7. ANALYTICAL METHODS
The purpose of this chapter is to describe the analytical methods that are available for detecting,
measuring, and/or monitoring diazinon, its metabolites, and other biomarkers of exposure and effect to
diazinon. The intent is not to provide an exhaustive list of analytical methods. Rather, the intention is to
identify well-established methods that are used as the standard methods of analysis. Many of the
analytical methods used for environmental samples are the methods approved by federal agencies and
organizations such as EPA and the National Institute for Occupational Safety and Health (NIOSH). Other
methods presented in this chapter are those that are approved by groups such as the Association of
Official Analytical Chemists (AOAC) and the American Public Health Association (APHA).
Additionally, analytical methods are included that modify previously used methods to obtain lower
detection limits and/or to improve accuracy and precision.
7.1 BIOLOGICAL MATERIALS
Diazinon is widely used for agricultural purposes, which may result in human exposure during
application, and residues on or in foods can result in exposure of humans by ingestion. Although all
indoor and outdoor residential use has been phased out and cancelled, additional exposure potentials exist
as a result of home gardening activities and pet pest control. Consequently, methods for the
determination of diazinon in biological samples can be used to verify that exposure and absorption has
occurred. Since diazinon is rapidly metabolized, determination of the parent compound can only provide
evidence of very recent exposures (see Chapter 3). Methods have been reported for metabolites, and
these are briefly discussed below and under Biomarkers of Exposure. Table 7-1 lists the applicable
analytical methods for determining diazinon and its metabolites in biological fluids and tissues.
The principal method used for the detection of diazinon or its metabolites in biological samples is gas