Effect of heating rates in graphite furnace atomic absorption spectrometry

Capacitive discharge heating in graphite furnace atomic absorption spectrometry

“…The above two limitations can be removed by using much faster heating rates with a capacitive discharge power supply together with an auxiliary power supply and anisotropic pyrolytic graphite tubes. The effect of heating rates in graphite furnace atomic absorption spectrometry has been reported in earlier publications (10,11) from the authors' laboratory.…”

“…At the instant of time when the sample has been completely atomized (t = 7q), N reaches its peak value, Npeai•. (10) If in addition iq/r2 « 1 (as is the case of capacitive discharge heating of an anisotropic pyrolytic graphite atomizer) iq --1 U=CV2/2 (14) where C = capacitance and V = voltage applied to the capacitor bank. By substituting the value of U from Equation 14into Equation It has been shown that, at constant r2, the absorbance should increase exponentially with the heating rate a.…”

“…Since this atomizer is similar in design to that of the Perkin-Elmer HGA-2100, it is called the modified HGA-2100. Details of this apparatus have been presented in earlier publications (4,10).…”

Electrothermal atomic absorption spectrometry with improved tungsten tube atomizer

“…Chakrabarti et al (7,8) reported that peak absorbances and integrated absorbances of relatively involatile elements increased exponentially with increasing heating rates and that relatively volatile elements increased in the peak absorbances with heating rates. Therefore, to improve sensitivity and detection limits further, it is necessary to heat an atomizer to its maximum temperature at an increased rate and/or develop a new adequate tube atomizer having a higher atomization efficiency and a longer residence time for neutral atoms.…”