Use of Validation Data for Fast and Simple Estimation of Measurement Uncertainty in Liquid Chromatography Methods

2005 ◽  
Vol 28 (19) ◽  
pp. 3005-3013 ◽  
Author(s):  
E. Campos Giménez ◽  
Sébastien Populaire
Keyword(s):  
Liquid Chromatography ◽  
Measurement Uncertainty ◽  
Validation Data ◽  
Simple Estimation

scholarly journals Detection and Quantification of Cocoa Butter Equivalents in Cocoa Butter and Plain Chocolate by Gas Liquid Chromatography of Triacylglycerols

2004 ◽  
Vol 87 (5) ◽  
pp. 1153-1163 ◽  
Author(s):  
Manuela Buchgraber ◽  
Chiara Senaldi ◽  
Franz Ulberth ◽  
Elke Anklam
Keyword(s):  
Liquid Chromatography ◽  
Cocoa Butter ◽  
Fat Content ◽  
Average Error ◽  
Gas Liquid Chromatography ◽  
Cocoa Butter Equivalent ◽  
Validation Data ◽  
Data Set ◽  
Cocoa Butter Equivalents ◽  
Detection And Quantification

Abstract The development and in-house testing of a method for the detection and quantification of cocoa butter equivalents in cocoa butter and plain chocolate is described. A database consisting of the triacylglycerol profile of 74 genuine cocoa butter and 75 cocoa butter equivalent samples obtained by high-resolution capillary gas liquid chromatography was created, using a certified cocoa butter reference material (IRMM-801) for calibration purposes. Based on these data, a large number of cocoa butter/cocoa butter equivalent mixtures were arithmetically simulated. By subjecting the data set to various statistical tools, reliable models for both detection (univariate regression model) and quantification (multivariate model) were elaborated. Validation data sets consisting of a large number of samples (n = 4050 for detection, n = 1050 for quantification) were used to test the models. Excluding pure illipé fat samples from the data set, the detection limit was determined between 1 and 3% foreign fat in cocoa butter. Recalculated for a chocolate with a fat content of 30%, these figures are equal to 0.3–0.9% cocoa butter equivalent. For quantification, the average error for prediction was estimated to be 1.1% cocoa butter equivalent in cocoa butter, without prior knowledge of the materials used in the blend corresponding to 0.3% in chocolate (fat content 30%). The advantage of the approach is that by using IRMM-801 for calibration, the established mathematical decision rules can be transferred to every testing laboratory.

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.

Determination of Vitamin B12 in Infant Formula and Adult Nutritionals Using HPLC After Purification on an Immunoaffinity Column: First Action 2011.09

2012 ◽  
Vol 95 (4) ◽  
pp. 933-936 ◽  
Author(s):  
Ursula Kirchner ◽  
Katharina Degenhardt ◽  
Guenther Raffler ◽  
Maria Nelson
Keyword(s):  
Vitamin B12 ◽  
Measurement Uncertainty ◽  
Infant Formula ◽  
Potassium Cyanide ◽  
Immunoaffinity Column ◽  
Validation Data ◽  
Method Performance ◽  
Expert Review ◽  
Wide Range

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.

Identification and quantitation of phosphatidylethanols in oral fluid by liquid chromatography-tandem mass spectrometry

2017 ◽  
Vol 55 (9) ◽  
Author(s):  
Shahid Ullah ◽  
Anders Helander ◽  
Olof Beck
Keyword(s):  
Liquid Chromatography ◽  
High Performance ◽  
Oral Fluid ◽  
Alcohol Exposure ◽  
Stability Study ◽  
Clinical Samples ◽  
Tandem Mass ◽  
Validation Data ◽  
Liquid Chromatography Tandem Mass ◽  
Alcohol Detoxification

AbstractBackground:Phosphatidylethanols (PEth) are formed from phosphatidylcholines and ethanol and are used as a specific and sensitive alcohol biomarker. An analytical method for analysis of PEth in oral fluid based on high-performance liquid chromatography coupled to a quadrupole tandem mass spectrometer (LC-MS/MS) was developed and validated and applied on samples collected from patients undergoing alcohol detoxification.Methods:A 200-μL aliquot of oral fluid, collected using the QuantisalResults:The detection limit for PEth 16:0/16:0, 16:0/18:1, and 16:0/18:2 was ~0.1 ng/mL, and the extraction recoveries at 2.0 ng/mL were in the range of 99%–114%. Method linearity over a concentration range up to 200 ng/mL was ≥0.99. No significant deviation in results was observed in an analyte stability study of two different concentrations at two different temperatures over 3 months. In 35 oral fluid samples collected from patients undergoing alcohol detoxification, the highest concentration was observed for PEth 16:0/18:1 (Detected range, 0.51–55.3 ng/mL; mean, 8.5; median, 3.1). In addition, all three PEth forms were variably identified in a majority (63%) of the oral fluid samples. The PEth 16:0/18:1 values in oral fluid showed a weak positive correlation with the corresponding values in whole blood samples (r=0.50, p=0.026, n=20).Conclusions:The LC-MS/MS method could reliably detect and quantify PEth in oral fluid samples collected after alcohol exposure. The method was characterized by validation data with satisfactory recovery, sensitivity, accuracy, and imprecision, and applied for analysis of clinical samples. The results suggest that measurement of PEth in oral fluid can be used as a biomarker for alcohol consumption, and as such a non-invasive complement to analysis in blood. However, further studies are required to evaluate the test characteristics (e.g. sensitivity and half-life) in comparison with PEth in blood.

