Synthesis Of New Acylhydrazones And Study On The Use In Analysing Heavy Metal Ions By Fluorometric Method

Studies have shown that the heavy metal ions can bring great danger to the body. So the determination of the heavy metal ions in food products is becoming more and more important. The experiment have shown that the ligand and the metal ions can react in the solution and the production can emit strong fluorescence , based on which a fluorometric method for the determination of metal ions was developed.In the first chapter, this paper offers a brief introduce about the danger of the heavy metal ions and the determination methods, as well as the characteristic, classification and the current situation of the development of acylhydrazone compounds.In the second chapter, l,5-bis(2-hydroxybenzylidene)-thiocarbohydrazide and 3-hydroxy-N'-[(lZ)-(2-hydroxyphenyl)methylene]-2-naphthohydrazide are composed. Then heavy metal ion(Co²⁺, Cu²⁺, Zn²⁺, Cd²⁺) complexes are synthesized. The structure of ligands and complexes is characterized by EA, UV, IR and TG.In the third chapter, the reaction of ligands with heavy metal ions in solution is studied. The influence of acidity on the ligands and the complexes is also studied. The best reaction time and mol ratio are confirmed.In the fourth chapter, the fluorescence reaction of l,5-bis(2-hydroxybenzylide-ne)-Thiocarbohydrazide with zinc(II) is studied emphatically. It is found that the complex emits strong fluorescence at 460nm while excitated at 395nm. Based on this, a fluorometric method for the determination of zinc is developed. The linear range of the method is 0-780μg · L^-1 with a correlation coefficient of 0.9998. The detection limit is 12μg · L^-1. The method has been applied to the determination of Zn²⁺ in zinc enriched salt and human hairs with satisfactory results.In the fifth chapter, the content of this test is summarized.