Determination of phosphorus by electrothermal atomic absorption spectrometry with a phosphorus hollow-cathode lamp as light source

Graphite tubes are pre-heated with a 10% (w/v) zirconium solution, and a 1% (w/v) zirconium solution is injected prior to each phosphorus sample solution. The calibration graph is linear up to ca. 100 ng P, and the detection limit is 5 ng. Phosphorus in water-soluble organic and inorganic compounds can be determined directly by the proposed method, which is also suitable for the determination of phosphorus in NBS standard reference plant materials and in green tea leaves.