Hemoglobin Calibration Curves by Photoacoustic Spectroscopy

Abstract In the present study, hemoglobin calibration curves were developed by photoacoustic spectroscopy (PAS) using hemoglobin solutions with controlled concentrations. Two types of samples exhibiting different optical properties were obtained: optically opaque (20–180 mg/mL concentrations) and optically transparent (0.0312–2 mg/ml concentrations). Optical absorption spectra were recorded in the wavelength range of 250–750 nm. From these spectra, the Soret band absorption peak at 412 nm and a secondary absorption at 450 nm were identified, and their ratio was determined. The ratios, plotted as a function of hemoglobin concentration, were fitted to the most suitable mathematical model, enabling the estimation of unknown hemoglobin concentrations in various biological samples, both optically opaque (e.g., blood and organs) and optically transparent (e.g., urine and plasma). The results show a strong correlation between the photoacoustic signal and hemoglobin concentration, validating the applicability of this technique to complex biological systems. Accurate quantification of hemoglobin in biological media is essential for the diagnosis and monitoring of numerous diseases. PAS proves to be a reliable tool for clinical and biomedical research applications, offering advantages in sensitivity, specificity, and minimal sample volume requirements.