Analytical Sciences

Abstract − Analytical Sciences, 23(11), 1291 (2007).

The Use of 3-(2-Pyridyl)-5,6-diphenyl-1,2,4-triazine as a Precolumn Derivatizing Reagent in HPLC Determination for Fe(II) in Natural Samples
Weihuang ZHU,*,** Fengchang WU,* Jian ZHENG,*** and Congqiang LIU*
*State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002, China
**School of Environmental and Civil Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
***Nakaminato Laboratory for Marine Radioecology, National Institute of Radiological Sciences, 3609 Isozaki-cho, Hitachinaka, Ibaraki 311-1202, Japan
3-(2-Pyridyl)-5,6-diphenyl-1,2,4-triazine (PDT) was used for the first time as a precolumn derivatizing reagent in the high-performance liquid chromatography (HPLC) method with UV absorbance detection for the Fe(II) determination. The Fe(II) reacts with PDT to form a magenta colored chelate in the presence of sodium dodecyl sulfate (SDS) and acetic acid-sodium acetate buffer solution medium of pH 4.65. The selection of maximum absorbance detection wavelength and the optimum composition of the organic modifier in the mobile phase were investigated in detail for the quantitative determination of Fe(II) using HPLC system. The formed Fe(II)-PDT chelate was satisfactorily separated from PDT on an Agilent Shim-pack ODS column (Eclipse XDB-C8, 4.6 × 150 mm) by isocratic elution with acetonitrile and 0.02 mol L-1 acetic acid-sodium acetate buffer solution (pH 4.65, containing 0.02% of SDS and 60 × 10-3 mol L-1 NaClO4) as mobile phase at a flow rate of 1 mL min-1, and monitored with a multiple wavelength detector. The detection limit (S/N = 3) is 0.35 ng mL-1. Due to the excellent separation ability of HPLC, the innovative introduction of PDT as the precolumn derivatizing reagent, and the proper selection of the detect wavelength, the sensitivity of our newly developed HPLC method was enhanced remarkably compared to those of the common spectrophotometric methods. The developed HPLC method was successfully applied to the determination of Fe(II) in lake water samples.