Organophosphorus pesticides were among the most widely used pesticides until the twenty-first century. They have a variety of uses in agriculture, home, garden, and veterinary practices. Thirty-six are registered in the United States, but because of their additive toxicity, many are being discontinued for use.1 These pesticides persist in the environment and are present in many agricultural products, often at very low levels, so it is important to identify and quantify their presence using the most up-to-date methodology.
USEPA Method 8141B is often used to analyze organophosphorus (OPP) pesticides. The method specifies flame photometric detection (FPD) or nitrogen – phosphorus detection (NPD). Use of a pulsed flame photometric detector (PFPD) is an alternative to these two detectors.
The PFPD uses a pulsed flame, instead of continuous or static flame of the FPD, which adds a time-dependent variable to the analysis. The PFPD is not subject to the interferences caused by organonitrogen compounds that naturally occur in plant tissue. There are several advantages in using a PFPD, including detectivity and selectivity of the phosphorus species as well as ease of use. The detector can also be configured to simultaneously detect phosphorus and sulfur, producing mutually selective chromatograms thus increasing information gathered for each analysis.
While this is a mature methodology, there have been improvements in instrumentation and column technology which will be explored using new technology and showing an optimized method for OPP pesticides.
