Roger C. Blinn

The utilization of infrared and ultraviolet spectrophotometric procedures for assay of pesticide residues

In the United States, the field of residue analytical chemistry has recently emerged from its infancy. This gestation logically can be divided into that period preceding the introduction of DDT1 in 1942 and that period extending from the introduction of DDT until the enactment of Public Law 518 (the Miller Pesticide Residue Amendment to the Federal Food, Drug, and Cosmetic Act) in 1954 and of Public Law 929 (the Food Additives Amendment to the Federal Food, Drug, and Cosmetic Act) in 1958. The first portion of this infancy, the pre-DDT period, was devoted principally to the elucidation of analytically scrutinizable factors pertaining to the field performance of available pest-control chemicals, e.g., the effects of stickers, spreaders, and other adjuvants on depositing efficiencies and residue longevities. Awakening interest as to the amounts of pest-control agent present at the time of consumption, as associated with possible hazards to the public health, was apparent at this time. The post-DDT period was evidenced by ever increasing concern with the hazards to health that might result from some penetrated pesticide residues, with associated concern about the possible risks to be associated with metabolites of pesticides that might be formed either during residual existence or after mammalian ingestion.

Infrared and ultraviolet spectrophotometry in residue evaluations

In order to begin this discussion of infrared and ultraviolet spectrophotometry in residue evaluations, it is important to discuss briefly the broad field of spectrophotometry and to define the various regions of the electromagnetic spectrum of interest.

Metabolism and the Pesticide Residue Analyst

Abstract Pesticide metabolism studies and residue analytical studies have some common objectives and some basically different ones. The metabolism chemist determines what metabolites are present in a biological environment after exposure to a pesticide but is not able to determine their concentrations under actual realistic field conditions. The residue analyst, after being informed what significant metabolites he must determine, then measures them after field exposure. This paper explores how a metabolism chemist achieves his identification and the significance of the metabolites he identifies.