Emission Spectroscopy Based upon Plasma, Arc, and Spark Atomization Arc Arc Higher Temperature Higher Temperature Lower interelement interference Lower interelement interference Single set of excitation conditions can excite multiple elements Single set of excitation conditions can excite multiple elements Permit low detection limits for refractory complexes Permit low detection limits for refractory complexes Larger linear range Larger linear range Can directly measure hard to measure samples Can directly measure hard to measure samples Flame Simpler, less expensive instrumentation Lower operating costs Greater reproducibility

Emission Spectroscopies Cont. Plasma (def.) Electrically conducting gaseous mixture containing significant concentrations of cations and electrons Plasma (def.) Electrically conducting gaseous mixture containing significant concentrations of cations and electrons ICP and DCP ICP and DCP

Inductively Coupled Plasma Inductively coupled means that the plasma is generated due to differences in the magnetic field and currents Temp. very hot ( K)  Good & bad

Direct Current Plasma (DCP) Plasma forms by bringing graphite and W electrodes in contact with one another Plasma forms by bringing graphite and W electrodes in contact with one another core 10,000K core 10,000K in viewing region 5000K

ICP DCP Comparison DCP is an order of magnitude less sensitive than ICP DCP is an order of magnitude less sensitive than ICP Similar reproducibilities Similar reproducibilities DCP requires less Ar DCP requires less Ar Auxillary power less expensive in DCP Graphite electrode must be replaced every couple of hours

Comparison of Plasma to Flame Emission Sources Plasma sources offer significantly better quantitative data than do other flame emission sources Plasma sources offer significantly better quantitative data than do other flame emission sources - High stability - Low noise - Low background - Freedom from interferences

Comparison between Atomic Absorption & Emission Techniques AASAES Instruments Requires HC lamp for each element No high quality MC required Flame/ sample is source Requires high quality MC Operator Skill Bkgd.Correction Prec. & Accuracy Interferences Detection limit

Comparison between Atomic Absorption & Emission Techniques AASAES Instruments Requires HC lamp for each element No high quality MC required Flame/ sample is source Requires high quality MC Operator Skill Lower skill Higher skill Bkgd.Correction Prec. & Accuracy Interferences Detection limit

Comparison between Atomic Absorption & Emission Techniques AASAES Instruments Requires HC lamp for each element No high quality MC required Flame/ sample is source Requires high quality MC Operator Skill Lower skill Higher skill Bkgd.Correction Harder to do Easier to do Prec. & Accuracy Interferences Detection limit

Comparison between Atomic Absorption & Emission Techniques AASAES Instruments Requires HC lamp for each element No high quality MC required Flame/ sample is source Requires high quality MC Operator Skill Lower skill Higher skill Bkgd.Correction Harder to do Easier to do Prec. & Accuracy Unskilled better Same for skilled Unskilled worse  Interferences Detection limit

Comparison between Atomic Absorption & Emission Techniques AASAES Instruments Requires HC lamp for each element No high quality MC required Flame/ sample is source Requires high quality MC Operator Skill Lower skill Higher skill Bkgd.Correction Harder to do Easier to do Prec. & Accuracy Unskilled better Same for skilled Unskilled worse  Interferences Spectral interferences corrected in AES Chemical interferences on AE (flame) bad, plasma eliminated Detection limit

Comparison between Atomic Absorption & Emission Techniques AASAES Instruments Requires HC lamp for each element No high quality MC required Flame/ sample is source Requires high quality MC Operator Skill Lower skill Higher skill Bkgd.Correction Harder to do Easier to do Prec. & Accuracy Unskilled better Same for skilled Unskilled worse  Interferences Spectral interferences corrected in AES Chemical interferences on AE (flame) bad, plasma eliminated Detection limit Flame some metals better on AA than AES Plasma comparable to flame for some metals, other metals plasma better

Comparison of Metal Spectroscopic Techniques Performance Criteria Flame AA Electrothermal Sampling Flame AES DCPICP Dynamic range limitedlimitedwidewideWide Qualitative analysis Elemental range Trace analysis

Comparison of Metal Spectroscopic Techniques Performance Criteria Flame AA Electrothermal Sampling Flame AES DCPICP Dynamic range limitedlimitedwidewideWide Qualitative analysis poorpoorexcellentexcellentexcellent Elemental range Trace analysis

Comparison of Metal Spectroscopic Techniques Performance Criteria Flame AA Electrothermal Sampling Flame AES DCPICP Dynamic range limitedlimitedwidewideWide Qualitative analysis poorpoorexcellentexcellentexcellent Elemental range excellentexcellentexcellentexcellentexcellent Trace analysis

Comparison of Metal Spectroscopic Techniques Performance Criteria Flame AA Electrothermal Sampling Flame AES DCPICP Dynamic range limitedlimitedwidewideWide Qualitative analysis poorpoorexcellentexcellentexcellent Elemental range excellentexcellentexcellentexcellentexcellent Trace analysis excellentexcellentexcellentexcellentexcellent

Comparison of Metal Spectroscopic Techniques Performance Criteria Flame AA Electrothermal Sampling Flame AES DCPICP Dynamic range limitedlimitedwidewideWide Qualitative analysis poorpoorexcellentexcellentexcellent Elemental range excellentexcellentexcellentexcellentexcellent Trace analysis excellentexcellentexcellentexcellentexcellent

Comparison of Metal Spectroscopic Techniques continued Performance Criteria Flame AA Electrothermal Sampling Flame AES DCPICP Matrix interfernces highhighhighlowlow Spectral Interferences Precision & Accuracy Costs

Comparison of Metal Spectroscopic Techniques continued Performance Criteria Flame AA Electrothermal Sampling Flame AES DCPICP Matrix interfernces highhighhighlowlow Spectral Interferences lowlowlowmoderatehigh Precision & Accuracy Costs

Comparison of Metal Spectroscopic Techniques continued Performance Criteria Flame AA Electrothermal Sampling Flame AES DCPICP Matrix interfernces highhighhighlowlow Spectral Interferences lowlowlowmoderatehigh Precision & Accuracy Better for unskilled Same skilled Worse for unskilled same skilled Costs

Comparison of Metal Spectroscopic Techniques continued Performance Criteria Flame AA Electrothermal Sampling Flame AES DCPICP Matrix interfernces highhighhighlowlow Spectral Interferences lowlowlowmoderatehigh Precision & Accuracy Better for unskilled Same skilled Worse for unskilled same skilled Costs$$$$$$$$$$$$$

Comparison of Metal Spectroscopic Techniques continued Performance Criteria Flame AA Electrothermal Sampling Flame AES DCPICP Costs Instrumentat ion lowlowlowmoderatehigh Maintenance Sample Preparation Operator skill

Comparison of Metal Spectroscopic Techniques continued Performance Criteria Flame AA Electrothermal Sampling Flame AES DCPICP Costs Instrumentat ion lowlowlowmoderatehigh Maintenancelowlowlowmoderatehigh Sample Preparation Operator skill

Comparison of Metal Spectroscopic Techniques continued Performance Criteria Flame AA Electrothermal Sampling Flame AES DCPICP Costs Instrumentat ion lowlowlowmoderatehigh Maintenancelowlowlowmoderatehigh Sample Preparation moderatemoderatelowmoderatemoderate Operator skill

Comparison of Metal Spectroscopic Techniques continued Performance Criteria Flame AA Electrothermal Sampling Flame AES DCPICP Costs Instrumentat ion lowlowlowmoderatehigh Maintenancelowlowlowmoderatehigh Sample Preparation moderatemoderatelowmoderatemoderate Operator skill lowerhigherhigherhigherhigher