5-磺酸钠-7-苯偶氮-8-氨基喹啉的合成及荧光光度法测定微量钴

Synthesis of 5-Sodium Sulfonate-7-Phenylazo-8-Amino-Quinoline and Fluorimetric Determination of Trace Amounts of Cobalt

首次合成了5-磺酸钠-7-苯偶氮-8-氨基喹啉(SPAAQ).产品通过了元素分析、红外光谱、热分析鉴定.用光度法测定了SPAAQ的酸离解常数,pKa_3=3.8(20℃,I=0.1).在弱碱性条件下,有H_2O_2存在时,SPAAQ与Co(Ⅱ)作用,在λex/λem=288nm/380nm处产生强烈荧光,其荧光强度与钴(Ⅱ)浓度在2～50ppb范围内呈线性关系,检出限0.08ppb.可用于蔬菜和矿石中痕量钴的测定.

5-sodiuin sulfonate-7-phenylazo-8-aminoquinoline (SPAAQ) were synthesized. The product was checked by infrared spectroscopy, elements analysis and tharmogravimetry. The acid dissociation constants of SPAAQ are determined with spectrophotometric method.Its pKa3 is found to be 3.80 (20℃). In the presence of H2O2, cobalt ( Ⅱ )r eacts with SPAAQ at pH 8.6-10.6, forming a product which shows intense fluorescence at ex/em=288nm/380nm. The fluorescence intensity is proportional to the concentration of cobalt ( Ⅱ ) in the range of 2-50ppb. The detection limit is 0.08ppb. This method has been used to the determination of trace amounts of cobalt in vegetable and ores.