Nucleosides, chromatography

A liquid chromatography-mass spectrometry (LC-MS) method that can quantitatively analyze urinar y normal and modified nucleosides in less than 30 min with a good resolution and sufficient sensitivity has been developed. Nineteen kinds of normal and modified nucleosides were determined in urine samples from 10 healthy persons and 18 breast cancer patients. Compounds were separ ated on a reverse phase Kromasil C18 column (2.1 mm I.D.) by isocratic elution mode using 20 mg/1 ammonium acetate - acetonitrile (97 3 % v/v) at 200 p.l/min. A higher sensitivity was obtained in positive atmospheric pressure chemical ionization mode APCI(-i-). 

These sorbents may be used either for selective fixation of biological molecules, which must be isolated and purified, or for selective retention of contaminants. Selective fixation of biopolymers may be easily attained by regulation of eluent polarity on the basis of reversed-phase chromatography methods. Effective isolation of different nucleic acids (RNA, DNA-plasmid) was carried out [115, 116]. Adsorption of nucleosides, nucleotides, tRN A and DNA was investigated. It was shown that nucleosides and nucleotides were reversibly adsorbed on... 

Floridi, A., Palmerini, C. A., and Fini, C., Simultaneous analysis of bases, nucleosides, and nucleoside mono- and polyphosphates by high-performance liquid chromatography,. Chromatogr., 138, 203, 1977. 

Simek, P., Jegorov, A., and Dusbabek, F., Determination of purine bases and nucleosides by conventional and microbore high performance chromatography and gas chromatography with an ion trap detector, J. Chromatogr., 679,1951,1994. 

A different strategy has been applied in our work, that emphasizes the importance of DNA stability on hole transfer within double-stranded DNA. This work is based on determination of the overall yield of oxidized nucleosides that arise from the conversion of initially generated purine and pyrimidine radical cations within DNA exposed to two-photon UVC laser pulses. On the one hand, this work benefits from the excellent current knowledge of chemical reactions involving the radical cations of DNA bases, and on the other hand, from major analytical improvements that include recent availability of the powerful technique of high performance liquid chromatography-electrospray ionization-tandem mass spectrometry (CLHP-ESI-MS/MS) [16-18]. 

A specific approach for the measurement of base damage to DNA involves the hydrolysis of DNA into monomeric units. Acidic hydrolysis leads to the release of bases while enzymatic treatment yields nucleosides. The resulting mixture of lesions together with the overwhelming presence of normal bases or nucleosides is resolved by chromatography. The targeted damage is then quantified by use of specific detection systems. 

A series of diastereomerically pure 5 -0-DMT-nucleoside 3 -0-(2-thio-l,3,2-oxathiaphospholanes) and their oxathiaphospholane ring-substituted analogues 283-294 were isolated in 80-83% yield by column chromatography on silica gel of the appropriate diastereomeric mixtures [the ratio ca 55 45 (31P NMR assay)] obtained from the reaction of 2 - A, IV- dii so p rop y I a m i n o- 1,3,2-oxathiaphospholane 279-281 with 5 - 0 -D M T- n uc I cosides 282a-d in the presence of tetrazole (phosphi-tylation), followed by addition of sulfur (Scheme 67) [105-107]. 

Singhal, R.P., Bajaj, R.K., Buess, G.M., Smoll, D.B., and Vakharia, V.N. (1980) Reversed-phase boro-nate chromatography for the separation of O-methylribose nucleosides and aminoacyl-tRNAs. Anal. Biochem. 109, 1-11. 

In view of the difficulty of hydrolyzing the pyrimidine nucleosidic linkages, ribonucleic acids have been hydrolyzed to a mixture of purine bases and pyrimidine nucleotides which is then separated by paper chromatography.132, 163 164 This method has been employed extensively for the analysis of ribonucleic acids, and gives reproducible results,166 but it has not been used to any great extent for deoxyribonucleic acids, probably because, under these conditions of hydrolysis, they yield some pyrimidine deoxy-ribonucleoside diphosphates.166... 

Oligonucleotides have also been separated by ion-exchange chromatography of yeast ribonucleic acid treated either with acid216 or with ribonuclease.209 Alkaline hydrolysis of the fission products obtained with the latter gives rise to pyrimidine nucleoside 3-phosphates and mixtures of purine nucleoside 2- and 3-phosphates. Bone phosphomonoesterase196 followed by alkaline hydrolysis gives pyrimidine nucleosides and purine... 

Zhu Y, Wong PS, Zhou Q, Sotoyama H, Kissinger PT. 2001. Identification and determination of nucleosides in rat brain microdialysates by liquid chromatography/ electrospray tandem mass spectrometry. J Pharm Biomed Anal 26 967. 

In addition to classical reverse phase separation of peptides on octadecyl derivatized silica monoliths, sugars and peptides as well as proteins and nucleosides have been analyzed on a 20-cm-long silica-based poly(acrylic acid) column (ID. 200 pm), employing HILIC and weak cation-exchange chromatography, respectively [194]. Furthermore, HILIC fractionation of polysaccharides delivered remarkable and promising results [84,194]. 

Glad, M., Ohlson, S., Hansson, L., Mansson, M.-O., and Mosbach, K., High-performance liquid affinity chromatography of nucleosides, nucleotides and carbohydrates with boronic acid-substituted microparticulate silica, J. Chromatogr., 200, 254-260, 1980. 

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