A fluorescence method to determine picomole amounts of Zn(II) in biological systems

J. G. Reyes, M. Santander, P. L. Martinez, R. Arce, D. J. Benos

Research output: Contribution to journalArticlepeer-review

16 Scopus citations


The formation of complexes between n-(6-methoxy-8-quinolyl)-p-toluensulfonamide (TSQ) and Zn(II) in methanol has been used as an analytical procedure for Zn(II) determination in biological systems. Using 1 ml cuvettes, the limit of detection of the method was approximately 20 pmoles of Zn(II). Linearity between fluorescence and zinc concentration was obtained up to approximately 1 μM Zn(II). Common multivalent cations present in biological systems like Al3+, Cu2+, Fe3+, Ca2+, and Mg2+, interfered with the measurement of Zn(II) only when present in excess of 20, 33, 60, 500 and 30,000 times the Zn(II) concentration, respectively. In human serum and semen, deproteinization of the samples permitted a good correlation between the TSQ method and the total Zn content determined by atomic absorption measurements. In rat spermatids, deproteinization and Zn(II) determination using the TSQ method gives approximately a 20% underestimation of the total Zn(II) content of the cells as compared to atomic absorption spectrophotometry. The method gives low resolution of Zn(II) peaks when tested as an analytical procedure to measure Zn(II) binding to protein fractions eluted during column chromatography.

Original languageEnglish
Pages (from-to)49-56
Number of pages8
JournalBiological Research
Issue number1
StatePublished - 1994


  • Zn(II)
  • fluorescence
  • human semen
  • human serum
  • rat spermatids
  • zinc content


Dive into the research topics of 'A fluorescence method to determine picomole amounts of Zn(II) in biological systems'. Together they form a unique fingerprint.

Cite this