There have been developed different kinds of methods for detecting citrate in body fluids since citrate is very important physiologically and biochemically. In particular, determination of citrate concentration in prostatic or seminal fluid is useful in early diagnosis of prostate cancer. Recently, a peroxotitanium complex(PTC) prepared from titanium tetrachloride and hydrogen peroxide has been found to have peroxidase-like activity which is greatly inhibited by some hydroxyalkanoic acids. Hence, we developed a method for determining citrate concentration in prostatic fluid using strong inhibition of citrate on the catalytic activity of the PTC.
According to the research results, citrate strongly inhibited the PTC's catalysis over the investigated ranges of pH values and H2O2 concentrations. Meanwhile, the major electrolytic components of prostatic fluids have no significant effect on the catalytic activity of the PTC. Even though the inorganic phosphate remarkably inhibited the PTC's catalysis, its interference was neglected due to the concentration much lower than that of citrate in prostatic fluid. Under the proposed reaction condition, citrate concentrations were measured in the concentration range of 10–40μM with the detection limit of 5.4 μM. Spiking test showed the recovery of 99.8%, indicating that the method could be reliable.
The results have been published in the journal "Analytical Biochemistry" with the title of "Determination of prostatic fluid citrate concentration using peroxidase-like activity of a peroxotitanium complex"(https://doi.org/10.1016/j.ab.2023.115152).
