Chromatographic retention time values are empirically derived and specific to each assay, sensitive to even minute differences in column and stationary phase manufacture, mobile phase and gradient composition, and LC-MS system configuration. Unlike metabolite libraries containing mass spectral and collisional cross section data, the more context-specific nature of metabolite retention precludes the creation of global chromatographic libraries and ultimately hinders direct comparison of data between distinct LC-MS assays. Consequently, metabolite annotations cannot be easily transferred between laboratories using divergent methods, and a non-trivial amount of feature assignment work must be repeated for newly developed assays.