scholarly journals Method for Reproducible Shipboard Segmented Flow Analysis Ammonium Measurement Using an In-House Reference Material for Quality Control

2021 ◽  
Vol 8 ◽  
Author(s):  
Christine Rees ◽  
Julie Janssens ◽  
Kendall Sherrin ◽  
Peter Hughes ◽  
Stephen Tibben ◽  
...  
Keyword(s):  
Quality Control ◽  
Reference Material ◽  
Certified Reference Materials ◽  
Flow Analysis ◽  
Ammonium Concentration ◽  
Analysis Method ◽  
Segmented Flow ◽  
Short Term ◽  
Accuracy And Repeatability ◽  
Laminar Flow Cabinet

Ammonium is a fundamental nutrient for phytoplankton growth in seawater and is a key component of the microbial loop. Ammonium measured in parallel with other nutrients is crucial in understanding the small temporal scale changes in oceanographic ecology. Despite the importance of measuring ammonium at sea, owing to its lability, there is no consensus on the best method. The lack of availability of certified reference materials for ammonium in seawater also makes it difficult to assess the accuracy and reproducibility of ammonium measurements. In this study we present a modified segmented flow analysis method using ortho-phthaldialdehyde (OPA) with fluorescence detection to measure ammonium at sea together with four other macro-nutrients (nitrate, nitrite, silicate and phosphate) in near real time. An in-house ammonium quality control (QC) material was produced to improve the accuracy and repeatability of the measurement at sea. The QC was prepared following two different methods and stored in two types of containers. The suitability of the in-house QC’s as a reference material were assessed onboard the RV Investigator in 2018 during two oceanographic voyages, including one on the repeat SR03 CLIVAR transect. This paper describes the production and assessment of the in-house QC for ammonium in seawater, providing groundwork for creating a short-term stable ammonium reference material for sea going voyages. The uncertainty of this method of ammonium measurement was found to be 0.10 μmol/L at ammonium concentration of 1.0 μmol/L. Results show that preparation of the QC inside a laminar flow cabinet and directly into 10 mL polypropylene sample tubes just prior to the commencement of the voyage improved its stability.

Development and Certification of Formononetin Reference Material for Quality Control of Functional Foods and Botanical Supplements

2019 ◽  
Vol 15 (5) ◽  
pp. 553-559
Author(s):  
Ningbo Gong ◽  
Baoxi Zhang ◽  
Kun Hu ◽  
Zhaolin Gao ◽  
Guanhua Du ◽  
...  
Keyword(s):  
Quality Control ◽  
Reference Material ◽  
Functional Foods ◽  
Certified Reference Materials ◽  
Coulometric Titration ◽  
Pharmaceutical Formulations ◽  
Uncertainty Estimation ◽  
Expanded Uncertainty ◽  
Scanning Calorimetry ◽  
Botanical Supplements

Background: Formononetin is a common soy isoflavonoid that can be found abundantly in many natural plants. Previous studies have shown that formononetin possesses a variety of activities which can be applied for various medicinal purposes. Certified Reference Materials (CRMs) play a fundamental role in the food, traditional medicine and dietary supplement fields, and can be used for method validation, uncertainty estimation, as well as quality control. Methods: The purity of formononetin was determined by Differential Scanning Calorimetry (DSC), Coulometric Titration (CT) and Mass Balance (MB) methods. Results: This paper reports the sample preparation methodology, homogeneity and stability studies, value assignment, and uncertainty estimation of a new certified reference material of formononetin. DSC, CT and MB methods proved to be sufficiently reliable and accurate for the certification purpose. The purity of the formononetin CRM was therefore found to be 99.40% ± 0.24 % (k = 2) based on the combined value assignments and the expanded uncertainty. Conclusion: This CRM will be a reliable standard for the validation of the analytical methods and for quality assurance/quality control of formononetin and formononetin-related traditional herbs, food products, dietary supplements and pharmaceutical formulations.

Experience with Certified Reference Material Proficiency Testing for Quality Control of Wheat

1998 ◽  
Vol 6 (A) ◽  
pp. A53-A61
Author(s):  
Judit Budai ◽  
Judit Fükó
Keyword(s):  
Quality Control ◽  
Reference Material ◽  
Proficiency Testing ◽  
Reference Materials ◽  
Certified Reference Material ◽  
Certified Reference Materials ◽  
Long Term Stability ◽  
Determining Factors ◽  
Chemical Section

The Chemical Section of OMH1,2 embarked on the preparation of a series of wheat samples as Certified Reference Materials (CRMs) in 1992. The certification processes were carried out according to the recommendations of ISO. Since then we have developed a series of flour samples as well. The investigations of the long-term stability and the application of wheat and flour CRMs are continuous. Wheat is one of the most widely grown crops in Hungary and it is one of the major determining factors of the economy. Its uniform and objective qualification is of great importance. There are well-equipped laboratories available with sufficient experience but, as the proficiency testing regularly showed, certified samples need to be used to achieve exact and uniform measuring results.

