Analysis of Fat-Soluble Vitamins. XVII. Comparison of Chemical and Biological Assays of Vitamin D

1978 ◽  
Vol 61 (1) ◽  
pp. 117-121
Author(s):  
Frits J Mulder ◽  
Roel Strik
Keyword(s):  
Vitamin D ◽  
Coefficient Of Variation ◽  
Chemical Method ◽  
Geometric Mean ◽  
British Standard Institution ◽  
Geometric Mean Ratio ◽  
British Standard ◽  
Biological Assays ◽  
Chemical Assay ◽  
Fat Soluble Vitamins

Abstract Two methods, the chemical assay using maleic anhydride addition and the British Standard Institution chick bioassay, were used to analyze samples from vitamin D3 resin batches manufactured over a period of about 4 years. Statistical analysis of data obtained for vitamin D shows that (1) the reproducibility of the chemical assay has a coefficient of variation of 0.7% ; (2) the chemical assay is suitable for controlling the dilution procedure of resins in oil, the product variability being represented by a coefficient of variation of 1.7% ; (3) the agreement between the average values obtained by the bioassay and the chemical method is satisfactory (geometric mean ratio = 99.7%, n = 39); (4) the chick bioassay has 95% limits of variation of about ±30% for single results.

Analysis of Fat-Soluble Vitamins. XIX. Collaborative Studies on the Chemical Assay for Vitamin D Concentrates

1978 ◽  
Vol 61 (2) ◽  
pp. 261-265
Author(s):  
Frits J Mulder ◽  
Ben Borsje ◽  
Roel Strik ◽  
Ellen J Vries
Keyword(s):  
Vitamin D ◽  
Maleic Anhydride ◽  
Chemical Method ◽  
Confidence Limits ◽  
Collaborative Studies ◽  
Collaborative Test ◽  
Chemical Assay ◽  
Assay Methods ◽  
Biological Methods ◽  
Fat Soluble Vitamins

Abstract In 1971, a chemical method for the assay of vitamin D in concentrates containing only vitamin D was collaboratively studied by 14 laboratories, using 6 different samples from 2 European manufacturers. On the basis of these results, the laboratories were divided into 2 groups: 5 with significant laboratory biases of ≥2%, and 9 laboratories with nonsignificant bias. The 9 laboratories were subdivided into 2 groups which differed significantly as to reproducibility within laboratories. The reproducibility between laboratories, expressed as a standard deviation in per cent with 95% confidence limits, was 1.2% (confidence range 0.6–7.3) and 4.7% (confidence range 2.4–29.3) for 3 and 6 laboratories, respectively. A second collaborative test was performed in 1974, using 12 vitamin D resin samples in oil from 3 United States manufacturers, to compare 2 chemical vitamin D assay methods (with and without maleic anhydride) and to compare results from the chemical and biological methods; 9 laboratories participated in the chemical method study and 3 in the rat bioassay study. The correlation of results of the chemical method including maleic anhydride treatment and the rat bioassays was satisfactory. The reproducibility of the chemical method was about the same as that in the first collaborative test.

Analysis of Fat-Soluble Vitamins. XXII. High Performance Liquid Chromatographic Determination of Vitamin D in Concentrates. Collaborative Study1

1979 ◽  
Vol 62 (5) ◽  
pp. 1031-1040
Author(s):  
Frits J Mulder ◽  
Ellen J De Vries ◽  
Ben Borsje
Keyword(s):  
Vitamin D ◽  
High Performance ◽  
Chemical Method ◽  
Collaborative Study ◽  
Chromatographic Determination ◽  
High Performance Liquid Chromatographic ◽  
Hplc Method ◽  
De Vries ◽  
Fat Soluble Vitamins ◽  
Liquid Chromatographic

