Method Performance Characteristics

2014 ◽  
pp. 73-190
Author(s):  
Joachim Ermer
Keyword(s):  
Performance Characteristics ◽  
Method Performance

Performance Characteristics of refined LC-FLD and HILIC-MS/MS methods for the Determination of Paralytic Shellfish Toxins in Shrimp, Whelk and Crab

2021 ◽  
Author(s):  
Karl J Dean ◽  
Robert G Hatfield ◽  
Andrew D Turner
Keyword(s):  
Performance Characteristics ◽  
Performance Criteria ◽  
Detection Methods ◽  
Official Method ◽  
Method Performance ◽  
Toxin Detection ◽  
Extraction Protocol ◽  
Paralytic Shellfish Toxins ◽  
Paralytic Shellfish ◽  
Bivalve Shellfish

Abstract Background PSP toxins have been reported in non-bivalve shellfish species, including crustaceans and gastropods. Routine surveillance of these species is currently conducted in parts of England. To date detection methods have not been validated for these matrices. Validation is required to ensure the test is fit for purpose, to give greater confidence in any results generated and ultimately facilitates accreditation. Objective The aim was to test and validate two independent PSP toxin detection methods previously validated for bivalve shellfish matrices, for applicability to commercial non-bivalve species of interest. Methods Matrices were shrimp (Crangon crangon), common whelk (Buccinum undatum) and edible crab (Cancer pagurus). The two methods assessed were the pre-column oxidation LC-FLD AOAC 2005.06 Official Method of analysis and an internationally validated HILIC-MS/MS method. Brown and white crab meat were assessed separately. Results A refined extraction protocol was implemented with an increased solvent to sample ratio. The same extraction protocol was utilized for both methods, allowing both methods to be run simultaneously. Method sensitivity, recovery, repeatability, and method uncertainty were characterized in all matrix/toxin combinations. Overall, both methods performed similarly to that previously reported in bivalve molluscs. Acceptability of the majority of toxin/matrix combinations was evidenced through comparison of method performance characteristics against specific performance criteria, including Horwitz ratio values. Conclusions Both PSP toxin detection methods were found to provide acceptable performance for the monitoring of shrimp, whelk and crab species. Highlights Two PSP toxin detection methods have been single-laboratory validated successfully for three non-bivalve shellfish species.

Assessment of Analytical Method Performance Characteristics : Systematic Error

1977 ◽  
Vol 60 (4) ◽  
pp. 940-945
Author(s):  
Thomas J Dols ◽  
Bernard H Armbrecht
Keyword(s):  
Systematic Error ◽  
Analytical Method ◽  
Performance Characteristic ◽  
Analytical Methods ◽  
Performance Characteristics ◽  
Method Performance

Abstract A random review of the analytical literature shows the need to define more clearly the terms for techniques that are used to assess the merits of analytical methods for a particular purpose. One such performance characteristic is the systematic error or bias of a method. This term is defined and contrasted with other terms commonly used in method assessment. Components of the systematic error are described and techniques are given for their measurement.

Determination of Dissolved Bromate in Drinking Water by Ion Chromatography and Post Column Reaction: Interlaboratory Study

2011 ◽  
Vol 94 (5) ◽  
pp. 1592-1600 ◽  
Author(s):  
Fernando Cordeiro ◽  
Piotr Robouch ◽  
Maria Beatriz de la Calle ◽  
Håkan Emteborg ◽  
Jean Charoud-Got ◽  
...  
Keyword(s):  
Drinking Water ◽  
Ion Chromatography ◽  
Standard Method ◽  
Collaborative Study ◽  
Swimming Pool ◽  
Performance Characteristics ◽  
Method Performance ◽  
Pool Water ◽  
Swimming Pool Water