Chromium powder as a reference material for the quality control of particle-size measurement by laser diffraction

2005 ◽  
Vol 155 (1) ◽  
pp. 85-91 ◽  
Author(s):  
N. Etxebarria ◽  
G. Arana ◽  
R. Antolín ◽  
E. Diez ◽  
G. Borge ◽  
...  
Keyword(s):  
Particle Size ◽  
Quality Control ◽  
Reference Material ◽  
Laser Diffraction ◽  
Size Measurement ◽  
Chromium Powder ◽  
Particle Size Measurement

scholarly journals On-line data splicing power flow analysis method based on sensitivity

2021 ◽  
Vol 7 ◽  
pp. 326-333
Author(s):  
Jun Lu ◽  
Lu Lu Zhang ◽  
Dong Yu Shi ◽  
Tie Li ◽  
Jun Ci Tang ◽  
...  
Keyword(s):  
Power Flow ◽  
Flow Analysis ◽  
Analysis Method ◽  
Power Flow Analysis ◽  
On Line

scholarly journals Development and certification of a reference material for zearalenone in maize germ oil

2021 ◽  
Author(s):  
Juliane Riedel ◽  
Sebastian Recknagel ◽  
Diana Sassenroth ◽  
Tatjana Mauch ◽  
Sabine Buttler ◽  
...  
Keyword(s):  
Reference Material ◽  
Reference Materials ◽  
Mass Fraction ◽  
High Performance ◽  
Certified Reference Materials ◽  
Maximum Level ◽  
Whole Process ◽  
Commission Regulation ◽  
Maize Oil ◽  
Maize Germ

AbstractZearalenone (ZEN), an estrogenic mycotoxin produced by several species of Fusarium fungi, is a common contaminant of cereal-based food worldwide. Due to frequent occurrences associated with high levels of ZEN, maize oil is a particular source of exposure. Although a European maximum level for ZEN in maize oil exists according to Commission Regulation (EC) No. 1126/2007 along with a newly developed international standard method for analysis, certified reference materials (CRM) are still not available. To overcome this lack, the first CRM for the determination of ZEN in contaminated maize germ oil (ERM®-BC715) was developed in the frame of a European Reference Materials (ERM®) project according to the requirements of ISO Guide 35. The whole process of CRM development including preparation, homogeneity and stability studies, and value assignment is presented. The assignment of the certified mass fraction was based upon an in-house study using high-performance liquid chromatography isotope dilution tandem mass spectrometry. Simultaneously, to support the in-house certification study, an interlaboratory comparison study was conducted with 13 expert laboratories using different analytical methods. The certified mass fraction and expanded uncertainty (k = 2) of ERM®-BC715 (362 ± 22) μg kg−1 ZEN are traceable to the SI. This reference material is intended for analytical quality control and contributes to the improvement of consumer protection and food safety. Graphical abstract

Development of Simultaneous Analysis Method for Multi-Compounds Content of New Shilajit Using HPLC-UV and the Cognitive Enhancing Effect: Mongolian Shilajit

2021 ◽  
Vol 16 (7) ◽  
pp. 1934578X2110304
Author(s):  
SukJin Lee ◽  
HyeSung Ryu ◽  
WanKyunn Whang
Keyword(s):  
Quality Control ◽  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
High Performance ◽  
High Resolution Mass Spectrometry ◽  
Radical Scavenging ◽  
Original Material ◽  
Analysis Method ◽  
Quality Control Standard ◽  
Quantitative Hplc Analysis

Shilajit has a longstanding use as an anti-aging and memory enhancing drug. It is known to have excellent anti-bacterial effects and is believed to be effective for cognitive enhancement, but is difficult to standardize because of the lack of quality control standards. This study, for the first time, proposes a quality control standard using a simultaneous analytical method for the drug’s multi-compound content using high-performance liquid chromatography-ultraviolet detection (HPLC-UV) as an aid for the internationalization of Mongolian Shilajit. Phenolic compounds 1-6 were isolated from Mongolian Shilajit extract using bioassay-guided isolation, and the isolated compounds were evaluated for cognitive-related anti-Alzheimer’s disease (AD) activities using 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical-scavenging, acetylcholinesterase (AChE), butyrylcholinesterase (BChE), β-site amyloid precursor protein-cleaving enzyme 1 (BACE1), and advanced glycation end-product (AGE) formation assays. The isolated compounds showed good effects for each activity. In addition, the isolated compounds were successfully quantified using a validated quantitative HPLC analysis method. As a result, the isolated compounds were suggested as standard marker compounds for Mongolian Shilajit. Also, we proved that the original material of Mongolian Shilajit is a lichen named Xanthoparmelia somloensis (Gyel.) Hale using HPLC-UV, ultra-high-performance liquid chromatography-electrospray ionization/hybrid linear trap-quadruple-orbitrap-high-resolution mass spectrometry (UHPLC-ESI/LTQ-HRMS).

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