Fluorimetric method for the determination of trace levels of mercury in sea water using 6-mercaptopurine Original Research Article

The luminescent reaction between Hg(II) and 6-mercaptopurine is investigated for the determination of this metal in sea water samples. The high fluorescence emitted by the complex 6-mercaptopurine+Hg(II) was measured at 380 and 540 nm, for excitation and emission wavelengths, respectively. Optimum experimental conditions include a buffer pH of 5.0, a reagent concentration of 5.0×10−5 M and a reaction time of 5 min at 40°C. Possible interferences present in sea water, including cations and anions which could affect the analytical response are evaluated in detail and the analytical performance characteristics investigated. A detection limit of 1.4 ng ml−1 of Hg(II) was obtained. The calibration was linear up to 1.2 mg l−1 and the relative standard deviation was ±1.3% (at 250 ng ml−1 Hg(II) level). Finally, the method was successfully applied to the determination of Hg(II) in spiked sea water samples.