Environmental contaminants, HPLC

Pesticides and polynuclear aromatics (PNAs) are the most commonly analyzed environmental contaminants. Analysis of PCBs, dioxans, and nitroor-ganics (explosives) is of growing importance. The major obstacles to adoption of environmental HPLC application are 1) awareness of the need, (i.e., environmental and drinking water contamination) and 2) the slow rate of development and acceptance of new AOAC and EPA-mandated HPLC and LC/MS methods. 

In the late 1970s HPLC provided an ideal tool for the analysis of pollutants and other environmental contaminants. Techniques were developed for analyzing chlorophenols, pesticide residues, and metabolites in drinking water and soil (parts per trillion) and trace organics in river water and marine sediments, and for monitoring industrial waste water and polynuclear aromatics in air. Techniques were also developed for determining fungicides and their decomposition products and herbicide metabolites in plants and animals. 

HPLC is a versatile technique applicable to diversified analytes, including labile molecules, ions, organic, and biopolymers. This chapter provides an overview of HPLC applications for the analysis of food, environmental, chemical, polymer, ion-chromatography, and life science samples. In food analysis, HPLC is widely used in product research, quality control, nutritional labeling, and residual testing of contaminants. In environmental testing, HPLC is excellent for the sensitive and specific detection of labile and nonvolatile pollutants... 

Organic compounds sought include naturally derived materials, such as mycotoxins and off-flavours (produced by rancidification or spoilage), and man-made/industrial chemicals, e.g. pesticides, veterinary drugs, environmental contaminants (such as polychlorodibenzo-p-dioxins, polychlorinated biphenyls, polynuclear aromatic hydrocarbons, etc.) and food tainting compounds (e.g. 2,4,6-trichloro-anisole, the compound responsible for musty cork taint in wine, arising from the inappropriate use of wood preservatives). GC-MS and HPLC-API-MS are widely used for these types of analyses. Desirable food components present at trace levels, such as nutrients, are also determined using these techniques. 

PCBs can be conveniently determined by most of the common analytical techniques which include GC-ECD, GC-HECD, GC-FID, GC/MS, HPLC, NMR, and enzyme immunoassay. Among these, GC-ECD and GC/MS are by far the most widely used techniques for the determination of PCBs in the environmental samples at a very low level of detection. While the former can detect the PCBs at subnanogram range, the mass selective detector (GC/MS) identifies the components relatively at a higher detection range, 10 to 50 times higher than the ECD detection level. GC/MS, however, is the best confirmatory method to positively confirm the presence of PCBs, especially in heavily contaminated samples. Aqueous and nonaqueous samples must be extracted into a suitable solvent prior to their analysis. 

A method for the determination of Sbm and Sbv in environmental samples was based upon HPLC-ICP-MS (Lintchinger et al., 1997). Inorganic Sbm and Sbv were separated from each other and from organic antimony species, (CH3)3SbCl2 and (CH3)3Sb(OH)2, on an anion-exchange column. The detection limits were in the lower mg dm-3 range. The method was applied to analyses of hot spring samples and soil samples that had been contaminated with antimony. 

Webster GRB, Sama LP, Friesen K, et al. 1984. HPLC techniques for the evaluation of the interactions of organic contaminants with individual environmental compartments. Am Chem Soc Div Environ Chem 24 42-45. 

The willingness to risk severe contamination of a GC or HPLC column, or some other critical instrument component, by a concentrated or high background environmental sample... 

As was the case in air-pollution research, in water pollution work the largest concern is the monitoring of the environment to determine if contamination is occurring and to follow the subsequent reduction of the level of problematic substances. As was mentioned earlier, PAHs are of environmental concern and, as such, are being monitored in air and water. Figure 2-14 shows the HPLC analysis of a National Bureau of Standards (NBS) sample of... 

For a good discussion of on-line SPE coupled to HPLC, the work of Hennion and Pichon (1994) and Hennion and co-workers (1990) discuss environmental applications. In their work, the styrene-divinylbenzene copolymers are used as SPE columns with good capacity for many of the environmentally relevant contaminants and allow for direct analysis by HPLC. Hennion and Pichon (1994) discuss and review a number of studies on pesticides and related compounds by on-line SPE. There is also more discussion of on-line SPE methods coupled to GC/MS in Chapter 10. 

Extracts from environmental samples are seldom sufficiently free of contaminants that they can be analyzed directly, since the high-resolution columns used for GC or FIPLC analysis must not be overloaded with compounds other than the analyte. Pretreatment of the sample before GC, GC-MS, or HPLC analysis is therefore often a critical step in the analysis of extracts from complex matrices, and this is particularly important when the concentrations of... 

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