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1.
The certification measurement for the cadmium concentration in the samples as performed by Isotope Dilution (ID) using Inductively
Coupled Plasma Mass Spectrometry (ICP-MS) is described in framework of the International Measurement Evaluation Programme
(IMEP). By using a primary method of measurement (ID), making up a full uncertainty budget and using a sensitive technique
(ICP-MS), reference values traceable to SI can be obtained for this material.
The uncertainty budget is performed in accordance with the ISO and EURACHEM guides on uncertainty. A comparison is made with
certification results of other experienced laboratories also using primary methods where possible.
Received: 8 July 1996/Revised 26 August 1996/Accepted: 1 September 1996 相似文献
2.
Lead (Pb) and cadmium (Cd) have been determined in six new environmental standard reference materials (SRMs) using isotope dilution inductively coupled plasma mass spectrometry (ID ICP-MS). The SRMs are the following: SRM 1944, New York-New Jersey Waterway Sediment, SRMs 2583 and 2584, Trace Elements in Indoor Dust, Nominal 90 mg/kg and 10,000 mg/kg Lead, respectively, SRMs 2586 and 2587, Trace Elements in Soil Containing Lead from Paint, Nominal 500 mg/kg and 3,000 mg/kg Lead, respectively, and SRM 2782, Industrial Sludge. The capabilities of ID ICP-MS for the certification of Pb and Cd in these materials are assessed. Sample preparation and ratio measurement uncertainties have been evaluated. Reproducibility and accuracy of the established procedures are demonstrated by determination of gravimetrically prepared primary standard solutions and by comparison with isotope dilution thermal ionization mass spectrometry (ID TIMS). Material heterogeneity was readily demonstrated to be the dominant source of uncertainty in the certified values. 相似文献
3.
Lead (Pb) and cadmium (Cd) have been determined in six new environmental standard reference materials (SRMs) using isotope dilution inductively coupled plasma mass spectrometry (ID ICP-MS). The SRMs are the following: SRM 1944, New York-New Jersey Waterway Sediment, SRMs 2583 and 2584, Trace Elements in Indoor Dust, Nominal 90 mg/kg and 10,000 mg/kg Lead, respectively, SRMs 2586 and 2587, Trace Elements in Soil Containing Lead from Paint, Nominal 500 mg/kg and 3000 mg/kg Lead, respectively, and SRM 2782, Industrial Sludge. The capabilities of ID ICP-MS for the certification of Pb and Cd in these materials are assessed. Sample preparation and ratio measurement uncertainties have been evaluated. Reproducibility and accuracy of the established procedures are demonstrated by determination of gravimetrically prepared primary standard solutions and by comparison with isotope dilution thermal ionization mass spectrometry (ID TIMS). Material heterogeneity was readily demonstrated to be the dominant source of uncertainty in the certified values. 相似文献
4.
Metrological certification through a primary method of measurement and how it can be achieved is demonstrated in this paper,
using the example of re-certification of cadmium and lead content in a biological material, the Bureau Communataire de Reference,
reference material CRM-278R mussel tissue. The measurement method used was isotope dilution in combination with inductively
coupled plasma mass spectrometry. Microwave digestion was applied to the samples prior to the measurements. A detailed uncertainty
budget was evaluated according to the International Organisation of Standardisation, Guide to the Expression of Uncertainty
and EURACHEM Guide, resulting in an expanded uncertainty.
Received: 20 August 1999 / Accepted: 3 January 2000 相似文献
5.
The present paper describes the certification of the amount content of Cd, Cr and Pb in two different polyethylene materials
within the third phase of the Polyethylene Elemental Reference Material (PERM) project. The analytical procedure to establish
the reference values for Cd, Cr and Pb amount contents in these materials is based on isotope dilution mass spectrometry used
as a primary method of measurement. Cd and Pb were measured with inductively coupled plasma-mass spectrometry and Cr with
positive thermal ionization-mass spectrometry. The decomposition of the polymer matrix was carried out using a high pressure
asher. Reference values for amount content, traceable to the SI-system, have been obtained for these three elements in both
of the polyethylene samples of PERM. For each of the certified amount content values an uncertainty budget was calculated
using the method of propagation of uncertainties according to ISO and EURACHEM guidelines. The measurement procedures, as
well as the uncertainty calculations, are described for all three elements. In order to keep the whole certification process
as transparent as possible, the preparations of various reagents and materials as well as the sample treatment and blending
are described in detail. The mass spectrometry measurements and the data treatment are also explained carefully. The various
sources of uncertainty present in the procedure are displayed in the uncertainty budgets. The obtained combined uncertainties
for the amount content values were less than 2% relative (k=1) for all investigated elements. The amount contents were in
the μmol/kg range, corresponding to mg/kg levels.
