Quantitative Enzyme-Linked Immunosorbent Assay for Determination of Polychlorinated Biphenyls in Environmental Soil and Sediment Samples

Abstract

An enzyme-linked immunosorbent assay (ELISA) for the quantitative determination of Aroclors 1242, 1248, 1254, and 1260 in soil and sediments was developed and its performance compared with that of gas chromatography (GC). The detection limits for Aroclors 1242 and 1248 in soil are 10.5 and 9 ng/g, respectively. The assay linear dynamic range is 50-1333 ng/g. Cross-reactivity of the assay with 37 structurally related potential cocontaminants in environmental soil samples was examined; none of the chlorinated anisoles, benzenes, or phenols exhibited >3% cross-reactivity, with <0.1% cross-reactivity being the norm. Soil spike recoveries of 107% and 104% were obtained for Aroclors 1242 and 1248, respectively, for a spike level of 5 mg/kg, with corresponding relative standard deviations of 14% and 17%. One hundred forty-eight environmental soil, sediment, and paper pulp samples, obtained from two EPA listed Superfund sites, were analyzed by ELISA and standard GC methods. Samples were extracted for ELISA analysis by shaking with methanol. Additional extractions of the same samples were performed either with supercritical carbon dioxide or by Soxhlet extraction with methanol. ELISA results for both the supercritical fluid and the Soxhlet extracts were in close agreement with the GC results, while the ELISA results for the methanol shake extracts were not. The data for the environmental samples demonstrated the capability of the ELISA to provide accurate results and reinforced the dependence of any detection method, including ELISA, on appropriate extraction procedures.

Direct competitive ELISA for the determination of polychlorinated biphenyls in soil samples

“…spiked}×100%]. It was observed that recoveries of added PCB from spiked soils by shaking with methanol were in the range 90.6-106.3%, in accordance with the results of Lawruk et al [1] and Johnson and Van Emon [8] who obtained recoveries of approximately 90%, irrespective of sample type and total Aroclor level.…”

“…This might be a partial cause of the discrepancies between ELISA and GC results. The sample extraction procedure plays a major role in the overall analytical result even the accuracy and precision of ELISA for analysis of spiked samples are high [2,8,13]. The data obtained by Johnson and Van Emon [8] demonstrated that ELISA was capable of providing quantitative results for PCB when Soxhlet or supercritical-fluid extraction was used.…”

“…The sample extraction procedure plays a major role in the overall analytical result even the accuracy and precision of ELISA for analysis of spiked samples are high [2,8,13]. The data obtained by Johnson and Van Emon [8] demonstrated that ELISA was capable of providing quantitative results for PCB when Soxhlet or supercritical-fluid extraction was used. ELISA analysis of the extract obtained by shaking with methanol, on the other hand, gave results which were not always in a close agreement with the values obtained by use of conventional GC-based methodologies [8].…”

“…Immunochemical techniques such as radioimmunoassay (RIA) [3,4], enzyme-linked immunosorbent assay (ELISA) [1,5,8], and use of immunosensors (IS) [9,10,11] have shown potential for providing simple, rapid, and economical methods for the analysis of PCB. Several PCB test kits are commercially available for semi-quantitative analysis of PCB in different matrixes, and considerable method-development activity has been focused on the quantitative determination of PCB in soil [1,2,8,12,13,14].…”

“…Several PCB test kits are commercially available for semi-quantitative analysis of PCB in different matrixes, and considerable method-development activity has been focused on the quantitative determination of PCB in soil [1,2,8,12,13,14].…”