Abstract A collaborative study was carried out which compared the official chemical method (43.B14- 43.B24), the HPLC method according to Hofsass et al. including maleic anhydride treatment, and the HLPC procedure according to De Vries et al. for vitamin D concentrates. A total of 396 samples were distributed to 33 collaborators for analysis. Five laboratories performed both the chemical and the HPLC methods. Five laboratories performed the Hofsass method and 16 laboratories performed the De Vries method. The results for the chemical method agreed with the theoretical values for the samples, and the standard deviation was comparable to that obtained in previous AOAC collaborative studies. Collaborative results for the Hofsass method were low. In addition, incorrect use of a fixed conversion factor (1/0.586) and necessity of a double chromatographic system on a non-treated and a treated vitamin D sample reduce the effectiveness of the method. There were no adverse reactions to the De Vries HPLC method. It is recommended that the method be adopted official first action as an alternative procedure for determining vitamin D in concentrates, excluding powders containing irradiated 7-dehydrocholesterol.

scholarly journals Chemical Analysis of Vitamin D in Concentrates and Its Problems. XII. Analysis of Fat-Soluble Vitamins

1971 ◽  
Vol 54 (5) ◽  
pp. 1168-1174
Author(s):  
F J Mulder ◽  
E J De Vries ◽  
B Borsje
Keyword(s):  
Vitamin D ◽  
Chemical Analysis ◽  
Oxidation Products ◽  
Phenolic Antioxidants ◽  
Colorimetric Determination ◽  
Reference Standard ◽  
Collaborative Test ◽  
Chemical Assay ◽  
Analytical Procedures ◽  
Fat Soluble Vitamins

Abstract Details of analytical procedures are given for the analysis of vitamin D concentrates, such as resins, powders, and solutions, all without vitamin A. For the analysis a choice had to be made between the potential vitamin D content (the sum of calciferol (D) and precalciferol (P)) and the actual vitamin D content (calciferol only) in partly isomerized solutions. The biological vitamin D assays can only give the potential vitamin D content when both sample and reference standard solutions are equilibrated simultaneously to the same P ⇋ D ratio. Therefore the biological vitamin D unit should be based on the potential vitamin D content. An important point in the chemical assay of vitamin D in concentrates is the prevention of the oxidation of fat-soluble phenolic antioxidants during saponification. These oxidation products of antioxidants inhibit the color reaction. The colorimetric determination becomes more specific after inactivation of tachysterol by the addition of maleic anhydride. A collaborative test was carried out in 3 laboratories with an oil containing 3 different concentrations of vitamin D. The results of this test have verified the correctness of the analytical procedures.

Analysis of Fat-Soluble Vitamins. XXIII. High Performance Liquid Chromatographic Assay for Vitamin D in Vitamin D3 and Multivitamin Preparations1

1979 ◽  
Vol 62 (6) ◽  
pp. 1285-1291
Author(s):  
Ellen J De Vries ◽  
Jakob Zeeman ◽  
Robert J E Esser ◽  
Ben Borsje ◽  
Frits J Mulder
Keyword(s):  
Vitamin D ◽  
Vitamin D3 ◽  
Coefficient Of Variation ◽  
High Performance ◽  
Conversion Factor ◽  
Internal Standard ◽  
High Performance Liquid Chromatographic ◽  
External Standard ◽  
Fat Soluble Vitamins ◽  
Liquid Chromatographic

Abstract Vitamin D is determined in preparations containing other fat-soluble vitamins by high performance liquid chromatography (HPLC). The unsaponifiable residue is extracted and separated from interferences by reverse phase chromatography; the fraction corresponding to vitamin D3 is collected and quantitated using normal phase chromatography (amylalcohol-n-hexane as mobile phase) by measuring the vitamin D3 and previtamin D3 peaks at 254 nm. Previtamin D3 content is calculated as vitamin D3 with a conversion factor (determined on the equipment used). Application of the method to vitamin AD3 mixtures in oils gives 98-102% recovery. The reproducibility, using an external standard, is 2-3%, calculated as the coefficient of variation; with an internal standard, the coefficient of variation is 1-1.5%. The method measures potential vitamin D3 content in preparations containing ≽ 200 IU/g in the presence of all known vitamin D3 isomers, vitamin A, and vitamin E.

scholarly journals Interactions between Vitamin D Status, Calcium Intake and Parathyroid Hormone Concentrations in Healthy White-Skinned Pregnant Women at Northern Latitude

