Determination of vitamin A and vitamin E esters in infant formulae and fortified milk powders by HPLC: Use of internal standardisation

2016 ◽  
Vol 197 ◽  
pp. 457-465 ◽  
Author(s):  
David C. Woollard ◽  
Anja Bensch ◽  
Harvey Indyk ◽  
Adrienne McMahon
Keyword(s):  
Vitamin E ◽  
Vitamin A ◽  
Infant Formulae ◽  
Fortified Milk

Determination of Vitamins A and E in Infant Formula and Adult/Pediatric Nutritional Formula by HPLC with UV and Fluorescence Detection: First Action 2012.09

2013 ◽  
Vol 96 (6) ◽  
pp. 1407-1413 ◽  
Author(s):  
Linda Butler Thompson ◽  
Karen Schimpf ◽  
Steve Baugh
Keyword(s):  
Vitamin E ◽  
Vitamin A ◽  
Infant Formula ◽  
Methylene Chloride ◽  
Lipid Fraction ◽  
Intermediate Precision ◽  
Silica Column ◽  
Vitamin E Acetate ◽  
Uv And Fluorescence Detection

Abstract The method presented is for quantification of α-tocopherol (vitamin E), vitamin E acetate, vitamin A acetate, and vitamin A palmitate in infant formula and adult/pediatric nutritionals. The entire lipid fraction, including vitamins A and E, is extracted from product with iso-octane after products are mixed with methanol, which precipitates proteins and disrupts micelles freeing lipids for extraction. Vitamin A palmitate, vitamin A acetate, and vitamin E acetate are separated from α-tocopherol on a 3 cm silica column with a 1% methylene chloride, 0.06% isopropanol in iso-octane mobile phase; eluted onto a 20 cm silica column; and, after a column switch, further separated on the 20 cm column before UV detection at 325 nm (vitamin A palmitate and vitamin A acetate) and 285 nm (vitamin E acetate). α-Tocopherol is further separated from other extraneous compounds on the 3 cm silica column and detected by fluorescence at excitation and emission wavelengths of 295 and 330 nm, respectively. Quantification limits in ready-to-feed products were estimated to be 80 IU/L for vitamin A palmitate, 207 International Units (IU)/L for vitamin A acetate, 2.4 mg/L for vitamin E acetate, and <0.15 mg/L for α-tocopherol. Over-spike recoveries and intermediate precision averaged 100.4 and 2.09% RSD for vitamin A palmitate, 100.4 and 1.52% RSD for vitamin E acetate, and 99.6 and 3.02% RSD for α-tocopherol. Vitamin A acetate spike recovery data averaged 96.6%, and the intermediate precision for the only product fortified with vitamin A acetate was 2.75% RSD.

Simultaneous Determination of 13-cis and all-trans Vitamin A Palmitate (Retinyl Palmitate), Vitamin A Acetate (Retinyl Acetate), and Total Vitamin E (α-Tocopherol and DL-α-Tocopherol Acetate) in Infant Formula and Adult Nutritionals by Normal Phase HPLC: First Action 2012.10

2013 ◽  
Vol 96 (5) ◽  
pp. 1073-1081 ◽  
Author(s):  
Adrienne McMahon ◽  
Scott Christiansen ◽  
Lynsey Shine ◽  
Calvin Loi ◽  
Dawn Dowell
Keyword(s):  
Vitamin E ◽  
Vitamin A ◽  
Simultaneous Determination ◽  
Infant Formula ◽  
Normal Phase ◽  
Total Vitamin ◽  
Validation Data ◽  
Tocopherol Acetate ◽  
Selection Of

