Introduction 1 2 3 4 118 118 118 118 118 4 3 5 1 6 11 12 14 6 7 6 9 Fig. 1 Overview of analysis for certification  Experimental Preparation of sediment material 60 Conversion to dry mass basis The concentrations of the constituents of this CRM are given on a dry-mass basis. A dry mass correction factor for sample humidity was determined by drying the sample at 110 °C. After 5 h the sediment sample reached constant weight, so it was decided the drying time would be 6 h in this experiment. The dry mass correction factor at the time of certification was 0.959±0.003 (average±standard deviation for ten different bottles). Chemicals 2 −1 4 m v 4 2 118 118 118 4 118 118 15 118 118 4 118 4 −1 118 118 4 118 118 4 118 118 18 4 118 Extraction procedure Ultrasonic extraction The ultrasonic extraction procedure for GC–ICP–MS and GC–MS was as follows. The sediment sample (ca. 0.5 g) was placed in a PFA centrifuge tube and spiked with an appropriate amount of the spikes. Then 2 g NaCl, 12 mL toluene containing 0.1% tropolone, and 10 mL acetic acid–methanol (1:1) were added to the tubes. The resulting mixtures were extracted in an ultrasonic bath for 30 min at 60 °C. After addition of 10 mL water the tubes were again shaken, for good phase separation, and then centrifuged at 3000 rpm for 5 min. Finally, the upper toluene layer was collected as the extract. For LC–ICP–MS, the extraction solvent was replaced with 10 mL acetic acid–methanol (1:1) containing 0.1% tropolone, and the same extraction procedure was performed. Mechanical shaking extraction −1 Microwave-assisted extraction −1 Pressurized liquid extraction −1 Derivatization procedure for GC–ICP–MS and GC–MS −1 4 Clean-up procedure 2 v v 2 2 Determination of organotin compounds by ID–GC–ICP–MS m z 4 1 16 17 1 \documentclass[12pt]{minimal}
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\begin{document}$$ C_{{\text{x}}}  = {\left[ {\frac{{P \cdot D}} {{Mw}} \cdot E \cdot \frac{{m_{{\text{y}}} }} {{w \times m_{{\text{x}}} }} \cdot \frac{{m_{{{\text{z}}}} }} {{m^{\prime }_{{\text{y}}} }} \cdot \frac{{K_{{\text{y}}}  \cdot R_{{\text{y}}}  - {\sum {{{\left( {K \cdot R} \right)}} \mathord{\left/  {\vphantom {{{\left( {K \cdot R} \right)}} n}} \right.  \kern-\nulldelimiterspace} n} }}} {{{\sum {{{\left( {K \cdot R} \right)}} \mathord{\left/  {\vphantom {{{\left( {K \cdot R} \right)}} n}} \right.  \kern-\nulldelimiterspace} n} } - R_{{\text{x}}} }} \cdot \frac{{{{\sum {{\left( {K\prime  \cdot R\prime } \right)}} }} \mathord{\left/  {\vphantom {{{\sum {{\left( {K\prime  \cdot R\prime } \right)}} }} {n - R_{{\text{z}}} }}} \right.  \kern-\nulldelimiterspace} {n - R_{{\text{z}}} }}} {{K_{{\text{y}}}  \cdot R_{{\text{y}}}  - {\sum {{{\left( {K\prime  \cdot R\prime } \right)}} \mathord{\left/  {\vphantom {{{\left( {K\prime  \cdot R\prime } \right)}} n}} \right.  \kern-\nulldelimiterspace} n} }}}} \right]} - B $$\end{document} C x −1 m x m y \documentclass[12pt]{minimal}
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\begin{document}$$ {\text{m}}^{\prime }_{{\text{y}}} $$\end{document} m z R 120 118 R 120 118 R x 120 118 R y 120 118 R z 120 118 w n k K y K 120 118 4 P D Mw B E Determination of organotins by ID–GC–MS m z m z m z m z 3 2 2 \documentclass[12pt]{minimal}
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\begin{document}$$ C_{{\text{x}}}  = \frac{{P \cdot D}} {{Mw}} \cdot E \cdot \frac{{m_{{\text{y}}} }} {{w \cdot m_{{\text{x}}} {\left[ {{{\left( {R - R_{{\text{L}}} } \right)}{\left( {RW_{{\text{H}}}  - RW_{{\text{L}}} } \right)}} \mathord{\left/  {\vphantom {{{\left( {R - R_{{\text{L}}} } \right)}{\left( {RW_{{\text{H}}}  - RW_{{\text{L}}} } \right)}} {{\left( {R_{{\text{H}}}  - R_{{\text{L}}} } \right)} + RW_{{\text{L}}} }}} \right.  \kern-\nulldelimiterspace} {{\left( {R_{{\text{H}}}  - R_{{\text{L}}} } \right)} + RW_{{\text{L}}} }} \right]}}} - B $$\end{document} C x −1 m x m y RW L RW H R R L R H w P D Mw B E R L R H R Determination of organotin compounds by ID–LC–ICP–MS v v −1 −1 2 −1 1 Homogeneity study MS within MS among s bb 3 3 \documentclass[12pt]{minimal}
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\begin{document}$$ s_{{{\text{bb}}}} = {\sqrt {\frac{{MS_{{{\text{among}}}} - MS_{{{\text{within}}}} }} {n}} } $$\end{document} u bb 18 u bb 4 4 \documentclass[12pt]{minimal}
