Comparison of ELSD and RID combined with HPLC for simultaneous determination of six rare sugars in food components

Evaporative light scattering detection (ELSD) and refractive index detection (RID) are two methods commonly used in high-performance liquid chromatography (HPLC) to quantitatively analyze sugars. The performance of two detectors for the detection and quantification of six rare sugars in food samples is systematically compared in this paper. Erythritol, allulose, tagatose, mannitol, isomaltulose and trehalose were separated by HPLC on an NH2 chromatographic column using a flow gradient or isocratic composition acetonitrile-water (80:20, v/v) as mobile phase. The analytical signals for six rare sugars were obtained using ELSD and RID. The intra-day and inter-day variations were lower 3.9 % and 3.5 % for ELSD and 2.4 % and 3.6 % for RID, respectively. The limits of detection (LODs) were between 0.02 mg & sdot;mL- 1 and 0.06 mg & sdot;mL- 1 for ELSD in the range of 0.06-0.6 mg & sdot;mL- 1. The LODs of RID were between 0.1 mg & sdot;mL- 1 and 1.0 mg & sdot;mL- 1 within a wider dynamic range (0.4-80 mg & sdot;mL- 1). The optimized method was used to analyze seven samples. Although both methods can be used for the detection of six rare sugars, the selectivity of isomaltulose and the detection results of six rare sugars under the HPLC-RID method are not as good as the HPLC-ELSD method. Therefore, the HPLC-ELSD method is more suitable for the detection of six rare sugars in food.