Sampling variance in analysis for trace components in solids.  Preparation of reference samples

Harris, W. E.; Kratochvil, Byron

doi:10.1021/ac60338a017

Cited by 37 publications

(19 citation statements)

References 7 publications

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“…Then, they can use eq 3 to determine the number of particles required to produce a given theoretical relative standard deviation (RSD) as derived from the binomial distribution. 33 q np Theoretical RSD = (3) Using the results from eqs 2 and 3 and plugging them into eq 4, students can calculate the mass (m) of sample required to produce a given relative standard deviation. It is assumed that the particles are spherical and have a volume (v p ) of r 4 3 3 π .…”

Section: ■ Description Of the Activitymentioning

confidence: 99%

Implementation of a Python Program to Simulate Sampling

Dickson‐Karn

Orosz

2021

J. Chem. Educ.

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Proper sampling techniques are of the utmost importance in obtaining accurate and precise results in chemical analysis. A Python language computer simulation providing fast feedback on sampling concepts and statistics was delivered to students through Google Colab. Students used the simulation to aid in their exploration of sampling and sampling statistics and to answer questions in a guided learning activity. This activity was conducted in a virtual environment, but it could easily be used in an in-person setting. Students reported that the simulation was easy-to-use, effectively illustrated the concepts of sampling, and supported the stated learning objectives.

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Section: ■ Description Of the Activitymentioning

confidence: 99%

Implementation of a Python Program to Simulate Sampling

Dickson‐Karn

Orosz

2021

J. Chem. Educ.

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“…When a great number of individual particles are present in the subsample of a given mass, then it can be assumed that all such subsamples have the same average elemental composition. Using a very simplified model (Harris and Kratochvil 1973, Dybczyński et.al. 2000, Dybczyński et.al.…”

Section: Materials Homogeneity and Stability Studymentioning

confidence: 99%

Preparation of Three New Certified Reference Materials for Food and Environmental Analysis and Certification Using Laboratory Intercomparison as well as Primary Reference Measurement Procedures

et al. 2021

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Three new reference materials: MODAS-3 Herring Tissue (M-3 HerTis), MODAS-4 Cormorant Tissue (M-4 CormTis), and MODAS-5 Cod Tissue (M-5 CodTis) were prepared and certified on the basis of results of a worldwide intercomparison exercise. Independently of our proven method of establishing the certified and information values, the content of several essential and toxic elements was additionally determined by the use of ratio primary reference measurement procedures (definitive methods) based on radiochemical neutron activation analysis (RNAA) in the case of As, Cd, Co, Cr, Fe, Mo, Se, and U and isotope dilution mass spectrometry (IDMS) in the case of Hg, respectively. Good agreement of the established certified values and the results obtained by ratio primary reference measurement procedures confirmed the validity of the certification procedure. The total number of elements which could be certified amounted to 30, 21, 18 in M-3 HerTis, M-4 CormTis, and M-5 CodTis, respectively. The relative frequency of use of individual analytical techniques in this intercomparison campaign was calculated and discussed. Inductively coupled plasma mass spectrometry (ICP-MS) is now a dominant technique, followed by atomic absorption spectroscopy (AAS), NAA, and emission spectroscopy (ES). The decreasing share of NAA as compared to several earlier intercomparison exercises should be noticed. NAA is the only method in the array of highly sensitive methods of inorganic trace analysis, which is essentially free from blank. The lack of this method in the foreseeable future may be an obstacle in the prospective certification campaigns and may endanger the implementation of quality assurance in trace analysis.

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“…This may be quite relevant in routine NAA in which relatively small sample (few hundreds of mg) are used. From the studies of e.g., Kratochvil [ 15 ] it appears that larger sample sizes can be necessary to minimize sampling errors particularly when analysing geological or environmental samples. Therefore, development of systems for routine analysis of samples of intermediate size, i.e., 1–10 g, might be beneficial for the accuracy and, implicitly, for the applicability and future relevance of NAA.…”

Section: Development Application Metrologymentioning

confidence: 99%

Trendwatcher or trendsetter; 50 years of MTAA

Bruin

Bode

2011

J Radioanal Nucl Chem

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The development on neutron activation analysis (NAA) into a technique of practical interest effectively started about 60 years ago, when nuclear reactors became available and widely accessible as intense sources of neutrons. During 50 out these 60 years, the series of Modern Trends in Activation Analysis (MTAA) Conferences acted as a true companion and facilitator of this growth. As trendwatcher they signalized the many initiatives that contributed to the development of activation analysis and its applications. A period has come to an end of impressive development resulting from sometimes revolutionary changes in radiation detection and data processing, and much improved irradiation facilities, NAA has reached a full stage of development, with emphasis on routine application and with remaining developments of in marginal impact. NAA is being challenged increasingly in the last 30 years by alternative techniques for multi trace element analysis. The MTAA Conference and with it the ICAA, the International Committee on Activation Analysis, can play an important and active role in this process of identifying and selecting key areas, and even promoting concerted action in those areas. Such an evolution of focus from retrospective to prospective, from trendwatcher to trendsetter, may well allow the MTAA Conference to continue and even expand its role in future development of NAA and its applications. The ideas about the future of the MTAA Conferences and its organization are elaborated upon and some possible subjects for focused development activities are indicated.

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Sampling variance in analysis for trace components in solids. Preparation of reference samples

Cited by 37 publications

References 7 publications

Implementation of a Python Program to Simulate Sampling

Implementation of a Python Program to Simulate Sampling

Preparation of Three New Certified Reference Materials for Food and Environmental Analysis and Certification Using Laboratory Intercomparison as well as Primary Reference Measurement Procedures

Trendwatcher or trendsetter; 50 years of MTAA

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