Determination of Morestan Residues in Water and Foodstuffs by Transmitted Room Temperature Solid Phase Spectrophosphorimetry

Abstract

A method for the determination of the pesticide morestan by means of transmitted room temperature solid phase spectrophosphorimetry has been developed. The method is based on the native phosphorescence showed by the morestan when it is fixed in a Whatman No 4 paper as a solid support. The excitation and emission wavelengths were 362 and 527 nm, respectively. The optimum phosphorescent emission was obtained when the delay time was 0.15 ms and the gate time 12.0 ms without need of a heavy atom. The linear dynamic range was between 0.1 and 1.0 μg.ml⁻¹, and the detection and quantification limits were 0.03 and 0.09 μg.ml⁻¹, respectively. The precision of the method, expressed as the relative standard deviation of ten samples at the 0.6 μg.ml⁻¹ concentration level, was 3.0%. The method was applied to the determination of the pesticide in different type of waters, potatoes and vegetables.

Key Words:

• Morestan determination
• Residues analysis
• Room temperature phosphorescence