2013 Annual Report
Objective 2: Develop and validate new or updated analytical methods using current technology to determine the levels of water-soluble vitamins (WSV), lipid soluble vitamins (LSV) and/or other components for foods and dietary supplements. Sub-Objective 2.A: Develop/update and optimize measurement procedures to establish validated capability for simultaneous measurements of multiple WSV (SimWSV). Sub-Objective 2.B: Develop and validate analytical methods for the determination and quantification of LSV (A, D, E, and K) and lipids in food matrices and dietary supplements. Sub-Objective 2.C Develop/update and optimize measurement procedures to establish validated capability for measurements of vitamin B12 in dietary supplements and foods. Sub-Objective 2.D Develop multivariate calibration methods for simultaneous determination of multiple vitamins in extracts with no prior chromatographic separations.
Objective 3: Develop and validate sample preparation procedures to optimize extraction, remove interferences, and/or to concentrate difficult to analyze vitamins in foods and dietary supplements.
Objective 4: Catalyze cooperative activities to identify and provide improved measurement systems and essential Reference Materials for vitamins in foods and dietary supplements. Provide analytical data to characterize the vitamin content of selected Reference Materials. Sub-Objective 4.A: Generate information with developed and validated methods to assign value-added information on vitamin content to available Reference Materials. Sub-Objective 4.B: Catalyze development of overall measurement systems for vitamins in foods and dietary supplements.
Objective 3: Multiple extractions for WSV with different buffers, pHs, and multiple extraction approaches (including classical and modern methods such as pressurized liquid extraction [PLE], microwave-assisted extraction [MAE], ultrasonic irradiation, stirring, shaking, and Soxhlet) will be systematically explored to ensure complete extraction and compare extraction efficiencies of different procedures. The lipid soluble vitamins (LSV) (A, D, E, K) would be similarily extracted with a organic solvents of different polarities.
Objective 4: FCMDL capability for high quality vitamin determinations will be applied to provide reference measurements to value to NIST SRMs such as the Adult/Infant Formula SRM and Fortified Cereal SRM. Through initiating and providing guidance for a number of nutrition metrology-related activities, FCMDL will catalyze improvement of the overall measurement system for vitamins. FCMDL will participate as collaborators in method validation studies as appropriate. FCMDL will continue to organize and advise the development and conduct of symposia, and other appropriate workshops.
A new method for the quantification of TAGs was developed based on response factors obtained from the comparison of HPLC-MS results with those obtained by gas chromatography with flame ionization detection (GC-FID). AOCS method Ce-1b-89 was implemented for GC-FID analysis but required modification and improvement to allow the very long chain fatty acid methyl esters to elute. GC-FID data were obtained for all oils in the dietary supplements (olive oil, soybean oil, sunflower oil, safflower oil, rice bran oil, canola oil) for comparison to results by LC-MS. A manuscript describing this new development has been submitted and is undergoing the first stage of review.
The “dilute and shoot” method was applied to the analysis of solid powdered dietary supplement capsules and NIST SRM 3280 compressed powder supplement tablets. The “dilute and shoot” method was also applied to the determination of vitamin D in irradiated mushroom powders. Preliminary data suggests that this approach is feasible for solid samples and further research will be included in the new project goals.
Byrdwell, W.C., Horst, R.L., Phillips, K.M., Holden, J.M., Patterson, K.Y., Harnly, J.M., Exler, J. 2013. Vitamin D levels in fish and shellfish determined by liquid chromatography with ultraviolet detection and mass spectrometry. Journal of Food Composition and Analysis. 10:1016/j.jfca.2013.01.005.