Azo dyes sulphonated

Haug W, Schmidt A, Nortemann B (1991) Mineralization of the sulphonated azo dye mordant yellow 3 by a 6-aminonaphthatene-2-sulphonate-degrading bacterium consortium. Appl Env Microbiol 57 3144—3149... 

Sulphonated azo dyes were separated and quantitated in various food products by ion-pair liquid chromatography with DAD and electrospray MS detection. The chemical structure of sulphonated azo dyes included in the investigation are shown in Fig. 3.36. Dyes were separated in an ODS column (125 X 2.0 mm i.d. particle size 5 pm) using gradient elution. An aqueous solution of 3 mM triethylamine (pH adjusted to 6.2 with acetic acid) and methanol... 

Various liquid chromatographic techniques have been frequently employed for the purification of commercial dyes for theoretical studies or for the exact determination of their toxicity and environmental pollution capacity. Thus, several sulphonated azo dyes were purified by using reversed-phase preparative HPLC. The chemical strctures, colour index names and numbers, and molecular masses of the sulphonated azo dyes included in the experiments are listed in Fig. 3.114. In order to determine the non-sulphonated azo dyes impurities, commercial dye samples were extracted with hexane, chloroform and ethyl acetate. Colourization of the organic phase indicated impurities. TLC carried out on silica and ODS stationary phases was also applied to control impurities. Mobile phases were composed of methanol, chloroform, acetone, ACN, 2-propanol, water and 0.1 M sodium sulphate depending on the type of stationary phase. Two ODS columns were employed for the analytical separation of dyes. The parameters of the columns were 150 X 3.9 mm i.d. particle size 4 /jm and 250 X 4.6 mm i.d. particle size 5 //m. Mobile phases consisted of methanol and 0.05 M aqueous ammonium acetate in various volume ratios. The flow rate was 0.9 ml/min and dyes were detected at 254 nm. Preparative separations were carried out in an ODS column (250 X 21.2 mm i.d.) using a flow rate of 13.5 ml/min. The composition of the mobile phases employed for the analytical and preparative separation of dyes is compiled in Table 3.33. 

It was further found that the methods separate well the dyes and impurities, as demonstrated on the preparative chromatographic profile of Reactive orange 16 in Fig. 3.115. It was concluded from the results that the method can be used in the future for the purification and analysis of a wide variety of sulphonated azo dyes [171],... 

CZE was also employed for the analysis of sulphonated azo dyes in river samples. The chemical structures of dyes are shown in Fig. 3.150. Separations were performed in a fused-silica capillary (total length 57 cm effective length, 50 cm 75 pm i.d.). Activation of the capillary was carried out by washing it with 1.0 M NaOH for 15 min, followed by water (5 min) and the running buffer (5 min). The buffer was prepared from 10 mM... 

M.-R. Fuh and K.-J. Chia, Determination of sulphonated azo dyes in food by ion-pair liquid chromatography with photodiode array and electrospray mass spectrometry detection. Talanta, 56 (2002) 663-671. 

M. Chen, D. Moir, F.M. Benoit and C. Kubwabo, Purification and identification of several sulphonated azo dyes using reversed-phase preparative high-performance liquid chromatography. J. Chromatogr.A, 825 (1998) 37-44. 

The more common and more important red lakes are those of cochineal, red wood, alizarin (or madder) and its derivatives, triphenylmethane dyes (fuchsine), safranine, eosin, developed and sulphonated azo-dyes the last give also orange lakes. 

Sulphonated Azo dyes - Optimisation of nH ion sonrco Thermospray HPLC-MS - [16]... 

Vanerkova, D., Jandera, R, and Hrabica, J. J. Chromatogr. A. Behaviour of sulphonated azo dyes in ion-pairing reversed-phase high-performance liquid chromatography... 

Ansorgov, D., Holcapek, M., and Jandera, R Ion-pairing high-performance liquid chromatography-mass spectrometry of impurities and reduction products of sulphonated azo dyes. J. Sep. Sci. 2003, 26, 1017-1027. 

Vanerkova, D. et al. Analysis of electrochemical degradation products of sulphonated azo dyes using high-performance liquid chromatography/tandem mass spectrometry. Rapid Commun. Mass Spectrom. 2006, 20, 2807-2815. 

Azo-dyes prepared by interaction of a diazo-compound and a pbenol are insoluble in waterj and therefore of no practical value. For this reason a sulpho-group is introduced (see p. 34), and this produces the solubility necessary for their application in ordinary dyeing processes. These sulphonated azo-dyes have a considerable affinity for wool and silk, but (with the exception of those of the tetrazo-series) are not easily fixed on cotton. Cotton may be dyed with certain azo-dyes of the Crocein series, hut the shades produced are not fast to washing. 

Wawrzkiewicz M, Hubicki Z. Kinetics of adsorption of sulphonated azo dyes on strong basic anion exchangers. Environ Technol 2009 30 1059-71. 

Szygula, A., Guibala, E., Ruiz, M., and Sastrec, A.M. 2008. The removal of sulphonated azo-dyes by coagulation with chitosan. Colloid Surf A Physicochem. Eng. Aspects 330 219-226. 

C. Ferndndez, M.S. Larrechi, R. Forteza, V. Cerda, M.P. Callao, Multisyringe chromatography (MSC) using a monolithic column for the determination of sulphonated azo dyes, Talanta 82 (2010) 137—142. 

Diffusion has been studied most extensively with relatively simple dyes such as anionic sulphonated azo dyes from the levelling acid and direct classes. Also a considerable amount of work has been carried out with reactive dyes, despite the fact that they eventually become immobilised by chemical reactions with the fibre. Other types of reactions, particularly those involving large increases in the relative molecitlar mass of dyes, make studies of diffusion behaviorrr even more complicated. As a consequence, little work has been carried out with chrome, vat, sulphur and azoic dyes. ... 

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