Investigating the Surface Morphology and Composition of the Methyl Orange by Different Spectroscopic Techniques

Abstract

Weak organic acids and bases function as pH or common anionic indicators for determining the endpoint in neutralization titrations. Methyl orange, a commonly used indicator, appears red in acidic conditions and yellow in alkaline solutions. In this study, surface and spectroscopic analyses were employed to characterize methyl orange. Energy Dispersive X-ray (EDX) analysis was conducted to determine its elemental composition, revealing that approximately 66% of the sample consists of carbon, along with about 24% of oxygen, sulfur, sodium, and other elements. The crystalline nature of the sample was confirmed through X-ray Diffraction (XRD) and Field Emission Scanning Electron Microscope (FE-SEM) analysis. Furthermore, Fourier Transform Infrared (FT-IR) Spectroscopy identified the presence of amino groups and double-bonded carbon atoms within the aromatic system. Raman spectroscopy, particularly in the 1000–1700 cm^-1 range, further validated the findings from FT-IR. This study serves as a significant contribution to the comprehensive characterization of methyl orange.