Evaluation of a wide range laser diffraction grain size analyser for use with sediments

Abstract

The qualities of a laser diffraction grain size analyser, the Coulter LS-100 (range claimed by the manufacturer: 0.4-900 mum in a single measurement), are evaluated on sediments of fluvial and lacustrine origin. Accuracy and resolution of measurement on standard latex spheres are excellent. Reproducibility of the results on natural sediments appears to be satisfactory, but the method underestimates the fraction of clay particles with an efficiency of detection (36-70%) proportional to the clay content determined from pipette analysis. This efficiency is somewhat higher than those reported from other instruments of the same generation. Comparison of the Coulter LS-100 with other sizing techniques shows good agreement with the sieving method but some differences appear with the electroresistance particle technique: median and mean size values measured by the Coulter Counter TA1 are systematically lower than those obtained by the Coulter LS-100. Analyses show good correlation with those of a Malvern Laser particle analyser but a discrepancy appears with very fine silt and clay sized sediments. The Coulter LS-100 detects a higher clay content than that measured with the Malvern Laser Sizer 2600. Except when precise measurements of clay content are needed, the Coulter LS-100 produces precise and accurate results in size ranges required for geological and environmental studies

Wastewater as a point source of antibiotic-resistance genes in the sediment of a freshwater lake

“…The sediment grain size was measured using a Coulter LS-100 laser diffractometer (Beckman Coulter, Fullerton, CA, USA), following 5-min ultrasonic dispersal in de-ionized water according to the method of Loizeau et al (1994).…”

A Debate on the Similarity of Particle Sizing Results Derived From the Analysis of Finegrained Sediments by Two Different Instrumentations

“…The comparison of the results was achieved by: (i) the mean differences of frequency distribution for each of seven grain-size intervals; >10; 10-9; 9-8; 8-7; 7-6; 6-5; and 5-4 0 (>1; 1-2; 2-4; 4-8; 8-16; 16-32; and 32-63 μπι) between the two datasets, (ii) the correlation coefficient between the two bulk datasets and between the silt and the clay fractions measured by the two instrumentations and (iii) the analysis of variation/residuals within individual grain size intervals. Similar approaches have been discussed by Behrens (1978), Konert and Vandenberghe (1997), Loizeau et al (1994) and Molinaroli et al (2000).…”

“…The two main diffraction theories which are typically used in the prediction of laser particle results are the Fraunhofer theory and Mie theory. Singer et al (1988) and Loizeau et al (1994) argue that the particulate model tends to underestimate particle sizes close to the wavelength of the laser source light.…”

“…McCave et al (1986), Singer et al (1988), Syvitski et al (1991), Konert and Vandenberghe (1997), Buurnman et al (1997), Loizeau et al (1994), Muggier et al (1997), Beuselinck et al (1999), McCave et al (2006) have compared the above mentioned instrumental techniques with the classical leading occasionally to conflicting results. However it should be mentioned that only a few works have studied the relation between the laser diffractometry and electozone particle counting (e.g.…”

“…However it should be mentioned that only a few works have studied the relation between the laser diffractometry and electozone particle counting (e.g. : Singer et al 1988, Loizeau et al 1994). …”