Reference

3,5,3',5'-Tetramethylbenzidine as a spray reagent in the thin-layer chromatographic detection of organochlorine pesticides

3,5,3',5'-Tetramethylbenzidine as a spray reagent in the thin-layer chromatographic detection of organochlorine pesticides. Makhubalo, John; Mainga, Aaron; Phiri, Annie (Dep. Chem., Univ. Zambia, Lusaka, Zambia). J. Chromatogr., 284(2), 518-22 (English) 1984. CODEN: JOCRAM. ISSN: 0021-9673. DOCUMENT TYPE: Journal CA Section: 5 (Agrochemical Bioregulators) 3-Methylbenzidine [67683-35-6], N,N'-dimethylbenzidine [2810-74-4], N,N'-tetramethylbenzidine [366-29-0], and 3,5,3',5'-tetramethylbenzidine (I) [54827-17-7] produced color with each of 10 organochlorine pesticides within 60 s of exposure of the TLC plate to direct sunlight; I produced colors almost instantaneously on exposure of the plate to sunlight. 50-29-3 and 60-57-1 which are cas registry numbers of chemicals are mentioned. The colors obtained with I faded within 5-10 min. However, I formed the most intense spots for a given concn. of an organochlorine pesticide and had a detection limit of 0.2 mg. .

Studies on steroids

Studies on steroids. CCXXV. A comparison of chromogenic substrates for horseradish peroxidase as a label in steroid enzyme immunoassay. Hosoda, Hiroshi; Takasaki, Wataru; Oe, Tomoyuki; Tsukamoto, Reiko; Nambara, Toshio (Pharm. Inst., Tohoku Univ., Sendai 980, Japan). Chem. Pharm. Bull., 34(10), 4177-82 (English) 1986. CODEN: CPBTAL. ISSN: 0009-2363. DOCUMENT TYPE: Journal CA Section: 2 (Mammalian Hormones) Section cross-reference(s): 9 Six chromogenic substrates for horseradish peroxidase (HRP) [62628-26-6] as an enzyme label were compared with regard to the sensitivity obtainable with a testosterone [58-22-0] enzyme immunoassay system. The chromogens tested were 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) [30931-67-0] o-phenylenediamine (OPD) [95-54-5], 5-aminosalicylic acid (5-AS) [89-57-6], 3-amino-9-ethylcarbazole (AEC) [132-32-1], 3,3',5,5',-tetramethylbenzidine (TMB) [54827-17-7] and 3-methyl-2-benzothiazolinone hydrazone (MBTH) [1128-67-2], for comparison, a fluorimetric assay using 3-(p-hydroxyphenyl)propionic acid was also carried out. An HRP-labeled antigen was prepd. by the N-succinimidyl ester method. The bound and free enzyme-labeled antigens were sepd. by a double antibody method. A dose-response curve with a satisfactory sensitivity was obtained in each system by the use of a min. amt. of the HRP label at an appropriate diln. of anti-testosterone antiserum (Ka = 2 ′ 1010M-1). The amts. of testosterone needed to displace 50% of the bound label ranged 9-150 pg. The sensitivity decreases in the order: TMB>OPD>ABT>5-AS>MBTH>AEC. The assay using the nonmutagenic substrate, TMB, gave a high sensitivity, comparable to that of the fluorimetric method.