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

Abstract

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 mixer mill were measured for ground material and slurries prepared from flowers, leaves, stem and roots of the same plant material. Normally the particle size distribution is reported either as number of particles versus size or volume of particles versus size. The advantage of using the latter mode of reporting is demonstrated. It is shown that detailed information about the larger particles is lost when the distribution is reported in terms of the number-percentage. In the present case, 60 min of grinding gave similar size distribution for all the plant materials. All particles had diameters less than 50 μm and the calculated number of particles per mg was 6–8 × 10⁷. It is shown that the ultrasonic agitation used to homogenize the slurries, prior to injection of the sample, also had an effect on the particle size distribution.