Molecularly Imprinted Solid Phase Extraction of Atrazine from Beef Liver Extracts

Abstract

Molecularly imprinted polymers were used as specific binding matrices for the solid phase extraction and cleanup of biological sample extracts. To demonstrate this, an anti-atrazine polymer was used to cleanup organic extracts of beef liver. Atrazine retention on the columns was greatest in chloroform. The binding capacity of the polymer in chloroform was 19 mumol of atrazine per gram. Purified and unpurified beef liver extracts were analyzed by both reversed-phase HPLC and ELISA. The use of molecularly imprinted solid phase extraction (MISPE) improved the accuracy and precision of the HPLC method and lowered the limit of detection (0.005 ppm). Atrazine recovery as determined by HPLC from beef liver homogenates spiked to levels from 0.005 to 0.5 ppm averaged 88.7% following MISPE and 60.9% for the unpurified extracts. Atrazine recovery as determined by ELISA averaged 92.8% following MISPE and 79.6% for the unpurified extracts. Crude tissue sample extracts interfered with both the HPLC and ELISA methods. However, the use of MISPE allowed for the rapid analysis of complex biological matrices using either method at the tolerance level of 0.02 ppm in meat products. The application of molecular imprinting technology for solid phase extraction is a new approach for the analysis of highly lipophilic low molecular weight contaminants.