Nowadays, the detection of albumin and determination of its concentration for early diagnosis of kidney diseases has attracted considerable attention as a simple and rapid method. In this work, two methods for detection and determination of albumin concentration were investigated and compared by using gold nanorods (GNRs) and spectrophotometry of their interaction with bovine serum albumin (BSA). By the changes in the typical synthesis protocol, GNRs' samples were synthesized and characterized. Synthesized GNRs were mixed with different concentrations of BSA. Ultraviolet–Visible (UV–Vis) spectroscopy and X-ray Fluorescence (FL) spectroscopy were applied to examine the mixed samples. The change of absorption spectrum in the UV region showed the detection limit of BSA concentration of 0.2 mg/mL. The detection limit of BSA concentration of 0.05 mg/mL was obtained from the investigation of absorption spectrum in visible-infrared (Vis-IR) regions. However, the study of the FL spectra proved the detection limit is as low as 0.0013 mg/mL. Therefore, it was found out that very low concentrations of albumin could be very accurately detected by FL spectroscopy. Also, comparing of the spectra obtained from the samples at various time intervals indicated that the measurement of concentration is possible after 1–20 min of mixing GNRs and BSA.
