Flow injection determination of metrifonate by immobilised acetylcholinesterase inhibition

✍ Scribed by T. Ghous; A. Townshend

• Publisher: Elsevier Science
• Year: 1996
• Tongue: English
• Weight: 552 KB
• Volume: 332
• Category: Article
• ISSN: 0003-2670
• DOI: 10.1016/0003-2670(96)00277-2

✦ Synopsis

A flow injection system for determination of metrifonate by inhibition of immobilised acetylcholinesterase (AChE) is described. Acetylthiocholine is hydrolysed by AChE, and the thiocholine produced is mixed with the chromogen 5,5dithiobis(2-nitrobenzoic acid) and the absorbance is measured at 405nm. The decrease in absorbance due to decrease in enzymatic activity after injecting metrifonate as an inhibitor is measured. On-line re-activation of the inhibited enzyme by buffer, substrate and pyridine-2-aldoxime methiodide is also studied so that system can be reused continuously. The calibration graph is linear in the range of 1 x 10e6 to 1 x lo-' M metrifonate (~0.998, n=5), the 3a limit of detection is 8x lop7 M and the relative standard deviation for 5 determinations of 6x 10e6M metrifonate is 2.0%. Common blood components did not interfere.