Received: 21 October 1999 / Accepted: 29 January 2000 相似文献
6.
Methods are described for the accurate and precise determination of lead concentrations and the isotopic composition of lead
in wine samples using Inductively Coupled Plasma Mass Spectrometry (ICP-MS). This method needs little sample preparation.
A comparison with lead isotope ratios measured by Thermal Ionization Mass Spectrometry (TIMS) in three wine samples reveals
a good agreement between the two techniques. The lead concentration in three certified wine samples were measured by isotope
dilution (ID) and the results are compared with those obtained by external calibration ICP-MS.
Received: 10 June 1996/Revised: 23 September 1996/Accepted: 30 September 1996 相似文献
7.
Reliable measurement results of electrolytic conductivity (EC), in particular for low values, must be metrologically traceable and be based on a realistic measurement uncertainty budget. The use of certified reference materials (CRMs) can help to achieve this goal. This paper presents results from all stages of the certification of an EC CRM with a conductivity of 1.5 μS cm ?1, including the preparation of the batch solution and the evaluation of the homogeneity and stability of the bottled CRM. An uncertainty budget is presented for the CRM, including the main contributions from each of these sources. The CRM batch remained stable within its certified uncertainty for more than 1 year. 相似文献
8.
The contribution of the Institute for Reference Materials and Measurements to the certification of the B, Cd, Cu, Mg, and Pb content of a synthetic water sample used in Comparison 12 of the International Measurement Evaluation Programme (IMEP-12) is described. The aim of the IMEP programme is to demonstrate objectively the degree of equivalence and quality of chemical measurements of individual laboratories on the international scene by comparing them with reference ranges traceable to the SI (Système International d'Unités). IMEP is organized in support of European Union policies and helps to improve the traceability of values produced by field chemical measurement laboratories. The analytical procedure used to establish the reference values for the B, Cd, Cu, Mg, and Pb content of the IMEP-12 sample is based on inductively coupled plasma-isotope-dilution mass spectrometry (ICP-IDMS) applied as a primary method of measurement. The measurements performed for the IMEP-12 study are described in detail. Focus is on the element boron, which is particularly difficult to analyze by ICP-MS because of potential problems of low sensitivity, high mass discrimination, memory effects, and abundance sensitivity. For each of the certified amount contents presented here a total uncertainty budget was calculated using the method of propagation of uncertainties according to ISO (International Organization for Standardization) and Eurachem guidelines. For all investigated elements with concentrations in the low micro g kg(-1) and mg kg(-1) range (corresponding to pmol kg(-1) to the high micro mol kg(-1) level), SI-traceable reference values with relative expanded uncertainties ( k=2) of less than 2 % were obtained. 相似文献
9.
The present paper describes the contribution of the Institute for Reference Materials and Measurements to the certification
of B, Cd, Mg, Pb, Rb, Sr, and U amount contents in a natural water sample, in round 9 of the International Measurement Evaluation
Programme (IMEP-9). The analytical procedure to establish the reference values for B, Cd, Mg, Pb, Rb, Sr, and U amount contents
was based on isotope dilution inductively coupled plasma-mass spectrometry used as a primary method of measurement. Applying
this procedure reference values, traceable to the SI, were obtained for the natural water sample of IMEP-9. For each of the
certified amount contents presented here a total uncertainty budget was calculated using the method of propagation of uncertainties
according to ISO and EURACHEM guidelines. The measurement procedures, as well as the uncertainty calculations are described
for all seven elements mentioned above. In order to keep the whole certification process transparent and so traceable, the
preparations of various reagents and materials as well as the sample treatment and blending, the measurements themselves,
and finally the data treatment are described in detail. Explanations focus on Pb as a representative example. The total uncertainties
(relative) obtained were less than 2% for all investigated elements at amount contents in the pmol/kg up to the high μmol/kg
range, corresponding to low μg/kg and mg/kg levels.
Received: 21 October 1999 / Accepted: 29 January 2000 相似文献
10.
建立了微波消解电感耦合等离子体质谱同位素稀释(ID/ICP-MS)测定微量汞的方法。考察了仪器参数及测量条件对汞同位素比值RHg(202Hg/200Hg)测量的影响,根据同位素比值测量误差的传递因子优化了富集同位素稀释剂(202Hg98%)的加入量,并以铊同位素比值(205Tl/203Tl)作为RHg(202Hg/200Hg)测量时发生质量歧视效应的校正因子;通过反同位素稀释法标定了富集汞同位素稀释剂的浓度。利用所建立的ID/ICP-MS方法测定了杨树叶(GBW07604)和湖积物(GBW07423)2种标准参考物中汞的含量,回收率分别为112%和100%。该方法具有准确度高、精密度好等优点,且样品前处理简便,适用于土壤及蔬菜等样品中微量及痕量汞的准确测定。 相似文献
11.
