The concentration of neodymium was determined in each sample by using UV–visible spectrophotometer. The UV–visible spectra of lanthanides were scanned starting from a wavelength of 500 nm by means of UV–visible spectrophotometer to check the interference with any possible other rare earth ions. The intense pink color solution of Nd is the bases for the determination of Nd concentration by photometry after dilution with 0.1 M HCl at wavelength 576 nm. The neodymium isotopic ratios of some selected samples were measured by using a Joel high-resolution inductively coupled plasma mass spectrometer (JMS-plasma ×2). The samples were first burned completely to remove any residues for the carboxylic acids, then dissolved in nitric acid. The samples in the form of Nd(NO3)3 were supplied to the inlet system which consists of the peristatic sample inlet section of the ICP-MS.