scholarly journals Determination of Choline in Infant Formula by Ion Chromatography

1999 ◽  
Vol 82 (5) ◽  
pp. 1156-1162 ◽  
Author(s):  
Mark Laikhtman ◽  
Jeffrey S Rohrer
Keyword(s):  
Infant Formula ◽  
Ion Chromatography ◽  
Alkaline Earth ◽  
Collaborative Study ◽  
Powdered Infant Formula ◽  
Enzymatic Method ◽  
Cation Exchange Column ◽  
Suppressed Conductivity Detection ◽  
Good Agreement

Abstract Choline was determined in infant formula by ion chromatography with suppressed conductivity detection. Samples were digested with 1M hydrochloric acid, filtered, diluted, and injected into the chromatographic system. Choline and the alkali and alkaline earth metals were separated on a high-resolution cation-exchange column and detected by suppressed conductivity. The method was linear between 2 and 200 mg/L (r2 = 0.9999), the concentration range of the diluted samples. This method accurately determined choline in powdered, concentrated, and ready-to-feed infant formulas. Recoveries of choline spikes into powdered infant formula at approximately 1, 0.8, 0.5, and 0.2 times the labeled value ranged from 85 to 114%. This method had good agreement for 8 blind duplicates. The values determined for these samples, which were used in an AOAC collaborative study of an enzymatic method, were consistent with the values determined by the enzymatic method.

scholarly journals A rapid ion chromatography column-switching method for online sample pretreatment and determination ofl-carnitine, choline and mineral ions in milk and powdered infant formula

RSC Advances ◽  
2017 ◽  
Vol 7 (10) ◽  
pp. 5920-5927 ◽  
Author(s):  
Dan Wei ◽  
Xu Wang ◽  
Nani Wang ◽  
Yan Zhu
Keyword(s):  
Infant Formula ◽  
Ion Chromatography ◽  
Detection Method ◽  
Sample Pretreatment ◽  
Column Switching ◽  
Powdered Infant Formula ◽  
Suppressed Conductivity Detection ◽  
Mineral Ions ◽  
Switching Method

A simple and rapid column-switching ion chromatography with non-suppressed conductivity detection method was developed for simultaneous determination ofl-carnitine, choline and mineral ions in milk and powdered infant formula samples.

Determination of Vitamin A (Retinol) in Infant Formula and Adult Nutritionals by Liquid Chromatography: First Action 2011.15

2012 ◽  
Vol 95 (2) ◽  
pp. 322-328
Author(s):  
Jonathan W DeVries ◽  
Karlene R Silvera ◽  
Elliot McSherry ◽  
Dawn Dowell
Keyword(s):  
Liquid Chromatography ◽  
Vitamin A ◽  
Infant Formula ◽  
Collaborative Study ◽  
Alpha Tocopherol ◽  
Powdered Infant Formula ◽  
Food Matrix ◽  
Validation Data ◽  
Method Performance

Abstract During the “Standards Development and International Harmonization: AOAC INTERNATIONAL Mid- Year Meeting,” held on June 29, 2011, an Expert Review Panel (ERP) reviewed the method for the “Determination of Vitamins A (Retinol) and E (alpha-Tocopherol) in Foods by Liquid Chromatography: Collaborative Study,” published by Jonathan W. DeVries and Karlene R. Silvera in J. AOAC Int. in 2002. After evaluation of the original validation data, an ERP agreed in June 2011 that the method meets standard method performance requirements (SMPRs) for vitamin A, as articulated by the Stakeholder Panel on Infant Formula and Adult Nutritionals. The ERP granted the method First Action status, applicable to determining vitamin A in ready-to-eat infant and adult nutritional formula. In an effort to achieve Final Action status, it was recommended that additional information be generated for different types of infant and adult nutritional formula matrixes at varied concentration levels as indicated in the vitamin A (retinol) SMPR. Existing AOAC LC methods are suited for specific vitamin A analytical applications. The original method differs from existing methods in that it can be used to assay samples in all nine sectors of the food matrix. One sector of the food matrix was powdered infant formula and gave support for the First Action approval for vitamin A in infant and adult nutritional formula. In this method, standards and test samples are saponified in basic ethanol–water solution, neutralized, and diluted, converting fats to fatty acids and retinol esters to retinol. Retinol is quantitated by an LC method, using UV detection at 313 or 328 nm for retinol. Vitamin concentration is calculated by comparison of the peak heights or peak areas of retinol in test samples with those of standards.