Abstract A collaborative study, International Evaluation Measurement Programme®-25a, was conducted in accordance with international protocols to determine the performance characteristics of an analytical method for the determination of dissolved bromate in drinking water. The method should fulfill the analytical requirements of Council Directive 98/83/EC (referred to in this work as the Drinking Water Directive; DWD). The new draft standard method under investigation is based on ion chromatography followed by post-column reaction and UV detection. The collaborating laboratories used the Draft International Organization for Standardization (ISO)/Draft International Standard (DIS) 11206 document. The existing standard method (ISO 15061:2001) is based on ion chromatography using suppressed conductivity detection, in which a preconcentration step may be required for the determination of bromate concentrations as low as 3 to 5 μg/L. The new method includes a dilution step that reduces the matrix effects, thus allowing the determination of bromate concentrations down to 0.5 μg/L. Furthermore, the method aims to minimize any potential interference of chlorite ions. The collaborative study investigated different types of drinking water, such as soft, hard, and mineral water. Other types of water, such as raw water (untreated), swimming pool water, a blank (named river water), and a bromate standard solution, were included as test samples. All test matrixes except the swimming pool water were spiked with high-purity potassium bromate to obtain bromate concentrations ranging from 1.67 to 10.0 μg/L. Swimming pool water was not spiked, as this water was incurred with bromate. Test samples were dispatched to 17 laboratories from nine different countries. Sixteen participants reported results. The repeatability RSD (RSDr) ranged from 1.2 to 4.1%, while the reproducibility RSD (RSDR) ranged from 2.3 to 5.9%. These precision characteristics compare favorably with those of ISO 15601. A thorough comparison of the performance characteristics is presented in this report. All method performance characteristics obtained in the frame of this collaborative study indicate that the draft ISO/DIS 11206 standard method meets the requirements set down by the DWD. It can, therefore, be considered to fit its intended analytical purpose.

scholarly journals Speciation analysis of organoarsenic species in marine samples: method optimization using fractional factorial design and method validation

2021 ◽  
Author(s):  
Jojo Tibon ◽  
Marta Silva ◽  
Jens J. Sloth ◽  
Heidi Amlund ◽  
Veronika Sele
Keyword(s):  
Cation Exchange ◽  
Factorial Design ◽  
Fractional Factorial Design ◽  
Speciation Analysis ◽  
Fractional Factorial ◽  
Performance Characteristics ◽  
Sample Weight ◽  
Method Performance ◽  
As Species ◽  
Icp Ms

AbstractOrganoarsenic species in marine matrices have been studied for many years but knowledge gaps still exist. Most literature focuses on monitoring of arsenic (As) species using previously published methods based on anion- and cation-exchange high-performance liquid chromatography-inductively coupled plasma mass spectrometry (HPLC-ICP-MS). These studies are often limited to few As species and/or only specific method performance characteristics are described. Most marine certified reference materials (CRMs) are only certified for arsenobetaine (AB) and dimethylarsinate (DMA), making it difficult to evaluate the accuracy of analytical methods for other organoarsenic species. To address these gaps, the main objective of this work was to develop and validate a method for speciation analysis of a broad range of organoarsenic species in marine matrices. Optimum extraction conditions were identified through a 27–3 fractional factorial design using blue mussel as test sample. The effects of sample weight, type and volume of extraction solution, addition of H2O2 to the extraction solution, extraction time and temperature, and use of ultrasonication were investigated. The highest As recoveries were obtained by using 0.2 g as sample weight, 5 mL of aqueous methanol (MeOH:H2O, 50% v/v) as extractant, extraction carried out at 90 °C for 30 min, and without ultrasonication. Anion- and cation-exchange HPLC-ICP-MS settings were subsequently optimized. The method detected a total of 33 known and unknown As species within a run time of 23 and 20 min for cation-exchange and anion-exchange, respectively. A single-laboratory validation was conducted using several marine CRMs: BCR 627 (tuna fish tissue), ERM-CE278k (mussel tissue), DORM-4 (fish protein), DOLT-5 (dogfish liver), SQID-1 (cuttlefish), TORT-3 (lobster hepatopancreas), and CRM 7405-b (hijiki seaweed). Method performance characteristics were evaluated based on selectivity, limits of detection and quantification, linearity, trueness, precision, and measurement uncertainty. This work proposes an extraction procedure which allowed satisfactory quantification of As species with low solvent and energy consumption, supporting “Green Chemistry” principles. The study also presents a new set of As speciation data, including methylated arsenic species and arsenosugars, in recently issued marine CRMs, which will be valuable for future speciation studies on As. This work is the first to report a total of 33 different As species in marine CRMs. Graphical abstract

Analytical goals developed from the inherent error of medical tests

1993 ◽  
Vol 39 (7) ◽  
pp. 1481-1494 ◽  
Author(s):  
J W Ross ◽  
M D Fraser
Keyword(s):  
Process Control ◽  
Total Error ◽  
Performance Characteristics ◽  
Medical Decision ◽  
Clinical Test ◽  
Diagnostic Efficiency ◽  
Method Performance ◽  
Analytical Error ◽  
Medical Tests ◽  
Analytical Goals

