Prediction of absorption coefficients by pulsed laser induced photoacoustic measurements

• Pulsed laser induced photoacoustic spectroscopy setup was developed.
• A method for predicating absorption coefficients using the setup is proposed.
• Absorption coefficient determined for tryptophan concentrations & serum samples.
• Outcomes were cross-validated with spectrophotometric measurements.

In the current study, a pulsed laser induced photoacoustic spectroscopy setup was designed and developed, aiming its application in clinical diagnostics. The setup was optimized with carbon black samples in water and with various tryptophan concentrations at 281 nm excitations. The sensitivity of the setup was estimated by determining minimum detectable concentration of tryptophan in water at the same excitation, and was found to be 0.035 mM. The photoacoustic experiments were also performed with various tryptophan concentrations at 281 nm excitation for predicting optical absorption coefficients in them and for comparing the outcomes with the spectrophotometrically-determined absorption coefficients for the same samples. Absorption coefficients for a few serum samples, obtained from some healthy female volunteers, were also determined through photoacoustic and spectrophotometric measurements at the same excitations, which showed good agreement between them, indicating its clinical implications.

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