Triethanolamine-based esterquat in sediments: New analytical method, environmental occurrence, and homologue composition

Abstract

The cationic surfactant triethanolamine-based esterquat (TEAQ) is a main ingredient in commercial fabric softeners and is produced and used in large quantities. However, little information is available for its occurrence in the environment, particularly in sediments. Here, we developed an analytical method for quantifying TEAQ in sediment and investigated TEAQ contamination in Japanese river and lake sediments. In our analytical method, TEAQ concentrations were measured by liquid chromatography–tandem mass spectrometry using a polymer-based size-exclusion column, which resulted in excellent peak shapes. TEAQ was detected at significant levels in procedural blanks, resulting in a method limit of detection in the sediment of 8.9–97 μg/kg-dry for TEAQ monoesters and 0.6–24 μg/kg-dry for TEAQ diesters. TEAQ was detected in 22 out of 26 sediment samples, with the sum of all homologue concentrations being up to 1340 μg/kg-dry. The concentration of TEAQ in sediments was high at locations where the concentrations of benzalkoniums and the organic carbon content were also high. TEAQ was detected in 8 out of 14 commercial fabric softeners at concentrations of 1.7–7.4 wt%. TEAQ homologues containing only saturated fatty acids accounted for 83 ± 5% of the total TEAQ in the sediments, whereas those with unsaturated fatty acids accounted for 71 ± 14% of the total TEAQ in a commercial technical mixture and the softener products. The results of this study will be useful for the environmental risk assessment of esterquats.