In the International Measurement Evaluation Programme (IMEP-12) comparison, a synthetically prepared water sample was offered to the analytical laboratories to perform measurements of As, B, Cd, Cr, Cu, Fe, Mg, Mn, Ni and Pb. The choice of elements to be measured was based on EU legislation, which the comparison was aiming to support. As to the IMEP policy, the laboratories’ results were presented according to the certified/assigned reference values established by several reference laboratories all around the world. The performed certification campaign is described in detail in this paper. Isotope dilution mass spectrometry (IDMS) was applied as a primary method of measurement (PMM), whenever possible, to achieve SI-traceable results. Apart from IDMS for reference measurements of some elements, k o-neutron activation analysis ( k o-NAA) and external calibration (Ext-Calib) using inductively coupled plasma-mass spectrometry (ICP-MS) were applied. The reference values were characterised as “certified” (for B, Cd, Cr, Cu, Fe, Mg, Ni and Pb) or “assigned” (for As and Mn) according to the IMEP policy. Measurement uncertainty of the certified/assigned reference values was calculated according to the ISO/BIPM guide using the specialised software GUM Workbench. 相似文献
12.
In the International Measurement Evaluation Programme (IMEP-12) comparison, a synthetically prepared water sample was offered to the analytical laboratories to perform measurements of As, B, Cd, Cr, Cu, Fe, Mg, Mn, Ni and Pb. The choice of elements to be measured was based on EU legislation, which the comparison was aiming to support. As to the IMEP policy, the laboratories’ results were presented according to the certified/assigned reference values established by several reference laboratories all around the world. The performed certification campaign is described in detail in this paper. Isotope dilution mass spectrometry (IDMS) was applied as a primary method of measurement (PMM), whenever possible, to achieve SI-traceable results. Apart from IDMS for reference measurements of some elements, k
o-neutron activation analysis (k
o-NAA) and external calibration (Ext-Calib) using inductively coupled plasma-mass spectrometry (ICP-MS) were applied. The reference values were characterised as “certified” (for B, Cd, Cr, Cu, Fe, Mg, Ni and Pb) or “assigned” (for As and Mn) according to the IMEP policy. Measurement uncertainty of the certified/assigned reference values was calculated according to the ISO/BIPM guide using the specialised software GUM Workbench. 相似文献
13.
A pragmatic method is proposed for the implementation of the Guide to the expression of uncertainty in measurement in the certification of reference materials by laboratory intercomparison. It is based on the establishment of a full uncertainty budget for each laboratory result and the estimation of the impact of various laboratory standard uncertainties and of between-units variability on the certified reference material (CRM) uncertainty. 相似文献
14.
A new selenized yeast reference material (SELM-1) produced by the Institute for National Measurement Standards, National Research
Council of Canada (INMS, NRC) certified for total selenium (2,059±64 mg kg −1), methionine (Met, 5,758±277 mg kg −1) and selenomethionine (SeMet, 3,431±157 mg kg −1) content is described. The ±value represents an expanded uncertainty with a coverage factor of 2. SeMet and Met amount contents
were established following a methanesulfonic acid digestion of the yeast using GC-MS and LC-MS quantitation. Isotope dilution
(ID) calibration was used for both compounds, using 13C-labelled SeMet and Met. Total Se was determined after complete microwave acid digestion based on ID ICP-MS using a 82Se spike or ICP-OES spectrometry using external calibration. An international intercomparison exercise was piloted by NRC
to assess the state-of-the-art of measurement of selenomethione in SELM-1. Determination of total Se and methionine was also
attempted. Seven laboratories submitted results (2 National Metrology Institutes (NMIs) and 5 university/government laboratories).
For SeMet, ten independent mean values were generated. Various acid digestion and enzymatic procedures followed by LC ICP-MS,
LC AFS or GC-MS quantitation were used. Four values were based on species-specific ID calibration, one on non-species-specific
ID with the remainder using standard addition (SA) or external calibration (EC). For total selenium, laboratories employed
various acid digestion procedures followed by ICP-MS, AFS or GC-MS quantitation. Four laboratories employed ID calibration,
the remaining used SA or EC. A total of seven independent results were submitted. Results for methionine were reported by
only three laboratories, all of which used various acid digestion protocols combined with determination by GC-MS and LC UV.
