Bases of nucleic acids, nucleosides and nucleotides

These derivatives have not gained more extensive use in the GC analysis of sugars, however, as they do not provide any particular advantages over other derivatives that have been utilized with respect to ease of their preparation, uniformity of the products or the separation of various substances. 

BSA was effective for the derivatization of purine and pyrimidine bases [456] and nucleosides [457]. Bases were silylated by heating at 150°C with BSA—acetonitrile (1 3) for 45 min. It was stated that under these conditions the TMS derivative of guanine can be prepared reproducibly, but both cytosine and 5-methylcytosine provided two peaks. Silylation of nucleosides, including pseudouridine, was carried out by heating at 120°C with a 100-fold excess of BSA for 2 h. With the use of OV-17 as the stationary phase, this procedure was adopted for the determination of the composition of ribonucleic acids. 

BSTFA has frequently been used for the silylation of the components of ribonucleic acids. After treatment for 15 min with a mixture containing pyridine (1 4) at room 

Gehrke and Patel [460] looked for optimal reaction and chromatographic conditions in the analysis of silyl derivatives of nucleosides prepared by reaction with BSTFA. They recommended performing the derivatization with a 225-fold molar excess of BSTFA at 150°C for 15 min in a closed vial and analysis on a 1 m X 4 mm ED. column packed with 4% of OV-11 on Supelcoport (100—120 mesh) with temperature programming at 5°C/ min from 140°C. 

The conditions were similarly optimized for methylated bases and the whole method was applied to the analysis of these bases in urine [461]. The silylating reaction was pre- 

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