THE APPLICATION OF CHEMICAL MODIFICATION IN DIRECT SAMPLE INSERTION INDUCTIVELY COUPLED PLASMA ATOMIC EMISSION-SPECTROMETRY

With a graphite cup based direct sample insertion device poor results are obtained for refractory and carbide forming elements, such as Al, B, Ca, Sr and Zr. In this work, several chemical modification reagents have been tested in order to improve the vaporization characteristics of such analytes. Reagents tested include KCl, KF, NaCI and NaF. The best overall results were obtained using NaF added as a 10 μl spike of 0.25 M NaF to the sample carrying cup. With this treatment the above analytes can be quantitatively determined. The direct determination of B in powdered CaSO4 is shown as an example of NaF chemical modification. © 1990.