tailieunhanh - ATOMIC ABSORPTION SPECTROPHOTOMETRY COOKBOOK

The atomic absorption spectrometry uses absorption of light of intrinsic wavelengths by atoms. All atoms are classified into those having low energies and those having high energies. The state having low energies is called the ground state and the state having high energies is called the excited state. The atom in the ground state absorbs external energies and is put in the excited state. For example, sodium is mainly in two excited states, having higher energies by and respectively than in the ground state, as shown in Fig. . (eV is a unit to measure energies and is called an “electron volt”.) When energy. | ATOMIC ABSORPTION SPECTROPHOTOMETRY COOKBOOK Section 1 Basic Conditions of Analysis of Atomic Absorption Spectrophotometry SHIMADZU CORPORATION Atomic Absorption Spectrophotometry Cookbook Section 1 CONTENTS 1. Principal of Atomic Absorption Spectrophotometry. 1 Why atoms absorb light. 1 Relation between light absorption rate and atomic density. 2 Sample atomization method . 3 a Flame atomic absorption. 3 b Electro-thermal atomic absorption . 4 2. Basic Condition for Analysis . 9 Conditions of equipment . 9 a Analysis line . 9 b Slit width. 13 c Lamp current value . 14 Analysis conditions of flame atomic absorption . 15 a Flame selection . 15 b Mixing ratio of oxidant and fuel gas. 17 c Beam position in flame. 17 Analysis conditions of electro-thermal atomic absorption . 18 a Drying condition . 18 b Ashing condition . 19 c Atomizing condition . 21 d Sample injection quantity . 23 1. Principal of Atomic Absorption Spectrophotometry Why atoms absorb light The atomic absorption spectrometry uses absorption of light of intrinsic wavelengths by atoms. All atoms are classified into those having low energies and those having high energies. The state having low energies is called the ground state and the state having high energies is called the excited state. The atom in the ground state absorbs external energies and is put in the excited state. For example sodium is mainly in two excited states having higher energies by and respectively than in the ground state as shown in Fig. . eV is a unit to measure energies and is called an electron volt . When energy is given to the sodium atom in the ground state it moves up to the excited state in I and when energy is given it moves up to the excited state in II . Energy is given as light and and respectively correspond to energy of light at and wavelength. In the case of sodium in the ground state only light of these wavelengths are absorbed and no