On Line Determination Of Emergency Pollution Of Lead, Chromium, Mercury In Food Water By Chemiluminescence System With Flow Injection

Heavy metal emergency pollution incidence in food water is increasing especially in urban drinking water in recent years and the safety of drink water face serious challege. Rapid monitoring the abrupt change of harmful chemicals such as heavy metals in food water has been the research emphasis in government the emergency management for early alert and prevention of food safety accidents.The purpose of this study was to investigate the possibility of the early warning of sudden pollution of heavy metal such as lead, chromium and mecury in food water, with the main content:(1) Evaluation of the correlation between the electric conductivity, pH value and heavy metal pollution; (2) Determination of Pb (Ⅱ) in drinking water by luminol-1,10-phenanthroline-H2O2 chemiluminescence system; (3) Determination of the sudden varying of Cr (Ⅲ) in food water by potassium bromide-luminol-H2O2 chemiluminescence system with flow injection; (4) Determination of Hg (Ⅱ) in food water by flow injection analysis chemiluminescence combined with mercury vapor analyzer. The main results were listed as follows:1. There was positive correlation between electric conductivity and the concentration of heavy metals, but the discrepancy wasn't significant when the concentration was below in 1000 times of the maximum levels prescribled in the national standard (GB). The turbidity of the drinking water changed when different concentrations of Pb (Ⅱ) were added into it. But there was no significant change when the concentration of Pb (Ⅱ) exceeds 100 times of the standards.2. Catalytic reaction of luminol-phenanthroline-H2O2 chemiluminescence by Pb (Ⅱ) was investigated using flowing-injection chemiluminescence. Results showed that Pb (Ⅱ) enhanced the chemiluminescence intensity of luminol-1, 10-phenanthroline-H2O2, and this stimulation of Pb (Ⅱ) had a positive correlation with its concentration in drinking water when its concentration ranged from 1.0×10-7 g/mL to 1.0×10-5g/mL with detection limit of 5.9x10-9g/mL.3. Based on the sensitive chemiluminescent of potassium bromide reaction in the system of luminol-H2O2-Cr (Ⅲ), a sensitive chemiluminescent method for determination of Cr(Ⅲ) with flow injection technique was developed. The method is simple,rapid and effective to determine Cr (Ⅲ) in the range of 1×10～6-1×10-3 mg/mL with detection limit of 2.06×10-7 mg/mL.4. Hg (Ⅱ) has the inhibiting effect to the chemiluminescence system of luminol-phenanthroline-H2O2 which can be used as an early alarming system. It can be combined with mercury vapor analyzer to detect the abrupt change of Hg (Ⅱ) in food water. The linear range of the mercury vapourmeter is 0～10μg/L with detection limit of 0.5μg/L.Rusults above conclude that combination of flow-injection and chemiluminescence is a potential on-line method to detect the emergency pollution of heavy metals in the food water and therefore used for early alert system.