scholarly journals Determination of trans Vitamin K1 in Infant and Medical Nutritional Products Using AOAC Method 999.15 with Modified Preparation and Extraction Procedures and C30 Bonded Phase Chromatography: Single-Laboratory Validation

2010 ◽  
Vol 93 (2) ◽  
pp. 650-662 ◽  
Author(s):  
Karen J Schimpf ◽  
Linda B Thompson ◽  
Daniel J Schmitz
Keyword(s):  
Amino Acids ◽  
Chromatographic Separation ◽  
Free Amino Acids ◽  
Free Amino ◽  
Extraction Procedure ◽  
Vitamin K1 ◽  
Infant Formulas ◽  
Aoac Method ◽  
Single Laboratory

Abstract Modifications were made to AOAC Official MethodSM 999.15 to extend its applicability to specialty infant formulas containing hydrolyzed proteins and free amino acids, and to medical and adult nutritional products. Minor changes to the sample preparation procedure and chromatographic separation improved vitamin K1 recoveries and reduced chromatographic interferences in these types of matrixes. Currently AOAC Method 999.15 is applicable only to the determination of total vitamin K1 (phylloquione) in infant formula and milk (fluid, ready-to-feed, and powdered) containing >1 g vitamin K1/100 g solids. AOAC Method 999.15 recoveries of vitamin K1 were improved by altering sample sizes, extraction solvents and amounts, and the reagent addition order and amount of water or aqueous solutions added. The chromatographic separation of vitamin K1 in medical nutritional products containing canola and marine oils was improved, and trans vitamin K1 was separated from the biologically inactive cis isomer in all products with a C30 3 m column and a 100 methanol mobile phase. With these modifications to the extraction procedure and chromatographic separation, AOAC Method 999.15 demonstrated acceptable precision and accuracy for the quantitation of trans vitamin K1 in specialty infant formulas containing hydrolyzed proteins and free amino acids, and medical and adult nutritional products. A single-laboratory validation of these minor modifications was completed. Fourteen different product matrixes were analyzed during validation. The intermediate precision averaged 4.15 RSD (range 2.525.81 RSD), and recovery data averaged 100.1 (range 92.2109).

Determination of Free Amino Acids in Coated Foods by GC–MS: Optimization of the Extraction Procedure by Using Statistical Design

2013 ◽  
Vol 7 (1) ◽  
pp. 172-180 ◽  
Author(s):  
T. Pérez-Palacios ◽  
A. Melo ◽  
S. Cunha ◽  
I. M. P. L. V. O. Ferreira
Keyword(s):  
Amino Acids ◽  
Free Amino Acids ◽  
Free Amino ◽  
Extraction Procedure ◽  
Statistical Design

Determination of free amino acids in infant formulas

1999 ◽  
Vol 9 (9) ◽  
pp. 653-656 ◽  
Author(s):  
Paola Zunin ◽  
Filippo Evangelisti
Keyword(s):  
Amino Acids ◽  
Free Amino Acids ◽  
Free Amino ◽  
Infant Formulas

Comparison of procedures for extracting free amino acids from polymorphonuclear lekocytes.

1976 ◽  
Vol 22 (10) ◽  
pp. 1618-1622 ◽  
Author(s):  
Y Houpert ◽  
P Tarallo ◽  
G Siest
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Quantitative Determination ◽  
Free Amino Acids ◽  
Free Amino ◽  
Polymorphonuclear Leukocytes ◽  
Extraction Procedure ◽  
Intracellular Pool ◽  
Human Polymorphonuclear Leukocytes

Abstract We studies five methods for extracting amino acids from human polymorphonuclear leukocytes. Both the use of cell lysis and of a deproteinizing agent interfere with quantitative determination of the amino acids, basic amino acids being the most sensitive to the extraction procedure. Among the methods used, disruption of the cells by freezing-thawing is the best method for extracting all the amino acids. Taurine is the only amino acid extracted in the same amount by all the methods studied, and it represents half of the intracellular pool.

