Liquid Chromatography with Fluorescence Detection in the Analysis of Biological Fluids

Recent progress in derivatization methods for LC and CE analysis

The derivatization procedure with a suitable fluorescence or chemiluminescence reagent is performed for the purpose of increasing the detection sensitivity and selectivity, in high-performance liquid chromatography (HPLC) and/or capillary electrophoresis (CE). In this article, recent derivatization methods and their applications to biosamples are described. In HPLC, femto mol order of mass detection limits are obtained by derivatization. Regarding the fluorescence reagents, the use of water-soluble reagents has been effective to avoid an undesired adsorption in the process of determination of peptides. In CE, the advantages of having extremely low mass detection limits (ranging from atto to yocto mol level) and requiring only a very short analysis time (less than a few minutes) are made possible by using laser-induced fluorescence or near infra-red detections.

Search for new urinary biochemical markers of collagen degradation in man

BACKGROUND

In the human body, collagen degradation produces various fragments released from the extracellular matrix, which end up in the urine as pyridinium cross-links, either free or bound to peptides or sugars.

METHODS

We developed a high-performance liquid chromatography (HPLC) technique, which measures not only free pyridinoline (Pyr) and deoxypyridinoline (Dpyr), but also glucosyl-galactosyl-pyridinoline (glc-gal-pyr) and four still unidentified bound pyridinolines. Assuming that in Paget's disease of bone and in growing children the cross-links (CL) mainly originate from bone tissue, whereas after spinal cord injury their high excretion rather reflects the degradation of non-osseous collagen, we compared the urinary output of seven different cross-links, among which four had not been described before.

RESULTS

Our results show that one of those, which we called CL1, is essentially originating from bone and is more specific in this respect than Dpyr, whereas glc-gal-pyr also reflects the degradation of non-osseous collagen. The best indicator of non-bone collagen degradation was CL3, one of the newly discovered cross-links.

CONCLUSIONS

In conclusion, we demonstrate that new sensitive pyridinoline cross-links can be identified and assayed in human urine and that their specificity helps to distinguish diseases related to bone collagen from those in which other forms of collagen are involved.