Naphtalene sulphonic acids

Congo Red 3,3 -[[l,l -biphenyl]-4,4 -diylbis-(azo)]bis[4-amino-l-naphtalene -sulphonic acid] disodium salt... 

Fig. 3.130. HPLC chromatograms of the test mixture detected by DAD (270 nm, upper lane) by APCI-MS-TIC (middle) and by ESI-MS-TIC (lower lane). Peak identification l=benzene sulphonic acid sodium salt 2=2-naphtalene sulphonic acid sodium salt 3=2-anthraquinone sulphonic acid sodium salt 4 = sulphorhodamine D sodium salt 5=crocein orange G 6=eriochrome black T 7=2,6-anthraquinone disulphonic acid disodium salt 8 = 1,5-naphtalene disulphonic acid disodium salt 9 = azophloxine 10 = 1,2-benzene disulphonic acid dipotassium salt. Reprinted with permission from G. Socher et al. [178].

The complex formation between Th(IV) and CF, Br and HF has been studied using liquid-liquid extraction nsing dinonyl naphtalene sulphonic acid (HDNNS), a liquid-cation exchanger solnble in organic solvents but not in water. The experiments have been made at 25°C and an ionic strength/ionic medium given in Table A-43. The... 

The most common probes used are l-anilino-8-naphtalene-sulphonate (ANS), 2-p-toluidinyl-6-naphtalene-sulphonate (TNS) and, more recently, 1-pyrenyl-butyric acid and N(l-pyrenyl)-maleimide, The fluorescence of the latter compound (Betcher-Lange et al., 1978, Graceffa et al., 1978, Lehrer et al., 1981 and Lee et al., 1976) is totally quenched when solubilized in the water phase, but after a reaction with the thiol group of cysteine, the probe becomes highly emissive. It has been shown however that this pyrene derivative also strongly adsorps on the hydrophobic parts of the protein and that an aminolysis (Wu et al., 1976) or hydrolysis (Lux et al., 1981) of the probe can occur within the protein. 

---