Fig. 5: Impact of reference on piperacillin quantification in female urine using Raman spectroscopy.

Median resonance Raman spectra of the female’s own urine (black, a1) as well as the female (orange, a2), male (blue, a3), and mixed (purple, a4) urine pools. These spectra were further used as a matrix for the quantification of piperacillin in female urine. The calibration curves using the female’s own urine (black, b1), female (orange, b2), male (blue, b3), and the mixed urine pool (purple, b4) as references show slight changes in their slope, while the female’s own urine leads to the lowest LoD, followed by the female pool, mixed pool, and male pool regarding their sensitivity. Despite the high slope, the high standard error of the axis intercept results in a worse LoD for the male pool [see Eq. (2)]. The boxplot represents the predicted intensity values of n = 3 replicate measurements.