Assessment of Tributyltin and Triphenyltin Compounds and Their Main Degradation Products in Saudi Coastal waters

Comprehensive studies to determine the level of predisposition of Saudi environment to many micro-contaminants are scanty. To improve on the available literature, an attempt was made here to determine concentrations of six species of organotins in water samples collected from 17 coastal sites in the Eastern Province of Saudi Arabia. These sites were grouped into three sampling stations: Near Dammam Corniche, King Abdulaziz Port (Inside), and King Abdulaziz Port (Outskirts). The samples were extracted using solid-phase extraction and then derivatized by propylation using Grignard reagent. Analytes were separated and quantitatively determined on gas chromatography–mass spectrometric system using selected ion monitoring mode. Recoveries for 0.1 μ g L⁻¹ spiked sea water samples were between 81 and 89 %, and limits of detection of 5.2–11 ng/L were estimated at S/N = 3. Total organotin concentration found at each station was averaged at 3.70 μ g L⁻¹. The individual species detected and quantified as the butylated species were tributyltin (0.14–1.9 μ g L⁻¹), dibutyltin (0.11–0.70 μ g L⁻¹), and monobutyltin (0.13–1.5 μ g L⁻¹). For the phenylated tins, triphenyltin (0.12–1.9 μ g L⁻¹), diphenyltin (0.21–1.9 μ g L⁻¹), and monophenyltin (0.11–0.62 μ g L⁻¹) were determined in the samples. These determinations had %RSD of 6.1–11.5 % for the different analytes. Using ratios of tributyltin and triphenyltin to their respective degradation products, fresh input of these micro-contaminants into the marine environment was inferred.