scholarly journals Evaluación de la calidad de la medición de carbono total en suelo mediante ensayo de intercomparación.

2019 ◽  
Vol 37 (3) ◽  
pp. 273
Author(s):  
Armando Guerrero Peña ◽  
Aarón Jarquín Sánchez ◽  
Jorge D. Etchevers Barra ◽  
Irma J. González Acuña ◽  
Lorena Del Carmen Hernández Nataren ◽  
...  
Keyword(s):  
Quality Control ◽  
Reference Material ◽  
Quality Evaluation ◽  
Total Carbon ◽  
Internal Quality ◽  
Control Procedures ◽  
Repeatability And Reproducibility ◽  
Different Characteristics ◽  
Validity Of Tests ◽  
Conservation And Management

The Mexican regulation NMX-EC-17025-IMNC-2006, establishes that laboratories must have quality control procedures to monitor the validity of tests and calibrations, such monitoring must be planned and reviewed with: a) the regular use of certif ied reference materials or internal quality control of secondary references; b) participation in inter-laboratory comparisons or a prof iciency testing program; c) the repetition of tests or calibrations using the same method or different methods; d) the repetition of the test or the calibration of determined objects; e) the correlation of results for different characteristics of a reference material certif ied by MRC. The quality evaluation of results from the eight laboratories of the Laboratory Network for Analysis, Use, Conservation and Management of Soil (REDLABS) included the elements of sections a), b), c), and d) in order to verify the hypothesis that laboratories emit repeatable, reproducible and unbiased results. In our study, elemental analyzers of different brands were used to measure the total carbon of soil. A certif ied reference material was included in the Inter-comparison Practice. Repeatability and reproducibility of the carbon analyzes were evaluated with samples from the inter-comparison practice; the precision of analyzes from each laboratory was qualif ied with MRC. The results obtained indicate that the laboratories show repeatability in their analyzes with no statistical differences, i.e. reproducibility is detected by inter-comparison. The data issued by the laboratories were unbiased according to their evaluation with certif ied reference material.

Determination of Nitrogen Content in Milk by the Kjeldahl Method Using Copper Sulfate: Interlaboratory Study

1988 ◽  
Vol 71 (5) ◽  
pp. 893-898 ◽  
Author(s):  
R Grappin ◽  
William Horwitz
Keyword(s):  
Quality Control ◽  
Nitrogen Content ◽  
Copper Sulfate ◽  
Interlaboratory Study ◽  
Internal Quality ◽  
Relative Standard ◽  
Nitrogen Concentrations ◽  
Kjeldahl Method ◽  
Repeatability And Reproducibility

Abstract Copper sulfate was substituted for mercury as the catalyst in the International Dairy Federation (IDF) Standard 20A:1986 method for the determination of nitrogen content in milk. The substitution was supported by results obtained in an interlaboratory study by 24 laboratories in 12 countries. Each laboratory analyzed 12 test samples of milk as blind duplicates in a double split level design with high, medium, and low nitrogen concentrations. The method protocol requires the concurrent analyses of an ammonium salt solution and a tryptophan solution as internal quality control standards with a minimum nitrogen recovery between 99 and 100% for the former and at least 98% for the latter. The repeatability and reproducibility relative standard deviations are 0.5 and 1%, respectively, for the range 0.35-0.70 g N/100 g. The performance of the laboratories that did not meet the required quality control specifications was clearly poorer than that of those that did meet the specifications.

scholarly journals Assessing the internal consistency of the CARINA data base in the Pacific sector of the Southern Ocean

2010 ◽  
Vol 2 (2) ◽  
pp. 195-204 ◽  
Author(s):  
C. L. Sabine ◽  
M. Hoppema ◽  
R. M. Key ◽  
B. Tilbrook ◽  
S. van Heuven ◽  
...  
Keyword(s):  
Quality Control ◽  
Southern Ocean ◽  
Data Base ◽  
Total Carbon ◽  
Total Alkalinity ◽  
Geochemical Data ◽  
Data Set ◽  
The Pacific ◽  
Crossover Analysis ◽  
Control Procedures

Abstract. The CARINA project is aimed at gathering and providing secondary quality control checks on carbon and carbon-relevant hydrographic and geochemical data from cruises all across the Atlantic, Arctic and Southern Ocean. In total the project gathered 188 cruises that were not previously available to the public. Of these 188 cruises, 37 are part of the Southern Ocean. Parameters from the Southern Ocean cruises, including total carbon dioxide (TCO2), total alkalinity, oxygen, nitrate, phosphate and silicate, were examined for cruise-to-cruise consistency. pH and chlorofluorocarbons (CFCs) are also part of the data base, but are not discussed here. This paper focuses on the quality control of the Southern Ocean data from the Pacific sector which consisted of 29 cruises of which 17 were included in a previous synthesis called GLODAP, 11 were new cruises from the CARINA dataset, and one cruise was included in GLODAP but was updated with new data and therefore also included in CARINA. The Pacific sector quality control procedures included crossover analysis between stations and inversion analysis of all crossover data. The GLODAP data were included into the analysis as reference cruises but without applying the GLODAP recommended adjustments so the corrections could be independently verified. The outcome of this effort is an internally consistent, high-quality carbon data set for all cruises, including the reference cruises.

