Ion chromatography, applying non-suppressed conductivity or UV/VIS detection, is a less-expensive method of determining lanthanides.
Lanthanides are commonly determined by atomic absorption spectroscopy, X-ray fluorescence, inductively coupled plasma-mass spectrometry (ICP-MS) or inductively coupled plasma-atomic emission spectroscopy (ICP-AES).
These techniques involve high instrumentation costs and require highly skilled operators.
The determination of trace-levels of lanthanides by ion chromatography is achieved using either direct non-suppressed conductivity detection or UV/VIS detection at 655nm after post-column reaction (PCR) with arsenazo III.
Conductivity detection under isocratic conditions results in overall analysis times of approximately 70 minutes.
A much faster method is the determination of lanthanides via gradient elution and subsequent spectrophotometric detection of the arsenazo III-lanthanide(III) complexes, which can be performed within just 22 minutes.
Besides the short analysis time, UV/VIS detection excels by its selectivity and sensitivity and does not suffer from interferences by ever-present impurities such as iron(III) or other transition metals.