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\begin{document}$$ u_{{{\text{bb}}}} = {\sqrt {\frac{{MS_{{{\text{within}}}} }} {n}} }\sqrt[4]{{\frac{2} {{\nu _{{MS_{{{\text{within}}}} }} }}}} $$\end{document} \documentclass[12pt]{minimal}
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\begin{document}$$ \nu _{{MS_{{{\text{within}}}} }} $$\end{document} MS within Results and discussion Homogeneity study s bb u bb s bb Stability of organotins in this material 19 118 118 4 2 m z 118 118 118 118 118 Fig. 2 118 120 118 118  118 120 118 4 120 118 118 n 120 118 118 Assay for the standard solution of the organotins 4 The main impurities in the organotin chloride reagents used are water and tin species. Small amounts of inorganic and organotin impurities were observed in both the ethylated MBT and ethylated DBT solutions, and significant amounts of several organotin impurities were observed in the ethylated TBT, ethylated TPhT, and ethylated DPhT solutions. Among the organotin impurities observed in each ethylated organotin solution, inorganic tin, MBT, DBT and tetrabutyltin (TeBT), MPhT, and DPhT were identified from their retention times in GC–ICP–MS measurement and isomers of TBT (iso-TBT) and dioctyldibutyltin (DOcDBT) were identified from the fragment-ion patterns obtained by GC–MS. Two organotin impurities that could not be identified from their retention time were also observed in the ethylated-MBT solution, but the amounts of those were small (<0.03%). The purities of the organotin chloride reagent obtained were 99.4±0.2% for MBT, 99.5±0.2% for DBT, 96.8±0.2% for TBT, 98.6±0.2% for DPhT, and 98.8±0.2% for TPhT. 20 −1 21 −1 20 −1 3 2 2 2 2 22 2 2 2 2 −1 Evaluation of the degradation of DBT and TPhT during extraction 6 11 6 7 11 12 117 15 118 117 118 118 120 118 117 117 118 117 117 120 118 6 7 Analytical results obtained by each method 3 4 5 118 3 4 1 1 2 P D 1 2 u c Fig. 3 118 120 118 118  Fig. 4 118 118  Fig. 5 118 120 118 118  Table 1 Analytical results obtained by use of six combinations of extraction and measurement methods     u a −1 b Measurement TBT DBT MBT TPhT DPhT USE GC–ICP–MS 44.3±1.1 51.2±0.9 65.9±1.1 7.8±1.4 3.4±0.3 USE GC–MS 43.8±1.7 50.7±0.8 66.6±1.7 5.8±1.5 3.9±0.4 USE LC–ICP–MS 44.2±1.7 50.7±0.8 65.6±1.7 7.4±1.9 c MAE GC–ICP–MS 43.8±1.5 52.1±0.9 68.2±1.2 7.0±1.0 3 PFE GC–ICP–MS 42.9±1.2 50.1±1.0 67.1±0.8 6.3±0.6 3.7±0.2 MWE GC–ICP–MS 47.0±1.3 52.5±1.2 67.6±0.8 8.7±1.7 4.4±0.8 a 1 2 b c The analytical results obtained by use of the six methods were in good agreement within the range of their uncertainties; this agreement may indicate there were no significant analytical biases between measurement and extraction techniques for all the analytes. Therefore, all the analytical results obtained were treated equally for calculation and evaluation of the certified values and their uncertainties. Establishing certified values 1 2 u i u i Table 2 Certified values and their uncertainties for mass fractions of organotin compounds in NMIJ CRM 7306-a   TBT DBT MBT TPhT DPhT −1 44 51 67 6.9 3.4 Relative standard uncertainty (%)      u cal 0.3% 0.3% 0.3% 0.5% 1.0% u anal 1.3% 0.7% 0.7% 7.0% 3.3% u method 1.6% 1.0% 0.2% – – s bb u bb 1.9% 1.9% 2.0% 5.8% 7.1% Combined uncertainty       Relative (%) 2.8% 2.3% 2.1% 9.1% 7.9% −1 1.3 1.2 1.4 0.6 0.3 U k −1 3 2 3 1.3 0.5 Uncertainty of the certified values 2 u cal u anal 5 5 \documentclass[12pt]{minimal}
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\begin{document}$$ u_{{{\text{anal}}}} {\left( x \right)} = {\sqrt {{\sum\limits_i {w_{i} ^{2} u^{2} {\left( {x_{i} } \right)}} }} } $$\end{document} x i w i u method u bb U ku c u c k Comparison with other CRMs 3 u bb u anal 3 Table 3 -1   TBT DBT MBT TPhT DPhT CRM7306-a 44±3 51±2 67±3 6.9±1.2 3.4±0.5 CRM7301-a 44±4 56±6 56±6   HIPA-1 78±9     SOPH-1 125±7 174±9    PACS-2 890±105 1047±64    3 23 25 The BCR 646 freshwater sediment for butyltins and phenyltins are also available from the European Commission Joint Research Centre (IRMM, Belgium), although SSID–MS was not used for the certification. The certified concentrations for BCR CRM646 are higher than those for CRM7306-a. –1 26