Determination of the pesticide chlorothalonil by HPLC and UV detection for occupational exposure assessment in greenhouse carnation culture.

An HPLC method was developed for application in the measurement of occupational exposure to the pesticide chlorothalonil. In addition, sampling methods were validated for the determination of exposure to chlorothalonil in the greenhouse culturing of carnations. Procedures for sampling of the inspirable fraction of aerosols, for the determination of hand contamination by hand rinse and the use of cotton gloves, and for the determination of dislodgable chlorothalonil residues on carnation leaves were validated. Normal phase HPLC with hexane-dioxane as the eluent and UV detection at either 254 or 325 nm appeared suitable for the determination of chlorothalonil in the described matrices. The limit of detection, after concentration on SepPak C18 cartridges was approximately 0.5 micrograms/L. Linear calibration curves were obtained in concentration ranges from 0.5 microgram/L to 100 mg/L. In general, no interferences were noticed in the analysis of the matrices. However, cotton gloves for determination of hand contamination had to be washed before use because they contained interfering material, and in the case of air sampling, glass fiber filters for air sampling appeared to degrade chlorothalonil very rapidly. Therefore, cellulose filters were used for collection of the inspirable fraction of aerosols containing chlorothalonil.