FLOW INJECTION SPECTROPHOTOMETRIC DETERMINATION OF PROPOXUR WITH DIAZOTIZED 4-AMINOBENZOIC ACID

ABSTRACT

A flow injection spectrophotometric method for the determination of propoxur with diazotized 4-aminobenzoic acid as the coupling agent was developed. The determination involves on-line hydrolysis at room temperature of the propoxur with sodium hydroxide. The resulting 2-isopropoxyphenol is coupled with diazotized 4-aminobenzoic acid in order to achieve an appropriate selectivity and sensitivity to the spectrophotometric measurements. The calibration curve is linear over the range 1–10 mg L⁻¹ of propoxur. The proposed method has provided a detection limit of 0.15 mg L⁻¹ of propoxur and a sample frequency of 120 injections per hour. The relative standard deviation of six independent determinations of a sample containing 5 mg L⁻¹ propoxur was 0.74%. The suitability of the proposed procedure for the determination of propoxur in commercial pesticide formulations was studied. The procedure provides results comparable to those obtained by the liquid chromatography analysis.

Keywords:

• Propoxur
• Pesticide Formulations
• Flow Injection
• Spectrophotometry

ACKNOWLEDGMENTS

This work was supported by the FAPERGS and CNPq, Brazil.