Fabrication of an Extra Sensitive Voltammetric Sensor Using Nanoparticles of Molecularly Imprinted Polymer for Determination of Ultra-Trace Promethazine in Plasma Sample

In this work, the nanoparticles of promethazine-imprinted polymers (MIP) were synthesized by the ultrasonic assisted suspension polymerization in silicon oil. The MIP particles were then embedded in a carbon paste (CP) electrode in order to prepare the MIP (nano)-CP electrode. This electrode showed higher response to analyte, compared to the carbon paste electrode, modified with non-imprinted polymer (NIP (nano)-CP). Also, the sensitivity and selectivity of the MIP (nano)-CP were considerably better than those of the sensor prepared by the bulky MIP particles (MIP (micro)-CP). Various factors, known to affect the response behavior of selective electrode, were investigated and optimized. The sensor exhibited two distinct linear response ranges of 4x10(-12)-1x10(-10) M and 1x10(-9)-1x10(-7) M with the sensitivities of 31.7 and 0.17 mu A nM(-1), respectively. The lower detection limit of the sensor was calculated equal to 2.8x10(-12) M (S/N). An interestingly low RSD equal to 0.81% was found for 5 separate determinations by the proposed sensor. The sensor was applied for promethazine (PMZ) determination in plasma samples without applying any sample pretreatment.