title: Convenient analysis of vitamin D in cheese and other food matrixes by liquid chromatography/mass spectrometry.
abstract: A convenient method is presented for determination of vitamin D in natural cheese, processed cheese, milk, cereals, noncarbonated soft drinks, and juice by liquid chromatography/ mass spectrometry (LC/MS). Samples were saponified, extracted, evaporated, redissolved in acetonitrile, and injected into an LC-atmospheric pressure chemical ionization-MS system with no preparative chromatographic steps. Vitamin D was determined by selected ion monitoring. MS response was linear for vitamin D3 and its internal standard vitamin D2, and overall average recoveries ranged from 98 to 105%. A blending experiment in which shredded vitamin D3-fortified cheddar was mixed with control nonfortified cheddar showed linearity. The limit of detection for vitamin D was 1.3 ng and the limit of quantitation was 3 ng. The method gave good accuracy and precision, with a standard deviation of 9.5 and relative standard deviation of 6.7%. Results for vitamin D3 obtained with this method for different food matrixes, at different levels, were in agreement with those obtained with the reference LC/UV method currently used by many laboratories and derived from AOAC Official Method 982.29.
authors.affiliation: Kraft Foods, Physical and Chemical Characterization, 200 Deforest Ave, East Hanover, NJ 07936, USA. gianluca.dimartino@kraft.com
authors.forename: Gianluca
authors.initials: G
authors.lastname: Dimartino
mesh_terms: D000097:Acetonitriles / Q000737:chemistry; D002611:Cheese; D002623:Chemistry Techniques, Analytical / Q000379:methods*; D002851:Chromatography, High Pressure Liquid; D002853:Chromatography, Liquid / Q000379:methods*; D004872:Ergocalciferols / Q000032:analysis; D005504:Food Analysis / Q000379:methods*; D013058:Mass Spectrometry / Q000379:methods*; D012016:Reference Values; D015203:Reproducibility of Results; D013056:Spectrophotometry, Ultraviolet / Q000379:methods; D013997:Time Factors; D014807:Vitamin D / Q000032:analysis* / Q000737:chemistry
chemical_list: D000097:Acetonitriles; D004872:Ergocalciferols; D014807:Vitamin D; C032159:acetonitrile