Abstract: A flow injection spectrophotometric method for the determination of carbofuran in commercial pesticide formulations was developed. The determination involves on-line hydrolysis of the extracted carbofuran at room temperature with sodium hydroxide. The resulting carbofuran-phenol is coupled with diazotized 4-aminobenzoic acid in order to achieve an appropriate selectivity and sensitivity for the spectrophotometric measurements. The calibration curve is linear over the range 110 mg L-1 of carbofuran. The proposed method has a detection limit of 0.15 mg L-1 of carbofuran and a sample frequency of 120 injections per hour. The relative standard deviation of six independent determinations of a sample containing 1 mg L-1 carbofuran was 0.6%. The suitability of the proposed procedure for the determination of carbofuran in commercial pesticide formulations was studied. The procedure provides results comparable to those obtained by liquid chromatographic analysis.

Abstract: The automated system consisted of a moveable membrane to which a pesticide-specific antibody was bound via protein A (Sigma). The immobilization of protein A and antiserum was carried out in special glass tubes (described), and up to a 2-m length of membrane (width 8 mm, 0.2 µm pore size; PALL Corp., USA) could be immobilized by this technique. A time-controlled sequence of pumping and injection caused the hapten and the corresponding enzyme-labelled hapten (6-aminohexanoic acid - atrazine - peroxidase, in the case of atrazine) to flow across the membrane, and the fluorescence of the enzyme-generated product was measured. One assay took 15 min. This technique has been applied to the measurement of atrazine and propazine in water, for which the lower detection limits were 0.02 and 0.03 µg l-1, respectively; the coefficient of variation was 5 to 20%. The measurements obtained were compared with those by a conventional ELISA for which the coefficient of variation was 2 to 10%.