Fluorescence/Spectrophotometric Determination Of Trace Ion In Environmental Water Samples

With the rapid development of industry, more and more toxic and harmful pollutants are brought about, such as heavy metals, pesticides, organic compounds, et al. Heavy metal ions are potentially harmful and important pollutants, it can cause environmental pollution even at low level. Thus, It is a great significance to establish the trace analysis determination technology of heavy metal ions. Fluorescence analysis and spectrophotometry are get the advantages of low detection limit, high sensitivity and good selectivity .They are important methods in chemical trace analysis, and widey applyed in environmental analytical chemistry.In this paper, the main task is to design and synthesis a new type molecular probe that have the excellent performance of easy to detect, sensitivity, selectivity and stability. Study the probe properties and the detection application in environmental water samples. Including the following three aspects:(1)A new fluorescent probe, N-(2-pyridylmethyl)-1, 8-naphthalimide(PMN) was synthesized and its application of detection of trace Fe3+ in water samples was investigated. The fluorescence intensity of the probe decreased with increasing concentration of Fe3+, while other cations have little or no response on the fluorescence intensity of PMN. In a certain range of 1×10-7~8×10-5mol/L, the fluorescence intensity was linear dependent on the concentration of Fe3+.The method was verified having the advantages of high sensitivity, good selectivity and ease to operate. It was successfully applied to determinate of Fe3+ in tap water, well water and domestic sewage samples,and got the recovery of 95.78%~104.02 %.(2) A novel type of color reagent(2-N-(monothiosemicarbazone-glyoxal)-fluorene) with good selectivity was synthesized and applied to detected mercury and copper pollu- tants in environmental samples. The influence of the acidity, the amount of reagent, the amount of active agent, interfering ions and others to the detection was studyed. Mercury ion with the reagent have the maximum absorption at the wavelength of 405nm. In the range of 1.5 ~ 100ug/25mL, Hg2+ content was lined with the absorbance,the linear equation was A = 0.0039C-0.0029 (A-absorption degrees, C-ugHg2 + / 25mL), correlation coefficient r was 0.9984, apparent molar absorptivityεwas 0.191×10-5L ? mol-1 ? cm-1.(3) copper ions reaction with the color reagent to form red complexes, there is the maximum absorption at wavelength of 475nm. Paper studied the best conditions for detection copper ions by spectrophotometry without active agent .The rusults showed that: in the range of 0.6 ~ 64ug/10mL ,Cu2+ content was a linear with absorption ,the regression equation was A = 0.0114C-0.004 (A-absorbance, C-ugCu2 + /10mL), correlation coefficient r was 0.9994, the apparent molar absorptivity was 0.072×105 L ? mol-1 ? cm-1.