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Determination of α ‐tocopherol in infant foods by liquid chromatography combined with atmospheric pressure chemical ionisation mass spectrometry
Author(s) -
Kalman Andras,
Mujahid Claudia,
Mottier Pascal,
Heudi Olivier
Publication year - 2003
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.970
Subject(s) - chemistry , mass spectrometry , chromatography , atmospheric pressure chemical ionization , tocopherol , liquid chromatography–mass spectrometry , direct electron ionization liquid chromatography–mass spectrometry interface , chemical ionization , analytical chemistry (journal) , atmospheric pressure , ionization , organic chemistry , antioxidant , ion , vitamin e , meteorology , physics
A novel, sensitive and specific method for the quantification of α ‐tocopherol in two infant foods (milk and cereals) using liquid chromatography on‐line with positive atmospheric pressure chemical ionisation mass spectrometry detection (LC/APCI‐MS) has been developed. The samples were first saponified in order to eliminate fats and to transform tocopherol esters into free tocopherol, followed up by a liquid–liquid extraction of the analyte in petroleum benzine/diisopropyl ether (75:25, v/v) prior to injection onto the LC system. For the quantification, deuterium‐labelled tocopherol was used as internal standard and the samples were monitored in selected ion monitoring (SIM) mode. Calibration curves between 1–40 μg/mL of α ‐tocopherol showed a good linear correlation (r 2 = 0.99994), and the detection limit was determined to be 2.5 ng/mL. The within‐day and between‐day precision were determined for several dietetic infant formulae and certified reference samples, and found to be below 3.5%. The accuracy determined on a Nestlé reference sample (milk powder) was calculated to be 115.2 ± 1.2%, which confirms the robustness of the proposed method. This study shows that single quadrupole LC/MS can be applied for the quantification of vitamins in food and the method offers better sensitivity and selectivity than traditional method such as LC‐UV. This would simplify the preparation of the food samples and consequently enhance the vitamin analysis throughput in the food area. Copyright © 2003 John Wiley & Sons, Ltd.