Accurate Determination of Tributyltin in Tannery Wastewater by a New Procedure Using ID-HPLC–ICP-MS Combined with Low Temperature Extraction

Isotope dilution mass spectrometry is recognized as a primary method to obtain traceable values in the measurement of substances including trace elements and their organometallic compounds. This paper reports a novel method where isotope dilution high performance liquid chromatography inductively coupled plasma mass spectrometry (ID-HPLC–ICP-MS) was combined with low temperature extraction for the determination of tributyltin (TBT) in tannery wastewater from the leather industry. It has been found that the liquid–liquid extraction at very low temperature is in the favor of extraction of organotin, as the enrichment factor for low temperature (−80 °C) extraction was about 1.3 times higher than for extraction at room temperature (20 °C). The method detection limit of TBT, obtained from the proposed ID-HPLC–ICP-MS procedure after extraction with a sample volume of 7.5 by 2.5 mL of organic phase, was found to be 0.13 ng g −1 . When TBT was determined in a range of 10–1000 ng g −1 in tannery wastewater samples, the analyte recoveries were in the range 90.1–107.2% with relative standard deviations of between 2.0 and 7.2%. Finally, the new method of ID-HPLC–ICP-MS combined with low temperature extraction was applied to the determination of TBT in actual tannery wastewater. The TBT contents from three different tanning procedures (chrome tanning, vegetable tanning and aldehyde tanning), expressed as the mean ± the expanded uncertainty ( k = 2) were 378.65 ± 20.38, 110.04 ± 5.96 and 690.17 ± 35.31 ng g −1 , respectively.