Ashing method

Ash and Inorganic Constituents. Ash may be measured gravimetdcaHy by incineration in the presence of sulfudc acid or, more conveniendy, by conductivity measurement. The gravimetric result is called the sulfated ash. The older carbonate ash method is no longer in use. Ash content of sugar and sugar products is approximated by solution conductivity measurements using standardized procedures and conversion factors. 

The higher calcium value obtained by the ash method is no doubt due to the presence of sodium (the counter ion for acetate commonly found in some lots). 

The state of the art for the decomposition of biological materials are the ashing methods. Of course, some of these methods stiU have teething troubles. TTie most recent include the following techniques and devices ... 

Barium carbonate is made commercially from barium sulfide either by treatment with sodium carbonate at 60 to 70°C (soda ash method) or by passing carbon dioxide at 40 to 90°C ... 

The USP XX (30) and the Official Methods of Analysis of the Association of Official Analytical Chemists (AOAC) (44) describe in detail the curative method more commonly known as the rat line method. This method is not applicable to products offered for poultry feeding. For poultry feeds, and fish liver oils and their extracts, the AOAC (44) also describes in detail the chick bone ash method. In addition to the above two methods, there is a method based on the comparative measurement of serum calcium in rats referred to as Intestinal Calcium Transport Assay and another method based on the comparative amounts of calcium absorbed by control and test chicken referred to as Calcium Absorption Test. These methods are described by DeLuca and Blunt (45). 

Look up a procedure that uses only a wet ash method. Which do you think is better Why ... 

Foreman et al. [631] compared the direct method of the chelate formation with the preliminary ashing method for the analysis of beryllium in rat urine. A detailed study showed that both of the methods are satisfactory, whereas testing of column material and packings showed the best results for a PTFE column packed with SE-52. Down to 1 ng/ml of the element could be detected in urine with the use of an ECD and EDTA as a masking reagent and a 0.05 M benzene solution of trifluoroacetylacetone. 

Samples of heavy duty and cmde oils, lubricating oils, worn oils, organic polymers, plastics, grease, etc., may be ashed with the retaining acid PTSA using the dry-ashing method up to temperatures of 650°C. This compound will retain most mono- and divalent states of elements in samples. The structure of PTSA is ... 

Gorsuch, T.T. (1959) Sample preparation using dry ashing method, Analyst (London), 84, pl35. 

The metal salts are added to plastic products as organometallic, metallocenes or inorganic salts. The ashing method of sample preparation is only suitable for elements that do not volatilise during the heating cycle. The results obtained and recorded in Table 4.10 are reproducible for most elements with the exception of Pb and Sb in which some loss had taken place using the opened dry ashing method even in the presence of PTSA. 

Analysis of Type C and D Fractions for Metal Content Using Dry Ashing Method [6]... 

Results. The results obtained by this experiment were between 95 and 109% which is indicative of a good recovery for the listed elements using the ashing method. The metals Pb and Sn were included to test for their volatility in this type of sample (Table 5.13). The method works well for some metals but not for volatile metals. These samples can also be prepared using microwave acid digestion or bomb combustion methods. 

Ashing Method of Type A and Type B Anaerobic Adhesives... 

Table 6.5 Results of analysis of metal for metal content of Type A and Type B adhesives after sample preparation using dry ashing method...

Results. The results of analysis of epoxy adhesives using the ashing method are shown in Table 6.16. 

Ashing Methods for Metal Analysis of Polyurethane Adhesives... 

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