170135_inorganicventures_flipping

4:3 Sample Prepara9on

Preliminary Issues (cont.)

Obvious conflicts - using the informa5on concerning the sample and analyte(s), the trace analyst can iden5fy any number of obvious conflicts.

For example, dry ashing samples containing chlorine could result in losses in analytes forming vola5le 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 transi5on elements tells the analyst about the complexity of the emission or mass spectrum.

As always, safety considera5ons are important. For example, the use of nitric acid without considering the chemical composi5on 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 addi5on of nitric acid to avoid explosive reac5ons.

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.