The majority of participants submitted values within the certified range for SeMet and total Se, whereas the intercomparison
was judged unsuccessful for Met because only two external laboratories provided values, both of which were outside the certified
range. 相似文献
15.
An example is presented of a traceability protocol for the measurement of a single-element strontium reference material solution,
executed by a "primary" method of measurement for certification. The method of measurement is briefly described together with
the measurement equation and the associated calculations for the estimation of uncertainties. This is followed by a discussion
and estimate of each component of uncertainty associated with the measurement, together with a final estimate of uncertainty.
The final estimate of uncertainty compares well with observed uncertainties for two previous laboratory measurements of the
reference material.
Received: 21 February 1998 · Accepted: 17 August 1998 相似文献
16.
Determination of zinc involved spiking with (68)Zn enriched solution, digestion by HNO(3)+H(2)O(2) in microwave decomposition unit, off-line separation of zinc on Chelex-100 column and measurement of ((64)Zn+(66)Zn)/(68)Zn isotope ratio on ICP-MS spectrometer with a quadrupole mass filter. After optimization of standard operation procedure (details are given) the method was validated. LOD was found to be 0.3 mug g(-1) for the procedure without zinc separation and 3.6 mug g(-1) for the procedure involving zinc separation, respectively. The accuracy of results was proved by analyses of several CRM and a primary solution of zinc, the concentration of which was verified by gravimetry and complexometric titration. Barium is the only element causing serious interferences and it must be removed from samples. The uncertainty budget is given together with the scheme of combined uncertainty calculation. The main uncertainty components are contamination during zinc separation and uncertainty of isotopic composition of natural zinc. 相似文献
17.
Measurement uncertainties evaluated according to GUM were given in an uncertainty budget for the measurement of mass fractions of 12 elements in conifer tree needle materials. The measurement was performed using ICP-AES, with prior microwave digestion of the dried sample material. The uncertainty budget for Ca as an example showed that correction for a systematic error was the main source of measurement uncertainty. The key to reduced measurement uncertainty therefore lies in identifying the main sources of systematic errors, and reducing the uncertainty associated with their correction. The usefulness of the uncertainty budget was demonstrated in its application to method validation, to the design of a quality control program, and finally for guiding method optimization. 相似文献
18.
The assessment of (non-)compliance in doping control and in particular the appreciation of uncertainty of measurement in such an assessment has become a subject of debate. In a previous paper, the requirements for evaluating measurement uncertainty have been addressed. The debate now focuses on the estimation of the standard uncertainty. The completeness of an uncertainty budget is discussed in view of the (metrological) traceability of the result. It is concluded that despite the fact that the new doping rules dictate that A-tests and B-tests be performed in the same laboratory, the uncertainty budget should encompass all factors, including between-laboratory effects. The assessment of (non-)compliance should be based on a one-sided t-test. There is also consensus about the level of confidence to be applied (99%), despite the fact that the regulations state 95% as the appropriate level. 相似文献
19.
Estimation of measurement uncertainty has become a more regularly performed part of the whole analytical process. However,
there is still much on-going discussion in the scientific community about ways of building up the uncertainty budget. This
study describes two approaches for estimation of measurement uncertainty in organic analysis: one which can be used for single
sets of measurements and the other based on validation studies. In both cases the main contributions to the uncertainty are
presented and discussed for the analysis of PCBs in mussel tissue, but the approaches can be extended to other organic pollutants
in environmental/food samples. The main contributions to the uncertainty budget arise from calibration, sample preparation,
and GC–MS measurements. A comparison of the relevant sources and their contributions to the expanded uncertainty is presented. 相似文献
20.
Under an international collaborative certification programme, two new Polish soil reference materials, PL-1 (loess) and BPGM-1
(sandy loam soil), were analysed for 34 trace elements including all the rare earth elements using the acid decomposition
method and inductively coupled plasma - mass spectrometry (ICP-MS). After the certification by the organisers, the analytical
data obtained at our institute were compared with the certified data. 'Z-score' values calculated for individual trace elements
helped in the assessment of the quality of the data. While the majority of the data obtained on ICP-MS was very precise and
accurate, some of the data especially for elements such as Zr, Hf and Nb suffered from incomplete dissolution of the sample
and spectroscopic interferences. For some trace elements, certified data are not available for comparison. These features
together with the usefulness of interlaboratory collaborative programmes and ICP-MS for the certification of soil reference
materials are discussed.
Received: 6 August 1999 / Accepted: 28 February 2000 相似文献
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