Modifications of AOAC Official Method 999.15 to Improve the Quantitation of Vitamin K1 in Complex Formulated Nutritional Products

2013 ◽  
Vol 96 (1) ◽  
pp. 91-101 ◽  
Author(s):  
Pierluigi Delmonte ◽  
Steven Barrientos ◽  
Jeanne I Rader
Keyword(s):  
Amino Acids ◽  
Infant Formula ◽  
Free Amino Acids ◽  
Free Amino ◽  
Extraction Efficiency ◽  
Extraction Procedure ◽  
Official Method ◽  
Vitamin K1 ◽  
Aoac Official ◽  
Aoac Official Method

Abstract Vitamin K1 (phylloquinone) occurs in foods in relatively low concentrations. It is synthesized for addition to formulated nutritional products (infant formulas, medical foods, and adult nutritional products). In recent years, nutritional products formulated with free amino acids and partially hydrolyzed proteins have been introduced in the market. Schimpf et al. demonstrated that the current AOAC Official Method 999.15 for determination of vitamin K in milk and infant formula is not adequate to quantitatively extract vitamin K1 from such products. We developed a modification of AOAC 999.15 for the analysis of vitamin K1 in these products that provides quantitative extraction by increasing the sample size, volume of extraction solvents, time of liquid/liquid partitioning, and order of the addition of solvents. This modified procedure showed extraction efficiency comparable to that of the original AOAC 999.15 procedure for analyzing infant formula matrixes and to the modified procedure of Schimpf et al. for the analysis of samples containing limited amounts of free amino acids and/or partially hydrolyzed proteins. Extraction efficiency increased more than 10% using the modified extraction procedure for samples containing higher amounts of these components. The chromatographic separation was improved by using a Dionex Acclaim triacontanol-bonded C30 column (250 × 3.0 mm id, 3 μm particle size) maintained at 15°C, with acetonitrile–methanol (50 + 50, v/v) mobile phase at a flow rate of 0.5 mL/min, which provided baseline separation of the cis and trans isomers of vitamin K1 from each other and from other compounds contained in the sample extracts.

scholarly journals Simple extraction procedure for free amino acids determination in selected gluten-free flour samples

2021 ◽  
Author(s):  
Sylwia Kowalska ◽  
Edward Szłyk ◽  
Aneta Jastrzębska
Keyword(s):  
Amino Acids ◽  
Free Amino Acids ◽  
Free Amino ◽  
Extraction Procedure ◽  
Chromatographic Determination ◽  
Gluten Free ◽  
Capillary Isotachophoresis ◽  
Hemp Seed ◽  
Simple Extraction

AbstractThe simple extraction of flours samples followed by free amino acids determination procedures was studied and optimised. The conditions of amino acids derivatisation reaction with ninhydrin for chromatographic determination of free amino acids sum was discussed. The developed method was processed in terms of linearity, precision, accuracy, and limits of detection and quantification. Moreover, capillary isotachophoresis and HPLC methods were applied for individual free amino acids determination. The proposed extraction procedure is simple, fast and convenient for different flours samples. Studied procedures were used for free amino acids determination in twelve gluten-free flour samples (corn, oat, soy, rice, pumpkin, millet, peanut, hemp seed, buckwheat, amaranth, pea and chickpea) and the obtained results were compared with wheat flour.

scholarly journals A METHOD FOR THE DETERMINATION OF FREE AMINO ACIDS IN RAT ORGANS AND TISSUES

1950 ◽  
Vol 182 (1) ◽  
pp. 29-37
Author(s):  
P.E. Schurr ◽  
H.T. Thompson ◽  
L.M. Henderson ◽  
C.A. Elvehjem
Keyword(s):  
Amino Acids ◽  
Free Amino Acids ◽  
Free Amino ◽  
Rat Organs
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