scholarly journals Liquid Chromatographic Method for Analysis of All-rac-α-Tocopheryl Acetate and Retinyl Palmitate in Milk-Based Infant Formula Using Matrix Solid-Phase Dispersion

1998 ◽  
Vol 81 (3) ◽  
pp. 582-586 ◽  
Author(s):  
G William Chase ◽  
Austin R Long
Keyword(s):  
Reference Material ◽  
Infant Formula ◽  
Chromatographic Method ◽  
Solid Phase ◽  
Retinyl Palmitate ◽  
Tocopheryl Acetate ◽  
Matrix Solid Phase Dispersion ◽  
Phase Dispersion ◽  
Liquid Chromatographic Method ◽  
Liquid Chromatographic

abstract A liquid chromatographic method is described for analysis of all-rac-α-tocopheryl acetate, tocopherols, and retinyl palmitate in milk-based infant formula. The vitamins are extracted from infant formula without saponification by matrix solid-phase dispersion and quantitated by normal-phase chromatography with fluorescence detection. Retinyl palmitate and vitamin E are quantitated isocratically with mobile phases of 0.125% (v/v) and 0.5% (v/v) isopropyl alcohol in hexane, respectively. Results were similar to the certified and non-certified ranges for all-rac-α-tocopheryl acetate, retinyl palmitate, and tocopherols in the infant formula standard reference material (SRM) 1846. Results also compared favorably with the label declaration on a retail infant formula. Recoveries were determined on an analyte-fortified zero control reference material for milk-based infant formula and averaged 96.8% (n = 30) for retinyl palmitate and 91.5% (n = 25) for all-rac-α-tocopheryl acetate. Examination of 5 concentrations for each analyte gave results that were linear (r = 0.999) over the concentration examined, with coefficients of variation ranging from 1.02 to 5.86%. The method provides a rapid, specific, and easily controlled assay for analysis of retinyl palmitate and vitamin E in fortified infant formula. Additionally, the method minimizes solvent use by using only 14 ml_ solvent per extraction.

scholarly journals A Liquid Chromatographic Method for Analysis of AU-Rac-α-Tocopheryl Acetate and Retinyl Palmitate in Medical Food Using Matrix Solid-Phase Dispersion in Conjunction with a Zero Reference Material as a Method Development Tool

1999 ◽  
Vol 82 (1) ◽  
pp. 107-111 ◽  
Author(s):  
G William Chase ◽  
Ronald R Eitenmiller ◽  
Austin R Long
Keyword(s):  
Solid Phase ◽  
Retinyl Palmitate ◽  
Tocopheryl Acetate ◽  
Medical Food ◽  
Matrix Solid Phase Dispersion ◽  
Phase Dispersion ◽  
Liquid Chromatographic Method ◽  
Zero Reference ◽  
Medical Foods ◽  
Liquid Chromatographic

Abstract A liquid chromatographic method is described for analysis of all-rac-α-tocopheryl acetate and retinyl palmitate in medical food. The vitamins are extracted from medical food without saponification by matrix solid-phase dispersion and chromatographed by normal-phase chromatography with fluorescence detection. Retinyl palmitate and all-rac-α-tocopheryl acetate are quantitated isocratically with a mobile phase of 0.125% (v/v) and 0.5% (v/v) isopropyl alcohol in hexane, respectively. Results compared favorably with label declarations on retail medical foods. Recoveries determined on an analyte-fortified zero reference material for a milk-based medical food averaged 98.3% (n = 25) for retinyl palmitate spikes and 95.7% (n = 25) for all-rac-α-tocopheryl acetate spikes. Five concentrations were examined for each analyte, and results were linear (r2 = 0.995 for retinyl palmitate and 0.9998 for all-rac-α-tocopheryl acetate) over the concentration range examined, with coefficients of variation in the range 0.81-4.22%. The method provides a rapid, specific, and easily controlled assay for analysis of retinyl palmitate and all-rac-α-toco-pheryl acetate in fortified medical foods.

