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

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.

2002 ◽  
Vol 85 (2) ◽  
pp. 424-434 ◽  
Author(s):  
Jonathan W DeVries ◽  
Karlene R Silvera ◽  
S Al-Hasani ◽  
J Alfiere ◽  
C Berge ◽  
...  

Abstract A collaborative study was conducted for the determination of vitamins A and E. Existing AOAC liquid chromatographic (LC) methods are suited for specific vitamins A and E analytical applications. This method differs from existing methods in that it can be used to assay samples in all 9 sectors of the food matrix. Standards and test samples are saponified in basic ethanol–water solution, neutralized, and diluted, converting fats to fatty acids and retinol esters and tocopherol esters to retinol and tocopherol, respectively. Retinol and alpha-tocopherol are quantitated on separate LC systems, using UV detection at 313 or 328 nm for retinol, and fluorescence detection (excitation 290 nm, emission 330 nm) for alpha-tocopherol. Vitamin concentrations are calculated by comparison of the peak heights or peak areas of vitamins in test samples with those of standards.


2003 ◽  
Vol 86 (4) ◽  
pp. 685-693 ◽  
Author(s):  
Guo-Fang Pang ◽  
Yan-Zhong Cao ◽  
Chun-Lin Fan ◽  
Jin-Jie Zhang ◽  
Xue-Min Li ◽  
...  

Abstract Eighteen laboratories participated in a collaborative study on the determination of clopidol residues in chicken muscle tissues by liquid chromatography. Of these, results from 16 laboratories which rigorously followed the method were subjected to statistical analysis. The method performance was assessed by all participants using 14 samples of chicken muscle fortified at concentrations ranging from 0.1 to 5.0 mg/kg. In addition, 9 participants each reported results for 6 clopidol-incurred samples in chicken muscle. Test portions were extracted with acetonitrile, and the extracts were purified with alumina and anion exchange resin solid-phase extraction cartridges in sequence. Clopidol was separated by reversed-phase liquid chromatography and quantified at 270 nm. Average recoveries ranged from 81.8 to 85.4%, reproducibility relative standard deviation (RSDR) ranged from 11.9 to 22.6%, and repeatability relative standard deviation (RSDr) ranged from 9.9 to 15.1%. For clopidol-incurred samples at concentrations of 0.100–0.687 mg/kg, the mean determination value range was 0.099–0.659 mg/kg; RSDR was 12.6–19.8%, RSDr was 3.1–8.5%; and HORRAT values were 0.7–1.1. The accuracy and precision of the method are in conformity with the requirements specified by AOAC INTERNATIONAL. The method was adopted Official First Action in April 2003.


2013 ◽  
Vol 96 (5) ◽  
pp. 1073-1081 ◽  
Author(s):  
Adrienne McMahon ◽  
Scott Christiansen ◽  
Lynsey Shine ◽  
Calvin Loi ◽  
Dawn Dowell

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.


2017 ◽  
Vol 100 (1) ◽  
pp. 139-144 ◽  
Author(s):  
Esther Campos Giménez ◽  
Frédéric Martin ◽  
K Schimpf ◽  
L Butler Thompson ◽  
D Aoude-Werner ◽  
...  

Abstract To determine the repeatability and reproducibility values of the AOAC INTERNATIONAL First Action Method 2012.22, Vitamin C in Infant Formula and Adult/Pediatric Nutritional Formula by Liquid Chromatography with UV Detection, a collaborative study was organized The study was dividedinto two parts: method setup and qualification of participants (part 1) and collaborative study participation (part 2). During part 1, each laboratory was asked to analyze two practice samples using the aforementioned method Laboratories that provided results within a range of expected levels were qualified for part 2, where they analyzed 10 samples in blind duplicates Two of the samples were suspected of spoilage during the test and new cans of the same type of product were analyzed by a subset of laboratories in part 3. The results were compared with Standard Method Performance Requirement (SMPR®) 2012.012 established for vitamin C The precision results were within the requirements stated in the SMPR: 1.4–7.3% and 3.2–11.4% respectively, for repeatability and reproducibility Finally, Horwitz ratio values were all <2 (0.5–1.7). The Expert Review Panel for Stakeholder Panel for Infant Formula and Adult Nutritionals Nutrient Methods determined that the data presented met the SMPR and therefore recommended the method be granted Final Action status.


2001 ◽  
Vol 84 (4) ◽  
pp. 1116-1124 ◽  
Author(s):  
Joerg Stroka ◽  
Elke Anklam ◽  
Urban Joerissen ◽  
John Gilbert ◽  
A Barmark ◽  
...  

