title: Quantification of lactose content in human and cow's milk using UPLC-tandem mass spectrometry.
abstract: A sensitive, accurate, and specific quantitative UPLC-MS/MS method was developed for lactose measurement of cow's and human milk and validated with cow's milk samples certified by an external laboratory. The new method employs only a dilution of raw cow's and human milk for simple preparation with no need to remove protein and fat prior to analysis with UPLC-MS/MS. It was operated in negative mode to detect lactose molecules and labeled (13)C(12)-lactose with the highest sensitivity. The principle advantages of the new LC-MS/MS method were: completed lactose determination in 5 min, absolute recovery of 97-107%, lower limit of detection <5 ng/L, and 99% linearity over the concentration range of 0.7-4.4 mg/L for both cow's and human milk. The mean lactose concentration of 51 human milk samples was measured as 56.8 ± 5.5 g/L ranging from 43 to 65 g/L. The described method represents validated lactose analysis with high accuracy and precision for a routine lactose determination in raw human milk.
authors: Division of Neonatology, Department of Pediatrics, McMaster University, Hamilton, Ontario, Canada.
authors: Gerhard
authors: G
authors: Fusch
authors: Arum
authors: A
authors: Choi
authors: Niels
authors: N
authors: Rochow
authors: Christoph
authors: C
authors: Fusch
mesh_terms: D000818:Animals; D002417:Cattle; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D006801:Humans; D007785:Lactose / Q000032:analysis*; D057230:Limit of Detection; D016014:Linear Models; D008892:Milk / Q000737:chemistry*; D008895:Milk, Human / Q000737:chemistry*; D015203:Reproducibility of Results; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D007785:Lactose