Effects of complexing agents and acid modifiers on the supercritical fluid extraction of native phenyl- and butyl-tins from sediment

Abstract

The effects of: (1) the modifier type (methanol and formic, acetic and propionic acids), (2) complexing agents (diethylammonium diethyldithiocarbamate, ammonium pyrrolidinedithiocarbamate) either with or without acidic modifiers, (3) the extraction temperature (50–80 °C) and pressure (30–50 MPa), (4) the extraction procedure (static–dynamic or dynamic), and (5) the volume of static modifier, on the extraction efficiency of native butyl‐ and phenyl‐tin compounds from sediment, were evaluated comprehensively. The highest extraction efficiency for butyl‐ and phenyl‐tin compounds was obtained at 30 MPa and 50 °C by using CO2 modified with acetic acid (200 μl in the cell). Supercritical fluid extraction (SFE) extracts were hexylated and determined by GC–FPD using a 610 nm bandpass filter without any clean‐up step. In summary, the developed analytical procedure is robust (no restrictor clogging; free from FPD interferences), it is low‐cost (no complexing agents needed), it has a high sample throughput (<3 h), it is independent of the matrix for the determination of butyltin compounds in sediment, and it provides the highest precision among the SFE procedures reported for organotin determination. © 1998 John Wiley & Sons, Ltd.

Phenyl- and Butyltin Analysis in Small Biological Samples by Cold Methanolic Digestion and GC/MS

“…12,20 In the case of sediments, the digestion and ligand-exchange processes have to be enhanced by microwave fields, 20 high temperature and pressure, 12 sonication, 21 or supercritical fluid CO 2 . 22 Biological tissues offer the advantage of better solubility in solvents, particularly if the samples are of small size. This allows digestion and extraction of the organotins at ambient temperature with satisfactory recovery rates, as is demonstrated for the spiked Chironomus larvae samples in Table 2.…”

“…In this study, the first task was fulfilled with methanol, whose osmotic activity induces rapid bursting of the cells and facilitates homogenization of the biological material. The acetic acid in the methanolic solution (1 M) acted as complexing agent. , In the case of sediments, the digestion and ligand-exchange processes have to be enhanced by microwave fields, high temperature and pressure, sonication, or supercritical fluid CO 2 . Biological tissues offer the advantage of better solubility in solvents, particularly if the samples are of small size.…”

Environmentally friendly sample treatment for speciation analysis by hyphenated techniques

“…The results of interlaboratory trials revealed the suitability of carbon dioxide-methanol SF for the extraction of tri-and tetrasubstituted organotin compounds, while the mono-and disubstituted species were extracted with poor efficiency. 122 More recently, the feasibility of other organic modifiers has been explored for phenyl-and butyl-tins in sediments (carboxylic acids 123 ) and for di-and tri-butyltins in mussel reference material (acetic acid 124 ). On the other hand, different carbamates 87,123,125 and tropolone 124,126 have been reported as complexing agents for ionic organotin species.…”

“…122 More recently, the feasibility of other organic modifiers has been explored for phenyl-and butyl-tins in sediments (carboxylic acids 123 ) and for di-and tri-butyltins in mussel reference material (acetic acid 124 ). On the other hand, different carbamates 87,123,125 and tropolone 124,126 have been reported as complexing agents for ionic organotin species. Derivatization through alkylation (ethylation or hexylation) enabled the improved extraction of butyl-and phenyl-tin.…”