The use of dialkyl acetals

The fatty add sample or biological acid extract is dissolved in DMF-DMA and injected into the gas chromatograph. Alternatively, the syringe is charged with 1 1 of DMF-DMA and ZfA of pyridine containing the adds (up to about 2 g) and again 1 fA of DMF-DMA. The contents are injected directly an inlet temperature of at least 190 °C should be used. 

Retinoic add was extraded from 30 ml of plasma, the extract was dried down and the residue was treated with 50 fA of DMF-DMA by essentially the same procedure as above. The product was analysed by GC or by GC-MS [133]. 

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