scholarly journals Validation of method for the determination of bovine casein in milk and milk products

2018 ◽  
Vol 1 (1) ◽  
pp. 18-24
Author(s):  
Minh Hoa Nguyen Thi ◽  
Ha Binh Nguyen Thị ◽  
Son Tran Cao ◽  
◽  
◽  
...  
Keyword(s):  
Liquid Chromatography ◽  
High Performance ◽  
Sandwich Elisa ◽  
Food Supplement ◽  
Elisa Method ◽  
Chromatography Method ◽  
Validation Data ◽  
Liquid Chromatography Method ◽  
Labeling Requirements

Bovine caseins in dairy and dairy products were determined by high performance liquid chromatography (HPLC) with a PDA detector at 280 nm or by sandwich ELISA method. Liquid chromatography method was developed to determine different types of casein including alpha, beta, and kappa casein at high content (% level), which calculate the proportion of casein forms, thus allow the identification of milk sources (cow's milk, goat's milk). The ELISA method determines casein at low content (LOD was of 3mg/kg) which meets the labeling requirements of EU and Japan for food allergens. The validation data show that both methods fit the purpose with the recovery of 78-98% and the coefficient of variation is from 2.4 to 9.5%. The methods have been applied for the determination of casein content in 20 samples of milk, food supplement, cake and candy from Hanois' markets.

scholarly journals Candidate Reference Measurement Procedures for Serum 25-Hydroxyvitamin D3 and 25-Hydroxyvitamin D2 by Using Isotope-Dilution Liquid Chromatography–Tandem Mass Spectrometry

2011 ◽  
Vol 57 (3) ◽  
pp. 441-448 ◽  
Author(s):  
Hedwig CM Stepman ◽  
An Vanderroost ◽  
Katleen Van Uytfanghe ◽  
Linda M Thienpont
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Tandem Mass Spectrometry ◽  
Isotope Dilution ◽  
Tandem Mass ◽  
Limit Of Quantification ◽  
Validation Data ◽  
Reference Measurement ◽  
Chromatography Tandem Mass Spectrometry ◽  
Liquid Chromatography Tandem Mass

BACKGROUND 25-hydroxyvitamin D [25(OH)D] assays are characterized by poor between-assay comparability. This result emphasizes the need for reference measurement procedures (RMPs) to establish calibration traceability and assist in method validation. We aimed at developing candidate RMPs on the basis of isotope- dilution liquid chromatography–tandem mass spectrometry (ID-LC-MS/MS) for separate quantification of serum 25(OH)D2 and 25(OH)D3. METHODS Hexa-deuterated 25(OH)D3/D2 was added to serum. This mixture was extracted with n-hexane and fractionated on Sephadex LH-20 before 2-dimensional LC-MS/MS. In the first dimension, both procedures used a C4 column; however, in the second dimension, the 25(OH)D2 procedure used a C18 and the 25(OH)D3 procedure used a Zorbax SB-CN column. Calibration was traceable to the NIST Standard Reference Material (SRM) 2972. Validation comprised assessment of interference and limit of quantification/detection. Imprecision and trueness were validated by analysis of the SRM 972 against specifications (CV <5% and bias <1.7%). The expanded uncertainty for quadruplicate measurements was estimated. RESULTS Testing of potentially interfering substances was negative. Interference by 3-epi-25(OH)D3 was resolved by sufficient chromatographic resolution. The limits of quantification/detection were 1.1 nmol/L and 0.09 pmol/L for 25(OH)D3 and 1.2 nmol/L and 0.05 pmol/L for 25(OH)D2. Mean total CVs and differences from the SRM 972 target (± 1-sided 95% CI) were 2.1% and 1.1% ± 1.5% [25(OH)D3] and 3% and 1.3% ± 0.6% [25(OH)D2], respectively. The respective expanded uncertainties were 3.4% and 3.9%. CONCLUSIONS From the validation data, we conclude that we achieved our objective of 2 state-of-the-art candidate RMPs for serum 25(OH)D3 and 25(OH)D2.

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