Stability and storage problems in organotin speciation in environmental samples

Abstract

The stability of both tributyltin (TBT) and triphenyltin (TPT) in water, sediment, oysters and cockles was studied over a period of 18 months using several storage conditions. Butyltins were stable in unacidified sea-water stored in polycarbonate bottles in the dark at 4 degrees C for 7 months, but half of the TBT concentration was lost after 540 d. A comparable preservation time was achieved for butyltins stored on C18 cartridges at room temperature. However, phenyltins extracted from sea-water were stable for only 60 d stored on cartridges and even more pronounced losses (about 90% after 540 d) occurred when they were stored in either polycarbonate or Pyrex glass bottles. Losses of organotins were observed in sediments after air drying and pasteurization treatments using a freeze-dried sediment as a comparator, whereas both butyltin and phenyltin species remained stable in sediments stored at -20 degrees C for the 18 months tested, irrespective of the treatment used for stabilization. Air drying followed by pasteurization was shown to be superior to other treatments for the stabilization of organotin compounds in sediments stored at higher temperatures, but 30% of TBT was lost after 540 d at 25 degrees C. Finally, butyltins were stable in both frozen cockles and oysters in the dark over a 7 month period and in freeze-dried samples stored at 4 degrees C for 5 months, but TBT losses of about 70% were observed after 540 d.

Interaction of 15 priority substances for water monitoring at ng L−1 levels with glass, aluminium and fluorinated polyethylene bottles for the containment of water reference materials

“…For this experiment, the final TBT concentration was 1 ng L -1 (expressed as Sn), while adsorption studies in the literature were conducted at much higher concentrations, even up to *10 5 times higher [24]. Adsorption effects are more relevant at lower concentrations [22], and this is probably the main reason why polymer bottles are less suitable for the experimental conditions of this study. It is also worth mentioning that tap water has been used in this adsorption study which poses a more complex, realistic and challenging matrix than traditionally used deionized water [24,31].…”

“…Moreover, this phenomenon is more pronounced the smaller the container is, as the surface-to-volume ratio is increasing [21]. Although several studies have been performed regarding the stability of PAHs and TBT inside different types of containers, the concentrations tested in those experiments were relatively high and none of them was close to EQS levels [18,[21][22][23]. The information available for PBDEs is even scarcer, and the interactions of these target analytes have not been studied in aluminium bottles.…”

Determination of methyltin species in sediments using a pervaporation–gas chromatographic approach

“…The current methods usually involve a separation technique, such as highperformance liquid chromatography (HPLC) 16,17 or gas chromatography (GC), 18,19 coupled to a tin detection method, such as atomic absorption spectrometry (AAS), 20,21 atomic emission spectrometry (AES), 22 mass spectrometry (MS) 23 or pulsed flame photometric detection (PFPD). 24 Hydride generation with sodium tetrahydroborate 25 or sodium tetraethylborate 26 and alkylation by Grignard reagents 27,28 are used to derivatize the ionic organotin compounds to stable and volatile species.…”

Trace Metal Speciation with ICP‐MS Detection

“…31 On the contrary, phenyltins degraded during the first month of storage. 32 The most efficient way is to store the samples deep-frozen immediately after sampling, using polyethylene or polycarbonate containers. Under this condition, TBT was shown to be stable for 2-3 months.…”

“…For organotin species in sediments, storage under wet and dry conditions has been investigated at temperatures between −20 and +40 • C. 31,32,54 A degradation of MBT, DBT and TBT was found when samples were stored above 4 • C, but stability for up to 1 year storage time was found when storing samples at −20 • C. 32,54 The long-term storage of sediments at 4 • C has proven to lead to significant degradation of organotins, 31 as demonstrated with the reference material BCR 462. 55 This coastal sediment had to be re-certified for its organotin content after 2 years of storage at 4 • C. Evidently, freeze-drying and storing at −20 • C is a preferred means of preserving organotin species in sediment samples.…”