MORNING
Fundamental aspects of ICP-AES.
Instrumentation
Overview of spectrometers - Solid-state detectors vs. conventional PMT-based
Systems. CIDs vs. CCDs.
Criteria for instrument selection - wavelength range, LODs, resolution, sample throughput, multielement capability. Advantages for real sample multielement analysis. Versatility in line selection – the ultra low UV region for determination of the halogens. Ion vs. atom lines.
Axially and radially viewed plasmas. Critical comparison using conventional figures of merit (limits of detection, response linearity, and matrix effects). Is dual view necessary?
Sample introduction
Conventional sample introduction. Pneumatic, cross-flow, low-consumption, high-salt V-groove, and desolvating nebulizers.
Practical approach to sample introduction. Limitations and advantages using LODS, matrix effects, convenience of operation and cost.
Types of nebulizers to be used as a function of the application
Decomposition strategies
Advantages of solution techniques, considerations for calibration and validation.
Decomposition strategies. Acid decomposition, fusions, sinters, open dish, pressurized containers, microwave dissolution, and digestion.
Critical evaluation of advantages and disadvantages. For example, chemical resistance of refractory samples, loss of volatiles, recovery, reagent cost and contamination.
Partial decomposition and extraction for determining mode of occurrence of elements and species for environmental evaluations
Recipes for preparation of geological, environmental, biological, and energy-based samples such as fly ash, coal, crude oil, and multiphase bituminous sludge.
Compliant methods of sample preparation for analysis of waters, wastewaters, and solid wastes (EPA 200.7, 200.8, SW-846 6010B and 6020A) will be summarized.
Performances will be evaluated using conventional figures of merit such as limits of detection, recovery, sample throughput, and contamination.
AFTERNOON
Problem Solving - Effect of the sample matrix on plasma and sample introduction systems.
Spectral interferences
Spectral line selection criteria
LODs, spectral interferences Procedures for compensation, background correction, interference equivalent coefficients. Importance of resolution. Mathematical procedures.
Nonspectroscopic interferences
Physical effects in the aerosol generation and transport systems. Salt and acid concentrations, memory effects. Effect of ICP operating conditions (RF power, nebulizer flow rate, and torch configuration). Salt clogging in torch injectors.
Plasma effects
Effect of sample composition – easily ionized elements and Ca. The use of Mg II 285/Mg I 280 and Mn II 257/Cu I 324 nm ratios as matrix effect criteria and instrument set up. Importance of spectral line energy -. Ion vs. atom lines.
Effect of organic solvents, in particular methanol on high ionization potential elements
Compensating nonspectroscopic effects
Optimization of ICP operating conditions – determination of robust conditions. Internal standards - criteria for selecting internal standards: Energy characteristics of spectral lines, excitation and ionization potentials, spectral proximity, low abundance in sample, stability in solution, freedom from spectral interference. Advantages and disadvantages
Methods development an exercise with the course participants - preparing a standard operating procedure for analysis of waters and wastes based on EPA 6010C
Selection of analyte spectral lines
How to select the internal standard
Getting started – Optimization of the ICP and nebulizer conditions
Calibration and calibration validation
Factors effecting accuracy and precision
QA/QC - calibration and interference checks, addition method and spikes, duplicates,
Validation - Role of CRMs and Proficiency Testing, Control charts
Conclusions and discussions
Analysis of geological samples – aspects of sample preparation
Speciation
Direct solids techniques - Bulk analysis of geological and related refractory materials and coal using spark and laser ablation and slurry nebulization. |
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