Determination of trans and Total Vitamin K1 in Infant, Pediatric, and Adult Nutritionals by HPLC with Post Column Reduction and Fluorescence Detection: Multilaboratory Testing Study, AOAC Final Action 2015.09

2019 ◽  
Vol 102 (1) ◽  
pp. 222-232
Author(s):  
Karen J Schimpf ◽  
Linda D Butler Thompson ◽  
Shang-Jing Pan ◽  
P Delmonte ◽  
C Domer ◽  
...  

Abstract A multilaboratory study was completed with AOAC INTERNATIONAL First Action Official MethodSM 2015.09, “Determination of trans and Total (cis+trans) Vitamin K1 in Infant, Pediatric, and Adult Nutritionals by HPLC with Post Column Reduction and Fluorescence Detection.” Eight laboratories from six countries participated in the multilaboratory study. Each laboratory analyzed 19 infant, pediatric, and adult nutritionals in duplicate. The product matrixes analyzed included milk, soy, partially hydrolyzed milk, partially hydrolyzed soy, and elemental-based infant formula powders; milk-based infant formula ready-to-feed liquids; pediatric powders; adult low- and high-fat powders; and high-protein ready-to-drink nutritionals. Vitamin K1 was extracted from product matrixes with isooctane after precipitation of proteins and the release of lipids with methanol. Prepared samples were injected onto a silica HPLC column in which cis and trans vitamin K1 were separated with an isooctane–isopropanol mobile phase. The column eluent was mixed with a dilute ethanolic solution of zinc chloride, sodium acetate, and acetic acid, and cis and trans vitamin K1 were reduced to fluorescent derivatives in a zinc reactor column. Overall, trans vitamin K1 repeatability averaged 3.06% relative standard deviation (RSD) with a range of 0.99–7.16% RSD and reproducibility averaged 6.36% RSD with a range of 3.15–16.1% RSD. Repeatability Standard Method Performance Requirements (SMPR®) were met for all 19 matrixes, and reproducibility SMPRs were met for 18 of the 19 product matrixes analyzed. Repeatability and reproducibility for total (cis + trans) vitamin K1 averaged 3.15% RSD with a range of 1.06–6.87% RSD and 6.11% RSD with a range of 2.94–16.7% RSD, respectively.

2018 ◽  
Vol 101 (6) ◽  
pp. 1881-1894 ◽  
Author(s):  
Sneh D Bhandari ◽  
Ming Gao ◽  
John Szpylka ◽  
N Collopy ◽  
H Chen ◽  
...  

Abstract Background: The need for an updated reference method for folate was identified as a priority by the AOAC’s Stakeholder Panel on Infant Formula and Adult Nutritionals (SPIFAN) in 2011. An Expert Review Panel (ERP) found AOAC Official MethodSM 2011.06 suitable for the purpose and approved it as a First Action Official Method. Objective: To determine the repeatability and reproducibility of Method 2011.06: Total Folate in Infant Formula and Adult Nutritionals by Trienzyme Extraction and LC-MS/MS Quantitation. Methods: A multilaboratory collaborative study was conducted. Eleven laboratories located in five countries participated and completed analysis of all multilaboratory testing (MLT) samples. The study was divided into two parts. In the first part, the laboratories analyzed two practice samples (blindly coded) using the updated folate Method 2011.06. The laboratories providing results within the expected range qualified for part two, in which they analyzed 11 MLT samples in blind duplicates. Results: The results were compared with the Standard Method Performance Requirements (SMPR 2011.006) established for folate. The precision results met the requirements stated in the SMPR for all of the samples. Repeatability and reproducibility relative standard deviations ranged from 3.5 to 6.6 and from 9.0 to 15.7%, respectively. Horwitz ratio values for all of the samples were well below 2 (0.61–1.06). Conclusions: The ERP determined that the method performance met the SMPR requirements in September 2017 after reviewing the presented MLT data. Highlights: The ERP recommended the method for Final Action status.


