Treffer: Isotopically-labelled compounds for validating organometallics speciation analysis

The possibilities of using isotopically-labelled species with GC-ICP-MS to validate speciation analysis of organometallic compounds in environmental samples are summarised. The analytical advantages of this unique way of quantification, based on isotope-ratio measurements in each separate species, are highlighted and compared with more conventional procedures. Particular emphasis is paid to validating published speciation procedures, which usually involve a large number of discrete steps, each a possible source of error. The preparation of isotopically-labelled butyltin species and its application to seawater and sediment organotin speciation quantitative analysis are reviewed. In addition, the impressive capability of the multi-isotope-labelled multispecies spikes to control every step in speciation, even the initial solid-liquid extraction of the species from a solid sample, is also addressed. Such an innovative strategy allows detection and correction for species degradation during this difficult step to follow the extraction process. Moreover, the use of such multi-isotope-labelled multispecies approaches opens the door to studies on reported extraction procedures in speciation work. This approach is shown to be extremely useful for both ensuring quantitative recoveries of the species being sought from the solid matrix and evaluating the extent of possible extraction-derived rearrangement reactions. The article reviews applications of this innovative tool to the study and validation of the reported solid-liquid extraction of butyltin species from a certified reference sediment (using different techniques, including mechanical shaking, microwave, ultrasonic and pressurized liquid extraction).