石墨炉原子吸收光谱分析法的原子化效率和特征量

CHARACTERISTIC MASS AND ATOMIZATION EFFICIENCY OF GRAPHITE FURNACE ATOMIC ABSORPTION SPECTROMETRY

采用Ｖ－舟日立ＧＡ－３石墨炉在较宽的温度范围内测量了Ａｇ、Ｂｉ、Ｃｄ、Ｃｒ、Ｇａ、Ｇｅ和Ｉｎ等元素的峰高、峰面积特征量（ｍｐ０（ｅｘｐ）、ｍｉ０（ｅｘｐ））和峰高、峰面积原子化效率（βｐ、βｉ），并将ｍｉ０（ｅｘｐ）与计算理论值（ｍｉ０（ｃａｌ））进行了比较。讨论了原子化温度对βｐ、βｉ以及α（峰面积理论化校正因子，α＝ｍｉ０（ｃａｌ）／ｍｉ０（ｅｘｐ））的影响。由于βｉ＝ατＤ／τＲ（τＲ是原子停留时间，τＤ＝ｌ２／８Ｄ），在高温下部分分析物蒸气被热管壁吸附，随后再蒸发和扩散，使得τＲ延长并常常大于τＤ值，因而呈现出元素的α值大于相应的βｉ值。

Measurements of peak height and peak area characteristic masses and atomization efficiency for 7 elements(Ag,Bi,Cd,Cr,Ga,Ge and In)have been studied.The m i 0( exp ) values are compared with theoretical data,m i 0( cal ),to assess the effect of temperature on the correction factor of theorization for characteristic mass value(α=m i 0( cal ) m i 0( exp )),the peak height and the peak area atomization efficiencies(β p and β i ) The peak area atomization efficiency(β i) was equal to the correction factor of theorization for characteristic mass value(α)times τ D/τ R value The τ R  was value experimentally measured of atomic residence time and the τ D  value calculated from τ D =l 2/8 D  The β i  value of elements always are smaller than the α values because the τ D /τ R  values is less than one for most elements in the operating conditions Past of the analyte vapours is readsorbed by the heated tube wall at high temperature and reevaporation of the adsorbed analyte followed by diffusion account for the larger atomic residence time and it appeared that the τ R  value was larger than the τ D  in graphite furnace