Sensitive detection of organophosphates in river water by means of a piezoelectric biosensor
| Authors | |
|---|---|
| Year of publication | 2005 |
| Type | Article in Periodical |
| Magazine / Source | Analytical and Bioanalytical Chemistry |
| MU Faculty or unit | |
| Citation | |
| Web | http://dx.doi.org/10.1007/s00216-005-3260-y |
| Field | Biochemistry |
| Keywords | Piezoelectric sensor; Quartz crystal microbalance; Acetylcholinesterase; Inhibitor |
| Description | A highly sensitive piezoelectric biosensor has been developed for detection of cholinesterase inhibitors.The inhibitor benzoylecgonine-1,8-diamino-3,4-dioxaoctane(BZE-DADOO) was immobilized on a monolayer of 11-mercaptomonoundecanoic acid (MUA) selfassembled on the gold surface of the sensor. The binding of high-molecular-weight cholinesterase to the immobilized cocaine derivative was monitored with a mass sensitive piezoelectric quartz crystal (quartz crystal nanobalance; QCN). In the presence of an inhibiting substance in the sample, the binding of cholinesterase to the immobilized inhibitor was reduced. The decrease of the rate of mass change was proportional to the concentration of free inhibitor in the sample. This way the affinity sensor followed anti-cholinesterase toxicity and the enzyme activity of ChE was not addressed. An assay for detection of organophosphates (OP) was optimized. Regeneration of the sensor surface was achieved with 1 mol/L formic acid, which enabled 40 measurements with one sensor. All assays were carried out in a flowthrough arrangement. The total measurement time (binding+regeneration) was 25 min and the detection limit for different OP (paraoxon, diisopropylfluorophoshate, chlorpyriphos, and chlorfenvinphos) was down to 10^-10 mol/L (0.02 ug/L). This sensor was used for determination of organophosphate (diisopropylfluorophosphate) levels in river water samples. |
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