Spectrophotometric and chromatographic analysis of creatine: creatinine crystals in urine.

Werle, Julia; Buresova, Kristyna; Cepova, Jana; Bjørklund, Geir; Fortova, Magdalena; Prusa, Richard; Fernandez, Carlos; Dunovska, Katerina; Klapkova, Eva; Kizek, Rene; Kotaska, Karel

Abstract

Creatinine is the end product of the catabolism of creatine and creatine phosphate. Creatine phosphate serves as a reservoir of high-energy phosphate, especially in skeletal and cardiac muscle. Besides typical known changes in serum and urinary creatinine concentrations, rare cases associated with changes in serum and urinary creatine levels have been described in the literature in humans. These cases are mostly linked to an excessive intake of creatine ethyl ester or creatine monohydrate, often resulting in increased urine creatinine concentrations. In addition, it is known that at such elevated creatinine concentrations, creatinine crystallisation may occur in the urine. Analysis of crystals and urinary concrements, often of heterogenous chemical composition, may provide diagnostic and therapeutic hints to the benefit of the patient. The aim of the present work was to analyse urine crystals of unclear composition with microscopic and spectroscopic techniques. On routine microscopic analysis of urine, a preliminary suspicion of uric acid or creatinine crystals was expressed. The crystals were of a cuboid shape and showed polarization effects in microscopy. The dried urine sample was whitish-orange in colour, odourless and dissolved well in water. Protein concentration in dry weight (DW) urine was about 0.3mg/mg. The measured zinc content in the studied sample was approximately 660µg/g DW sample and copper content was approximately 64µg/g DW sample. A lead signal of around 10µg/g DW sample was also observed. UV–Vis analysis showed a maximum peak around 345nm, compatible with the spectrum of creatine. Using HPLC technique, an extreme high ratio of creatine to creatinine of about 38 was measured, which led to the conclusion of the occurrence of rare creatine crystals in urine.

Citation

WERLE, J., BURESOVA, K., CEPOVA, J., BJØRKLUND, G., FORTOVA, M., PRUSA, R., FERNANDEZ, C., DUNOVSKA, K., KLAPKOVA, E., KIZEK, R. and KOTASKA, K. 2024. Spectrophotometric and chromatographic analysis of creatine: creatinine crystals in urine. Spectrochimica acta part A: molecular and biomolecular spectroscopy [online], 322, article number 124689. Available from: https://doi.org/10.1016/j.saa.2024.124689

• Journal Article Type: Article
• Acceptance Date: Jun 18, 2024
• Online Publication Date: Jun 19, 2024
• Publication Date: Dec 4, 2024
• Deposit Date: Jun 25, 2024
• Publicly Available Date: Jun 20, 2025
• Journal: Spectrochimica acta part A: molecular and biomolecular spectroscopy
• Print ISSN: 1386-1425
• Electronic ISSN: 1873-3557
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 322
• Article Number: 124689
• DOI: https://doi.org/10.1016/j.saa.2024.124689
• Keywords: Urine analysis; UV–Vis spectroscopy; FTIR spectroscopy; Electrochemistry; Polarization microscopy analysis; High-performance liquid chromatography
• Public URL: https://rgu-repository.worktribe.com/output/2378266
• Additional Information: This article has been published with separate supporting information. This supporting information has been incorporated into a single file on this repository and can be found at the end of the file associated with this output.