Liquid Chromatographic Method for Analysis of AU-rac-α-Tocopheryl Acetate and Retinyl Palmitate in Soy-Based Infant Formula Using a Zero-Control Reference Material (ZRM) as a Method Development Tool

1998 ◽  
Vol 81 (3) ◽  
pp. 577-581 ◽  
Author(s):  
G William Chase ◽  
Austin R Long ◽  
Ronald R Eitenmiller
Keyword(s):  
Reference Material ◽  
Infant Formula ◽  
Chromatographic Method ◽  
Method Development ◽  
Isopropyl Alcohol ◽  
Chlorinated Solvents ◽  
Retinyl Palmitate ◽  
Tocopheryl Acetate ◽  
Liquid Chromatographic Method ◽  
Liquid Chromatographic

abstract A liquid chromatographic method is described for analysis of all-rac-α-tocopheryl acetate, tocopherols, and retinyl palmitate in soy-based infant formula. The vitamins are extracted in isopropyl alcohol and hexane-ethyl acetate without saponification and quantitated by normal-phase chromatography with fluorescence detection. All-rac-α-tocopheryl acetate and retinyl palmitate are quantitated isocratically with mobile phases of 0.5% (v/v) and 0.125% (v/v) isopropyl alcohol in hexane, respectively. Recoveries from zero control reference material soy-based formula averaged 97.2% (n = 25) for retinyl palmitate and 100% (n = 25) for all-rac-α-tocopheryl acetate. Coefficients of variation ranged from 1.21 to 2.86% for retinyl palmitate and from 1.49 to 5.16% for all-rac-α-tocopheryl acetate. The method provides a rapid, specific, and easily controlled assay for analysis of vitamin A and vitamin E in fortified infant formula. Additionally, the method eliminates use of chlorinated solvents.

scholarly journals An Interlaboratory-Verified Method for the Determination of Vitamins Aand E inMilk- and Soy-Based Infant Formula by Liquid Chromatography with Matrix Solid-Phase Dispersion Extraction

2004 ◽  
Vol 87 (5) ◽  
pp. 1173-1178 ◽  
Author(s):  
G William Chase ◽  
Lin Ye ◽  
Vicky C Stoakes ◽  
Ronald R Eitenmiller ◽  
Austin R Long
Keyword(s):  
Infant Formula ◽  
Solid Phase ◽  
Extraction Procedure ◽  
Retinyl Palmitate ◽  
Tocopheryl Acetate ◽  
Matrix Solid Phase Dispersion ◽  
Phase Dispersion ◽  
Sample Extract ◽  
Relative Standard

Abstract An interlaboratory-verified, liquid chromatographic (LC) method is presented for determination of all-racemic α-tocopheryl acetate and retinyl palmitate in infant formula. The extraction procedure uses matrix solid-phase dispersion. A sample is mixed with C18, and the mixture is packed into a reservoir and eluted with selective solvents to extract the analytes. After evaporation and filtration, the sample extract is injected directly into a normal-phase LC system with fluorescence detection. All-racemic α-tocopheryl acetate and retinyl palmitate are quantitated isocratically with a mobile phase of hexane containing isopropanol at 0.2% (v/v) and 0.125% (v/v), respectively. A nonfortified zero control reference material (ZRM) was spiked at 5 levels, with 5 replicate analyses of 1/2x, x, 2x, 4x, and 16x where “x” represents the minimum levels of 250 IU/100 kcal (vitamin A) and 0.7 IU/100 kcal (vitamin E) as specified in Title 21 of the Code of Federal Regulations, part 107.100. Recoveries of retinyl palmitate ranged from 83.8 to 107%, and those of all-racemic α-tocopheryl acetate ranged from 87.7 to 108%. Two additional laboratories analyzed the ZRM samples at 4 spiking levels with 6 replicates. Recoveries of retinyl palmitate and all-racemic α-tocopheryl acetate ranged from 92.2 to 104% and from 91.7 to 101%, respectively, in the second laboratory. Recoveries of retinyl palmitate and all-racemic α-tocopheryl acetate ranged from 85.3 to 97.0% and from 86.6 to 110%, respectively, in the third laboratory. Relative standard deviations for all 3 laboratories ranged from 0.2 to 7.5% with an average of 2.9%. In addition, each laboratory analyzed a commercial milk- and commercial soy-based infant formula. Excellent agreement in results was obtained between the 3 laboratories for vitamins A and E in all matrixes.

scholarly journals Liquid Chromatographic Analysis of Vitamin K1 in Milk-Based Infant Formula with Matrix Solid-Phase Dispersion

1999 ◽  
Vol 82 (5) ◽  
pp. 1140-1145 ◽  
Author(s):  
G William Chase ◽  
Ronald R Eitenmiller ◽  
Austin R Long
Keyword(s):  
Infant Formula ◽  
Limit Of Detection ◽  
Solid Phase ◽  
Reversed Phase ◽  
Vitamin K1 ◽  
Matrix Solid Phase Dispersion ◽  
Phase Dispersion ◽  
Limit Of Quantitation ◽  
Liquid Chromatographic Analysis ◽  
Liquid Chromatographic