2015 ◽  
Vol 98 (5) ◽  
pp. 1382-1389 ◽  
Author(s):  
Mary Bidlack ◽  
Linda D Butler Thompson ◽  
Wesley A Jacobs ◽  
Karen J Schimpf

Abstract This normal-phase HPLC method with postcolumn reduction and fluorescence detection allows for the quantitative determination of trans vitamin K1 in infant, pediatric, and adult nutritionals. Vitamin K1 is extracted from products with iso-octane after precipitation of proteins and release of lipids with methanol. Prepared samples are injected onto a silica HPLC column where cis and trans vitamin K1 are separated with an iso-octane–isopropanol mobile phase. The column eluent is mixed with a dilute ethanolic solution of zinc chloride, sodium acetate, and acetic acid, and vitamin K1 is reduced to a fluorescent derivative in a zinc reactor column. The resulting hydroquinone is then detected by fluorescence at an excitation wavelength of 245 nm and an emission wavelength of 440 nm. During a single-laboratory validation of this method, repeatability and intermediate precision ranged from 0.6 to 3.5% RSD and 1.1 to 6.0% RSD, respectively. Mean overspike recoveries ranged from 91.9 to 106%. The method demonstrated good linearity over a standard range of approximately 2–90 μg/L trans vitamin K1 with r2 averaging 0.99995 and average calibration errors of <1%. LOQ and LOD in ready-to-feed nutritionals were estimated to be 0.03 and 0.09 μg/100 g, respectively. The method met AOAC Stakeholder Panel on Infant Formula and Adult Nutritionals Standard Method Performance Requirements® and was approved as a first action method at the 2015 AOAC Mid-Year Meeting.


2020 ◽  
Vol 103 (3) ◽  
pp. 818-832
Author(s):  
Gregory L Hostetler ◽  
S Benét ◽  
R Buis ◽  
E Campos-Giménez ◽  
S Christiansen ◽  
...  

Abstract Background Lutein, β-carotene, and lycopene are among the most common carotenoids present in human milk and are frequently added to infant formula and adult nutritionals. Objective A collaborative study was conducted to assess the interlaboratory performance of AOAC Official MethodSM2016.13 for the determination of lutein, β-carotene, and lycopene in infant formula and adult nutritionals. Methods Thirteen laboratories agreed to participate in the study and 10 laboratories from seven different countries reported results. The study samples included blind duplicates of 6 matrices fortified with lutein, 7 matrices fortified with β-carotene, and 1 fortified with lycopene. NIST SRM 1869 was included in the sample set as a reference material. Results After the removal of outliers and invalid data, the repeatability (RSDr) data was ≤10.0% for all-trans-lutein, ≤12.0% for total lutein, ≤4.2% for all-trans-β-carotene, ≤6.0% for total β-carotene, and 1.6% for total lycopene. Reproducibility (RSDR) was ≤14.8% for all-trans-lutein, ≤19.9% for total lutein, ≤15.3% for all-trans-β-carotene, ≤13.7% for total β-carotene, and 7.4% for total lycopene. Conclusions The repeatability and reproducibility values met the criteria in the Standard Method Performance Requirements (SMPRs) for β-carotene and lycopene and it was recommended that the method be approved as a Final Action for these analytes. Since the method did not meet the SMPR for lutein, it was recommended that it remain a First Action method for this analyte. Highlights AOAC Official MethodSM2016.13 was validated through a collaborative study to be accurate and reproducible for the determination of β-carotene and lycopene in infant formula and adult nutritionals.


2019 ◽  
Vol 102 (2) ◽  
pp. 564-569
Author(s):  
Greg Jaudzems ◽  
Fengxia Zhang ◽  
Wu Bolong ◽  
Lei Bao ◽  
Jing Xiao

Abstract Background: In September 2015, both AOAC Official Methods 2015.07and 2015.08 single-laboratory validations (SLVs) were reviewed against Standard Method Performance Requirements® (SMPR) 2014.015by the AOAC Stakeholder Panel for Infant Formula andAdult Nutritional (SPIFAN) Expert Review Panel (ERP). Looking at the similarity and uniqueness of the two methods, the authors agreed, as advised by the ERP, to work together to merge the two methods intoone. This combined method was assigned Method 2016.03. Objective: In order to determine the repeatability and reproducibility of the AOAC First Action 2016.03 method, a collaborative study was organized. The study was divided in two parts: (Part 1) method set up and qualification of participants and (Part 2) collaborative study participation. During Part 1, each laboratory was asked to analyze two practice samples. The laboratories that provided results within a range of expected levels were qualified for Part 2, during which they analyzed 25 samples in blind duplicates. Results: The results were compared with SMPR 2014.015 established for chloride. The precision results (repeatability and reproducibility) were within therequirements stated in the SMPR. In general, the precision results (repeatability and reproducibility)were well within the limits stated in the SMPR. Repeatability ranged from 0.4 to 1.9%, in accordance with data obtained during SLV, with reported RSD of repeatability from 0.03 to 1.6%. Meanwhile, reproducibility ranged from 0.6 to 4.0%. Finally, the Horwitz ratio values were all below 1, from 0.2 to 0.9%. Conclusions: The ERP determined that the data presented met the SMPR and accordingly recommended the method to be granted Final Actionstatus. In January 2018, the Official Methods Boardapproved the method as Final Action.


