The use of scanning gradients can significantly reduce method-development time in reversed-phase liquid chromatography. However, there is no consensus on how they can best be used. In the present work we set out to systematically investigate various factors and to formulate guidelines. Scanning gradients are used to establish retention models for individual analytes. Different retention models were compared by computing the Akaike information criterion and the prediction accuracy. The measurement uncertainty was found to influence the optimum choice of model. The use of a third parameter to account for non-linear relationships was consistently found not to be statistically significant. The duration (slope) of the scanning gradients was not found to influence the accuracy of prediction. The prediction error may be reduced by repeating scanning experiments or – preferably – by reducing the measurement uncertainty. It is commonly assumed that the gradient-slope factor, i.e. the ratio between slopes of the fastest and the slowest scanning gradients, should be at least three. However, in the present work we found this factor less important than the proximity of the slope of the predicted gradient to that of the scanning gradients. Also, interpolation to a slope between that of the fastest and the slowest scanning gradient is preferable to extrapolation. For comprehensive two-dimensional liquid chromatography (LC × LC) our results suggest that data obtained from fast second-dimension gradients cannot be used to predict retention in much slower first-dimension gradients.

在反相液相色谱中，使用扫描梯度可以显着减少方法开发时间。但是，关于如何最好地使用它们尚无共识。在目前的工作中，我们着手系统地研究各种因素并制定指导方针。扫描梯度用于建立单个分析物的保留模型。通过计算Akaike信息准则和预测准确性，比较了不同的保留模型。发现测量不确定度会影响模型的最佳选择。始终发现使用第三个参数来说明非线性关系在统计上并不重要。未发现扫描梯度的持续时间（斜率）会影响预测的准确性。可以通过重复扫描实验来减少预测误差，或者最好通过减少测量不确定度来减少预测误差。通常假设梯度斜率因子即最快和最慢扫描梯度的斜率之比应至少为3。但是，在当前的工作中，我们发现该因素不如预测梯度的斜率与扫描梯度的斜率接近。同样，内插到最快和最慢扫描梯度之间的斜率比外推更可取。对于全面的二维液相色谱（LC×LC），我们的结果表明，不能从快速的二维梯度获得的数据用于预测在慢得多的一维梯度中的保留。