Evaluation of alternative approaches for screening contaminated sediments and soils for polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans

Immunoanalysis methods for the detection of dioxins and related chemicals

With the development of biotechnology, approaches based on antibodies, such as enzyme-linked immunosorbent assay (ELISA), active aryl hydrocarbon immunoassay (Ah-I) and other multi-analyte immunoassays, have been utilized as alternatives to the conventional techniques based on gas chromatography and mass spectroscopy for the analysis of dioxin and dioxin-like compounds in environmental and biological samples. These screening methods have been verified as rapid, simple and cost-effective. This paper provides an overview on the development and application of antibody-based approaches, such as ELISA, Ah-I, and multi-analyte immunoassays, covering the sample extraction and cleanup, antigen design, antibody preparation and immunoanalysis. However, in order to meet the requirements for on-site fast detection and relative quantification of dioxins in the environment, further optimization is needed to make these immuno-analytical methods more sensitive and easy to use.

Application of GC-HRMS and GC×GC-TOFMS to aid in the understanding of a dioxin assay's performance for soil and sediment samples

There have been numerous attempts to correlate results obtained by gas chromatography-mass spectrometry (GC-MS) to alternative techniques such as immunoassays and bioassays for the analysis of dioxins in environmental samples. In spite of these efforts, uncertainties about the performance of these methods remain. Following a series of performance studies of various dioxin assays, an in-depth evaluation of sample extracts from the Procept Rapid Dioxin Assay was conducted to provide users with a clearer understanding of the differences in the assay's results compared to traditional mass spectrometry. Two powerful analytical techniques [high-resolution mass spectrometry (HRMS) and two-dimensional gas chromatography coupled with time-of-flight mass spectrometry (GC×GC-TOFMS)] were used to provide a unique perspective about the assay's underlying analytical performance. HRMS analyses demonstrated that the target dioxin and furans were consistently captured in the assay's extracts. TOFMS analyses revealed that interferents in the sample extracts resulting from inconsistencies in the sample preparation process appear to be the primary factor contributing to the assay's imprecision. The conclusion of this research was the assay results cannot be expected to correlate directly with HRMS and should only be utilized as a screening technique (e.g., to identify the relative ranking of contamination, to determine if samples are above/below threshold levels, or to monitor a cleanup) for environmental matrices such as soil and sediment.

The analysis of dioxins and related compounds

The analysis of polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans, polychlorinated biphenyls, and other related compounds requires complex sample preparation and analytical procedures using highly sensitive and selective state-of-the-art instrumentation to meet very stringent data quality objectives. The analytical procedures (extraction, sample preparation), instrumentation (chromatographic separation and detection by mass spectrometry) and screening techniques for the determination of dioxins, furans, dioxin-like polychlorinated biphenyls and related compounds with a focus on new approaches and alternate techniques to standard regulatory methods are reviewed.