Radio-labelling uniform

Although pure labelled products are obtainable nowadays, one should make sure before using them that they are chemically and radio-chemically uniform. 

In order to examine the metabolic pathways of the various molecular products, we have first chosen to use,as tracer, uniformly radio-labelled linoleic acid. We have followed the fate of the radioactivity in water soluble and nucleo-... 

Compound 232 has been obtained232 in 19.7% overall yield from uniformly labelled 14C-L-alanine according to the reaction scheme of equation 96. The acid 232 had specific activity of 66.7 /iCimmol-1 and radiochemical purity of 98% as determined by radio-... 

We can now understand how the atomic beam technique may be used to detect magnetic resonance transitions between ground-state hyperfine sub-levels. In the region labelled C in Fig.18.10 the atoms experience a uniform static field and in addition a radio frequency field which usually rotates in the perpendicular plane at the angular frequency (Oq. At resonance, magnetic dipole transitions are induced between the hyperfine sub-levels and the orientation of the magnetic moments of a substantial number of the atoms will have been altered before they leave the C-field region. 

There is, however, another and rather interesting way of approaching this problem by the use of radio-active carbon ( C). This technique involves the use as respiratory substrates of samples of glucose phosphate in which only the first carbon atom or only the 6th carbon atom of the sugar is enriched with radio-active carbon (the glucose molecule is not uniformly labelled but specifically labelled in particular carbon atoms). The carbon dioxide which is released immediately after supplying the glucose phosphate will come, in the pentose... 

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