120 likes | 133 Views
What is Atomic Spectroscopy? – Sec 20-1. Atomic Absorption Spectroscopy (AAS) versus Atomic Emission Spectroscopy (AES). Flame Atomization – Sec 20-2. Atomization process =. Complete atomization results in ____________________. Fuels and Flame Temperatures – Table 20-1.
E N D
Atomic Absorption Spectroscopy (AAS) versus Atomic Emission Spectroscopy (AES)
Flame Atomization – Sec 20-2 Atomization process = Complete atomization results in ____________________
Instrumentation – Sec 20-4 The Linewidth Problem – absorbance is proportional to concentration (i.e. Beer’s Law holds) when the linewidth of the probing light is narrower than the absorption band
Line Broadening Mechanisms Both mechanisms result in more line broadening as the temperature increases. 1. Doppler Effect – atom moving towards the lamp samples EM wave more often = higher frequency (shorter wavelength) absorbed
2. Pressure Broadening – colliding atoms (and molecules) absorb a broader range of frequencies (wavelengths)
Hollow Cathode Lamps Cathode composed of the same element as the analyte. As long as line broadening within the cathode is less than within the flame, the linewidth of the lamp is always less than the linewidth of the absorbing atoms and Beer’s Law is followed.
Interferences – Sec 20-5 1. Spectral Interference -