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15.3 ICP-OES Measurement

Concerns with measurement: Precision

• Try to keep the analyte concentra/on well within the linear working range. When the concentra/on falls < 100 /mes the detec/on limit, the precision begins to fall. • Avoid lines requiring spectral correc/on. • Avoid lines that are in spectrally complex regions requiring sophis/cated background correc/on algorithms. • Increasing the integra/on /me to as high as 5 seconds should improve the precision. It need not be increased any higher. • Use an all glass introduc/on system including a glass concentric nebulizer. Your washout /mes will improve along with your precision.

15.4 ICP-OES Measurement

Concerns with measurement: Precision

• Be weary of sal,ng out effects when analyzing high salt containing solu,ons, but do not use high solids nebulizers unless necessary. • If your samples and standards have the same background then you should skip background correc,on. • If the matrices of the samples and standards can be matched then eliminate the peristal,c pump and go 'free flow'. The pump introduces pulsing and the pump tubing stretches, causing the introduc,on rate to gradually change. If you can avoid the pump then make sure the liquid levels of your samples and standards are the same.

NOTE: Slight differences in hydrosta,c pressure will make a difference.