Improved method for hexachlorobenzene and mirex determination with hexachlorobenzene confirmation in adipose tissue:...

Area of Science:

• Environmental Chemistry
• Analytical Chemistry
• Toxicology

Background:

• Hexachlorobenzene (HCB) and mirex are persistent organic pollutants (POPs) with significant environmental and health concerns.
• Accurate determination and confirmation of HCB and mirex in biological matrices like adipose tissue are crucial for risk assessment.
• Existing methods required modification to simultaneously analyze both HCB and mirex residues.

Purpose of the Study:

• To collaboratively study and validate a modified analytical method for the determination and confirmation of hexachlorobenzene (HCB) and mirex in adipose tissue.
• To assess the interlaboratory performance, recovery, and precision of the proposed method.
• To establish a reliable method for routine analysis of these contaminants.

Main Methods:

• A previously published method for HCB determination was modified to include mirex analysis.
• The modified procedure involved direct application of extracted fat to a Florisil cleanup column with one-fraction elution.
• Gas-liquid chromatography (GLC) was used for direct determination, with HCB confirmation via a BITB derivative and mirex destruction.

Main Results:

• Interlaboratory recoveries for HCB ranged from 87.4% to 92.6% across fortification levels of 20.0-50.0 ppb.
• Interlaboratory recoveries for mirex ranged from 89.0% to 92.3% across fortification levels of 150-500 ppb.
• Coefficients of variation (CV) for HCB were generally low (6.8-10.0%), while mirex CVs were acceptable (7.6-18.1%).

Conclusions:

• The modified method provides reliable and accurate determination and confirmation of both HCB and mirex in adipose tissue.
• The method demonstrated good interlaboratory reproducibility and recovery, making it suitable for routine analysis.
• The method has been officially adopted as a first action method.