C.I. Acid Black 194

• CAS: 61931-02-0
• Catalog Number: ACM61931020
• Category: Main Products
• Molecular Formula: C20H12N3NaO7S
• Synonyms: Black MSRL
• Melting Point: >360 °C
• Appearance: Dark brown powder

Case Study

Fungal Decolorization of Acid Black 194 by Aspergillus Species

Osman, Mohamed E., et al. Int. J. Curr. Microbiol. App. Sci 4.3 (2015): 866-891.

The removal ability of Acid Black 194 dye was screened by Aspergillus fungal isolates (A. flavus, A. tamarii, A. parasiticus). The most effective isolates were optimized on various parameters to get the best decolorization potential for a wastewater treatment system. In the present investigation, an attempt has been made to study the species specific parameters for the maximum decolorization of Acid Black 194 and to characterize the treated dye.
Seven Egyptian fungal isolates were screened against five acid dyes; A. flavus AUMC 9060, A. tamarii AUMC 9061, and A. parasiticus AUMC 9062 demonstrated highest efficacy for Acid Black 194. Optimization tested temperature (20-30°C), pH (3-9), incubation (2-10 days), inoculum size (0.5-2 discs), age (3-15 days), dye concentration (50-500 mg/L), and sucrose (1-5%). FT-IR compared treated vs. untreated dye structures.
Key Findings
· A. tamarii achieved 91.15% decolorization, outperforming A. flavus and A. parasiticus (85% each). Optimal parameters for the three strains were 24°C, pH 7, 8-day incubation, 1-cm inoculum disc.
· Variable Factors: Inoculum age, dye concentration, and sucrose requirements differed by species.
· Mechanism: FT-IR showed identical spectra for treated/untreated dye, indicating physical removal (e.g., adsorption) without molecular degradation.

Micellar Electrokinetic Chromatography for Impurity Analysis of Acid Black 194 Dye

Sebastiano, Roberto, et al. Dyes and Pigments 94.2 (2012): 258-265.

This study demonstrated the application of Micellar Electrokinetic Chromatography (MEKC) to resolve complex impurity profiles in commercial Acid Black 194 dye, identifying impurities in industrial batches of Acid Black 194 undetectable by standard HPLC or Capillary Zone Electrophoresis (CZE) methods.
Methodology
Commercial Acid Black 194 was analyzed using reversed-phase HPLC, CZE, and MEKC; key components (three synthesis-derived Cr(III) complexes and one major impurity) were isolated via silica flash chromatography and characterized by MS/NMR; the optimized MEKC protocol employed surfactant-containing background electrolyte (BGE) with mandatory replacement after each run; cross-validation was performed on Acid Brown 432/434 dyes.
Key Findings
MEKC resolved over twelve previously undetectable compounds in Acid Black 194 with low %RSD, outperforming HPLC and CZE which failed to separate the complex mixture and suffered from electrode polarization (CZE); two impurities were structurally confirmed; identical MEKC conditions successfully analyzed Acid Brown 432/434 without modification.