Raw Material
i s o l a
Solvent Partition
Ion Exchange HPLC
0.1% Collection Impurity
Reverse Phase HPLC
•KSH
Why there's no better acid than a Corco acid.
•ΕΠΙΖΕβ
•ΕΠΙΖΕβ
iùiZL: Isolated Impurity
Not 6-N-phenyladenine
in
I D E N T I F I C
GC/MS
Synthesis
E
O-pHENYLADENINE
Figure 7. Flow diagram of problem solving
ed adenine derivative and suggest sub stitution a t the N-9 position. In an effort to confirm t h e hypothe sized structure, 9-phenyladenine was synthesized. Its mass and IR spectra were obtained and compared with spectra of the adenine impurity. T h e infrared spectrum of the synthesized A/-(9-phenyl)adenine is shown in Fig ure 6. T h e fingerprint region of this spectrum is identical to that of the isolated impurity. T h e mass spectrum of the synthesized compound was the same as t h a t obtained from the raw material contaminant. Once the impu rity was identified, changes were made in t h e production process to ensure t h a t 9-phenyladenine would not be present in the raw material. Identifi cation of the impurity and elimination of it as a contaminant in the raw ma terial enabled production of adeninefortified blood storage solution to con tinue. T h e general scheme and approach to solving this particular problem is shown in the flow diagram in Figure 7. T h e most significant factor is that assumptions were made about the properties of the impurity based on its chromatographic behavior. This in formation was then used to make an
educated guess about how best to iso late t h e impurity. Furthermore, the data obtained from several different instrumental techniques were com bined, and a hypothesized structure of the impurity was fomulated based on the assembled data. T h e hypothe sized structure was then confirmed by synthesis. Acknowledgment
We would like to acknowledge L. Streips for analytical work, and A. Berger and S. Scharffenberg for syn thetic work.
References
(1) G. B. Bartlett, "Changes of red cell phosphate compounds during storage of human blood in ACD," International Symposium on Erythrocytes, Thrombo cytes, Leukocytes, Vienna, 1972, pp 139-148. (2) C. W. Gehrke and D. B. Kaking, J. Chromatogr., 61, 45^63 (1971). (3) J. A. McCloskey, Mass Spectrometry in Nucleic Acid Chemistry, in "Basic Principles in Nucleic Acid Chemistry," P. Tso, Ed., Academic Press, New York, 1974, pp 209-309. (4) Sadtler Research Labs, "Infra-red Spectra, 1969," Spectrum No. 1559.
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ANALYTICAL CHEMISTRY, VOL. 5 1 , NO. 1 1 , SEPTEMBER
1979 ·
1131 A