Abstract Biological variation is inherent in all medical tests and is a major source of error in clinical test interpretation. We use inherent test error due to biological variability as the touchstone by which to validate the clinical acceptability of analytical goals. Analytical goals should consist of sets of complementary limits for total error, bias, and imprecision and a medical usefulness criterion (MUC) to ensure that the total error goal is met with stated certainty. We propose analytical goals that are limits for the total error of a measurement system, the joint capability of the process control procedures and the measurement process. Thus, the goals are the allowable analytical error for proficiency evaluation, internal process control, and the total error budget for design of method performance characteristics. We define MUC as the allowable maximum proportion of test diagnostic efficiency lost due to analytical error near medical decision points. MUCs < 0.03 are not routinely clinically useful; MUCs > 0.08 allow method performance characteristics that are undesirable for general clinical use. Using MUC = 0.05 and recommendations that imprecision not exceed one-half of the biological CV, we propose that fixed bias should not exceed one-fourth to one-third of the intraindividual biological CV of the analyte and that total analytical error should not exceed 1.25 to 1.40 times the biological CV. Modification of these analytical goals may arise for reasons of documented clinical practice or process stability. Our model quantifies in medical utility terms the results of such modifications.

scholarly journals Determination of Total Fat in Milk- and Soy-Based Infant Formula Powder by Supercritical Fluid Extraction: PVM 2:2002

2003 ◽  
Vol 86 (1) ◽  
pp. 86-95 ◽  
Author(s):  
Denis E LaCroix ◽  
Wayne R Wolf ◽  
Denis E LaCroix ◽  
Wayne R Wolf ◽  
Leslie J D Myer ◽  
...  
Keyword(s):  
Reference Material ◽  
Supercritical Fluid Extraction ◽  
Infant Formula ◽  
Supercritical Fluid ◽  
Performance Characteristics ◽  
Fluid Extraction ◽  
Method Performance ◽  
Relative Standard ◽  
Total Fat

Abstract Commercially available simple benchtop systems using CO2 supercritical fluid extraction (SFE) eliminate expensive organic solvent disposal problems and offer potential to meet a demand for rapid, accurate high-volume gravimetric determinations of total fat content of infant formula powders. A Data Quality Objectives (DQOs) approach was used to evaluate the performance characteristics of instrumental SFE extraction for determination of total gravimetric fat in infant formula. The established DQOs included the following: Accuracy.—Correct values were obtained for a suitable reference material, SRM 1846 Infant Formula [National Institute of Standards and Technology (NIST), Gaithersburg, MD]. Ruggedness.—Variables were defined as (1) extraction time (35 min optimum); (2) ratio of sample size to diatomaceous earth support material (1 g sample/2 g support); (3) ratio of distilled water to alcohol (50% isopropanol optimum for both milk- and soy-based infant formula samples); (4) extraction flow rate was 3–3.5 mL/min optimum. Precision.—Relative standard deviations of multiple determinations fell within the Horwitz limits of acceptability of ≤2.8% at the level of analyte determined (0.34–2.5% obtained). Scope of applicability.—Includes milk- and soy-based infant formula powders. Research data were obtained by use of a commercially available fat analyzer. Samples of the SRM, 2 commercial milk-based and 3 commercial soy-based infant formula products were distributed to 2 additional collaborating laboratories. Very good agreement was obtained among the submitting and collaborating laboratories for these samples. The use of clearly defined DQOs to establish method performance characteristics, along with the commercially available reference material, provided the mechanism for verification and validation of analytical methodology.

scholarly journals Determination of Bisphenol A (BPA) in Commercially Packaged Ready-to-Consume Carbonated and Noncarbonated Water and Nonalcoholic Beverages: A Single-Laboratory Validation Study, First Action 2017.15

2019 ◽  
Vol 102 (2) ◽  
pp. 605-611 ◽  
Author(s):  
Siheng Li ◽  
Jeffrey Shippar ◽  
Katerina Mastovska
Keyword(s):  
Bisphenol A ◽  
Internal Standard ◽  
Performance Characteristics ◽  
Official Method ◽  
Intermediate Precision ◽  
Method Performance ◽  
Negative Ionization ◽  
Nonalcoholic Beverages ◽  
Concentration Levels