2019 ◽  
Vol 102 (4) ◽  
pp. 1205-1220 ◽  
Author(s):  
Jan Kuhlmann

Abstract Background: Fatty acid esters of glycidol, 2-Monochloropropanediol (MCPD), and 3-MCPD are heat-induced foodborne processing contaminants with possible adverse health effects. These compounds occur frequently in refined edible oils. Consequently, glycidyl esters and 2- and 3-MCPD esters might also be present in foods that contain refined edible oils. Objective: This manuscript describes the single-laboratory validation of an analytical method for the quantitative determination of glycidol, 2-MCPD, and 3-MCPD present as fatty acid esters or as free 2- or 3-MCPD in infant and adult/pediatric nutritional formula. Methods: Technically, the presented method is based on the combination of a Heat-Ultrasound Pressure-supported Solvent Extraction and a GC–MS determination of glycidol, 2-MCPD, and 3-MCPD. From a chemical perspective, the method includes an alkaline catalyzed transesterification, conversion of the unstable glycidol into monobromopropanediol, and the parallel derivatization of all analytes with phenylboronic acid. Results: Validation results showed that method linearity for all analytes in powdered and liquid infant formula ranged from 0.9981 to 0.9999 (n = 18). Repeatability relative standard deviation values for concentration levels between 1.3 μg/kg and 331 μg/kg were in the range of 1 to 12%. Relative recoveries were found to be between 93 and 107%. The analytes were quantifiable down to 5–10 μg/kg in powdered samples and 1–2 μg/kg in liquid samples. Conclusions: The reported results met actual AOAC Standard Method Performance Requirements. Highlights: In terms of consumer protection, the presented method is a novel approach for the sensitive and accurate determination of glycidol, 2-MCPD, and 3-MCPD in infant formula and related foodstuffs.


2019 ◽  
Vol 102 (5) ◽  
pp. 1574-1588 ◽  
Author(s):  
Greg Jaudzems ◽  
Joseph Guthrie ◽  
Sabine Lahrichi ◽  
Christophe Fuerer

Abstract Background: An acid hydrolysis ultrahigh-performance LC–UV method was evaluated for the determination of total amino acids in infant formula and adult/pediatric nutritional formula. Objective: It was assessed for compliance against AOAC INTERNATIONAL Standard Method Performance Requirements (SMPR®) established by the Stakeholder Panel for Infant Formula and Adult Nutritionals (SPIFAN). Methods: A single-laboratory validation (SLV) study was conducted as a first step in the process to validate the method. In this SLV, 17 SPIFAN matrices representing a range of infant formula and adult nutritional products were evaluated for their amino acid content. Results: The analytical range was found to be within the needs for all products; some may require a dilution. Evaluation of trueness performed on Standard Reference Material 1849a (Infant/Adult Nutritional Formula) showed all compounds met the SMPR theoretical value, with exceptions for threonine and tyrosine. These may have a bias for the National Institute of Standards and Technology (NIST) data, depending on hydrolysis used in the determination of the NIST certificate of analysis. Conclusions: Based on the results of this SLV, this method met the SMPR and was approved as a First Action method by the AOAC Expert Review Panel on Nutrient Methods on August 28, 2018.


