Abstract
Competitive inhibitors of acetylcholinesterase (AChE) are detected using an evanescent wave technique to monitor changes in the absorbance spectrum of an AChE-monosulfonate tetraphenyl porphyrin (TPPS(1)) complex immobilized on the surface of a glass slide. In this technique, porphyrin is displaced from the AChE active site by the inhibitor. The loss in absorbance intensity of the characteristic absorbance peak for the AChE-TPPS(1) complex at 446 nm is linearly dependent on the log of the inhibitor concentration. This technique yields detection limits at 3:1 S/N of 37 ppt for eserine, 50 ppt for galanthamine, 100 ppt for scopolamine, 250 ppt for tetracaine, 45 ppt for diazinon, and 83 ppb for Triton X-100. When stored under vacuum, the enzymatic lifetime of the immobilized AChE surface is greater than 73 days while the responsive lifetime of the immobilized AChE-TPPS(1) surface is currently 49 days.
Publication types
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Comparative Study
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Evaluation Study
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Research Support, Non-U.S. Gov't
MeSH terms
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Acetylcholinesterase / chemistry*
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Binding, Competitive
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Biosensing Techniques / instrumentation*
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Biosensing Techniques / methods
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Cholinesterase Inhibitors / analysis*
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Cholinesterase Inhibitors / chemistry
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Diazinon / analysis
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Diazinon / chemistry
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Enzymes, Immobilized / chemistry
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Equipment Design
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Equipment Failure Analysis*
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Equipment Reuse
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Galantamine / analysis
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Galantamine / chemistry
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Indicators and Reagents
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Octoxynol / analysis
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Octoxynol / chemistry
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Physostigmine / analysis
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Physostigmine / chemistry
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Porphyrins / chemistry*
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Quality Control
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Reproducibility of Results
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Scopolamine / analysis
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Scopolamine / chemistry
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Sensitivity and Specificity
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Spectrum Analysis / instrumentation*
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Spectrum Analysis / methods
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Tetracaine / analysis
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Tetracaine / chemistry
Substances
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Cholinesterase Inhibitors
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Enzymes, Immobilized
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Indicators and Reagents
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Porphyrins
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Tetracaine
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Galantamine
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tetraphenylporphine sulfonate
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Octoxynol
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Physostigmine
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Scopolamine
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Acetylcholinesterase
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Diazinon