LC-MS/MS with atmospheric pressure chemical ionisation to study the effect of UV treatment on the formation of vitamin D3 and sterols in plants

Some plant species are known to cause calcium intoxification in grazing animals. This has been attributed to the presence of vitamin D-3-like activity. However, research into the presence of vitamin D-3 in plants has been limited. One reason for this may be limitations in the analytical methods available for unambiguous detection and quantification of vitamin D-3. This paper presents a new method for determining vitamin D-3 and its sterol precursors. The method is based on saponification and extraction followed by solid phase clean-up of the compounds from plant leaves and detection by APCI-MS. Recoveries ranged from 101% to 114% and precision from 3% to 12%. Detection limits were 2-8 ng/g fresh weight for the substances tested. In a pilot study we found that Solanum glaucohyllum Desf. and Solanum lycopersicum L produced vitamin D-3 after UV-treatment. The preliminary results presented suggest that vitamin D-3 formation in plants is dependent on light exposure. (C) 2011 Elsevier Ltd. All rights reserved.