Analysis of the Elution Curve in Eluting Lutetium from Cation-Exchanger with α-Hydroxyisobutyric Acid

Abstract

Abstract The elution behavior of lutetium from a cation-exchange column with α-hydroxyisobutyric acid solution (pH 3.77) was studied as a function of column distribution ratio of lutetium, flow rate, temperature and amount of lutetium. The elution curve fitted the normal distribution when the flow rate was smaller than 40 cm hr−1 for 0.14 M of the eluant, 60 cm h−1 for 0.12 M and 120 cm h−1 for 0.10 M. However, the normal distribution and constancy of the peak position could not be maintained when the amount of lutetium exceeded 200 μg cm−2. Within the range 15–35 °C, the peak position appeared late and the elution curve became sharper with temperature rise, but the diffusion coefficients remained constant. The value of the height equivalent to the theoretical plate was determined from the position and width of the elution peak which varied as a function of the flow rate. The diffusion coefficients of lutetium ions in the ion-exchange resin and the solution were calculated to be 2.6×10−7−6.4×10−9λ″ cm2s−1 and 4.2×10−5λ″ cm2s−1, respectively, according to Glueckauf’s theoretical equation, where λ″ is the column distribution ratio of lutetium ions. The experimental results make it possible to construct an elution curve for any column distribution ratio of lutetium in the range 2–20, temperature and flow rate.