Coulter particle analysis used for studying the effect of sample treatmentin slurry sampling electrothermal atomic absorption spectrometry

This work focuses on the potential of using a Coulter particle analyzer for method development in slurry sampling ETAAS. Plant materials were used as an example; the particle size distributions obtained after grinding in a mi xer mill were measured for ground material and slurries prepared from flowe rs, leaves, stem and roots of the same plant material. Normally the particl e size distribution is reported either as number of particles versus size o r volume of particles versus size. The advantage of using the latter mode o f reporting is demonstrated. It is shown that detailed information about th e larger particles is lost when the distribution is reported in terms of th e number-percentage. In the present case, 60 min of grinding gave similar s ize distribution for all the plant materials. All particles had diameters l ess than 50 mu m and the calculated number of particles per mg was 6-8 x 10 (7). It is shown that the ultrasonic agitation used to homogenize the slurr ies, prior to injection of the sample, also had an effect on the particle s ize distribution.