scholarly journals Repeatability and reproducibility assessment in a large-scale population-based microbiota study: case study on human milk microbiota

2020 ◽  
Author(s):  
Shirin Moossavi ◽  
Kelsey Fehr ◽  
Theo J. Moraes ◽  
Ehsan Khafipour ◽  
Meghan B. Azad
Keyword(s):  
Quality Control ◽  
Data Structure ◽  
Large Scale ◽  
Population Based ◽  
Microbiome Composition ◽  
Scale Population ◽  
Microbiome Research ◽  
Control Procedures ◽  
Repeatability And Reproducibility ◽  
Downstream Analysis

AbstractBackgroundQuality control including assessment of batch variabilities and confirmation of repeatability and reproducibility are integral component of high throughput omics studies including microbiome research. Batch effects can mask true biological results and/or result in irreproducible conclusions and interpretations. Low biomass samples in microbiome research are prone to reagent contamination; yet, quality control procedures for low biomass samples in large-scale microbiome studies are not well established.ResultsIn this study we have proposed a framework for an in-depth step-by-step approach to address this gap. The framework consists of three independent stages: 1) verification of sequencing accuracy by assessing technical repeatability and reproducibility of the results using mock communities and biological controls; 2) contaminant removal and batch variability correction by applying a two-tier strategy using statistical algorithms (e.g. decontam) followed by comparison of the data structure between batches; and 3) corroborating the repeatability and reproducibility of microbiome composition and downstream statistical analysis. Using this approach on the milk microbiota data from the CHILD Cohort generated in two batches (extracted and sequenced in 2016 and 2019), we were able to identify potential reagent contaminants that were missed with standard algorithms, and substantially reduce contaminant-induced batch variability. Additionally, we confirmed the repeatability and reproducibility of our reslults in each batch before merging them for downstream analysis.ConclusionThis study provides important insight to advance quality control efforts in low biomass microbiome research. Within-study quality control that takes advantage of the data structure (i.e. differential prevalence of contaminants between batches) would enhance the overall reliability and reproducibility of research in this field.

scholarly journals Procedure of matter identification of reference material for composition of azithromycin with use of spectral method

2021 ◽  
Vol 17 (3) ◽  
pp. 21-34
Author(s):  
V. I. Gegechkori ◽  
N. A. Shulga ◽  
O. Iu. Shchepochkina ◽  
N. V. Gorokhovets ◽  
A. A. Levko ◽  
...  
Keyword(s):  
Quality Control ◽  
Reference Material ◽  
Quantitative Determination ◽  
Spectral Method ◽  
Russian Federation ◽  
Medicinal Products ◽  
Control Procedures ◽  
Physicochemical Methods ◽  
The Russian Federation ◽  
Reliable Methods

In new medicinal products development, as well as actualisation of assessment approaches of medicinal products in circulation, the development of quality control procedures remains one of the most important issues in standardisation. Besides, such development should include using reliable, accurate and sensitive physicochemical methods which determine the need development and implementation of reference materials. This paper discusses the development of reliable methods for identifying the structure of azithromycin, which will guarantee the purity of the reference material, as well as adequately and unambiguously choose a method of quantitative determination in accordance with the current requirements of regulatory acts, and according to the Pharmacopoeia of the Russian Federation of the XIV Edition. 

scholarly journals Assessing the internal consistency of the CARINA data base in the Pacific sector of the Southern Ocean

2009 ◽  
Vol 2 (1) ◽  
pp. 555-578 ◽  
Author(s):  
C. L. Sabine ◽  
M. Hoppema ◽  
R. M. Key ◽  
B. Tilbrook ◽  
S. van Heuven ◽  
...  
Keyword(s):  
Quality Control ◽  
Southern Ocean ◽  
Data Base ◽  
Total Carbon ◽  
Total Alkalinity ◽  
Geochemical Data ◽  
Data Set ◽  
The Pacific ◽  
Crossover Analysis ◽  
Control Procedures

Abstract. The CARINA project is aimed at gathering and providing secondary quality control checks on carbon and carbon-relevant hydrographic and geochemical data from cruises all across the Atlantic, Arctic and Southern Ocean. In total the project gathered 188 cruises that were not previously available to the public. Of these 188 cruises, 37 are part of the Southern Ocean. Parameters from the Southern Ocean cruises, including total carbon dioxide (TCO2), total alkalinity, oxygen, nitrate, phosphate and silicate, were examined for cruise-to-cruise consistency. pH and chlorofluorocarbons (CFCs) are also part of the data base, but are not discussed here. This paper focuses on the quality control of the Southern Ocean data from the Pacific sector which consisted of 29 cruises of which 17 were included in a previous synthesis called GLODAP, 11 were new cruises from the CARINA dataset, and one cruise was included in GLODAP but was updated with new data and therefore also included in CARINA. The Pacific sector quality control procedures included crossover analysis between stations and inversion analysis of all crossover data. The GLODAP data were included into the analysis as reference cruises but without applying the GLODAP recommended adjustments so the corrections could be independently verified. The outcome of this effort is an internally consistent, high-quality carbon data set for all cruises, including the reference cruises.

