T. Montesinos et al., Disposable cholinesterase biosensor for the detection of pesticides in water-miscible organic solvents, ANALYT CHIM, 431(2), 2001, pp. 231-237
A disposable cholinesterase biosensor based on screen-printed electrodes wa
s assembled and used to assess the effect of miscible organic solvents on t
he acetylcholinesterase activity and on the inhibitory effect of organophos
phorus pesticides on acetylcholinesterase activity. Acetonitrile, ethanol a
nd DMSO were tested in a range 0-30% mixed with phosphate buffer (0.1 M, pH
7). With 5% acetonitrile and 10% ethanol, an increase of the recorded curr
ent was observed. The addition of 0.2% polyethylenimine to the enzyme prepa
ration, before immobilisation, allowed the utilisation of 15% acetonitrile
without negative effect on the enzyme activity. An inhibition calibration c
urve was obtained using chlorpyrifos-ethyl-oxon, a compound widely used for
agricultural purposes. The lowest detectable amount was 1 ppb following an
incubation time of 10 min. The use of 5% acetonitrile and 0.2% polyethylen
imine did not interfere with the enzyme-inhibitor interactions. (C) 2001 El
sevier Science B.V. All rights reserved.