scholarly journals Single-Laboratory Validation Study of a Proton NMR Method for the Determination of L-Arginine, L-Citrulline, and Taurine Contents in Dietary Supplements

2020 ◽  
Vol 103 (4) ◽  
pp. 1140-1147
Author(s):  
Isaac Lee ◽  
Jennie Vo ◽  
Quanyin Gao ◽  
Piyush Purohit ◽  
Veronica Zarraga ◽  
...  
Keyword(s):  
Quality Control ◽  
Dietary Supplement ◽  
Proton Nmr ◽  
Hplc Method ◽  
Rapid Analysis ◽  
Test Method ◽  
Method Performance ◽  
Single Laboratory ◽  
Concentration Levels

Abstract Background A quantitative NMR (qNMR) method can provide rapid analysis compared to chromatographic methods. Sample preparation steps are relatively simpler and run time is shorter. Rapid analysis methods for release tests in quality control laboratories are very important for laboratory efficiency. Here, we describe a single-laboratory validation study for a rapid qNMR analysis of L-arginine, L-citrulline, and taurine in powdered and tablet dietary supplement products. Objectives This validation work is to provide documented evidence for the qNMR method validity as well as method performance. Methods The method used Bruker 400 MHz high-resolution proton NMR spectroscopy for simultaneous determination of L-arginine, L-citrulline, and taurine contents in dietary supplement product 1 (powder) and dietary supplement product 2 (tablet). The absolute NMR quantitation is based on a principle of universal proton response intensity correlation with the number of protons in each target analyte (amino acids) vs. that of a reference standard (maleic acid). Results The test method performance was validated with dietary supplement-1 (powder) and dietary supplement-2 (tablet). The linearity of the method was studied from about 360 mg/g to about 675 mg/g of L-arginine; from about 15 mg/g to about 30 mg/g of L-citrulline; and from about 20 mg/g to about 40 mg/g of taurine in dietary supplement-1, and from about 15 mg/g to about 30 mg/g of taurine in dietary supplement-2. The coefficients of determination (R2) are 1.0000 for L-arginine, 0.9967 for L-citrulline, and 0.9995 for taurine in dietary supplement-1 and 0.9903 for taurine in dietary supplement-2. The accuracies measured from the sample matrices are 102%, 101%, and 100% average recoveries for 80%, 100%, and 120% concentration levels of L-arginine, 105%, 105%, and 103% average recoveries for 80%, 100%, and 120% concentration level of L-citrulline, and 101%, 102%, and 100% average recoveries of taurine for 80%, 100%, 120% concentration levels in dietary supplement-1; and 95, 98%, and 93% average recoveries of taurine for 80%, 100%, 120% concentration levels in dietary supplement-2, respectively. The precisions (RSD) are 1% for L-arginine, 5% for L-citrulline, and 2% for taurine in dietary supplement -1, respectively; and 4% for taurine in dietary supplement-2. The ruggedness of the test method is within 2%, 4%, and 2% for L-arginine, L-citrulline, and taurine for dietary supplement -1, respectively, and within 4% for dietary supplement-2. The method is specific for the quantitation of each nutrient with no background interference from the matrix for the proton peaks of L-arginine, L-citrulline, taurine, and maleic acid (standard). Conclusions The test method is proven to be specific, precise, accurate, rugged, and suitable for intended quantitative analysis of L-arginine, L-citrulline, and taurine in powdered and tablet finished products. Highlights The simultaneous determination of all three nutrients of L-arginine, L-citrulline, and taurine using proton NMR provides rapid analysis for quality control release tests that is more efficient versus that of two HPLC methods. Previously, our laboratory was using one HPLC method to analyze L-arginine and L-citrulline while using a second HPLC method to analyze taurine. That approach required two HPLC instruments and two analysts for parallel analysis that takes 2 days using volatile and flammable solvents for extraction and chemical derivatization. This rapid NMR method can analyze the sample “as is” with results obtained in less than 4 h, and is efficient, safe, and environmentally friendly. The initial higher NMR instrument investment versus two HPLC instruments is rewarded with high returns for continued quality control tests.

