Separation/preconcentration of lanthanum and europium by micro-column packed with immobilized 1-phenyl-3-methyl-4-bonzoyl-5-pyrazone on microcrystalline naphthalene and determination by electrothermal vaporization inductively coupled plasma-atomic emission spectrometry

A sensitive and rapid method for electrothermal vaporization-inductively coupled plasma atomic emission spectrometry (ETV-ICP-AES) determination of La3+ and Eu3+ after separation/preconcentration by a micro-column packed with immobilized 1-phenyl-3-methyl-4-bonzoyl-5-pyrazone (PMBP) on microcrystalline naphthalene has been developed. Various influencing factors, such as the acidity of the aqueous solution, flow rate, volume of the sample, dimension of the microcolumn on the separation and the preconcentration of the analyte, have been studied, and the working parameters were optimized experimentally. The choice of the solvent for dissolving the concentrated material and the effects of diverse ions have also been discussed in detail. The detection limits for ETV-ICP-AES determinations of La and Eu with PMBP as a chemical modifier are 160 pg and 30 pg, respectively, under optimized experimental conditions. Relative standard deviations of 4.2% and 3.1% have been obtained after eight replicate determinations at the 10 ng/ml level for La and Eu, respectively. The La and Eu contents in the standard reference material of "Vehicle Exhaust Particulates" (NIES No.8) and "Citrus Leaves" (NIST SRM 1752) determined by the proposed method are in good agreement with the reference values.