NONDESTRUCTIVE ANALYSIS OF CHLORPYRIFOS ON APPLE SKIN USING UV REFLECTANCE.

Analysis of chlorpyrifos using UV was performed to assess the possibility of nondestructive detection of pesticides on agricultural products. Absorbance of chlorpyrifos dissolved in acetonitrile was positively proportional to its concentration at 229 and 290 nm at limits of detection (LOD) of 0.0233 and 0.0113 mg kg-1 and limits of quantification (LOQ) of 0.0778 and 0.0378 mg kg-1 respectively. This suggested that a UV method is suitable for detection and quantification of chlorpyrifos. UV reflectance changes were used to estimate the amount of chlorpyrifos dried on apple skin. Differences between reflectance at 280 and 300 nm were positively proportional to the amount of chlorpyrifos standard dried on apple skin, and the LOD was 0.0849 mg cm-2. Reflectance differences between 260 and 290 nm were positively proportional to the amount of chlorpyrifos included in water-dispersible Dursban dried on apple skin, and the LOD was 0.000214 mg cm-2 These LOD values were below the amount required for acute intoxication in mammals resulting from oral dosage. This UV optical method is practical for 100% nondestructive inspection and detection of chemicals present on product surfaces and thus may be suitable for use in sorting lines. However, it may not be effective for detecting chemicals in products' internal tissues as can be achieved through immunochemical techniques and gas chromatography with mass spectrometry, which, while more sensitive than this UV method, are destructive and therefore not suitable for 100% inspection of shipping products. [ABSTRACT FROM AUTHOR]