Determination of Vitamin K1 in Infant, Pediatric, and Adult Nutritionals by HPLC with Fluorescence Detection: Single-Laboratory Validation, First Action 2015.09

2015 ◽  
Vol 98 (5) ◽  
pp. 1382-1389 ◽  
Author(s):  
Mary Bidlack ◽  
Linda D Butler Thompson ◽  
Wesley A Jacobs ◽  
Karen J Schimpf
Keyword(s):  
Fluorescence Detection ◽  
Hplc Method ◽  
Excitation Wavelength ◽  
Vitamin K1 ◽  
Intermediate Precision ◽  
Method Performance ◽  
Performance Requirements ◽  
Normal Phase Hplc ◽  
Single Laboratory

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.

Determination of Lutein and β-Carotene in Infant Formula and Adult Nutritionals by Ultra-High-Performance Liquid Chromatography: Single-Laboratory Validation, First Action 2016.13

2017 ◽  
Vol 100 (3) ◽  
pp. 768-781
Author(s):  
Gregory L Hostetler
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Infant Formula ◽  
High Performance ◽  
Hplc Method ◽  
Method Performance ◽  
Performance Requirements ◽  
Single Laboratory ◽  
Β Carotene

Abstract An ultra-HPLC method for the determination of lutein and β-carotene in infant formula and adult nutritionals wasvalidated using both unfortified and fortified samples provided by the AOAC Stakeholder Panel on Infant Formula and AdultNutritionals (SPIFAN). All experiments showed separation of all-trans-lutein and β-carotene from their major cis isomers, apocarotenal, α-carotene, lycopene, and zeaxanthin. Samples spiked with all-trans-lutein and β-carotene showed no isomerization during sample preparation. Linearity of the calibration solutions correlated to approximately 0.8–45 μg/100 g (reconstituted basis) for samples prepared for the lowest sample concentrations. With dilutions specified in the method, the range can be extended to approximately 2250 μg/100 g. The LOD for both lutein and β-carotene was 0.08 μg/100 g, and the LOQ for both was 0.27μg/100 g. For all measurements in the range of 1–100 μg/100 g, repeatability RSD was ≤5.8% forlutein and ≤5.1% for β-carotene. For measurements >100 μg/100 g, repeatability RSD was ≤1.1% for lutein and ≤1.7% for β-carotene. Accuracywas determined by recovery from spiked samples and ranged from 92.3 to 105.5% for lutein and from 100.1 to 107.5% for β-carotene. The data provided show that the method meets the criteria specified in the Standard Method Performance Requirements for carotenoids (SMPR 2014.014).

Determination of Total Phenolic Content Using the Folin-C Assay: Single-Laboratory Validation, First Action 2017.13

2018 ◽  
Vol 101 (5) ◽  
pp. 1466-1472 ◽  
Author(s):  
Steve Kupina ◽  
Chris Fields ◽  
Mark C Roman ◽  
Sharon L Brunelle
Keyword(s):  
Gallic Acid ◽  
Dietary Supplement ◽  
Total Phenolic Content ◽  
Phenolic Content ◽  
Collaborative Study ◽  
Total Phenolic ◽  
Skin Extract ◽  
Method Performance ◽  
Single Laboratory

Abstract A single-laboratory validation of a method using Folin & Ciocalteu’s phenol reagent (Folin-C reagent) for determination of total phenolic content of selected dietary supplement extracts was performed. The method is composed of a water extraction of dried extracts with sonication followed by reaction with the Folin-C reagent. The resulting colorimetric reaction is measured at 765 nm and compared with a standard curve generated with gallic acid standard solutions. The validation results were compared with Standard Method Performance Requirement (SMPR®) 2015.009, developed by the Stakeholder Panel on Dietary Supplements. The method demonstrated acceptable within-day RSDr of 1.96–7.47% for the five matrixes studied (grape seed extract, grape skin extract, black tea extract, green coffee extract, and cocoa extract). When gallic acid was spiked into maltodextrin (a surrogate dietary supplement carrier) at 30 or 70%, the recovery ranged from 91 to 104%, within the acceptable range established by SMPR 2015.009. Selectivity testing with glucose, fructose, and sucrose demonstrated no positive interference by these compounds. Finally, ruggedness studies demonstrated no significant effects due to changes in the heating apparatus, test material weight, read time after reaction, amount of Folin-C reagent, reaction time, reaction temperature, and amount of Na2CO3. The single-laboratory validation results support adoption of the method as First Action Official MethodSM 2017.13 and further evaluation in a collaborative study.