Nutrients ◽  
2018 ◽  
Vol 10 (7) ◽  
pp. 916 ◽  
Author(s):  
Andrea Hemmingway ◽  
Karen O’Callaghan ◽  
Áine Hennessy ◽  
George Hull ◽  
Kevin Cashman ◽  
...  
Keyword(s):  
Vitamin D ◽  
Parathyroid Hormone ◽  
Pregnant Women ◽  
Calcium Intake ◽  
Geometric Mean ◽  
Vitamin D Status ◽  
Metabolic System ◽  
Cross Sectional ◽  
The Mean ◽  
In Pregnancy

Adverse effects of low vitamin D status and calcium intakes in pregnancy may be mediated through functional effects on the calcium metabolic system. Little explored in pregnancy, we aimed to examine the relative importance of serum 25-hydroxyvitamin D (25(OH)D) and calcium intake on parathyroid hormone (PTH) concentrations in healthy white-skinned pregnant women. This cross-sectional analysis included 142 participants (14 ± 2 weeks’ gestation) at baseline of a vitamin D intervention trial at 51.9 °N. Serum 25(OH)D, PTH, and albumin-corrected calcium were quantified biochemically. Total vitamin D and calcium intakes (diet and supplements) were estimated using a validated food frequency questionnaire. The mean ± SD vitamin D intake was 10.7 ± 5.2 μg/day. With a mean ± SD serum 25(OH)D of 54.9 ± 22.6 nmol/L, 44% of women were <50 nmol/L and 13% <30 nmol/L. Calcium intakes (mean ± SD) were 1182 ± 488 mg/day and 23% of participants consumed <800 mg/day. The mean ± SD serum albumin-adjusted calcium was 2.2 ± 0.1 mmol/L and geometric mean (95% CI) PTH was 9.2 (8.4, 10.2) pg/mL. PTH was inversely correlated with serum 25(OH)D (r = −0.311, p < 0.001), but not with calcium intake or serum calcium (r = −0.087 and 0.057, respectively, both p > 0.05). Analysis of variance showed that while serum 25(OH)D (dichotomised at 50 nmol/L) had a significant effect on PTH (p = 0.025), calcium intake (<800, 800–1000, ≥1000 mg/day) had no effect (p = 0.822). There was no 25(OH)D-calcium intake interaction effect on PTH (p = 0.941). In this group of white-skinned women with largely sufficient calcium intakes, serum 25(OH)D was important for maintaining normal PTH concentration.

Examination of Calculations and Colorimetric Procedures in the Chemical Evaluation of Vitamin D

1965 ◽  
Vol 48 (4) ◽  
pp. 855-858
Author(s):  
Glen M Shue
Keyword(s):  
Vitamin D ◽  
Collaborative Study ◽  
Internal Standard ◽  
High Potency ◽  
Chemical Evaluation ◽  
Accuracy And Precision ◽  
Chemical Assay ◽  
Color Reagent ◽  
Colorimetric Procedure ◽  
Better Than

Abstract Examination of data obtained from the 1963 collaborative study of a proposed chemical assay of vitamin D shows the following: the vitamin D content of the sample may be calculated by vising a reading at 550 mμ as the blank, with an accuracy and precision equal to or better than that of the proposed calculation; an internal standard is not necessary. These findings suggest a simplified colorimetric procedure which requires less than 5 μg (200 units). Data demonstrate a marked improvement in the color reagent resulting from reduction of the concentration of antimony trichloride. Preliminary data indicate that the method can be applied to high potency irradiated yeast.

Analysis of Fat-Soluble Vitamins. XX. Determination of Vitamin D in Multivitamin Preparations. Second Collaborative Study

1978 ◽  
Vol 61 (3) ◽  
pp. 735-745
Author(s):  
Ellen J De Vries ◽  
Frits J Mulder ◽  
Ben Borsje
Keyword(s):  
Vitamin D ◽  
Vitamin A ◽  
Test Data ◽  
Vitamin D3 ◽  
Collaborative Study ◽  
Three Samples ◽  
The Mean ◽  
Fat Soluble Vitamins

Abstract The official first action method for determining vitamin D in multivitamin preparations was modified. The method was collaboratively studied by 7 laboratories, using 6 preparations in oil. The preparations consisted of vitamin D at various levels and at various ratios (in w/w) to vitamin A. Three samples contained cholecalciferol and 3 samples contained vitamin D3 from vitamin D3 resin. After outliers were eliminated by the Dixon test, data were analyzed and averages were compared with amounts of vitamin D known to be in each sample. For samples with vitamin D: vitamin A ratios of 1:0.5, 1:5, and 1:10, the mean vitamin D recoveries were 98.8, 94.6, and 90.7%, respectively. The method has been adopted as official final action.

