In situ determination of carbaryl in complex biological matrices using a potentiometric chemical sensor, and study of superionic barium-tin-fluorine(4) as a potential transducer material

Carbamate insecticides such as carbaryl (1-naphthyl N-methylcarbamate) are broad-spectrum insecticides that comprise the major portion of agricultural pesticides used in today's agricultural industry. Therefore, the synthesis of molecularly imprinted polymeric beads that can be used for isolating carbaryl from complex matrices would be a great asset. Conventional molecular imprinting technology allows the synthesis in organic solvents of molecularly imprinted polymers (MIPs) that have considerable molecular recognition ability, and can be used as a separation media. The results obtained showed that the use of an imprinted polymer cartridge as a pre-column in high performance liquid chromatography (HPLC), using ultra-violet detection and a "dilute and shoot" approach for the rapid, inexpensive and accurate determination of carbaryl in complex biological matrices (rat plasma and apple homogenate) with a detection limit of 1.00 ng/mL and a response that is linear (r² > 0.98) over the concentration range of 1.00 to 10.0 ng/mL, was successful. In the past decade, numerous biosensing methods for the detection of pesticides have been developed using enzyme-based and affinity-based sensors as well as several types of transducers and this has been the subject of several recent reviews. We report that the use of an imprinted carbaryl polymer column in a non-enzymatic flow injection potentiometric chemical sensor system for the determination of carbaryl in complex biological matrices (rat plasma) was successful. The potentiometric chemical sensor system efficiency in the determination of carbaryl in rat plasma was validated in terms of selectivity, carry-over, calibration range and precision and accuracy in accordance with the Guidance for Industry Bioanalytical Method Validation, U.S. Department of Health and Human Services, Food and Drug Administration. However, the results showed that the use of BaSnF 4 as a solid state conductivity electrode as a part of a conductivity chemical sensor system for the determination of carbaryl in solution was not successful due to limitations in preparing a BaSnF4 sheet resistant to the capillary pressure applied by the micro-fluid passing through the conductivity cell.