Evaluation of continuous solvent extraction of organic acids from biological fluids

We evaluated the efficiency of continuous solvent extraction with ether for the analysis of organic acids by gas chromatography using a representative group of organic acids and urine from several normal children. Variables examined were the time of extraction, volume of sample, and the quantity and chemical class of acid present. In terms of the decreased time required and invariant extraction of acids of pathologic significnace continuous solvent extraction compares favorably with the more time consuming albeit less discriminatory ion-exchange procedure. Continuous solvent extraction appears especially well suited for analysis of short chain aliphatic acids by gas chromatography.