Transition metal ion Co(II)-assisted photochemical vapor generation of thallium for its sensitive determination by inductively coupled plasma mass spectrometry

Herein, a sensitive method for the determination of trace thallium (Tl) in water samples was established using photochemical vapor generation (PVG) for gaseous sample introduction into an inductively coupled plasma mass spectrometer (ICP-MS) for quantitation. Various transition metal ions were spiked and studied as enhancement reagents to assist the photochemical generation of volatile thallium species in the medium of formic acid. An impressive limit of detection (LOD) of 11 ng L-1 was obtained with 20% formic acid solution containing 5 mg L-1 of cobalt ions, 210 s for UV irradiation and 50 mL min(-1) carrier gas flow rate. The accuracy and reliability of the present method was validated by analysis of a water certified reference material, BWB2198-2016, as well as two types of real water samples (tap water and bottled drinking water), with spike recoveries between 102% and 109% achieved.