scholarly journals Development and Validation of a GMP-Compliant High-Pressure Liquid Chromatography Method for the Determination of the Chemical and Radiochemical Purity of [18F]PSMA-1007, a PET Tracer for the Imaging of Prostate Cancer

2021 ◽  
Vol 14 (3) ◽  
pp. 188
Author(s):  
Ines Katzschmann ◽  
Heike Marx ◽  
Klaus Kopka ◽  
Ute Hennrich
Keyword(s):  
Prostate Cancer ◽  
Quality Control ◽  
Radiochemical Purity ◽  
Control Method ◽  
Solid Phase ◽  
Hplc Method ◽  
Attractive Alternative ◽  
Chromatography Method ◽  
Pet Tracer

For the PET imaging of prostate cancer, radiotracers targeting the prostate-specific membrane antigen (PSMA) are nowadays used in clinical practice. [18F]PSMA-1007, a radiopharmaceutical labeled with fluorine-18, has excellent properties for the detection of prostate cancer. Essential for the human use of a radiotracer is its production and quality control under GMP-compliance. For this purpose, all analytical methods have to be validated. [18F]PSMA-1007 is easily radiosynthesized in a one-step procedure and isolated using solid phase extraction (SPE) cartridges followed by formulation of a buffered injection solution and for the determination of its chemical and radiochemical purity a robust, fast and reliable quality control method using radio-HPLC is necessary. After development and optimizations overcoming problems in reproducibility, the here described radio-HPLC method fulfills all acceptance criteria—for e.g., specificity, linearity, and accuracy—and is therefore well suited for the routine quality control of [18F]PSMA-1007 before release of the radiopharmaceutical. Recently a European Pharmacopeia monograph for [18F]PSMA-1007 was published suggesting a different radio-HPLC method for the determination of its chemical and radiochemical purity. Since the here described method has certain advantages, not least of all easier technical implementation, it can be an attractive alternative to the monograph method. The here described method was successfully validated on several radio-HPLC systems in our lab and used for the analysis of more than 60 batches of [18F]PSMA-1007. Using this method, the chemical and radiochemical purity of [18F]PSMA-1007 can routinely be evaluated assuring patient safety.

Determination of total proteinogenic amino acids and taurine by pre-column derivatisation and UHPLC: Single Laboratory Validation, First Action 2019.09

2020 ◽  
Author(s):  
George Joseph ◽  
Asha Varughese ◽  
Ann Daniel
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Infant Formula ◽  
Retention Time ◽  
Sulfonic Acid ◽  
Internal Standard ◽  
The Other ◽  
Method Performance ◽  
Single Laboratory

