Figure 1.

Spectral comparison of 0 h and 4 h peritoneal dialysis (PD) effluent samples. (a) Average spectra of vector-normalized, baseline corrected spectra (0 h, n = 39; 4 h, n = 40). (b) Average spectra of second derivative, baseline corrected spectra (0 h, n = 39; 4 h, n = 40). (c) Subtraction spectra generated of second derivative, baseline corrected spectra at the relevant spectral range of 1800–800 cm⁻¹. Spectra from 4 h were subtracted from 0 h. Wavenumbers responsible for discrimination are indicated. A.U., arbitrary units.