Ermittlung, Auswertung und Ursachen von Fehlern bei Betriebsanalysen

Zitter, Herbert; God, Christiane

doi:10.1007/bf00423819

Cited by 24 publications

(10 citation statements)

References 3 publications

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“…Only a robustied t to a Zitter-God equation (item 7) remains generally applicable. 1 Zitter and God proposed their equation in a short paper that seems to have been the rst to explore the dependence of standard deviation on mass fraction or concentration but the topic was not followed up by the original authors. Since then it has been tested experimentally and shown to represent rather well precision information obtained at different mass fractions, under various conditions of measurement and in a diverse range of analytical application sectors.…”

Section: Summarising the Statisticsmentioning

confidence: 99%

Summarising the precision statistics from collaborative trials

No¹

2022

Anal. Methods

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Section: Summarising the Statisticsmentioning

confidence: 99%

Summarising the precision statistics from collaborative trials

No¹

2022

Anal. Methods

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“…The method employed for uncertainty estimation produces estimates of the standard uncertainty of an analyte concentration equal to the mean value (0.031 mg kg 21 for myclobutanil). Uncertainty is known to vary as a function of concentration, [9][10][11] and this is simply recognised here by expressing standard uncertainty estimates in a relative way as a percentage of the mean (u% in Table 1). From these Table 1 Estimates of uncertainty for sampling (u samp ), physical sample preparation (u prep ) and chemical analysis (u anal ) and the combined measurement uncertainty (u meas ) for the case study of myclobutanil in retail strawberries.…”

Section: Uncertainty Estimatesmentioning

confidence: 99%

Optimising uncertainty in physical sample preparation

Lyn

Damant

Wood

2005

Analyst

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Uncertainty associated with the result of a measurement can be dominated by the physical sample preparation stage of the measurement process. In view of this, the Optimised Uncertainty (OU) methodology has been further developed to allow the optimisation of the uncertainty from this source, in addition to that from the primary sampling and the subsequent chemical analysis. This new methodology for the optimisation of physical sample preparation uncertainty (u(prep), estimated as s(prep)) is applied for the first time, to a case study of myclobutanil in retail strawberries. An increase in expenditure (+7865%) on the preparatory process was advised in order to reduce the s(prep) by the 69% recommended. This reduction is desirable given the predicted overall saving, under optimised conditions, of 33,000 pounds Sterling per batch. This new methodology has been shown to provide guidance on the appropriate distribution of resources between the three principle stages of a measurement process, including physical sample preparation.

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“…9,30 Actually, this definition is based on the fact that the repeatability expressed as the RSD of the net signal increases when the concentration tends to the limit of detection. This is a general trend in analysis, [36][37][38][39][40] which has been studied with geological samples in ICP-AES 41 and modelled in the case of ICP spectrochemistry. [42][43][44] It may be demonstrated that the %RSD net is given by:…”

Section: Limit Of Detection and Limit Of Quantitationmentioning

confidence: 99%

Validation of the determination of lead in whole blood by ICP-MS

Bonnefoy¹,

Menudier²,

Mœsch³

et al. 2002

J. Anal. At. Spectrom.

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Validation of the determination of lead in whole blood by ICP-quadrupole MS has been performed. Blood was 1 : 45 v/v diluted in an aqueous solution containing 0.1 mg l 21 NH 4 OH, 0.1 g l 21 EDTA, 5 mg l 21 n-butanol and 0.1% Triton X 100. It was verified that a synthetic matrix made of 7.5 g l 21 NaCl and 0.5 g l 21 CaCl 2 behaved similarly to the whole blood and to QC samples. Limits of detection and of quantitation were determined by plotting the RSD of the net signal as a function of the concentration, and were 0.01 and 0.1 mg l 21 , respectively, which was below the lowest Pb concentration in blood, i.e., 0.2 mg l 21 after dilution. Uncertainty of the centroid of the calibration graph was preferred to the evaluation of the linearity with ANOVA to validate the calibration procedure. At 95% confidence level, a warning limit was set up at 5% uncertainty, while rejection was decided on for 20% uncertainty. Internal standardization based on the use of 187 Re provided improvement in the uncertainty and the reproducibility. Intra-and inter-day reproducibilities were evaluated. Good agreement was observed between the concentrations obtained by ICP-MS and GF-AAS.

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Ermittlung, Auswertung und Ursachen von Fehlern bei Betriebsanalysen

Cited by 24 publications

References 3 publications

Summarising the precision statistics from collaborative trials

Summarising the precision statistics from collaborative trials

Optimising uncertainty in physical sample preparation

Validation of the determination of lead in whole blood by ICP-MS

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