Detection of organophosphorus compounds by covalently immobilized organophosphorus hydrolase

Jhony Orbulescu, Celeste A. Constantine, Vipin K. Rastogi, Saumil S. Shah, Joseph J. DeFrank, Roger M. Leblanc

Research output: Contribution to journalArticlepeer-review

35 Scopus citations


As a consequence of organophosphorus (OP) toxins posing a threat to human life globally, organophosphorus hydrolase (OPH) has become the enzyme of choice to detoxify such compounds. Organophosphorus hydrolase was covalently immobilized onto a quartz substrate for utilization in paraoxon detection. The substrate was cleaned and modified prior to chemical attachment. Each modification step was monitored by imaging ellipsometry as the thickness increased with each modification step. The chemically attached OPH was labeled with a fluorescent dye (7-isothiocyanato-4-methylcoumarin) for the detection of paraoxon in aqueous solution, ranging from 10-9 to 10-5 M. UV-visible spectra were also acquired for the determination of the hydrolysis product of paraoxon, namely p-nitrophenol.

Original languageEnglish (US)
Pages (from-to)7016-7021
Number of pages6
JournalAnalytical Chemistry
Issue number19
StatePublished - Oct 1 2006

ASJC Scopus subject areas

  • Analytical Chemistry


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