Abstract A collaborative study was conducted to evaluate the effectiveness of an immunoaffinity column cleanup liquid chromatography (LC) method for determination of aflatoxin B1 in a milk powder based infant formula at a possible future European regulatory limit (0.1 ng/g). The test portion was extracted with methanol–water (8 + 2 [v + v]), filtered, diluted with water, and applied to an immunoaffinity column. The column was washed with water to remove interfering compounds, and the purified aflatoxin B1 was eluted with methanol. The separation and determination of the aflatoxin B1 was performed by reversed-phase LC and detected by fluorescence after postcolumn derivatization (PCD) involving bromination. PCD was achieved with either pyridinum hydrobromide perbromide (PBPB) or an electrochemical (Kobra) cell by addition of bromide to the mobile phase. The baby food (infant formula) test samples, both spiked and naturally contaminated with aflatoxin B1, were sent to 14 laboratories in 13 different European countries. Test portions were spiked at levels of 0.1 and 0.2 ng/g for aflatoxin B1. Recoveries ranged from 101 to 92%. Based on results for spiked test samples (blind pairs at 2 levels) and naturally contaminated test samples (blind pairs at 3 levels), the relative standard deviation for repeatability (RSDr) ranged from 3.5 to 14%. The relative standard deviation for reproducibility (RSDR) ranged from 9 to 23%. Nine participants used PBPB derivatization, and 5 particpants used the Kobra cell. There was no evidence of method performance depending on the derivatization method used. The method showed acceptable within- and between-laboratory precision for baby food matrix, as evidenced by HORRAT values, at the target levels of determination for aflatoxin B1.


1999 ◽  
Vol 82 (5) ◽  
pp. 1156-1162 ◽  
Author(s):  
Mark Laikhtman ◽  
Jeffrey S Rohrer

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.


2012 ◽  
Vol 95 (4) ◽  
pp. 933-936 ◽  
Author(s):  
Ursula Kirchner ◽  
Katharina Degenhardt ◽  
Guenther Raffler ◽  
Maria Nelson

Abstract During the “Standards Development and International Harmonization: AOAC INTERNATIONAL Mid-Year Meeting,” on June 29, 2011, the method “Determination of Vitamin B12 in Infant Formula and Adult Nutritionals Using HPLC After Purification on an Immunoaffinity Column” was recommended by an Expert Review Panel and adopted as AOAC Official First Action status. The method is applicable for the determination of vitamin B12 in milk-based infant formula. Vitamin B12 is extracted from the sample in sodium acetate buffer in the presence of potassium cyanide. After purification and concentration with an immunoaffinity column (IAC), vitamin B12 is determined by LC with UV detection (361 nm). Data supplied by CLF demonstrated linear response over a wide range of concentrations (1.4–39 μg/100 mL). The analytical range is 0.2–10 μg/100 g, depending on the capacity of the IACs (0.01–0.5 μg), the input weight, and dilutions. Recovery rates were assessed using National Institute of Standards and Technology SRM 1849, and determined to be 95.1%, with SD of 0.34 and CV of 9.0. Measurement uncertainty (UE) was 0.8 μg/100 g, which was calculated from the validation data. It is an expanded measurement uncertainty and was obtained through multiplication with a coverage factor k. LOQ values were reported as 0.10 μg/100 g. The performance characteristics of the method met the standard method performance requirements set forth by the AOAC Stakeholder Panel on Infant Formula and Adult Nutritionals; thus, the method was determined to be appropriate for First Action status.


2016 ◽  
Vol 99 (1) ◽  
pp. 210-222 ◽  
Author(s):  
Pierre-Alain Golay ◽  
Julie Moulin ◽  
M Alewijn ◽  
U Braun ◽  
L F Choo ◽  
...  

Abstract A collaborative study was conducted on AOAC First Action Method 2012.13 “Determination of Labeled Fatty Acids Content in Milk Products and Infant Formula by Capillary Gas Chromatography,” which is based on an initial International Organization for Standardization (ISO)–International Dairy Federation (IDF) New Work Item that has been moved forward to ISO 16958:2015|IDF 231:2015 in November 2015. It was decided to merge the two activities after the agreement signed between ISO and AOAC in June 2012 to develop common standards and to avoid duplicate work. The collaborative study was performed after having provided highly satisfactory single-laboratory validation results [Golay, P.A., & Dong, Y. (2015) J. AOAC Int. 98, 1679–1696] that exceeded the performance criteria defined in AOAC Standard Method Performance Requirement (SMPR®) 2012.011 (September 29, 2012) on 12 products selected by the AOAC Stakeholder Panel on Infant Formula (SPIFAN). After a qualification period of 1 month, 18 laboratories participated in the fatty acids analysis of 12 different samples in duplicate. Six samples were selected to meet AOAC SPIFAN requirements (i.e., infant formula and adult nutritionals in powder and liquid formats), and the other Six samples were selected to meet ISO-IDF requirements (i.e., dairy products such as milk powder, liquid milk, cream, butter, infant formula with milk, and cheese). The fatty acids were analyzed directly in all samples without preliminary fat extraction, except in one sample (cheese). Powdered samples were analyzed after dissolution (i.e., reconstitution) in water, whereas liquid samples (or extracted fat) were analyzed directly. After addition of the internal standards solution [C11:0 fatty acid methyl ester (FAME) and C13:0 triacylglycerols (TAG)] to the samples, fatty acids attached to lipids were transformed into FAMEs by direct transesterification using methanolic sodium methoxide. FAMEs were separated using highly polar capillary GLC and were identified by comparison with the retention times of pure analytical standards. Quantification of fatty acids was done relative to C11:0 FAME as internal standard and to instrument response factors (determined separately using calibration standards mixture). The performance of the method (i.e., transesterification) was monitored in all samples using the second internal standard, C13:0 TAG. RSDR values were summarized separately for labeled fatty acids in SPIFAN materials and ISO-IDF materials due to different expression of results. This method was applied to representative dairy, infant formula, and adult/pediatric nutritional products and demonstrated global acceptable reproducibility precision for all fatty acids analyzed (i.e., 46 individuals and/or groups) for these categories of products.


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