Direct determination of major elements in solid plant materials by electrothermal vaporization inductively coupled plasma atomic emission spectrometry

The present work demonstrates the capability of electrothermal vaporization (ETV) to become an important tool of solid sample introduction in ICP-AES for plant sample analysis. Direct determination of Al, Ca, Fe, K, Mg, Mn, Na and Zn was investigated in powdered plant samples. Obtaining good results for major elements in plant samples was governed by some special operating conditions. The sensitivity of the method necessitated the use of ICP in radial view configuration. The behavior of elements during vaporization was studied between 500 and 2600 °C. External calibration was carried out using solid external (cellulose) spiked with aqueous standard solutions. However, performances of the analytical method were found dependent of argon flow rates. Analytical accuracy of the method was tested in three reference materials. Analytical results agreed with certified values when cellulose was used in calibration. However, K could not be determined because of excessive sensitivity. Without cellulose, it was found that Fe results were underestimated and Zn results overestimated. Relative standard deviations varied from 3 to 23%. Limits of detection varied from 1 to 80 ng g−1 from one element to the other for a typical mass sample of 2 mg.