Titrimetric and Spectrophotometric Determination of Some Thiadiazole Derivatives by Using Amplification Reactions  

作　　者：Mahmood M. Barbooti Ridha I. Al-Bayati Asra A. Hussain Mahmood M. Barbooti;Ridha I. Al-Bayati;Asra A. Hussain(Department of Applied Science, University of Technology, Baghdad, Iraq;Department of Chemistry, College of Science, Al-Mustansiriya University, Baghdad, Iraq)

机构地区：[1]Department of Applied Science, University of Technology, Baghdad, Iraq [2]Department of Chemistry, College of Science, Al-Mustansiriya University, Baghdad, Iraq

出　　处：《American Journal of Analytical Chemistry》2021年第2期46-58,共13页美国分析化学（英文）

摘　　要：The principle of using amplification reactions of iodine was employed in this paper to estimate the thiadiazole derivatives on basis of their reactions with iodine I chloroform, removal of the excess iodine and determination of the resulting iodide, after oxidation to iodate. The overall reaction gave an amplification of the iodide that is (12) times larger for the compounds: 2-amino-5-mercapto-1,3,4-thiadiazole (I);2,5-dimercapto-1,3,4-thiadiaole (II) and 2,5-diamino-1,3,4-thiadiazole (III) and (36) times for 2,5-dihydrazino-1,3,4-thiadiazole (IV) and (6) times for 5-mercapto-2[(3[5’-nitro-2-’furyl]·methylene)amino]-1,3,4-thiadiazole (V) and 5-mercapto-2[(3[5’-nitro-2-’furyl]-prop-2-enylidene)amino]-1,3,4-thiadiazole (VI). By titration, 1-mL of standard thiosulfate solution was found equivalent to 0.108 mg of (I);0.126 mg of (II), 0.16 mg of (III), 0.041 mg of (IV), 0.40 mg of (V) and 0.435 mg of (VI). Using the spectrophotometric detection for the amplification reaction gave high absorbance values at 605 nm for the blue starch-iodine complex. Beer’s law was obeyed up to 4.0 ppm for compounds (I and II);6.0 ppm for compounds (III, IV and VI) and 5.0 ppm for compound (V). The mechanism of the reactions was proposed and the analytical parameters were evaluated for both methods. The method was applied for synthetic samples of industrial importance. The recovery was comparable while the sensitivity and detection limits were better for the spectrophotometric detection.The principle of using amplification reactions of iodine was employed in this paper to estimate the thiadiazole derivatives on basis of their reactions with iodine I chloroform, removal of the excess iodine and determination of the resulting iodide, after oxidation to iodate. The overall reaction gave an amplification of the iodide that is (12) times larger for the compounds: 2-amino-5-mercapto-1,3,4-thiadiazole (I);2,5-dimercapto-1,3,4-thiadiaole (II) and 2,5-diamino-1,3,4-thiadiazole (III) and (36) times for 2,5-dihydrazino-1,3,4-thiadiazole (IV) and (6) times for 5-mercapto-2[(3[5’-nitro-2-’furyl]·methylene)amino]-1,3,4-thiadiazole (V) and 5-mercapto-2[(3[5’-nitro-2-’furyl]-prop-2-enylidene)amino]-1,3,4-thiadiazole (VI). By titration, 1-mL of standard thiosulfate solution was found equivalent to 0.108 mg of (I);0.126 mg of (II), 0.16 mg of (III), 0.041 mg of (IV), 0.40 mg of (V) and 0.435 mg of (VI). Using the spectrophotometric detection for the amplification reaction gave high absorbance values at 605 nm for the blue starch-iodine complex. Beer’s law was obeyed up to 4.0 ppm for compounds (I and II);6.0 ppm for compounds (III, IV and VI) and 5.0 ppm for compound (V). The mechanism of the reactions was proposed and the analytical parameters were evaluated for both methods. The method was applied for synthetic samples of industrial importance. The recovery was comparable while the sensitivity and detection limits were better for the spectrophotometric detection.

关 键 词：THIADIAZOLES TITRIMETRY Amplification Reaction Spectrophotometric Determination 

分 类 号：O62[理学—有机化学]