Hemoglobin Calibration Curves by Photoacoustic Spectroscopy

In the present study, hemoglobin calibration curves were developed by photoacoustic spectroscopy (PAS), by using hemoglobin solutions with controlled concentrations. Two optically types of samples were obtained; optically opaque (20–180 mg/mL concentrations) and optically transparent (0.0312–2 mg/ml concentrations). Optical absorption spectra were obtained in the wavelength range from 250 nm to 750 nm. From these spectra the Soret band absorption peak at 412 nm, and 450 nm absorption were identified, and the ratio between these two optical absorptions was obtained. These ratios, as a function of the hemoglobin concentrations, were fitted to the best mathematical model, which allows estimating unknown hemoglobin concentrations from different biological samples, both optically opaque (e.g. blood or organs) and optically transparent (e.g. urine and plasma). The results show a high correlation between the photoacoustic signal and the hemoglobin concentration, validating the applicability of this technique in complex biological systems. Accurate quantification of hemoglobin in biological media is essential for the diagnosis and monitoring of several diseases. PAS is a reliable tool for clinical and biomedical research applications, offering advantages in terms of sensitivity, specificity, and minimal sample volume.