Isomer-specific analysis of PCBs

STALLING ET AL. Isomer Specific Analysis of PCBs Table I. Continued Chlorines Peak RRT Total Ortho Structure 203 Cone. uk/k... 

No isomer specific analysis of PCB has been performed on any sample. However, over the period 1981 to 1987 chromatograms of some human and animal samples have been analyzed according to the Sawyer method [30] and peaks assigned relative to the... 

A principal components multivariate statistical approach (SIMCA) was evaluated and applied to interpretation of isomer specific analysis of polychlorinated biphenyls (PCBs) using both a microcomputer and a main frame computer. Capillary column gas chromatography was employed for separation and detection of 69 individual PCB isomers. Computer programs were written in AMSII MUMPS to provide a laboratory data base for data manipulation. This data base greatly assisted the analysts in calculating isomer concentrations and data management. Applications of SIMCA for quality control, classification, and estimation of the composition of multi-Aroclor mixtures are described for characterization and study of complex environmental residues. 

For example, a single estimate for total PCB s has been historically collected in the NHATS program. Current advances in chemical analysis protocols now allow for the determination of isomer specific resolution of PCB s. Given the 209 PCB s that are now possible to detect, an adequate evaluation of the data without the use of pattern recognition techniques seems impossible. From a QA/QC perspective, these methods can facilitate the detection of outliers and aid in the interpretation of human chemical residue data. The application of statistical analysis must keep abreast with these advances made in chemisty. To handle the complexity and quantity of such data, the use of more sophisticated statistical analyses is needed. 

Kannan, K., Tanabe, S., and Borrell, A. et al. (1993). Isomer specific analysis and toxic evaluation of PCBs in striped dolphins affected by an epizootic in the western Mediterranean sea. Archives Environmental Contamination and Toxicology 25, 227-233. 

Tandem MS monitoring selected fragment ions produced in the collision cell of a sector or multiquadrupole instrument or in an ion-trap chamber offers advantages over single-stage MS in terms of selectivity of analysis and specificity in molecular structure determination [104]. Tandem MS techniques have been widely used with good results for the analysis of polyhalogenated compounds, such as isomers of the polychlorinated dibenzo-y dioxines and dibenzofurans [105], PCBs [106], PCNs, and related compounds [107]. However, the applica tion of MS-MS to the analysis of PCTs and toxaphene has been very limited. 

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