A TOMIC A BSORPTION S PECTROSCOPY By Hisham E Abdellatef 1

Flame Principles of Operation Review Optimizing the Flame Multielement vs Single Element Lamps Lamp Performance Check Increasing the Linear Range Slit Selection Background Correction Air Acetylene and Nitrous Oxide Flames Matrix Modifiers Instrument Detection Limits (IDL), Method Detection Limits (MDL), and Limits of Quantification (LOQ) Basic Quality Control Hydride Generation Mercury Cold Vapor Furnace Principles of Operation Background Correction and Performance Checks The Three Steps Dry, Char, Atomize How to Enhance each Step and Modifiers Handling Difficult Matrixes Graphite Tube Selection Quality Controls Detection Limits Quality Assurance Method development/Standard Operating Procedures (SOP) EPA Quality Assurance programs Standards/Blanks Advanced Flame and Graphite Furnace Atomic Absorption Spectroscopy Course Instructor: prof. Dr. Hisham Ezzat Abdellatef

Introduction AAS is used to determine metal element concentration in a sample Can analyze over 62 metal elements Cold Vapor AA, Flame AA, and Graphite furnace AA Standard addition and standard calibration technique can be used to compute for metal element concentration

4 Technique – Flame Test

5 Atomic Absorption Spectroscopy: An Aussie Invention Developed by Alan Walsh in early 1950s.

Introduction

ATOMS Nucleus- protons (+ve) and neutrons (neutral). Electrons- (-ve) charged particle. Shells- consists of subshells. Nucleus Bohr’s shell model: SODIUM atom Shells Electrons

Shell, Subshells, Electrons Electrons are arranged according to their energy levels. They are arrange in subshells, the subshells are arrange in shells and shells are arrange around the nucleus. Shells Atom (around the nucleus) Subshells Electrons !Note: Electrons that are near the nucleus has a lower energy level than the electrons that are much far away. However, they experience stronger attraction in the nucleus than those ones that are further away.

‘Exciting’ atoms ‘ground’ state: is a status where the atom’s electrons are in their lowest possible energy level. (stable) ‘excited’ state: another status where the atom’s electrons absorb enough energy to be promoted to a higher level. Therefore, they are not in their lowest energy level. (unstable)

‘Excited’ atom Generally, atoms are in their ‘ground state’ but when an atom receives enough input of energy that their electrons requires to be promoted to a higher energy level. They will then turn to their ‘excited state’. Ground state: sodium atom Excited state: sodium atom Since, an atom’s excited state is very unstable it rapidly ‘jump’ back down to its ground state. This ‘jump’ then causes the atom to release the energy it absorbed in the form of photons of light. !Note: Take note that the electron can go back down to its ‘original’ place in more than one jump.