Comparison of GC?ICP?MS and HPLC?ICP?MS for species-specific isotope dilution analysis of tributyltin in sediment after accelerated solvent extraction

Abstract

This study describes a direct comparison of GC and HPLC hyphenated to ICP-MS determination of tributyltin (TBT) in sediment by species-specific isotope dilution analysis (SS-IDMS). The certified reference sediment PACS-2 (NRC, Canada) and a candidate reference sediment (P-18/HIPA-1) were extracted using an accelerated solvent extraction (ASE) procedure. For comparison of GC and LC methods an older bottle of PACS-2 was used, whilst a fresh bottle was taken for demonstration of the accuracy of the methods. The data obtained show good agreement between both methods for both the PACS-2 sediment (LC-ICP-IDMS 828+/-87 ng g(-1) TBT as Sn, GC-ICP-IDMS 848+/-39 ng g(-1) TBT as Sn) and the P-18/ HIPA-1 sediment (LC-ICP-IDMS 78.0+/-9.7 ng g(-1) TBT as Sn, GC-ICP-IDMS 79.2+/-3.8 ng g(-1) TBT as Sn). The analysis by GC-ICP-IDMS offers a greater signal-to-noise ratio and hence a superior detection limit of 0.03 pg TBT as Sn, in the sediment extracts compared to HPLC-ICP-IDMS (3 pg TBT as Sn). A comparison of the uncertainties associated with both methods indicates superior precision of the GC approach. This is related to the better reproducibility of the peak integration, which affects the isotope ratio measurements used for IDMS. The accuracy of the ASE method combined with HPLC-ICP-IDMS was demonstrated during the international interlaboratory comparison P-18 organised by the Comité Consultatif pour la Quantité de Matière (CCQM). The results obtained by GC-ICP-IDMS for a newly opened bottle of PACS-2 were 1087+/-77 ng g(-1) Sn for DBT and 876+/-51 ng g(-1) Sn for TBT (expanded uncertainties with a coverage factor of 2), which are in good agreement with the certified values of 1090+/-150 ng g(-1) Sn and 980+/-130 ng g(-1) Sn, respectively.

Speciation and quantification of organotin compounds in sediment and drinking water by isotope dilution liquid chromatography-inductively coupled plasma-mass spectrometry

“…20 Increasing acetic acid concentration also reduces the retention time of all organotins. Complete separation was achieved in under 7 minutes, less than half the time required for methods reported by Chiron et al 6 and Inagaki et al 5 Total separation times were similar to that obtained by GC-ICP-MS. 18 However, the re-equilibration time of 2 minutes before sequential runs is less than the time typically required by GC-ICP-MS between injections and temperature ramps. The system was very sensitive to small changes in organic modier concentrations.…”

Construction and Evaluation of a Low Cost Interface for the Determination of Elemental Speciation by Gas Chromatography Coupled to Inductively Coupled Plasma Mass Spectrometry (GC‐ICP‐MS)

“…[16,17] With this structured approach an approximate concentration of the analyte being measured has to be determined prior to spiking and this was achieved using external calibration using TPT as the internal standard. The spike material, enriched in 199 Hg, was added ("spiked") to the dry tuna CRM material (BCR464) so as to achieve an approximate match between the mercury isotopes 199 Hg (spike isotope) and 200 Hg (reference isotope) in this so called "sample blend".…”

Butyltin compounds in a sediment core from the old Tilbury basin, London, UK

“…The analytical method used for extraction, derivatisation and quantification has been described in detail elsewhere (Wahlen and Wolff-Briche, 2003). Samples of approximately 1.6 g dry weight were weighed into 11 ml accelerated solvent extraction (ASE) cells fitted with PTFE liners and filled with a diatomaceous dispersing agent.…”