Abstract Background: Bisphenol A (BPA) is an endocrine-disrupting compound that could migrate to beverages from packaging materials. AOAC INTERNATIONAL issued a call for methods for determination of free BPA in beverages based on the AOAC Standard Method Performance Requirement (SMPR®) 2017.018. Objective: The objective of the single-laboratoryvalidation (SLV) study was to validate a method forthe analysis of BPA in relevant beverages and evaluate its performance characteristics against the AOAC SMPR 2017.18. Methods: The analytical method involves extraction of a beverage sample (10 mL) using 10 mL 1% acetic acid in acetonitrile after the addition of isotopically labeled internal standard. Sodium chloride is added to salt out BPA into the acetonitrile phase. After centrifugation, a freeze-out step is used to remove coextracted lipids. An aliquot of the supernatant upper layer is then analyzed using high-pressure LC coupled to tandem mass spectrometry in electrospray negative ionization mode. Results: Accuracy, repeatability, and intermediate precision were determined by spiking 10 representative nonalcoholic beverage matrixes at three concentration levels. Individual percent recoveries ranged between 76.5 and 113.2%, 86.2 and 114.8%, and 90.9 and 109.3% for thespike levels of 0.3, 1.5, and 20 μg/L, respectively. The repeatability and intermediate precision results were in the range of 0.2–11.3% and 1.8–11.1%, respectively. The LOD was estimated at ≤0.1 μg/L and LOQ was validated at 0.3 μg/L. Conclusions: The validated method performance characteristics met the requirements stated in the AOAC SMPR 2017.018. This method was approved AOAC First Action Official MethodsSM 2017.15.Highlights: SLV study evaluating free BPA at three concentration levels (0.3, 1.5, and 20 μg/L) in 10 types of commercially packaged nonalcoholic beverages (as recommended for themethod validation in the AOAC SMPR 2017.018). Validated method performance characteristics (LOD, LOQ, analytical range, accuracy, and precision) met the AOAC SMPR 2017.018. Method approved as the AOAC First Action Official Method 2017.15.

Performance characteristics of two-lobe pressure dam bearings with micropolar lubrication

2018 ◽  
Vol 233 (5) ◽  
pp. 805-819 ◽  
Author(s):  
Sanyam Sharma ◽  
Rajeev Verma
Keyword(s):  
High Speed ◽  
Reynolds Equation ◽  
Critical Mass ◽  
Detailed Comparison ◽  
Performance Characteristics ◽  
The Finite Element Method ◽  
Method Performance ◽  
Oil Whirl ◽  
Coupling Number ◽  
Micropolar Lubrication

A circular bearing experiences the instability problem due to oil whirl, causing violent vibrations at high speed. Two-lobe pressure dam bearing is a solution to the instability arising in high-speed rotating machineries. The paper presents the various static and dynamic characteristics of two-lobe pressure dam bearings, while operating with micropolar fluid. The modified Reynolds equation used to model the lubrication is solved using the finite element method. Performance characteristics such as load, attitude angle, critical mass, threshold speed and whirl frequency are computed, presented graphically and analysed. A detailed comparison of the performance characteristics is done for various micropolar and dam parameters. It is concluded that bearing performance is significantly influenced by dam parameters (dam angles) and micropolar parameters (coupling number and characteristics length).

Performance Characteristics of Methods of Analysis Used for Regulatory Purposes.Part II. Pesticide Formulations

1991 ◽  
Vol 74 (5) ◽  
pp. 718-744 ◽  
Author(s):  
William Horwttz ◽  
Richard Albert
Keyword(s):  
Performance Characteristics ◽  
International Union ◽  
Method Performance ◽  
Applied Chemistry ◽  
The Past ◽  
Chromatographic Methods ◽  
Decimal Fraction ◽  
Collaborative Studies ◽  
Pesticide Formulations ◽  
Relative Standard

Abstract The precision parameters of the method-performance (collaborative) studies published In the AOAC Journal from 1915 through 1990 for pesticide formulations have been recalculated on a uniform basis by the International Union of Pure and Applied Chemistry 1987 protocol. About 93% of the 953 accepted assays, which are predominantly gravimetric (G), volumetric (V), and gas (GC) and liquid (LC) chromatographic methods, exhibit relative standard deviations among laboratories (RSDR) that are generally less than 2 times the values predicted from the Horwitz equation: RSDR (%) = 2 exp (1 - 0.5 log C), where C is the concentration expressed as a decimal fraction. UV, VIS, and IR spectrophotometrlc (S) methods are somewhat poorer, with about 80% of the reported RSDR values less than twice the predicted RSDR value. The precision parameters of pesticide formulations analyzed by the older methods (G, V, GC) are equivalent to those previously found for drug preparations in the same concentration range; the precision parameters of pesticide formulations analyzed by LC and S are somewhat poorer. Overall, however, the precision parameters of pesticide formulations are generally independent of analyte, method, and matrix, and are primarily a function of concentration. The method-acceptability decisions of the AOAC for pesticide formulations during the past 75 years can be approximated retrospectively by using a criterion for RSDR that is less than 2 times the RSDR calculated from the Horwitz equation.

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