Liquid chromatography with ultraviolet and dual parallel mass spectrometric detection for analysis of vitamin D in retail fortified orange juice

Samples of vitamin D fortified orange juice obtained from retail food stores were analyzed for vitamin D3 content using a method developed by combining the best features of two AOAC methods. Detection by ultraviolet absorption at 265 nm was compared to detection by selected ion monitoring (SIM) using atmospheric pressure chemical ionization (APCI) mass spectrometry (MS). Furthermore, an ion trap (IT) mass spectrometer was employed in a ‘dual parallel MS’ arrangement to simultaneously obtain qualitative APCI-ITMS data. The method was applied to 33 samples of 3 national American orange juice brands and 7 samples of 5 other American brands collected using a statistically designed sampling plan as part of the National Food and Nutrient Analysis Program to provide values for the USDA National Nutrient Databank for Standard Reference. Vitamin D3 values ranged from 1.071 μg/100 g (43 IU/100 g) to 1.663 μg/100 g (67 IU/100 g), with an average across 55 samples analyzed, including duplicates, of 1.4 ± 0.1 μg/100 g (57 ± 5 IU/100 g). The average of the 38 non-zero uniquely identified samples, using the averages of duplicate sets, was 1.4 ± 0.1 μg/100 g (57 ± 5 IU/100 g), indicating that a typical 8 oz. (∼240 mL = 240 cm3) glass of orange juice provided 3.4 ± 0.3 μg (140 ± 10 IU) vitamin D3.