Quantitative analysis of sodium carbonate and sodium bicarbonate in solid mixtures using Fourier transform infrared spectroscopy (FT-IR).

An analytical methodology is proposed based on constant ratio and absorbance correction methods to quantify sodium carbonate, Na₂CO₃ (1450 cm⁻¹), and sodium bicarbonate, NaHCO₃ (1000 cm⁻¹, 1923 cm⁻¹), in solid mixtures using Fourier transform infrared (FT-IR) spectroscopy. Potassium ferricyanide, K₃Fe(CN)₆ (2117cm⁻¹), was used as an internal standard to get characteristic parameters. NaHCO₃ was quantified using the constant ratio method. Spectral interference of NaHCO₃ in Na₂CO₃ (1450 cm⁻¹) was corrected using the absorbance correction method. The corrected absorbance was successfully applied to quantify Na₂CO₃ (1450 cm⁻¹) in the mixture using the constant ratio method. The results obtained for simulated samples were satisfactory (relative standard deviation less than 7%) for all samples.