title: A Highly Sensitive and Selective Catalytic Determination of Mercury in Environmental Samples.
abstract: A simple, selective and highly sensitive spectrophotometric method has been developed for mercury determination utilizing its catalytic effect on the isoniazid-hexacyanoferrate (II) reaction. The paper presents for the first time (1) the catalytic effect of Hg (I) on the cited ligand substitution reactions and (2) the activating effect of thiourea on the behavior of mercury. The reaction was monitored spectrophotometrically at 423 nm using the initial rate method. The optimized reaction conditions were 5.0 mmol L(-1) hexacyanoferrate (II), 0.5 mmol L(-1) isoniazid, 150 mmol L(-1) citrate buffer (pH 3.30 ± 0.05), and 0.2 mmol L(-1) thiourea, at 50°C. Linear calibration graphs were obtained for 1-100 and 1-55 µg L(-1) with detection limits, based on the 3Sb-criterion, of 1.2 and 1.8 µg L(-1) of Hg (II) and Hg (I), respectively. The method was conveniently applied to samples of wastewaters, inactivated vaccines, and frozen Bass fish fillet, without any prior separation or preconcentration.
authors.affiliation: Department of Chemistry, Faculty of Science, Ain Shams University, Abbassia, Cairo, 11566, Egypt. aamohamd@sci.asu.edu.eg.
authors.forename: Ashraf A
authors.initials: AA
authors.lastname: Mohamed
authors.affiliation: Department of Chemistry, Faculty of Science, Ain Shams University, Abbassia, Cairo, 11566, Egypt.
authors.forename: Nagat A
authors.initials: NA
authors.lastname: Ahmed
authors.affiliation: Department of Chemistry, Faculty of Science, Ain Shams University, Abbassia, Cairo, 11566, Egypt.
authors.forename: Mohamed F
authors.initials: MF
authors.lastname: El-Shahat
mesh_terms: D000818:Animals; D001492:Bass; D002138:Calibration; D002384:Catalysis; D004777:Environment; D004784:Environmental Monitoring / Q000379:methods; D004785:Environmental Pollutants / Q000032:analysis* / Q000737:chemistry; D057230:Limit of Detection; D008628:Mercury / Q000032:analysis* / Q000737:chemistry; D013053:Spectrophotometry / Q000379:methods*
chemical_list: D004785:Environmental Pollutants; D008628:Mercury
keywords: Bass fish fillet; Catalyzed ligand exchange; Mercury determination; Thiourea activator; Vaccines; Wastewaters