A Drift Correction Procedure

Salit, Marc; Turk, Gregory C.

doi:10.1021/ac980095b

Cited by 65 publications

(51 citation statements)

References 8 publications

(8 reference statements)

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“…It is well-known that highly element-specific and reproducible ICP/OES analysis combined with rigorous drift correction permits the determination of major inorganic constituents in solution with relative expanded uncertainty down to 0.1%. [20][21] Therefore, the content of major element can be determined accurately if quantitative recovery of the element is guaranteed. 22 The total Sn content in the standard DBT material was 0.3832 g/ g (as Sn) with relative standard uncertainty of around 1% as shown in the Table 3, which includes uncertainty component due to the sample inhomogeneity.…”

Section: Resultsmentioning

confidence: 99%

Determination of Dibutyltin in Sediments Using Isotope Dilution Liquid Chromatography-Inductively Coupled Plasma Mass Spectrometry

2005

Bulletin of the Korean Chemical Society

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A method is described for the determination of dibutyltin (DBT) in sediment by isotope dilution using liquid chromatography inductively-coupled plasma/mass spectrometry (LC-ICP/MS). To achieve the highest accuracy and precision, special attentions are paid in optimization and evaluation of overall processes of the analysis including extraction of analytes, characterization of the standards used for calibration and LC-ICP/MS conditions. An approach for characterization of natural abundance DBT standard has been developed by combining inductively-coupled plasma/optical emission spectrometry (ICP/OES) and LC-ICP/MS for the total Sn assay and the analysis of Sn species present as impurities, respectively. An excellent LC condition for separation of organotin species was found, which is suitable for simultaneous DBT and tributyltin (TBT) analysis as well as impurity analysis of DBT standards. Microwave extraction condition was also optimized for high efficiency while preventing species transformation. The present method determines the amount contents of DBT in sediments with expanded uncertainty of less than 5% and its result shows high degree of equivalence with reference values of an international inter-comparison and a certified reference material (CRM) within stated uncertainties.

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Section: Resultsmentioning

confidence: 99%

Determination of Dibutyltin in Sediments Using Isotope Dilution Liquid Chromatography-Inductively Coupled Plasma Mass Spectrometry

2005

Bulletin of the Korean Chemical Society

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“…Q ICP/MS typically shows about 5% drift of signal within couple of hours. To correct for the drift, Salit and Turk method 28 was applied. The advantage of this method was that no reference solutions were required but samples themselves served only to correct for the drift.…”

Section: Methodsmentioning

confidence: 99%

Errors in Isotope Dilution Caused by Matrix-induced Mass Bias Effect in Quadrupole Inductively Coupled Plasma-Mass Spectrometry

Pak¹

2014

Bulletin of the Korean Chemical Society

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Matrix-induced mass bias and its effect on the accuracy of isotope ratio measurements have been examined for a quadrupole-based inductively coupled plasma-mass spectrometer (Q ICP-MS). Matrix-induced mass bias effect was directly proportional to % mass difference, and its magnitude varied for element and nebulizer flow rate. For a given element and conditions in a day, the effect was consistent. The isotope ratio of Cd106/Cd114 under 200 µg g −1 U matrix deviated from the natural value significantly by 3.5%. When Cd 111 and Cd114 were used for the quantification of Cd with isotope dilution (ID) method, the average of differences between the calculated and measured concentrations was −0.034% for samples without matrix (0.076 µg g −1 to 0.21 µg g −1 for the period of 6 months). However, the error was as large as 1.5% for samples with 200 µg g −1 U. The error in ID caused by matrix could be larger when larger mass difference isotopes are used.

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“…Prediction is widely used, not only in physical etalons but in chemistry as well. In some cases the drifts are not considered as part of the measurand but as something that must be removed to get the "true" value of the measurand [5] (result of chemical analysis, in this case).…”

Section: Introductionmentioning

confidence: 99%

“…Also, we note that drift (referred to in [5] as low frequency noise) can be removed optimally by a low-degree polynomial only if the remaining "noise" is white. As the precision of chemical analysis improves with the advent of more accurate methods and instrumentation, we may expect that other types of instabilty are apparent and appropriate prediction methods should be used.…”

Section: Introductionmentioning

confidence: 99%

The metrology of unstable measurands

Lepek¹

1999

Accreditation and Quality Assurance

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Type A statistical uncertainty in measurements is usually derived from the standard deviation of the measured data. This is correct as long as the measurand is stable over time and has a meaningful constant value. In such a case the average measurement and the standard deviations are meaningful. However, as measurement methods are refined and become more precise, we can observe that a given measurand may be unstable and change with time and the uncertainty in measurement must be redefined. This is specifically true in the metrology of time which can be measured today more precisly than any other measurand. We argue that in such a case the uncertainty in the prediction of the next measurement should be used instead of the uncertainty in measurement. Both uncertainties coincide for a stable measurand. The prediction of the next measurement is achieved by means of predictors. In this paper we describe the application of linear predictors and especially optimum linear predictors to predict in the presence of various types of instability. To illustrate the issues we use clock instabilities and clock metrology as this field is most developed. A measurand can be unstable but still predictable and thus useful. This is well known in the case of white noise about a linear drift for which the optimum predictor is a linear regression. Since the deviations from prediction of optimum prediction are of white noise, we can now use simple statistics to estimate the uncertainty of the optimum or close to optimum prediction. In this paper we present the various optimum or close to optimum linear predictors optimized for different types of instability and estimate the associated prediction uncertainties.

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A Drift Correction Procedure

Cited by 65 publications

References 8 publications

Determination of Dibutyltin in Sediments Using Isotope Dilution Liquid Chromatography-Inductively Coupled Plasma Mass Spectrometry

Determination of Dibutyltin in Sediments Using Isotope Dilution Liquid Chromatography-Inductively Coupled Plasma Mass Spectrometry

Errors in Isotope Dilution Caused by Matrix-induced Mass Bias Effect in Quadrupole Inductively Coupled Plasma-Mass Spectrometry

The metrology of unstable measurands

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