Determination of non-protein-bound iron in human synovial fluid by high-performance liquid chromatography with electrochemical detection.
Non-protein-bound iron in human synovial fluid was determined using high-performance liquid chromatography with electrochemical detection. The procedure was based on the separation of the iron-diethylenetriaminepentaacetic acid (DTPA) complex formed directly on a chromatographic column containing an anion-exchange resin followed by electrochemical detection. The method enabled more than 0.1 microM Fe(III) to be determined with an injection volume of 10 microliters. A mixture of synovial fluid, 20 microM DTPA and acetate buffer was incubated in the presence and absence of superoxide (O2-) generated by a xanthine-xanthine oxidase system and was ultrafiltered through a 30,000 molecular mass cut-off filter. No iron was detected in the ultrafiltrate at physiological pH. However, the presence of iron was observed in the ultrafiltrate at low pH, and O2- facilitated the release of iron into the synovial fluid. This result suggested that in an inflamed joint with generated O2- and decreased pH, iron may be released into the synovial fluid.
Kawasaki
N
N
Division of Biological Chemistry and Biologicals, National Institute of Health Sciences, Tokyo, Japan.
Tanimoto
T
T
Tanaka
A
A
Hayakawa
T
T
Miyasaka
N
N
D001172:Arthritis, Rheumatoid / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D004563:Electrochemistry; D005293:Ferritins / Q000737:chemistry; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007501:Iron / Q000032:analysis*; D007502:Iron Chelating Agents / Q000032:analysis; D010003:Osteoarthritis / Q000378:metabolism; D004369:Pentetic Acid / Q000032:analysis; D013582:Synovial Fluid / Q000737:chemistry*; D014168:Transferrin / Q000737:chemistry; D014462:Ultrafiltration
D007502:Iron Chelating Agents; D014168:Transferrin; D004369:Pentetic Acid; D005293:Ferritins; D007501:Iron