Analysis of residual acrylamide in field crops

Abstract

Polyacrylamide (RAM) is a widely used product for a large number of applications. Many of the emerging applications are in the area of agriculture. PAM is blended with pesticides as a thickening agent, added to irrigation water to minimize soil erosion, and used as a medium for hydroponically grown crops. Although PAM is stable and considered to be safe, residual acrylamide (AMD) monomer is a neurotoxin and animal carcinogen. In this work, residual AMD is analyzed in a variety of crops that were grown under PAM treatment to stabilize soil erosion. Corn, potatoes, sugar beets, and beans are analyzed for AMD. A sample of the crop is homogenized with water, and the water layer is filtered and derivatized with bromine to form 2,3-dibromopropionamide. The derivative is then extracted with ethyl acetate and converted to the more stable 2-propenamide prior to gas chromatographic analysis using an electron capture detector. Capillary Carbowax columns were used. All tested crops show < 10 ppb AMD. Furthermore, it seems that AMD is not stable when it comes in contact with the crop tissues. In the presence of plant tissues, AMD will dissapear as a function of time. Beans blended with 100 ppb AMD for 10 min yield a recovery of only 22%. For a bean sample that was soaked with 500 ppb AMD solution for 18 h, the recovery is 7%. Other crops show different AMD recoveries.