title: Sources of error in determinations of carnitine and acylcarnitine in plasma.
abstract: Radioactive and nonradioactive L-carnitine and acyl-L-carnitine were used to evaluate the washing procedures used during the determination of free, total, short-chain, and long-chain acylcarnitine in human and sheep plasma. The volume of fluid trapped by the protein precipitated by perchloric acid is approximately 24% of the total fluid volume and thus contains 24% of free carnitine and short-chain acylcarnitine. Washing twice with distilled water removes about 25% of the long-chain acylcarnitine along with the trapped free carnitine and short-chain acylcarnitines. Washing the pellet twice with a 60 g/L solution of perchloric acid completely removes the trapped free carnitine and short-chain acylcarnitine but does not remove the bound long-chain acylcarnitines. Thus washing with perchloric acid is essential for accurate measurement of long-chain acylcarnitines in plasma samples.
mesh_terms: D000108:Acetylcarnitine / Q000097:blood*; D000818:Animals; D002331:Carnitine / Q000031:analogs & derivatives* / Q000097:blood* / Q000302:isolation & purification; D002855:Chromatography, Thin Layer; D005188:False Negative Reactions; D006801:Humans; D010172:Palmitoylcarnitine / Q000097:blood; D012756:Sheep
chemical_list: D010172:Palmitoylcarnitine; D000108:Acetylcarnitine; D002331:Carnitine