Chemical Method for the Determination of Vitamin D in Evaporated Milk With Elimination of Cholesterol by Digitonin Precipitation

1969 ◽  
Vol 52 (6) ◽  
pp. 1189-1195 ◽  
Author(s):  
J Eisses ◽  
H Dk Vries
Keyword(s):  
Vitamin D ◽  
Standard Deviation ◽  
Calibration Curve ◽  
Chemical Method ◽  
Colorimetric Method ◽  
Sterol Content ◽  
Alumina Column ◽  
Decomposition Products ◽  
Colorimetric Measurement

Abstract The colorimetric method of Jones et al. for the determination of vitamin D in evaporated milk, based on theUSPXVI method, was modified to obtain a simpler colorimetric measurement and more accurate results. The main modification is the elimination of nearly all cholesterol, according to the procedure of Den Herder for the determination of the sterol content of fats, by precipitation with digitonin in the saponified mass. The Florex column, used in the procedure of Jones et al. for the elimination of decomposition products of vitamin A, was omitted since it gave high blank values; an alumina column was substituted. The resulting method, when applied to samples of evaporated milk to which a known quantity of vitamin D had been added, showed a recovery of 78% with a standard deviation of 6%, using a calibration curve based on crystalline vitamin D. Data from these measurements, as well as data from vitamin D determination on several brands of fortified and unfortified evaporated milk, are presented.

Analysis of Fat-Soluble Vitamins. XXVI. High Performance Liquid Chromatographic Determination of Vitamin D in Fortified Milk and Milkpowder

1982 ◽  
Vol 65 (5) ◽  
pp. 1225-1227
Author(s):  
Ben Borsje ◽  
Ellen J De Vries ◽  
Jakob Zeeman ◽  
Frits J Mulder
Keyword(s):  
Vitamin D ◽  
Vitamin D3 ◽  
High Performance ◽  
Chromatographic Determination ◽  
High Performance Liquid Chromatographic ◽  
Hplc Method ◽  
Fortified Milk ◽  
Liquid Chromatographic Determination ◽  
Fat Soluble Vitamins ◽  
Liquid Chromatographic

Abstract Vitamin D is determined by high performance liquid chromatography (HPLC) in samples containing other fat-soluble vitamins. The vitamin D in the unsaponifiable residue is extracted and separated from interferences by straight phase chromatography, and the fraction corresponding to vitamin D3 is collected and quantitated using the AOAC official final action HPLC method for vitamin D3. Analysis of a synthetic mixture gave reasonable recoveries. The method measures potential vitamin D3 content in milkpowder samples containing 2IU vitamin D/g in the presence of all known vitamin D3 isomers, vitamin A, and vitamin E.

Modification of the USP Chemical Method for Determining Vitamin D in Evaporated Milk

1965 ◽  
Vol 48 (6) ◽  
pp. 1212-1217
Author(s):  
S W Jones ◽  
J B Wilkie ◽  
D A Libby
Keyword(s):  
Vitamin D ◽  
Standard Deviation ◽  
Sample Preparation ◽  
Relative Standard Deviation ◽  
Chemical Method ◽  
Statistical Data ◽  
Color Reaction ◽  
Bioassay Method ◽  
Modified Method ◽  
Relative Standard

Abstract The USP XVI chemical method for vitamin D in USP products has been substantially modified and applied to evaporated milk containing approximately 30 units of vitamin D per fluid ounce. A major modification is a 15 second reading at 500 mμ which most nearly represents the vitamin D content of the sample. An improved sample preparation eliminates much of the background interference, which also produces a color reaction. This method, when applied to a variety of samples, will show a relative standard deviation of 10%. Statistical data are presented to compare the modified method with the rat bioassay method for assaying vitamin D in evaporated milk.

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