Background: This study aims to determine the concentrations of tramadol in earwax (μg/g) and urine (μg/ml) samples taken from postoperative patients, to evaluate the sensitivity of earwax (cerumen) as an alternative analyte and compare it with the findings in urine samples. Results: The results indicated that tramadol concentrations in earwax samples were averaged 45.08 μg/g (range: 13.5-107.7 μg/g), whereas tramadol concentrations in urine samples were averaged 4.97 μg/ml (range: 1.57-10.11 μg/ml). There were significant differences when comparing age groups, duration and sex between earwax and urine samples (p < 0.05). Conclusion: Despite the significant differences between earwax and urine samples, earwax can be used as a bioindicator of tramadol detection.
Keywords: HPLC; analysis; earwax; tramadol; urine.