Dicyclohexylcarbodiimide as a cleaving agent for colorimetric determination of pyridyl and pyrimidinyl compounds

Abstract

1461were dispersed within each other with sufficient reproducibility that standard addition could be performed over a wide, controllable range of standard/analyte concentration ratios. I t is interesting to observe that the new variant of the gradient technique is partially based on the underlying concept of FIA titration ( I ) , where elements of fluid with identical D values are exploited, and partially on the concept of zone penetration (5) as designed for selectivity measurements, where elements of fluid with identical delay times t were used.Thus, another variation of the concept dispersed sample zone has been discovered and exploited. Its use is not limited to flame methods, as reaction based assays, like spectrophotometry, would equally benefit from the novel way of performing standard addition. Instruments equipped with photodiode arrays and appropriate fast data collection and storage facilities should increasingly find use in future applications.By use of dlcyclohexylcarbodAmIde (DCC) and dimethylbarblturic acid (DMBA) as reagents, a colorlmetric method for the deterrninatlon of pyrldyl and pyrlmldlnyl compounds has been established. DCC breaks the pyrldlne or pyrlmldine ring to afford giutaconaldehyde or maionaldehyde and then reacts wlth DMBA to produce chromophores. These heterocycles could be determined by measuring the chromophores. The reiatlve standard devlatlons obtained with different amounts of these compounds were In the range of 0.63 to 5.36% ( n

Functional group analysis

“…The cleavage of pyridine and pyrimidine rings by dicyclohexylcarbodiimide to form glutaconaldehyde and malonaldehyde, respectively, forms the basis of colorimetric determination of these compounds. The colored species results from the reaction of the aldehydes with dimethylbarbituric acid reagent (36).…”

Ultraviolet and light absorption spectrometry

“…Triglycerides in the concentration range of 400-4000 ppm have been determined by extraction with 2-propanol-heptane, saponification to release glycerol, oxidization of the glycerol with a known excess of periodate, and determination the excess periodate with 5,5-dimethyl-1,3-cyclohexanediol-bisthiosemicarbazone (415 nm) (65). Dicyclohexylcarbodiimide has been suggested as a cleaving agent for pyridyl and pyrimidinyl compounds, leading to glutaconaldehyde and malonaldehyde, which then reacts with dimethylbarbituric acid to form highly absorbing products (73). A scheme for identifying and determining microgram quantities of 26 phenols has been reported, based on the colored products formed by the silver(I)-catalyzed oxidation with potassium peroxydisulfate (166).…”