Melanoidin served as proxy for a class of organic materials likely to interfere with BC separations. Melanoidin was defined first by Maillard, 1917 (Annales de chimie (Paris) 7: 113-152). A synthesis protocol also has been published: Allard et al. 1997 (Organic Geochemistry 26: 691-703) and Olsson et al. 1978 (Acta Chem. Scandinavica B32: 249-256). Here we advocate a simple approach which requires no specialized technical equipment, involves inexpensive reagents and is not labour-intensive. We produced melanoidin by mixing glucose with urea in deionized water.
Urea-glucose melanoidin is prepared by making a solution of 100 g/L D-glucose and 10 g/L urea in Schott glass jars. Caps are screwed on lightly and bottles are kept in a water bath at a temperature of 90 degrees Celsius for 30 days. The solutions in the bottles is stirred every second day to prevent a skin from forming on the surface of the liquid. The solution turns brown overnight. After 30 days, the bottles are removed from the water bath, centrifuged and washed four times to remove any low molecular weight urea and glucose still present and to isolate the insoluble melanoidin. The washed melanoidin is freeze dried and kept sealed in the dark at room temperature for analysis. This method yields approximately 2 g melanoidin per litre solution. The sample was prepared by Univ. Zurich, Switzerland.
Subsamples prepared by this method can be ordered from Michael W. I. Schmidt, Univ. Zurich, Dept. Geography, 8057 Zurich, Switzerland (firstname.lastname@example.org).
Cost: 40 Euro per 1 g subsample.
The U.S. Geological Survey reference Green River Shale (SGR-1) was collected from the Mahogany zone of the Green River Formation. It is a petroleum and carbonate-rich shale (Ctot 28 mass%, Cinorg 3.2 mass%). At the time of preparation, shale oil tests yielded 51 to 57 gallons per ton. Element concentrations were determined by cooperating laboratories using a variety of analytical methods. Certificate values are based primarily on international data compilations (1,3,4). Initial USGS studies (2) provide limited background information on this reference material.
Material can be ordered through: Dr. Stephen A. Wilson, U.S. Geological Survey, Box 25046, MS 973, Denver, CO 80225, USA. Ordering information: http://minerals.cr.usgs.gov/geo_chem_stand/shale.html
Cost: USD 80 per bottle (price as on 15 April 2011)
1) Abbey, S., 1983, Studies in "Standard Samples" of Silicate Rocks and Minerals 1969-1982, Canadian Geological Survey Paper 83-15, p-114.
2) Flanagan, F.J., 1976, Descriptions and Analyses of Eight New USGS Rock Standards, U.S. Geological Survey Professional Paper 840, p 192.
3) Gladney E.S., and Roelandts, I., 1988, 1987 Compilation of Elemental Concentration Data for USGS BHVO-1, MAG-1, QLO-1, RGM-1, SCo-1, SDC-1, SGR-1, and STM-1, Geostandards Newsletter, 12: 253-362.
4) Govindaraju, K., 1994, 1994 Compilation of Working Values and Descriptions for 383 Geostandards, Geostandards Newsletter, 18:1-158.
We suggest two coal samples representing typical end-members in coal rank, a lignite and a low-volatile bituminous coal. Anthracites were not included because of their low reactivity and relative scarcity.
As an indicator of coal rank, the lignite (Beulah-Zap) has a low reflectance (0.25). No inertinite values are available for the lignin standard. PCS Characteristics: Mass % C, H, O values on moisture and ash free basis, S and ash are on the dry basis.
C 73 / H 4.8 / O 20 / S 0.8 / ash 10.
The bituminous coal (Pocahontas) has a higher reflectance (1.68). The bituminous coal contains about 10% of inertinite, suspected to represent (at least partly) fossil charcoal. PCS Characteristics: Mass % C, H, O values on moisture and ash free basis, S and ash are on the dry basis. C: 91 / H 4.4 / O 2 / S 0.7 /ash 5.
Subsamples can be purchased from the Argonne National Laboratory USA (Assistant Controller, OCF/201, Argonne National Laboratory, 97000 South Cass Avenue, Argonne, IL 60439, USA, web: http://www.anl.gov/PCS/
Cost: USD 16 per 5 g (-100 mesh) sample (price as on 15 April 2011).