Abstract A liquid chromatographic method for vitamin K1 in milk-based infant formula is described. The vitamins are extracted from infant formula by matrix solid-phase dispersion and quantitated by reversed-phase chromatography with fluorescence detection. Vitamin K1 is converted to the fluorescent hydroquinone with a postcolumn zinc reductive reactor. The limit of detection is 12 pg, and the limit of quantitation is 38 pg on-column. Linear responses were obtained in the range 0.55-22.1 ng/mL (r2 = 0.9998). Recoveries of vitamin K1 from an analyte-fortified blank material for milk-based infant formula averaged 91.7% (n = 25). The method provides a rapid, specific, and easily controlled assay for vitamin K1 in fortified infant formula.

scholarly journals Analysis of β-Carotene in Medical Food by Liquid Chromatography with Matrix Solid-Phase Dispersion

1999 ◽  
Vol 82 (3) ◽  
pp. 663-665 ◽  
Author(s):  
G William Chase ◽  
Ronald R Eitenmiller ◽  
Austin R Long
Keyword(s):  
Solid Phase ◽  
Retinyl Palmitate ◽  
Fluorescence Detector ◽  
Medical Food ◽  
Matrix Solid Phase Dispersion ◽  
Phase Dispersion ◽  
Limit Of Quantitation ◽  
Standard Response ◽  
Liquid Chromatographic ◽  
Β Carotene

Abstract A liquid chromatographic method is described for analysis of β-carotene in medical food. The nutrient is extracted from medical food without saponification by matrix solid-phase dispersion and quantitated by isocratic normal-phase chromatography with a Si 60 column and a mobile phase of hexane containing 0.125% (v/v) isopropyl alcohol. The limit of quantitation is 0.02 μg/mL at 436 nm. Standard response was linear over the concentration range of 0.02μ1.0 μg/ml(r2 = 0.99998). Recoveries were determined on a zero control reference material containing added β-carotene at various levels. Recoveries averaged 91.2% (n = 25) with coefficients of variation from 0.50 to 3.10%. The method provides a rapid, specific, sensitive, and easily controlled assay for analysis of β-carotene in fortified medical food. In addition, retinyl palmitate can be assayed simultaneously with an in-line fluorescence detector.

scholarly journals Interlaboratory Verified Liquid Chromatographic Method for Analysis of Vitamins A and E in Soy-Based Infant Formula Powder

2004 ◽  
Vol 87 (6) ◽  
pp. 1329-1333 ◽  
Author(s):  
G William Chase ◽  
Lin Ye ◽  
Vicky C Stoakes ◽  
Ronald R Eitenmiller ◽  
Austin R Long
Keyword(s):  
Infant Formula ◽  
Extraction Procedure ◽  
Retinyl Palmitate ◽  
Tocopheryl Acetate ◽  
Federal Regulations ◽  
Minimum Level ◽  
Sample Extract ◽  
Liquid Chromatographic Method ◽  
Liquid Chromatographic ◽  
Analysis Of Vitamins

Abstract An interlaboratory verified, liquid chromatographic (LC) method is presented for the analysis of all-rac-α-tocopheryl acetate and retinyl palmitate in soy-based infant formula. The extraction procedure uses sample dehydration with magnesium sulfate followed by extraction with isopropanol, hexane–ethyl acetate (85 + 15, v/v). After evaporation and filtration, the sample extract is injected directly onto a normal-phase LC system with fluorescence detection. All-rac-α-tocopheryl acetate and retinyl palmitate are quantitated isocratically with a mobile phase of hexane containing 0.50% (v/v) and 0.125% (v/v) isopropanol, respectively. A zero control reference material (ZRM) was spiked at 5 levels, with 5 replicate analyses of 1/2x, x, 2x, 4x, and 16x where “x” is the minimum level of 250 IU/100 kcal (vitamin A) and 0.7 IU/100 kcal (vitamin E) as specified in 21 Code of Federal Regulations 107.100. The following recoveries and RSD values represent an average (n = 25) of the 5 levels for each analyte: all-rac-α-tocopheryl acetate, 100% (RSD = 3.5%); retinyl palmitate, 97.2% (RSD = 2.1%). Two additional laboratories analyzed the fortified ZRM samples. Average recoveries (n = 24) of all-rac-α-tocopheryl acetate and retinyl palmitate at 4 levels were all-rac-α-tocopheryl acetate, 99.0% (RSD = 4.0%), and retinyl palmitate, 96.2% (RSD = 1.4%) at the second laboratory. Average recoveries (n = 24) of all-rac-α-tocopheryl acetate and retinyl palmitate at 4 levels were all-rac-α-tocopheryl acetate, 102% (RSD = 1.4%) and retinyl palmitate, 95.7% (RSD = 2.0%) at the third laboratory. In addition, 6 replicates of the same commercial soy-based infant formula powder were run by the 3 laboratories.

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