Determination of organotin compounds in water, sediments, and sewage sludge using perdeuterated internal standards, accelerated solvent extraction, and large-volume-injection GC/MS

Two new methods for the simultaneous identification and quantification of organotin compounds (OTs) including monobutyltin, dibutyltin, tributyltin, monophenyltin, diphenyltin, triphenyltin, and tricyclohexyltin (TCyT) in natural waters and sediments, respectively, are presented. For water samples, aqueous ethylation followed by liquid-liquid extraction (LLE) or solid-phase extraction and large-volume-injection GC/MS (50-200 mu L) were used. For sediment samples, accelerated solvent extraction at 100 degrees C with a methanolic mixture of sodium acetate and acetic acid was developed. By using for the first time perdeuterated OTs as internal standards, excellent precision (relative standard deviations <5%) and low method detection limits ranging from 0.3 to 1.5 ng/L for 50 mL of aqueous samples and from 0.4 to 2 ng/g for 2.5 g of dried sediments were achieved. Using LLE, recoveries determined in spiked harbor water (+5 ng/L) and sediment pore water (+25 ng/L) were in the range of 93-103 (RSD 0.5-4.6%) and 97-108% (RSD 0.8-4.2%), respectively. For spiked sediment samples (+10 ng/g) recoveries of 98-105% (RSD 1-7%) were achieved for all OTs, except for TCyT (51%, RSD 4%), The developed analytical procedures were validated with reference material and applied to various environmental samples, such as fresh- and seawater, field runoff, wastewater, sediments,and sewage sludge.