Cg. Kontoyannis et al., Analysis of prostatic stent encrustation and of entrapped urinary stone using FT-IR and FT-Raman spectroscopy, APPL SPECTR, 54(2), 2000, pp. 225-229
Fourier transform infrared spectroscopy (FT-IR) and Fourier transform Raman
spectroscopy (FT-RS) were used in order to characterize the encrusted depo
sits formed on a metallic thermosensitive prostatic stent. A 4 mm urinary s
tone entrapped within the lumen was also analyzed, Six different substances
, a very rare occurrence, were detected, yielding complex spectra. Struvite
(STR), hydroxyapatite (HAP), calcium oxalate monohydrate (COM), potassium
urate (PU), and ammonium urate (AU) were the main components of concretion
formed on the metal surface. STR and PU were detected on the 0.2 mm externa
l surface of the stone, while the 3.8 mm core was found to be uric acid (UA
). The broad and overlapping FT-IR bands of STR and COM made their identifi
cation difficult, while the detection of HAP was hindered by the presence o
f numerous urates bands, which, on the other hand, were used for the discri
mination among UA, AU, and PU, Raman spectroscopy proved to be more sensiti
ve tct urate presence than did FT-IR, while the identification of STR, COM,
and HAP was easier for FT-RS but more difficult with respect to AU and UA
since all their bands, but three, coincide. A combination of the two techni
ques was necessary for the qualitative analysis of the encrustation and the
stone.