Handbook of Vitamin Analyses for Health (original) (raw)
Related papers
Annals of Clinical Biochemistry: International Journal of Laboratory Medicine, 2009
Aim To survey laboratories enrolled in the Royal College of Pathologists of Australasia (RCPA) Chemical Pathology Quality Assurance Programme (QAP) for vitamin A and E testing to determine differences between methods of analysis. Methods A detailed questionnaire covering the major aspects of serum vitamin A and E analysis was sent to all participating laboratories in 2007. Results Thirteen out of the 22 laboratories completed the questionnaire. Methods between laboratories showed a great deal of commonality. All respondents performed a liquid extraction step, which included the addition of an internal standard, followed by high-performance liquid chromatography (C18 columns with predominantly methanol-based mobile phases) with spectrophotometric detection. Major inter-laboratory differences were whether the sample was protected from light, the extraction solvents and ratios used, the drying down temperature used post-liquid extraction and choice of calibrator. Conclusions The questi...
Laboratory medicine best practice guideline: vitamins a, e and the carotenoids in blood
The Clinical biochemist. Reviews / Australian Association of Clinical Biochemists, 2014
Despite apparent method similarities between laboratories there appear to be confounding factors inhibiting uniform reporting and standardisation of vitamin assays. The Australasian Association of Clinical Biochemists (AACB) Vitamins Working Party, in conjunction with The Royal College of Pathologists of Australasia Quality Assurance Programs, has formulated a guideline to improve performance, reproducibility and accuracy of fat-soluble vitamin results. The aim of the guideline is to identify critical pre-analytical, analytical and post-analytical components of the analysis of vitamins A, E and carotenoids in blood to promote best practice and harmonisation. This best practice guideline has been developed with reference to the Centers for Disease Control and Prevention (CDC) "Laboratory Medicine Best Practices: Developing an Evidence-Based Review and Evaluation Process". The CDC document cites an evaluation framework for generating best practice recommendations that are sp...
Final report on CCQM-K62: Nutrients in infant/adult formula—Vitamins
Metrologia, 2010
Key Comparison CCQM-K62 was designed to enable demonstration of the equivalence in capabilities for measurement of vitamins in a food matrix. A milk-based fortified human infant/adult formula was selected as the matrix based upon material availability and relevance. Because vitamins were added to the CCQM-K62 study material in a single form and at levels significantly higher than those that would be naturally occurring in the milk base, the ability of a laboratory to measure the study vitamins is only indicative of a laboratory's ability to measure vitamins in fortified foods. Target analytes were selected for study because of the ready availability of suitable standard materials and the range of their chemical properties: folic acid (vitamin B9) is a single watersoluble molecular entity that typically occurs at low levels and can be unstable, niacin (vitamin B3) is a single stable molecular entity and is typically present at higher concentrations than the other water-soluble vitamins, vitamin A has multiple molecular forms (including retinol and retinyl palmitate), is fat-soluble and typically occurs at relatively high levels. Results for participants measuring only folic acid or niacin are only indicative of their ability to make that measurement; results for participants measuring both folic acid and niacin are indicative of a laboratory's ability to measure folic acid, thiamine, niacin, and riboflavin in fortified foods but not vitamin C or other water-soluble vitamins. The ability to measure vitamin A (reported as retinol equivalents) in this material is also indicative of the participant's ability to measure vitamin E (as alpha-tocopherol and alpha-tocopheryl acetate) but is not indicative of the ability to measure vitamins D and K, which typically occur at much lower concentrations. The relative degrees of equivalence of the reported measurements for all three analytes in CCQM-K62 were within 10%; however, since only two results were submitted for niacin and vitamin A and one of the three results for folic acid was withdrawn, no strong conclusions as to the expected comparability of higher-order vitamin measurements can be established.
Aim: Hyperhomocysteinemia and vitamins B 6 , B 9 , and B 12 deficiencies usually result in various neurological, vascular, ocular, renal, and pulmonary abnormalities. However, to date, there are no simultaneous detection methods available for determining homocysteine, vitamins B 6 , B 9 , and B 12 levels in various biological fluids. In this study, we aim to develop a new validated simultaneous detection method for all four compounds to save both cost and time of analysis. Materials and Methods: The mobile phase consisted of a mixture of methanol and 1-heptanesulfonic acid sodium salt (33:67) with 0.05% triethylamine. The pH of the entire mixture was adjusted to 2.3 and the flow rate was 0.5 mL/min. Separation was achieved using a C-18 column (5 µm; 150 mm × 4.6 mm) maintained at 28°C in a column oven and the detection was conducted at 210 nm. Results: The method was linear between 50 and 1600 ng/mL for all of the drugs. The limits of detection for homocysteine, vitamins B 6 , B 9 , and B 12 were 5, 5, 10, and 10 ng/mL, respectively, while the limits of quantification were 10, 10, 25, and 25 ng/L, respectively. The developed method achieved good precision and accuracy and complies with the Food and Drug Administration (FDA) requirements.
Holotranscobalamin as an Indicator of Dietary Vitamin
2000
We report that serum holotranscobalamin (holoTC) compares favorably with serum vitamin B 12 for identifying vegans likely to have vitamin B 12 deficiency as judged by measurements of the metabolites methylmalonic acid (MMA) and homocysteine (tHcy). We also report that measurement of holoTC may possibly replace combined testing with serum vitamin B 12 (B12), MMA, and tHcy in this population.
2014
The National Institute of Standards and Technology coordinates the Micronutrients Measurement Quality Assurance Program (MMQAP) for laboratories that measure fatand water-soluble vitamins and carotenoids in human serum and plasma. This report describes the design of and results for the Winter, Spring and Fall 1995 MMQAP measurement comparability improvement studies: 1) Round Robin XXXIII Fat-Soluble Vitamins and Carotenoids in Human Serum, 2) Round Robin XXXIV Fat-Soluble Vitamins and Carotenoids in Human Serum, 3) Round Robin XXXV Fat-Soluble Vitamins and Carotenoids in Human Serum, 4) Round Robin 7 Ascorbic Acid in Human Serum, and 5) Round Robin 8 Ascorbic Acid in Human Serum. The materials for Round Robin XXXIII were shipped to participants in January 1995; participants were requested to provide their measurement results by March 20, 1995. The materials for Round Robin XXXIV were shipped to participants in April 1995; participants were requested to provide their measurement resu...
Rapid and simple HPLC analysis of vitamin K in food, tissues and blood
Food Chemistry, 2000
The lack of precise data in food composition tables and also in human and animal plasma concentrations of phylloquinone and other vitamers demands intensive investigation of both; appropriate analytical methods are necessary. Sensitive and selective detection, simplicity and rapidity of the method, and precision and reliability of the data are recommended. Based on a RP-HPLC assay using post-column derivatization and¯uorescence detection, combined with a liquid±liquid sample clean-up, a simple and rapid assay is presented. The application to food, human plasma and animal tissues is shown. The samples cover a wide range of matrices, from those of fairly low, e.g. human plasma and milk, to those of high phylloquinone content, e.g. broccoli. For ver-i®cation purposes mass-spectroscopy (for human plasma) or dierent¯uorescence wavelengths (for the food items) were applicated. Coecients of variation did not exceed 10% for any matrix and there were no remarkable losses over the whole analytical process. The lower limit of detection for plasma samples was estimated as 0.04 ng/ml.