Choline in Infant Formula and Adult Nutritionals by Ion Chromatography and Suppressed Conductivity: First Action 2012.20

2013 ◽  
Vol 96 (6) ◽  
pp. 1400-1406 ◽  
Author(s):  
Kassandra Oates ◽  
Lillian Chen ◽  
Brian De Borba ◽  
Deepali Mohindra ◽  
Jeffrey Rohrer ◽  
...  
Keyword(s):  
Infant Formula ◽  
Ion Chromatography ◽  
Method Performance ◽  
Expert Review ◽  
Performance Requirements ◽  
Technology Standard ◽  
Expert Review Panel ◽  
Suppressed Conductivity Detection ◽  
Single Laboratory

Abstract Single-laboratory validation (SLV) data from a method for the determination of choline in infant formula and adult nutritionals by ion chromatography (IC) and suppressed conductivity were generated and presented to the Stakeholder Panel on Infant Formula and Adult Nutritionals (SPIFAN) Expert Review Panel (ERP) at the AOAC Annual Meeting held in Las Vegas, NV, during September 30 to October 3, 2012. The ERP reviewed the data and concluded that the data met the standard method performance requirements (SMPRs) established and approved the method as AOAC Official First Action. At the ERP's request, a second, full SLV was performed on 17 SPIFAN matrixes that included fortified and placebo products. Prior to IC analysis, microwave-assisted acid hydrolysis was used to digest and release bound choline from powder and ready-to-feed (RTF) infant formula and adult nutritional samples. Following hydrolysis, separation of choline from common cations was achieved on a Thermo ScientificTM DionexTM IonPacTM CS19 column followed by suppressed conductivity detection. Total choline was measured and reported as the choline ion in mg/100 g reconstituted material or RTF as-is. The system was calibrated over the analytical range specified in the SMPR (2–250 mg/100 g). Recoveries of spiked samples at 50 and 100% of the fortified choline amounts ranged from 93.1 to 100.7% with RSDs ≤6.7% for product containing <2 mg/100 g and ≤4.1% for product containing 2–100 mg/100 g. Accuracy for the National Institute of Standards and Technology Standard Reference Material 1849a was determined over a 6-day interval and found to be 10.2 ± 0.2 mg/100 g calculated as the reconstituted powder with an RSD of 1.8%. The LOD was determined to be 0.009, and the LOQ 0.012 mg/100 g, well below the SMPR requirements of 0.7 and 2 mg/100 g, respectively. Repeatability RSDs over the range of the assay (2–200 mg/100 g) ranged from 1.0 to 5.93%

Determination of Sevin Insecticide Residues in Fruits and Vegetables

1964 ◽  
Vol 47 (2) ◽  
pp. 283-286
Author(s):  
D P Johnson
Keyword(s):  
Fruits And Vegetables ◽  
Collaborative Study ◽  
Colorimetric Determination ◽  
Average Recovery ◽  
Insecticide Residues ◽  
Chromogenic Agent ◽  
Hydrolysis Of ◽  
Concentration Levels ◽  
Good Agreement

Abstract Collaborative study of a method for Sevin insecticide residues was repeated with apples and lettuce as test crops. The method is based on alkaline hydrolysis of Sevin and colorimetric determination of the resulting 1-naphthol with p-nitrobenzenediazonium fluoborate as chromogenic agent. Data from 5 collaborators were in good agreement with an average recovery of 87.8% at 2 concentration levels. It is recommended that the method be adopted as official, first action.

Collaborative Study of Two New Methods for the Determination of Phosphorus in Fruits and Fruit Products

1970 ◽  
Vol 53 (3) ◽  
pp. 575-578
Author(s):  
Ben Estrin ◽  
Frederick E Boland
Keyword(s):  
Aqueous Solution ◽  
Satisfactory Agreement ◽  
Collaborative Study ◽  
Volumetric Method ◽  
Acid Solutions ◽  
Dilute Acid ◽  
New Methods ◽  
Molybdate Method ◽  
Good Agreement

Abstract A collaborative study was conducted to compare a spectrophotometric molybdovanadate method and the official gravimetric quinoline molybdate fertilizer method 2.025(b), slightly modified, with the official volumetric method 20.032. Six collaborating laboratories analyzed dilute acid solutions of the ash of 5 different kinds of fruit products and an aqueous solution containing only KH2PO4 by each of the 3 methods. Satisfactory agreement between laboratories and good agreement between methods were obtained. From the results of this collaborative study it appears that the quinoline molybdate and the molybdovanadate methods are more accurate and precise than the official volumetric method. It is recommended that both the spectrophotometric molybdovanadate method and the gravimetric quinoline molybdate method for the determination of phosphorus in fruits and fruit products be adopted as official first action.

