The discussion centers on the search for UV-VIS absorbance spectra of urine, with an emphasis on the challenges of obtaining this data. While some participants have found spectra focusing on the deep UV range and fluorescence peaks, the high cost of using a spectrophotometer is a concern. One participant highlights the significance of bilirubin, which peaks at 450nm and contributes to urine's color. The conversation notes that urine composition varies greatly based on diet, leading to a complex array of peaks in the spectra, many of which may be difficult to identify. There is mention of potential diagnostic applications for urinary spectra, although it remains unclear if this is widely practiced. Some papers have explored using HPLC with UV spectroscopy to identify specific compounds in urine, but an overall spectral analysis may not provide clear results.