Solid-phase extraction technique for gas-chromatographic profiling of acylcarnitines

We present a simple, new clean-up method for the gas-chromatographic profiling analysis of acylcarnitines. The use of a solid-phase, cation-exchange extraction combined with gas-chromatographic separation, based on the derivatization into acyloxylactones by Lowes and Rose (Analyst 1990;115:511-6), allows a selective and sensitive screening for acylcarnitines in urine. As such, a quantitative approach was developed for differential evaluation of acylcarnitines for detection of inborn errors of metabolism; the evaluation is both fast and routinely applicable in any biochemical laboratory. We validate the analysis method for acylcarnitines of various chain-lengths and present examples of its application to urine samples from diseased patients. We give special attention to the medium-chain acylcarnitines because of their association with medium-chain acylCoA dehydrogenase deficiency. Finally, the quantitative nature of the analysis allows evaluation of the acylcarnitine excretion over time.