Carboxyl organic trace analysis

Microanalysis, the detection and identification of materials present in small size but relatively high concentration, is distinct from trace analysis, which is concerned with the characterization of small concentrations of material. Organic microanalysis is usually taken to mean elemental analysis (primarily C, H, O, N, P, S, Cl, Br, 1, and Si), and functional group analysis (acetyl, carboxyl, benzoyl, amino, nitro, hydroxy, etc.) on samples usually 1-10 mg in size. The semiquantitative results, accurate to about 10%, serve as a measure of impurities, or inhomogeneity, or for structure determination in solid organic substances. Accurate results of 1 % or better may be expected when large (1 g) samples are taken for analysis and the entire chemical apparatus is scaled upward in size. However, small samples take less time to analyze, so the micro methods are more popular than macro methods. 

In contrast to the other large cats, the urine of the cheetah, A. jubatus, is practically odorless to the human nose. An analysis of the organic material from cheetah urine showed that diglycerides, triglycerides, and free sterols are possibly present in the urine and that it contains some of the C2-C8 fatty acids [95], while aldehydes and ketones that are prominent in tiger and leopard urine [96] are absent from cheetah urine. A recent study [97] of the chemical composition of the urine of cheetah in their natural habitat and in captivity has shown that volatile hydrocarbons, aldehydes, saturated and unsaturated cyclic and acyclic ketones, carboxylic acids and short-chain ethers are compound classes represented in minute quantities by more than one member in the urine of this animal. Traces of 2-acetylfuran, acetaldehyde diethyl acetal, ethyl acetate, dimethyl sulfone, formanilide, and larger quantities of urea and elemental sulfur were also present in the urine of this animal. Sulfur was found in all the urine samples collected from male cheetah in captivity in South Africa and from wild cheetah in Namibia. Only one organosulfur compound, dimethyl disulfide, is present in the urine at such a low concentration that it is not detectable by humans [97]. 

It is used in organic synthesis as a methylating agent to methylate acidic compounds such as carboxylic acids and phenols. It is used in trace environmental analysis to methylate chlorophenoxy acid herbicides. 

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