Carbonizable substances test

Revision Description revised Heavy Metals (as Pb) and Ultraviolet Absorbance specifications and determinations deleted Tridodecylamine specification revised Readily Carbonizable Substances test replaced Residue on Ignition test reworded. ... 

Food/medicinal grade specifications (21 CFR 172.878) are designed such that products meeting these specifications can be safely used in food and pharmaceuticals.6 The specifications control PNA levels by the UV absorption limits given in Table 11.2 and by the carbonizable substances test (ASTM D565). These are discussed in more detail later in the chapter, and these are the difficult specifications to meet. 

When reactor temperature increases sufficiently the rate of the reverse reaction becomes competitive with that of the forward saturation reaction, and with further temperature increases, the reverse reaction becomes predominant and polyaromatic levels cause product failure in either the carbonizable substances test, the UV test, or both. 

The key toxicity specifications required by FDA food/medicinal requirements are the readily carbonizable substances test (ASTM D565) and the UV test for polynuclear aromatics (ASTM D2269). 

Carbonizeable Substances. Pipette 5ml of the sample into a 20x150mm test tube. Slowly and carefully add 5ml of coned H2SO4 and swirl the tube gently during the addition. The H2S04 used must be no darker in color than the methanol. Do Not Cool The Mixt. Allow the tube and contents to stand for 5 minutes at room temp. Examine the contents visually for any evidence of discoloration... 

USP acid test analy chem A United States Pharmacopoeia test to determine the carbonizable substances present In petroleum white oils. yti es pe as ad. test) UV stabilizer chem Any chemical compound that, admixed with a thermoplastic resin, selectively absorbs ultraviolet rays used to prevent ultraviolet degradation of polymers. Also known as ultraviolet stabilizer. yu ve sta ba.iTz ar)... 

Readily Carbonizable Substances. .. 845 Chloride Limit Test... 863... 

Colorimetric solutions are used in the preparation of colorimetric standards for certain chemicals and for the carbonization tests with sulfuric acid that are specified in several monographs. Directions for the preparation of the primary colorimetric solutions and Matching Fluids are given under the test for Readily Carbonizable Substances, Appendix IIB. Store the solutions in suitably resistant, tight containers. 

Readily Carbonizable Substances Transfer 1.00 + 0.01 g of finely powdered Citric Acid to a 150-mm x 18-mm (od) tube previously rinsed with 10 mL of 98% sulfuric acid at 90° or used exclusively for this test. Add 10 + 0.1 mL of 98% sulfuric acid, carefully agitate the tube until solution is complete, and immerse the tube in a water bath at 90° + 1° for 1 h. Occasionally remove the tube from the water bath and carefully agitate it to ensure that the Citric Acid is dissolved and gaseous decomposition products are allowed to escape to the atmosphere. Cool the tube to ambient temperature, carefully shake the tube to ensure that all gases are removed, and using an adequate spectrophotometer, measure the absorbance and transmission of the solution at 470 nm in a 1-cm cell. The absorbance does not exceed 0.52, and the transmission is equal to or exceeds 30%. 

The ash from 0.5 Gm. is negligible. Dissolve 0.1 Gm. of finely powdered Cocaine in 1 cc. of sulphuric acid not more than a slightly yellow tint is produced (readily carbonizable substances). Dissolve 0.3 Gm. of finely powdered Cocaine in 1 cc. of normal hydrochloric acid, gently warming, if necessary, to aid solution, and dilute with distilled water to 15 cc. 5 cc. portions of this solution do not respond to the tests for cinnamyl-cocaine and for isoatropyl-cocaine under Cocaince Hydrochloridum. ... 

Medicinal oil requires a test in which the reaction of the oil to hot, strong sulfuric acid is used to determine the presence of carbonizable substance in the oil. However, the test for carbonizable substances (ASTM D-565)... 

Mineral oils are usually considered to have a high propensity for carbon formation and deposition under thermal conditions. Nevertheless, the tests that are applied to determine the carbon-forming propensity of fuel oil (and other petroleum products) are also available for application to mineral oils. The test methods for the carbon residue should not be confused with the test method for carbonizable substances (ASTM D-565). The former test methods are thermal in nature, whereas the latter test method involves the use of sulfuric acid in a search for specific chemical entities within the oil. 

The test for carbonizable substances (ASTM D-565) should not be confused with the test methods for determining carbon residue (ASTM D-189, ASTM D-524, ASTM D4530, IP 13, IP 14, IP 398) (q.v.). 

To determine the presence of carbonizable substances in paraffin wax (ASTM D-612) 5 ml of concentrated sulfuric acid is placed in a graduated test tube and 5 ml of the melted wax are added. The sample is heated for 10 min at 70°C (158°F). During the last 5 min the tube is shaken periodically. The acid layer is compared with a standard reference solution, and the wax sample passes if the color is not darker than the standard color. 

---