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). Sophisticated as they are, these techniques go along with high costs of instrumentation and require highly skilled operators.

The determination of trace-levels of lanthanides by ion chromatography is achieved by using either direct non-suppressed conductivity detection or UV/VIS detection at 655 nm after post-column reaction (PCR) with arsenazo III. Conductivity detection under isocratic conditions results in overall analysis times of approx. 70 minutes. A much faster way 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.

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