Is there anybody who has experience with the laser analyser Analysette 22 or any other former versions of analysers distributed by Fritsch? I wonder what kind of soil sample preparation methods for wet measurement are used elsewhere. Every answer will be welcomed.
Hi Elena
I have used the Malvern Mastersizer (MMS) which has produced results which do not correspond with those of other methods. My samples appeared to have far too much sand and too little clay, even compared with hand texturing. The literature suggests exactly this and advises against laser methods for soil scientists, eg see Vdovic et al 2010. However I met Evgeny Shein from Moscow and he believes laser methods are accurate if you first separate the 200-2000 micron particles by sieve: [email protected]. This is from memory so best to check with him!
Our lab uses a CILAS 1190, for context we generally do not look at soil textures but lake sediments. For sample preparation it depends on the environment and question we want to address. Typically we dissolve the carbonate and organic portion of the sediment using HCl and H202 respectively. We then soak the samples in sodium hexametaphosphate to prevent clay flocculation (which would give an apparently coarser grain-size). Our methods generally follow from Sperezza et al (2004, JSR v. 74) titled, HIGH-RESOLUTION PARTICLE SIZE ANALYSIS OF NATURALLY OCCURRING VERY FINE-GRAINED SEDIMENT THROUGH LASER DIFFRACTOMETRY. Sperezza et al (2004) look at different sample preparation techniques (and other issues) related to laser diffractometry.
i have used Malvern Mastersizer 2000G and i got good results from laser diffraction method. for this analysis we prepared the solution which is sodium . We took .5 gram of 2mm sieved soil with 10 ml 5% hexametaphosphate solution. put it for 48 hr in shaker. then continue your laser deffraction experiment. hope you will get good results.
We use the Fritsch Analysette 22 for all our standard measurments and have compared the results with the standard sedimentation and pipette analyses at more than 300 forest sites. Due to the different physical background of both methods, distinct differences (have to) occur. However, via the use of linear regressions both data sets could be correlated very well. A restriction is the clay content, soils with more than 30% of clay could not be compared because we didn´t have enough samples in this category. Sample preparation followed DIN ISO 11277 (destruction of organic carbon with H2O2 and dispersion with Na4P2O7).
reference (in German only):
TREFZ-MALCHER, G.; PUHLMANN, H. & WILPERT V., K. (2010): Vergleich von Texturanalysen mit Lasersizer und Köhnpipette. in: Bodenzustandserfassung, aktuelle Gefährdungen und Trends. Gemeinsames Kolloquium des AK „Waldböden“ der DBG und der Sektion „Wald & Wasser“ im DVFFA und des vTI Eberswalde in Freiburg am 18. - 19. Mai 2010. Freiburg, S. 63-70.
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