2019 ◽  
Vol 102 (1) ◽  
pp. 156-163 ◽  
Author(s):  
Tugrul Kaymak ◽  
Ercan Koca ◽  
Mustafa Atak ◽  
Ercan Sarikaya ◽  
Joerg Stroka

Abstract Background: Tarhana is a traditional fermented, sun-dried Turkish food containing yogurt and cereals. There are several potential sources of mycotoxins in tarhana, such as contamination of ingredients or formation during preparation, when water activity is suitable for fungal growth and may lead to mycotoxin production during fermentation or subsequent sun-drying. Objective: To optimize an immunoaffinity column method and carry out single-laboratory validation for the determination of aflatoxins B1, B2, G1, and G2 together with ochratoxin A (OTA) in tarhana. Method: A homogenized sample was extracted with methanol–acetonitrile–water (25 + 25 + 50) using a high-speed blender. The sample extract was filtered, diluted with phosphate buffered saline (PBS) solution, and applied to a multi-immunoaffinity column (AFLAOCHRA PREP®). Aflatoxins and OTA were removed with neat methanol and then directly analyzed by reverse-phase LC with fluorescence detection using post-column bromination (Kobra® Cell). Results: Test portions of blank tarhana were spiked with a mixture of total aflatoxins and OTA to give levels ranging from 2.5 to 10.0 and 1.5 to 6.0 μg/kg, respectively. Recoveries for total aflatoxins and OTA ranged from 82 to 93 and 78 to 94%, respectively, for spiked samples. Based on results for spiked tarhana (30 replicates, each at three levels), the relative standard deviation for repeatability ranged from 1.4 to 7.2 and 3.6 to 7.7% for total aflatoxins and OTA, respectively. Conclusions: The performance characteristics for recovery, repeatability, and sensitivity have demonstrated that the method meets method performance criteria for use for official purposes. The method was demonstrated as being applicable to naturally contaminated samples of tarhana of varied composition obtained from local markets in Turkey. Highlights: This is the first immunoaffinity column method for simultaneous analysis of aflatoxins and OTA in traditional Turkish food (tarhana). Suitability was demonstrated by single-laboratory validation for official purposes in Turkey. The method was demonstrated as suitable for naturally contaminated samples of tarhana of varied composition.


1993 ◽  
Vol 76 (5) ◽  
pp. 1143-1145 ◽  
Author(s):  
Mei-Chich Hsu ◽  
Weng F Huang

Abstract A previously published liquid chromatographic method proposed for the analysis of dicloxacillin preparations was subjected to an interlaboratory study. The method is rigorously defined in terms of performance requirements, yet allows a degree of flexibility to the individual analyst. Eight laboratories participated in a study to analyze 3 samples in duplicate. Estimates for the repeatability and reproducibility of the method, expressed as relative standard deviations of the results of the determination of dicloxacillin preparations, were <0.57 and 2.56%, respectively.


2012 ◽  
Vol 95 (3) ◽  
pp. 583-587 ◽  
Author(s):  
Donald L Gilliland ◽  
Charles K Black ◽  
James E Denison ◽  
Charles T Seipelt ◽  
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) on behalf of AOAC INTERNATIONAL adopted the method “Simultaneous Determination of Vitamins D2 and D3 by LC-MS/MS in Infant Formula and Adult Nutritionals” as an AOAC Official First Action method. Vitamins D2 and D3 are extracted from the sample using pentane–ether; the extract is collected and dried under nitrogen. Vitamin D is separated from interfering compounds using UPLC, and quantitated using tandem mass spectrometry (MS/MS). Preliminary data showed the intermediate precision ranged from 3.34–8.05% and an accuracy range of 98.5–111% over the samples tested for vitamin D3. For vitamin D2, the intermediate precision ranged from 2.37–5.45% and accuracy ranged from 96.4–104% over the four matrixes evaluated. The analytical range for the method is bounded by the concentrations of the working standards, 21–270 ng/mL, and is equivalent to 0.168–2.16 mcg/100 g in ready-to-feed product. The practical method quantitation limit is 0.168 mcg/100 g product with method detection limit of 60 ng/100 g product. The ERP reviewed the data and determined that the performance characteristics of the method met the standard method performance requirements, and therefore the method was granted First Action status.


2013 ◽  
Vol 96 (6) ◽  
pp. 1400-1406 ◽  
Author(s):  
Kassandra Oates ◽  
Lillian Chen ◽  
Brian De Borba ◽  
Deepali Mohindra ◽  
Jeffrey Rohrer ◽  
...  

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%


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