Cloud-point extraction of molybdenum in plants and determination by isotope dilution inductively coupled plasma mass spectrometry

Molybdenum in plant digests was accurately determined by cloud point extraction and quanti. cation by isotope dilution inductively coupled plasma mass spectrometry. Plant digests spiked with Mo-98 received 8-hydroxyquinoline and the surfactant Triton X-100, attaining an enrichment factor close to 70. The Mo-98/Mo-95 measurements were characterized by RSDs from 0.5 to 1%. Instrumental mass discrimination of 1.4% was experimentally determined and used to correct the results. Concentrations found in plant reference materials were in agreement at the 95% significant level with certified values. A limit of detection of 0.8 ng g(-1) was calculated based on the blank uncertainties and calibration curve on both isotopes.