Research Article

Synthesis of Bis-Schiff Base Reagents and their Application in the Spectrophotometric Determination of Mesalazine via Azo Dye Formation

Volume: 2026 Number: 2 October 22, 2026

Synthesis of Bis-Schiff Base Reagents and their Application in the Spectrophotometric Determination of Mesalazine via Azo Dye Formation

Abstract

Mesalazine (5-aminosalicylic acid) is an important first-line anti-inflammatory drug widely used in the management of inflammatory bowel diseases, particularly ulcerative colitis, making its reliable determination in pharmaceutical formulations important for routine quality control. In this study, bis-Schiff base reagents were synthesized by condensation of 4,4′-diaminoazobenzene with substituted aromatic aldehydes. Among the synthesized derivatives, 4,4′-bis[(4-hydroxybenzylidene)amino]azobenzene (SH1) was selected as the chromogenic reagent because it provided a superior analytical response compared with SH2. The novelty of the proposed method lies in the use of laboratory-synthesized SH1 as a coupling reagent for diazotized mesalazine, producing a color-stable azo product in alkaline medium with a maximum absorbance at 530 nm. The analytical procedure is simple and low-volume, employs a predominantly aqueous final reaction medium, and does not require chromatographic separation or solvent-extraction steps, thereby reducing solvent and instrumental requirements. Under optimized conditions, Beer’s law was obeyed over the concentration range of 2.0–20.0 μg/mL, with a molar absorptivity of 7.580 × 10³ L/mol/cm and Sandell’s sensitivity of 0.0202 μg cm⁻². The method showed recoveries of 99.20–100.83%, with RSD values of 0.70–0.80%, and a limit of detection of 0.1540 μg/mL. Good selectivity and robustness were observed, and the method was successfully applied to the determination of mesalazine in Pentasa® tablets. These findings support the applicability of the proposed SH1-based spectrophotometric method for routine pharmaceutical quality-control analysis.

Keywords

Thanks

The authors would like to express their sincere gratitude to the College of Science, Kirkuk University, for providing the necessary facilities and support to carry out this research. They also extend their appreciation to the laboratory staff for their technical assistance and to everyone who contributed to the successful completion of this work.

References

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Details

Primary Language

English

Subjects

Analytical Spectrometry

Journal Section

Research Article

Publication Date

October 22, 2026

Submission Date

July 22, 2026

Acceptance Date

September 12, 2026

Published in Issue

Year 2026 Volume: 2026 Number: 2

APA
Mohammed, A. S., Majeed, E., Hamed, M., & Atiyah, A. (2026). Synthesis of Bis-Schiff Base Reagents and their Application in the Spectrophotometric Determination of Mesalazine via Azo Dye Formation. Journal of the Turkish Chemical Society Section A: Chemistry, 2026(2), 1-16. https://doi.org/10.18596/jotcsa.2000541
AMA
1.Mohammed AS, Majeed E, Hamed M, Atiyah A. Synthesis of Bis-Schiff Base Reagents and their Application in the Spectrophotometric Determination of Mesalazine via Azo Dye Formation. JOTCSA. 2026;2026(2):1-16. doi:10.18596/jotcsa.2000541
Chicago
Mohammed, Ammar S., Esraa Majeed, Muner Hamed, and Ali Atiyah. 2026. “Synthesis of Bis-Schiff Base Reagents and Their Application in the Spectrophotometric Determination of Mesalazine via Azo Dye Formation”. Journal of the Turkish Chemical Society Section A: Chemistry 2026 (2): 1-16. https://doi.org/10.18596/jotcsa.2000541.
EndNote
Mohammed AS, Majeed E, Hamed M, Atiyah A (October 1, 2026) Synthesis of Bis-Schiff Base Reagents and their Application in the Spectrophotometric Determination of Mesalazine via Azo Dye Formation. Journal of the Turkish Chemical Society Section A: Chemistry 2026 2 1–16.
IEEE
[1]A. S. Mohammed, E. Majeed, M. Hamed, and A. Atiyah, “Synthesis of Bis-Schiff Base Reagents and their Application in the Spectrophotometric Determination of Mesalazine via Azo Dye Formation”, JOTCSA, vol. 2026, no. 2, pp. 1–16, Oct. 2026, doi: 10.18596/jotcsa.2000541.
ISNAD
Mohammed, Ammar S. - Majeed, Esraa - Hamed, Muner - Atiyah, Ali. “Synthesis of Bis-Schiff Base Reagents and Their Application in the Spectrophotometric Determination of Mesalazine via Azo Dye Formation”. Journal of the Turkish Chemical Society Section A: Chemistry 2026/2 (October 1, 2026): 1-16. https://doi.org/10.18596/jotcsa.2000541.
JAMA
1.Mohammed AS, Majeed E, Hamed M, Atiyah A. Synthesis of Bis-Schiff Base Reagents and their Application in the Spectrophotometric Determination of Mesalazine via Azo Dye Formation. JOTCSA. 2026;2026:1–16.
MLA
Mohammed, Ammar S., et al. “Synthesis of Bis-Schiff Base Reagents and Their Application in the Spectrophotometric Determination of Mesalazine via Azo Dye Formation”. Journal of the Turkish Chemical Society Section A: Chemistry, vol. 2026, no. 2, Oct. 2026, pp. 1-16, doi:10.18596/jotcsa.2000541.
Vancouver
1.Ammar S. Mohammed, Esraa Majeed, Muner Hamed, Ali Atiyah. Synthesis of Bis-Schiff Base Reagents and their Application in the Spectrophotometric Determination of Mesalazine via Azo Dye Formation. JOTCSA. 2026 Oct. 1;2026(2):1-16. doi:10.18596/jotcsa.2000541