Abstract This HPLC method, with both variable UV and fluorescence detection, allows for the simultaneous determination of vitamin A palmitate, vitamin A acetate, and total vitamin E in infant, pediatric, and adult nutritional formulas. The concentration of each vitamin form is calculated by comparison with standards of known concentration. Following hydrolysis, the vitamins are extracted into iso-octane and analyzed by normal phase (NP) HPLC. The method was evaluated for linearity, precision, and accuracy using a selection of the Stakeholder Panel on Infant Formula and Adult Nutritionals (SPIFAN) matrixes, including milk-based, soy-based, and hydrolyzed protein, as well as high- and low-fat products. A single-laboratory validation has been completed for all analytes using a selection of SPIFAN matrixes. Performance parameters included a working range of 2–450 μg/100 g ready-to-feed for vitamin A and 0.03–8.0 mg/100 g reconstituted final product for vitamin E. LOD was <1.0 μg and <0.1 mg/100 g reconstituted final product for vitamins A and E, respectively; RSD was 1.08–8.70% over a range of concentration; and average recoveries of 97.4–101.3%. Repeatability of <4% for vitamin A and <8% for vitamin E was calculated from five laboratories using this method. Results indicate that this method is suitable for the analysis of vitamins A and E in all forms of infant, adult, and pediatric formulas (powders, ready-to-feed liquids, and liquid concentrates). The Expert Review Panel (ERP) of Infant Formula reviewed this method separately for vitamins A and E, including all available method validation data at the AOAC INTERNATIONAL Annual Meeting on September 29, 2012. Following evaluation of the data for both methods, the ERP agreed that both methods met the standard method performance requirements articulated by SPIFAN. The ERP granted First Action status to both methods, and recommended that a single method be published for the simultaneous determination of vitamin A palmitate, vitamin A acetate, and total vitamin E (DL-α-tocopherol and DL-α-tocopherol acetate) in infant formula and adult nutritionals by NP HPLC.

Automated Fluorometric Determination of Vitamin A in Milk

1978 ◽  
Vol 61 (6) ◽  
pp. 1370-1373
Author(s):  
James N Thompson ◽  
René Madère
Keyword(s):  
Steady State ◽  
Vitamin A ◽  
Colorimetric Method ◽  
Fluorometric Method ◽  
Fluorometric Determination ◽  
Extraction And Separation ◽  
Milk Samples ◽  
Fortified Milk ◽  
Coefficients Of Variation

Abstract A previously published fluorometric method for vitamin A in milk, involving saponification in centrifuge tubes and extraction with hexane, was automated using conventional automated equipment including a filter fluorometer. The extraction and separation steps were affected by the presence of fat, so standards were prepared in milk. The peaks obtained with samples were 95% of steady state values. The coefficients of variation for 10 replicate analyses were 1.9% for unfortified milk and 1.3% for fortified milk. In tests on 19 different milk samples, the results of the automated and manual fluorometric methods differed by less than 10%; a colorimetric method using SbCl3 gave more erratic results and was more lengthy and laborious.

Comparison of Carr-Price Analysis and Liquid Chromatographic Analysis for Vitamin A in Fortified Milk

1985 ◽  
Vol 68 (1) ◽  
pp. 56-58
Author(s):  
Robert S Mills
Keyword(s):  
Vitamin A ◽  
Potassium Hydroxide ◽  
Extraction Procedure ◽  
Hexane Extraction ◽  
Average Value ◽  
Fortified Milk ◽  
Liquid Chromatographic Analysis ◽  
Price Analysis ◽  
Liquid Chromatographic

Abstract The determination of the vitamin A concentration in fortified milk was compared using Carr-Price analysis and liquid chromatography (LC). Carr-Price analysis required saponification of the sample with alcoholic potassium hydroxide, extraction with ether, and colorimetry with antimony trichloride in chloroform. LC analysis required hexane extraction of a 71% alcohol-sample solution and centrifugation at 2000 rpm. A 100 μL aliquot of the extract was analyzed on a LiChrosorb Si-60, 5 μm column, using an ethyl ether-hexane (2 + 98) mobile phase and detection at 313 nm. Each method was statistically evaluated for precision and sample-to-sample reproducibility. The LC extraction procedure was examined for efficiency. Each LC value was divided by the Carr-Price value obtained for the same sample; an average value of 0.975 with a coefficient of variation of 6.90% was obtained. It was concluded that the procedures were statistically equivalent.

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