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International Journal of Analytical Chemistry
Volume 2014, Article ID 841084, 4 pages
Research Article

Quantitation of α-Lactalbumin by Liquid Chromatography Tandem Mass Spectrometry in Medicinal Adjuvant Lactose

1College of Pharmacy, Liaoning University, Shenyang 110036, China
2Yichang Humanwell Pharmaceutical Co., Ltd., Yichang 443005, China

Received 28 September 2014; Accepted 20 November 2014; Published 4 December 2014

Academic Editor: Frantisek Foret

Copyright © 2014 Rui Yan et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Lactose is a widely used pharmaceutical excipient, sometimes irreplaceable. Traces of residual proteins left during production of lactose are potential allergen to body. The present paper describes a sensitive and specific LC-MS method for the determination of α-lactalbumin (α-La) in lactose samples. Chromatographic separation was performed on an Acquity UPLC BEH300 C18 column ( mm, 1.7 μm) with an isocratic mobile phase consisting of water containing 0.1% TFA and acetonitrile containing 0.1% TFA (80 : 20, v/v). Mass spectrometric detection was achieved by a triple-quadrupole mass spectrometer equipped with an ESI interface operating in positive ionization mode. Quantitation was performed using selected ion monitoring of m/z 2364 for α-La. The calibration curve was linear from 0.2 to 10 µg/mL. The intra- and interday precisions were less than 7.6% and the accuracy ranged from 96.4 to 104.5%. The limit of quantification (LOQ) was 0.15 µg/mL and the limit of detection (LOD) was 0.05 µg/mL. This method was then successfully applied to investigate 6 different lactose samples. The application can provide technical preparation for the development of specification of lactose.