Abstract Background A method has been developed and validated for selective, accurate and precise determination of total proteinogenic amino acids and taurine from Infant Formula and Adult/Pediatric Nutritional Formulas (powders, ready-to-feed liquids, and liquid concentrates). The method was reviewed by the AOAC INTERNATIONAL SPIFAN Expert Review Panel (ERP) during the 133rd AOAC Annual Meeting & Expo on September 7, 2019 in Denver, CO, USA and was recommended to First Action Official MethodsSM status. Objective The method involves protein hydrolysis to amino acids, a simple pre-column derivatisation of amino acids and separation of derivatised amino acids by UHPLC. The quantification of amino acids is performed by multi-point calibration using norvaline as the internal standard. The analytical method is capable of quantitative determination for 22 proteinogenic amino acids, but cannot be used to quantitate tryptophan, which is destroyed during the acid hydrolysis step. Asparagine is determined as aspartic acid and glutamine as glutamic acid. The cystine and cysteine are converted to S-2-carboxyethylthiocysteine (CYSx) and the derivative is separated from the other amino acids. Citrulline which is present in some matrices and it is separated from other amino acids is not included in the method performance evaluation in the single laboratory validation (SLV). Method The proposed method met all the performance requirement limits set in standard method performance requirements (SMPR) 2014.013 for total proteinogenic amino acids and taurine. The correlation coefficient of multi-point calibration was not less than 0.999 for any amino acids at any point in the SLV study confirming the validity of linear dynanic range (LDR) and linearity of the method. The individual amino acids in the chromatogram were identified by absolute retention time and relative retention time (RRT) with respect to the internal standard norvaline. There were no significant (S/N Ratio <10) interferences from the reagents or by-products of derivatisation and targeted matrices. The method demonstrated high selectivity. Result Accuracy of the method was validated using standard reference materials (NIST SRM 1869 and 1849a) and spike recovery studies. The amino acid results in the SRMs were within the ranges of Reference Mass Fraction Values. The accuracy of the method was corroboratively validated by spike recovery studies. The average spike recovery range between 93 to 107% ensure the accuracy of the method for amino acids and compliance to the AOAC SMPR 2014.013. Conclusions Precision data of the method demonstrate that it meets the stakeholder requirements as per the SMPR. The mean RSDr for all the amino acids for 17 matrices selected for the SLV were not more than 4%. The method is very sensitive and the LOQ can go down to approximately ten times lower than the SMPR requirements. The sensitivity of method is a direct reflection of its signal to noise ratio which ensures guaranteed method performance at the lower levels of amino acids in these matrices. Highlights Taurine (aminoethane sulfonic acid) unlike the other amino acids is a beta-sulfonic amino acid that is not used in protein synthesis but is found as a free amino acid in tissues. The acidic functional group (-COOH) in common amino acid is replaced with a sulfonic acid (-SO3H) group in Taurine. The method offers baseline separation of citrulline which is an alpha amino acid generally present in Infant Formula and Adult/Pediatric Nutritional products. The separation of citrulline eliminates the risk of interference of this compound with other amino acids. The method can also separate and quantitate hydroxyproline, an important component of collagen that is often used to quantitate collagen. The method is simple and does not include any proprietary chemicals or instruments and can be performed on any basic reverse phase UHPLC system with UV detection.

scholarly journals Determination of Chondroitin Sulfate Content in Raw Materials and Dietary Supplements by High-Performance Liquid Chromatography with UV Detection After Enzymatic Hydrolysis: Single-Laboratory Validation First Action 2015.11

2016 ◽  
Vol 99 (1) ◽  
pp. 53-54
Author(s):  
Sharon L Brunelle
Keyword(s):  
Chondroitin Sulfate ◽  
Dietary Supplements ◽  
High Performance ◽  
Raw Materials ◽  
Method Performance ◽  
Expert Review ◽  
Performance Requirements ◽  
Expert Review Panel ◽  
Single Laboratory

Abstract A previously validated method for determination of chondroitin sulfate in raw materials and dietary supplements was submitted to the AOAC Expert Review Panel (ERP) for Stakeholder Panel on Dietary Supplements Set 1 Ingredients (Anthocyanins, Chondroitin, and PDE5 Inhibitors) for consideration of First Action Official MethodsSM status. The ERP evaluated the single-laboratory validation results against AOAC Standard Method Performance Requirements 2014.009. With recoveries of 100.8–101.6% in raw materials and 105.4–105.8% in finished products and precision of 0.25–1.8% RSDr within-day and 1.6–4.72% RSDr overall, the ERP adopted the method for First Action Official Methods status and provided recommendations for achieving Final Action status.

