Response to the comment on “Halogenated indigo dyes: A likely source of 1,3,6,8-tetrabromocarbazole and some other halogenated carbazoles in the environment”

Abstract

Since polyhalogenated carbazoles (PHCZs) were first detected in 1984, analytical methods have advanced greatly. With increasing knowledge of their adverse effects, more advanced detection methods are required to fill relevant knowledge gaps of PHCZs, such as their environmental distribution, migration, transformations and sources. We summarize the pretreatment methods of PHCZs. The performances of diverse instruments for detecting PHCZs are compared. Although an increasing number of standards of PHCZs are now available, they are still insufficient for congener specific quantification and identification by the isotope dilution method owing to the complex congeners of PHCZs. So we generalize the qualitative and quantitative strategies used when available standards for specific congeners are lacking. Finally, we propose the necessity of simultaneous detection of PHCZs along with multiple dioxin-like analogues in the environment. It is expected this review could provide a basis for understanding current progress in the analysis of PHCZs and addressing research gaps.