Basic Training 4th Annual ICP Conference

4:3 Sample Prepara9on

Preliminary Issues (cont.)

Obvious conflicts - using the information concerning the sample and analyte(s), the trace analyst can identify any number of obvious conflicts.

For example, dry ashing samples containing chlorine could result in losses in analytes forming volatile chlorides. Another example -- a sulfated ash of samples containing Ba or Pb as the matrix element will result in insoluble sulfates.

The presence of matrix elements such as the Rare Earths or many transition elements tells the analyst about the complexity of the emission or mass spectrum.

As always, safety considerations are important. For example, the use of nitric acid without considering the chemical composition of the sample can lead to hazardous results. Samples that may contain significant amounts of alcohols are reacted first with sulfuric acid prior to the addition of nitric acid to avoid explosive reactions.

4:4 Sample Preparation

Preliminary Issues (cont.)

The selec6on of a prepara6on method is dependent upon:

• the analyte(s) • the analyte concentra6on level(s) • the sample matrix • the instrumental measurement technique • the required sample size

The method selected will require specific sample prepara6on equipment and reagents. Contamina6on from the atmosphere, apparatus, and reagents is a key issue when addressing the selec6on process.