Determination of butyltin compounds in environmental samples by isotope-dilution GC–ICP–MS

Abstract

Isotope-dilution analysis in combination with GC-ICP-MS detection has been applied to the determination of butyltin species in environmental samples. Different spikes containing the isotopically labeled butyltin species have been synthesized in the laboratory after optimization of the reaction conditions. The isotopic compositions of the tin species in the different spike solutions were determined by GC-ICP-MS after derivatization by aqueous ethylation with sodium tetraethylborate. Reverse isotope-dilution analysis was used for quantitation of the spike solutions by means of natural MBT, DBT, and TBT standards. The mixed spikes were used for simultaneous analysis of MBT, DBT and TBT in the certified reference materials, PACS-2, CRM 462, and CRM 646, with satisfactory results. The excellent agreement of the different speciation results obtained by use of the different spikes is a good indicator of the precision, accuracy, and reliability which can be achieved by using isotope-dilution analysis for trace metal speciation. Application of a double spike containing (119)Sn-enriched MBT (79.7 At%), (118)Sn-enriched DBT (86.7 At%), and (119)Sn-enriched TBT (83.1 At%) also enabled evaluation of the conditions resulting in quantitative extraction of the species from the solid matrix, in combination with possible alterations depending on the different extraction procedures used (mechanical shaking, ultrasounds, and microwaves). Mathematical equations used for this purpose computed the correct species concentrations directly and, additionally, the decomposition factors (from TBT to DBT and from DBT to MBT) after precise measurement of the (119)Sn/(120)Sn and (118)Sn/(120)Sn ratios for all butyltin species by GC-ICP-MS.

Microwave-assisted steam distillation with simultaneous liquid/liquid extraction of pentachlorophenol from organic wastes and soils

“…According to previous work [17,21], this loss of analyte can be related to catalytic matrix effects on irregular surfaces supported by the introduced microwave energy. Alonso et al [22] demonstrated the degradation of tributyltin into dibutyltin and monobutyltin under conditions of microwave-assisted extraction. Microwave-hydrothermal decomposition of PCP was described by Park et al [23]: however, the molecule was destroyed by substitution of chlorine atoms by hydroxyl groups under alkaline conditions.…”

An overview of recent applications of inductively coupled plasma-mass spectrometry (ICP-MS) in determination of inorganic impurities in drugs and pharmaceuticals

“…In addition to its low detection limits, the dynamic range of ICP-MS allows detection of both major constituents and trace components simultaneously. Furthermore, the multielemental capability of ICP-MS enables the detection of individual isotopes, which permit the use of isotopic-dilution techniques for internal standardization and also to monitor species transforma- tions occur during sample pre-treatment or separation [70,71]. Fig.…”

Trace element speciation by ICP-MS in large biomolecules and its potential for proteomics

“…At least two useful aspects can be foreseen: first, the direct use of available inorganic elemental standards for protein determination at extremely low concentrations in a very fast, on-line manner (hybrid technique) [100]; secondly, more accurate quantifications of such biocompounds (again at very low levels) can be attempted by adequate exploitation of speciated isotope dilution analysis (SIDA) [105,106,107], recently extended to multi-labelled multi-species SIDA techniques and demon- [89] strated for sediments and biological tissues in our laboratory [108,109]. In brief, so far ICP-MS has proved to be an invaluable tool for the "screening" of the presence of metals in biomolecules even at extremely low concentrations.…”