Study On The Rapid Determination Of Several Trace Heavy Metals

In recent years, toxic heavy metal ions move into the animal food chain with industrial waste. It causes the deterioration of ecosystems and obvious lesions or death of animals. Then threat the health of people. Therefore, it is greatly significant for rapid the determination of heavy metals. In this paper, the determining methods have been established to detect trace toxic heavy metals by Spectrophotometry, and get the following several conclusions:(1) In the presence of cetrimonium bromide(CTMAB),the trace amounts of Pb(Ⅱ) was determined by Spectrophotometry using phenylfluorone(PF) as colouring reagent. The results show that in the pH 12-13 buffer solution beer's law was obeyed in the concentration range of Pb(Ⅱ) over 0-18.0μg/50 mL with the molar absorptivity of 3.63×104 L·mol-1·cm-1, r=0.9988. The average recovery of water sample was 99.83% with RSD of 1.58%.The recovery was 99.6%-101.4%for Pb(Ⅱ) content in cosmetic with RSD of 1.16%-1.33%. The method was simple, rapid, sensitive and accurate and could be applied to detect trace lead in daily supervision and on-site detection of toxic samples.(2) The conditions of the color reaction between the titanium yellow---Tween 80 and Cd(Ⅱ) were studied in this paper, and simplified the reagent determination of trace amounts cadmium in the operation of the spectrophotometry. Discussed a interfering ions of the masking method. In alkaline solution the titanium yellow---Tween 80 and Cd(Ⅱ) were easy to form orange yellow complex. The results show that the maximum absorption wavelength is 472 nm. Beer's law was obeyed in the concentration range of Cd(Ⅱ) over 0-15.0μg/50 mL with the molar absorptivity of 1.38×105 L·mol-1·cm-1 The recovery range was 99.87%-100.5%. The method was sensitive, simple, and had been used for the determination of cadmium in water with satisfactory results.(3) a new reagent bis(2-phenyl-benzothiazolate)iridium(Ⅲ)(acetylacetonate) ((bt)2Ir(acac)) was synthesized, and the product was confirmed by elemental analysis, and 1H NMR. The conditions of the color reaction between (bt)2Ir(acac) and Hg(Ⅱ) were studied. Based on this color reaction, a new spectrophotometric method for the determination of Hg(Ⅱ) was developed. The results show that the surfactant and the solution pH can't affect the complexation reaction and the complex with a molar ratio of (bt)2Ir(acac) to Hg(Ⅱ) of 1:1. The maximum absorption wavelength is 396 nm. Beer's law was obeyed in the concentration range of Hg(Ⅱ) over 0-8μg/10 mL with the molar absorptivity of 1.06×104 L·mol-1·cm-1. The method was sensitive, simple, and had been used for the determination of mercury in water with satisfactory results.