Molecularly imprinted polymer solid-phase extraction coupled to square wave voltammetry at carbon fibre microelectrodes for the determination of fenbendazole in beef liver.
A molecularly imprinted polymer was developed and used for solid-phase extraction (MISPE) of the antihelmintic fenbendazole in beef liver samples. Detection of the analyte was accomplished using square wave voltammetry (SWV) at a cylindrical carbon fibre microelectrode (CFME). A mixture of MeOH/HAc (9:1) was employed both as eluent in the MISPE system and as working medium for electrochemical detection of fenbendazole. The limit of detection was 1.9x10(-7) mol L-1 (57 microg L-1), which was appropriate for the determination of fenbendazole at the maximum residue level permitted by the European Commission (500 microg kg-1 in liver). Given that the SW voltammetric analysis could not be directly performed in the sample extract as a consequence of interference from some sample components, a sample clean-up with a MIP for selectively retaining fenbendazole was performed. The MIP was synthesized using a 1:8:22 template/methacrylic acid/ethylene glycol dimethacrylate ratio. A Britton-Robinson Buffer of pH 9.0 was selected for retaining fenbendazole in the MIP cartridges, and an eluent volume of 5.0 mL at a flow rate of 2.0 mL min-1 was chosen in the elution step. Cross-reactivity with the MIP was observed for other benzimidazoles. The synthesized MIP exhibited a good selectivity for benzimidazoles with respect to other veterinary drugs. The applicability of the MISPE-SWV method was tested with beef liver samples, spiked with fenbendazole at 5,000 and 500 microg kg-1. Results obtained for ten different liver samples yielded mean recoveries of (95+/-12)% and (96+/-11)% for the upper and lower concentration level, respectively.
Guzmán-Vázquez de Prada
A
A
Department of Analytical Chemistry, Faculty of Chemistry, Complutense University of Madrid, 28040, Madrid, Spain.
Loaiza
Oscar A
OA
Serra
B
B
Morales
D
D
Martínez-Ruiz
P
P
Reviejo
A J
AJ
Pingarrón
J M
JM
D000818:Animals; D000969:Antinematodal Agents / Q000032:analysis*; D002244:Carbon / Q000737:chemistry*; D002417:Cattle; D004563:Electrochemistry; D005273:Fenbendazole / Q000032:analysis*; D005506:Food Contamination / Q000032:analysis; D008099:Liver / Q000737:chemistry*; D008461:Meat Products / Q000032:analysis / Q000592:standards; D008839:Microelectrodes; D011108:Polymers / Q000737:chemistry*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D052616:Solid Phase Extraction
D000969:Antinematodal Agents; D011108:Polymers; D005273:Fenbendazole; D002244:Carbon