2-Monochloropropanediol (2-MCPD), 3-Monochloropropanediol (3-MCPD), and Glycidol in Infant and Adult/Pediatric Nutritional Formula: Single-Laboratory Validation, First Action 2018.12

2019 ◽  
Vol 102 (4) ◽  
pp. 1205-1220 ◽  
Author(s):  
Jan Kuhlmann
Keyword(s):  
Fatty Acid ◽  
Infant Formula ◽  
Edible Oils ◽  
Accurate Determination ◽  
Fatty Acid Esters ◽  
Method Performance ◽  
Relative Standard ◽  
Single Laboratory ◽  
Acid Esters

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.

scholarly journals Simultaneous Determination of Four Major Constituents of Semen Vaccariae Using HPLC-DAD

2012 ◽  
Vol 7 (9) ◽  
pp. 1934578X1200700 ◽  
Author(s):  
Haijiang Zhang ◽  
Wei Yao ◽  
Yunyun Chen ◽  
Peipei He ◽  
Yao Chen ◽  
...  
Keyword(s):  
Quality Control ◽  
Quantitative Analysis ◽  
Simultaneous Determination ◽  
Chromatographic Separation ◽  
Gradient Elution ◽  
Hplc Method ◽  
Frying Temperature ◽  
Simultaneous Quantification ◽  
Frying Process

A simple and reliable HPLC method was developed and validated for the simultaneous quantification of four major constituents in Semen Vaccariae. The chromatographic separation was performed on an Agilent Zorbax SB-C18 column with gradient elution using methanol and water. The calibration curves showed good linearity of R2 > 0.9999 with LOQs (S/N = 10) of 0.20–1.16 μg/mL. The precision was evaluated by intra- and inter-day assays and R.S.D. values were less than 2.09%. The recovery rates were between 97.0% and 105.0%. The developed method was applied to the quantitative analysis of Semen Vaccariae and its stir-fried products. During the stir-frying process, vaccarin degraded and yielded isovitexin-2″- O-arabinoside. The preferable stir-frying temperature is around 120°C. The developed HPLC method can be applied to the quality control of crude and stir-fried Semen Vaccariae.

Method for the Determination of Catechin and Epicatechin Enantiomers in Cocoa-Based Ingredients and Products by High-Performance Liquid Chromatography: Single-Laboratory Validation

2012 ◽  
Vol 95 (2) ◽  
pp. 500-507 ◽  
Author(s):  
Philip R Machonis ◽  
Matthew A Jones ◽  
Brian T Schaneberg ◽  
Catherine L Kwik-Uribe
Keyword(s):  
Mobile Phase ◽  
High Performance ◽  
Chiral Stationary Phase ◽  
Ammonium Acetate ◽  
Hplc Method ◽  
Routine Laboratory ◽  
Performance Results ◽  
Single Laboratory ◽  
Monomeric Flavanols

Abstract A single-laboratory validation study was performed for an HPLC method to identify and quantify the flavanol enantiomers (+)- and (–)-epicatechin and (+)- and (–)-catechin in cocoa-based ingredients and products. These compounds were eluted isocratically with an ammonium acetate–methanol mobile phase applied to a modified β-cyclodextrin chiral stationary phase and detected using fluorescence. Spike recovery experiments using appropriate matrix blanks, along with cocoa extract, cocoa powder, and dark chocolate, were used to evaluate accuracy, repeatability, specificity, LOD, LOQ, and linearity of the method as performed by a single analyst on multiple days. In all samples analyzed, (–)-epicatechin was the predominant flavanol and represented 68–91% of the total monomeric flavanols detected. For the cocoa-based products, within-day (intraday) precision for (–)-epicatechin was between 1.46–3.22%, for (+)-catechin between 3.66–6.90%, and for (–)-catechin between 1.69–6.89%; (+)-epicatechin was not detected in these samples. Recoveries for the three sample types investigated ranged from 82.2 to 102.1% at the 50% spiking level, 83.7 to 102.0% at the 100% spiking level, and 80.4 to 101.1% at the 200% spiking level. Based on performance results, this method may be suitable for routine laboratory use in analysis of cocoa-based ingredients and products.

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