scholarly journals Determination of Choline in Milk and Infant Formulas by Enzymatic Analysis: Collaborative Study

2000 ◽  
Vol 83 (1) ◽  
pp. 131-138 ◽  
Author(s):  
David C Woollard ◽  
Harvey E Indyk
Keyword(s):  
Acid Hydrolysis ◽  
Infant Formula ◽  
Spectrophotometric Method ◽  
Collaborative Study ◽  
Analytical Techniques ◽  
Choline Oxidase ◽  
Infant Formulas ◽  
Enzymatic Analysis ◽  
Data Screening

Abstract A collaborative study was conducted on a coupled enzymatic–spectrophotometric method for the determination of choline in infant formula and milk powders. Twenty-nine laboratories participated in the analysis of 8 blind duplicates over the range of 45–175 mg/100 g sample. After the combined acid hydrolysis–phospholipase release of choline, incubation with choline oxidase in the presence of peroxidase and phenol generates a quinoneimine chromophore with 4-aminoantipyrine. Following raw data screening, overall mean RSDR was estimated at 5.14% (range, 4.26–6.34%) with a HORRAT value of 0.91 (range, 0.76–1.00) and an overall mean RSDr:RSDR value of 0.53 (range, 0.42–0.74). The method was also compared with alternative independent analytical techniques for several of the collaborative study samples.

scholarly journals Determination of Vitamin B12 in Fortified Bovine Milk- Based Infant Formula Powder, Fortified Soya-Based Infant Formula Powder, Vitamin Premix, and Dietary Supplements by Surface Plasmon Resonance: Collaborative Study

2011 ◽  
Vol 94 (4) ◽  
pp. 1217-1226 ◽  
Author(s):  
Pathik Vyas ◽  
Anthony A O'kane ◽  
E Ager ◽  
S Crooks ◽  
C Elliott ◽  
...  
Keyword(s):  
Surface Plasmon Resonance ◽  
Protein Binding ◽  
Vitamin B12 ◽  
Infant Formula ◽  
Surface Plasmon ◽  
Plasmon Resonance ◽  
Binding Protein ◽  
Collaborative Study ◽  
Wide Range

Abstract A collaborative study was conducted on an inhibition-based protein-binding assay using the Biacore Q™ biosensor instrument and the Biacore Qflex™ Kit Vitamin B12 PI. The samples studied included infant formula, cereals, premixes, vitamin tablets, dietary supplements, and baby food. The collaborative study, which involved 11 laboratories, demonstrated that the assay showed an RSDr of 1.59–27.8 and HorRat values for reproducibility of 0.34–1.89 in samples with levels ranging from ppm to ppb. The assay studied is a label-free protein binding-based assay that uses the principle of surface plasmon resonance (SPR) to measure the interaction between vitamin B12 and a specifc binding protein. A Biacore Q biosensor uses this principle to detect binding directly at the surface of a sensor chip with a hydrophilic gold-dextran surface. The instrument passes a mixture of prepared sample extract and binding protein solution across a covalently immobilized vitamin B12 chip surface, and the response is given as free-binding protein as the mixture binds to the immobilized surface. This technique uses the specifcity and robustness of the protein-ligand interaction to allow minimal sample preparation and a wide range of matrixes to be analyzed rapidly. The reagents and accessories needed to perform this assay are provided as the ready-to-use format “Qflex Kit Vitamin B12 PI.” The method is intended for routine use in the quantitative determination of vitamin B12 (as cyanocobalamin) in a wide range of food products, dietary vitamin supplements, and multivitamin premixes.

Collaborative Study of a Method for the Determination of Trimethylamine Nitrogen in Fish

1971 ◽  
Vol 54 (3) ◽  
pp. 725-727 ◽  
Author(s):  
Frederick E Boland ◽  
Dorothy D Paige
Keyword(s):  
Statistical Analysis ◽  
Collaborative Study ◽  
Standard Solution ◽  
Good Agreement

Abstract Dyer’s method for the determination of trimethylamine was collaboratively studied. Six samples of fish extract and one standard solution were sent to each of 9 collaborators. The results from one laboratory differed significantly from the remainder and were not included in the statistical analysis. The results from the remainder of the collaborators were generally in good agreement. Results clearly differentiate between the acceptable and decomposed samples which were used in this study. The method for determining trimethylamine nitrogen in fish has been adopted as official first action.

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