Abstract: α-Capric betaine (CB) was prepared from α-chlorododecanoic acid (CDA) and trimethylamine (TMA) as starting materials.The content of CB in the product was analyzed adopting HPLC-ELSD method.The residual fatty acids containing in the product were extracted with Soxhlet extractor and then the relative content of dodecanoic acid (DA),CDA and α-hydroxydodecanoic acid (HDA) in the residual of fatty acid extract were further analyzed with gas chromatography (GC).Results showed that,using a solution composed of V(methanol)∶V(water)=7∶1 as the mobile phase of HPLC-ELSD,the linear relationship,the reproducibility and the accuracy were good and the signal separation is high in the mass concentration range of 0.004-0.08 g·L^-1;the residual fatty acids can be completely extracted with petroleum ether (60-90 ℃) as the solvent of Soxhlet extraction,and the relative content of DA,CDA and HDA can be quantitatively analyzed using GC.

Key words: α-capric betaine, fatty acid, HPLC-ELSD, Soxhlet extraction, gas chromatography