytical method in milk ranged from 90.6 to 103.4% for nisin A and from 83.8 to 104.4% for nisin Z. The coefficient of variation values of intra- and interday in milk determined to be less than 5% in both nisin A and nisin Z. Because the proposed method has comparatively high recovery and low coefficient of variation, it seems appropriate for the determination of nisin A and nisin Z in milk samples. As the quantification of nisin A and nisin Z in milk samples by using LC-MS/MS has only been rarely reported until now, this study provides a meaningful technological advance for the dairy industry. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Citation

Kyung Yuk Ko, So Ra Park, Chae A Lee, Meehye Kim. Analysis method for determination of nisin A and nisin Z in cow milk by using liquid chromatography-tandem mass spectrometry. Journal of dairy science. 2015 Mar;98(3):1435-42