Tailoring biosensors for Brazil: Detection of insecticides in foods

An acetylcholinesterase (AChE) B multisensor from Nippostrongylus brasiliensis (Nb) was developed, able to detect the most frequently used insecticides in Brazil. The objective was to establish a fast screening-out method, separating the negative samples from the positive ones. The four mutants, which together presented the widest sensitivity spectrum, were: F345A, M301A, W346V and W346A. The combination of these four mutants in a multienzyme biosensor array enabled the detection of 11 out of the 12 most important insecticides at concentrations below 10 mu g/kg. The biosensor test was compared with traditional analysis methods, and validated with food samples previously analyzed. The storage stability revealed that the enzyme activity remained stable for 40 weeks; however the sensitivity decreased with time. The biosensor screened out samples with an analysis duration of about 2 h. (C) 2011 Elsevier Ltd. All rights reserved.