scholarly journals Repeatability and reproducibility assessment in a large-scale population-based microbiota study: case study on human milk microbiota

Microbiome ◽  
2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Shirin Moossavi ◽  
Kelsey Fehr ◽  
Ehsan Khafipour ◽  
Meghan B. Azad
Keyword(s):  
Quality Control ◽  
Data Structure ◽  
Large Scale ◽  
Population Based ◽  
Microbiome Composition ◽  
Scale Population ◽  
Microbiome Research ◽  
Control Procedures ◽  
Repeatability And Reproducibility ◽  
Downstream Analysis

Abstract Background Quality control including assessment of batch variabilities and confirmation of repeatability and reproducibility are integral component of high throughput omics studies including microbiome research. Batch effects can mask true biological results and/or result in irreproducible conclusions and interpretations. Low biomass samples in microbiome research are prone to reagent contamination; yet, quality control procedures for low biomass samples in large-scale microbiome studies are not well established. Results In this study, we have proposed a framework for an in-depth step-by-step approach to address this gap. The framework consists of three independent stages: (1) verification of sequencing accuracy by assessing technical repeatability and reproducibility of the results using mock communities and biological controls; (2) contaminant removal and batch variability correction by applying a two-tier strategy using statistical algorithms (e.g. decontam) followed by comparison of the data structure between batches; and (3) corroborating the repeatability and reproducibility of microbiome composition and downstream statistical analysis. Using this approach on the milk microbiota data from the CHILD Cohort generated in two batches (extracted and sequenced in 2016 and 2019), we were able to identify potential reagent contaminants that were missed with standard algorithms and substantially reduce contaminant-induced batch variability. Additionally, we confirmed the repeatability and reproducibility of our results in each batch before merging them for downstream analysis. Conclusion This study provides important insight to advance quality control efforts in low biomass microbiome research. Within-study quality control that takes advantage of the data structure (i.e. differential prevalence of contaminants between batches) would enhance the overall reliability and reproducibility of research in this field.

scholarly journals Study on the production of Reference Material (RM) for Vitamin B1, B2, B6 in health supplements

2021 ◽  
Vol 4 (4) ◽  
pp. 307-314
Author(s):  
Hang Nguyen Thi ◽  
Phuong Thao Le Thi ◽  
Huu Cuong Dang ◽  
Huyen Trang Luu Thi ◽  
Hong Hao Le Thi ◽  
...  
Keyword(s):  
Quality Control ◽  
Reference Material ◽  
Reference Materials ◽  
Vitamin B1 ◽  
Assessment Method ◽  
Internal Quality ◽  
Standard Samples ◽  
Mandatory Requirement ◽  
The Cost ◽  
Health Supplements

Vitamins are essential nutrients commonly found in food products in general and health supplements in particular. In order to accurately evaluate product quality, laboratories need to use reference material in analysis, proficiency assessment, method validation and ensure the validity of the results. The use of reference materials plays an important role in the quality control of test results and is a mandatory requirement for laboratories wishing to demonstrate appropriate competence as required by ISO/IEC 17025:2017. The need to provide reference materials for laboratories is huge. However, at present, there are very few domestic organizations that can produce reference materials, while the cost of buying reference materials from reputable firms in the world is expensive. In this study, we introduced the procedure and production reference materials for the analysis of B-group vitamins (B1, B2, B6). These reference materials were evaluated for homogeneity and stability in 322 days. The certified values are consistent with the concentrations of substances present in normal samples in practice. The measurement uncertainty ranges from 14.5 - 23.3 %. The reference materials can be used for internal quality control for domestic laboratories and is also a premise for further research on standard samples with different matrix and analytical criteria.

scholarly journals UNCERTAINTY ASSESSMENT AND QUALITY CONTROL FOR ENVIROMENTAL MEASUREMENTS OF TRITIUM IN WATER SAMPLES

2017 ◽  
Vol 44 (4) ◽  
pp. 53
Author(s):  
Marija Lekić ◽  
Nevena Zdjelarević ◽  
Dalibor Arbutina ◽  
Nataša Lazarević
Keyword(s):  
Quality Control ◽  
Scintillation Counter ◽  
Accurate Determination ◽  
Uncertainty Assessment ◽  
Internal Quality ◽  
Tritium Concentration ◽  
Monthly Precipitation ◽  
Precipitation Sample ◽  
Control Procedures

The main aim of this paper was to evaluate uncertainty for low level tritium measurements in monthly precipitation collected at PC NFS site and to clarify quality control procedures which provide reasonable assurance that the analytic results obtained are valid and accurate. Determination of tritium concentration in precipitation sample was conducted using liquid scintillation counter Quantulus 1220. The most important sources of uncertainty are discussed. Four different internal quality control methods have been presented and explained in detail.

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