The temperature of the capillary and the needle voltage only depend on the flow rate and nature of the eluent. In our case (water-based eluent at 0.25 ml min−1), the best results were obtained with 500 ◦C and 3.5 kV. Conversely, the cone voltage is fully compound-dependant. As expected, low molecular weight carbohydrates require a lower accelerating voltage than heavier carbohydrates. As an example, the optimal cone voltage for pentoses was found to be 70V whereas the best results for trisaccharides were obtained with 90V. In addition to these MS parameters, the post-column addition has to be optimized. On one hand, the concentration of the LiCl solution has to be sufficient to form adducts with the highest expected amounts of carbohydrates but, on the other hand, an excessive input of LiCl in MS can induce a high chemical noise and increases the risk of capillary plugging. As LiCl concentration, the solution flow rate should not be a limiting factor for adducts formation, but it has to be kept as low as possible to prevent analyte dilution. In our case, the optimal LiCl concentration and flow rate were found to be 0.5 mmol l−1 and 0.05 ml min−1, respectively