chemistry

Sampling Techniques for Atomic Absorption Spectrometry Home > Analytical Chemistry > Analytical Chemistry - Atomic Absorption > Atomic Absorption Spectrometry (AAS) > Sampling Techniques for Atomic Absorption Spectrometry Sampling Techniques for Atomic Absorption Spectrometry   Two systems are commonly used to produce atoms from the sample in atomic absorption spectrometry : Aspiration & electrothermal atomization (graphite furnace).   Aspiration involves sucking a solution of the sample into a flame. Figure I.1 shows a typical burner and spray chamber. Ethylene/air or ethylene /dinitrogen oxide are used. A flexible capillary tube connects the solution to the nebulizer. At the tip of the capillary, the solution is “nebulized” that means is broken into small drops. The larger drops fall out and drain off while smaller ones vaporize in the flame. Only 1% of the sample is nebulized .   Electrothe

Lewis dot of Nitrogen Monoxide (NO) Home > Lewis structures and the Octet rule > Simple Procedure for writing Lewis Structures - Lewis Structures for NO2+ and HCN > Lewis dot of Nitrogen Monoxide (NO) Lewis dot of Nitrogen Monoxide (NO) A simple procedure for writing Lewis Structures is given in a previous article entitled Lewis Structures and the Octet Rule . Several worked examples relevant to this procedure were given in previous posts please see the index page Lewis Structures & the Octet Rule - Theory & Examples . Another example for writing Lewis structures following the above procedure is given in this post. The Lewis structures of Nitrogen Monoxide NO are drawn. Let us consider the case of NO. NO is a free radical and is an important intermediate in the chemical industry . Nitric oxide is a by-product of combustion of substances as in automobile engines , fossil fuel power plants

Light sources for atomic absorption Home > Analytical Chemistry > Analytical Chemistry - Atomic Absorption > Atomic Absorption Spectrometry (AAS) > Light sources for atomic absorption Light sources for atomic absorption It is well known that an atom in its ground state absorbs light at discrete wavelengths (E = h*c/λ). In order to measure this narrow light absorption with maximum sensitivity, it is necessary to use a line source, which emits the specific wavelengths which can be absorbed by the atom. Narrow line sources not only provide high sensitivity, but also make atomic absorption a very specific analytical technique. The two most common line sources used in atomic absorption are the “ hollow cathode lamp, HCL ” and the “ electrodeless discharge lamp, EDL ”.   The Hollow Cathode Lamp HCL The common source of light is a “ hollow cathode lamp ”. This contains a tungsten anode and a cylindrical hollow c