摘要
Consistent retention time ( t R ) of metabolites is vital for identification in metabolomic analysis with ultrahigh-performance liquid-chromatography (UPLC). To minimize inter-experimental t R variations from the reversed-phase UPLC-MS, we developed an endo genous r etention- i ndex (endoRI) using in-sample straight-chain acylcarnitines with different chain-length ( L C , C0–C26) without additives. The endoRI-corrections reduced the t R variations caused by the combined changes of mobile phases , gradients, flow-rates, elution time, columns and temperature from up to 5.1 min–0.2 min for most metabolites in a model metabolome consisting of 91 metabolites and multiple biological matrices including human serum, plasma, fecal, urine, A549 cells and rabbit liver extracts. The endoRI-corrections also reduced the inter-batch and inter-platform t R variations from 1.5 min to 0.15 min for 95 % of detected features in the above biological samples. We further established a quantitative model between t R and L C for predicting t R values of acylcarnitines when absent in samples. This makes it possible to compare metabolites’ t R from different t R databases and the UPLC-based metabolomic data from different batches.
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